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Document and Entity Information - USD ($)	6 Months Ended
Document and Entity Information - USD ($)	Feb. 12, 2011	Mar. 11, 2011	Feb. 13, 2010
Document and Entity Information [Abstract]
Entity Registrant Name	AUTOZONE INC
Entity Central Index Key	0000866787
Document Type	10-Q
Document Period End Date	Feb. 12, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--08-27
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 7,831,536,378
Entity Common Stock, Shares Outstanding		42,209,933

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Feb. 13, 2010	Aug. 28, 2010	Feb. 12, 2011
Current assets:
Cash and cash equivalents	$ 105,161	$ 98,280	$ 107,881
Accounts receivable		125,802	140,227
Merchandise inventories		2,304,579	2,418,751
Other current assets		83,160	71,256
Total current assets		2,611,821	2,738,115
Property and equipment:
Property and equipment		4,067,261	4,173,972
Less: Accumulated depreciation and amortization		(1,547,315)	(1,619,108)
Property and equipment, net		2,519,946	2,554,864
Goodwill		302,645	302,645
Deferred income taxes		46,223	59,634
Other long-term assets		90,959	110,345
Other long-term assets, total		439,827	472,624
Assets		5,571,594	5,765,603
Current liabilities:
Accounts payable		2,433,050	2,524,539
Accrued expenses and other		432,368	414,502
Income taxes payable		25,385	85,356
Deferred income taxes		146,971	159,809
Short-term borrowings		26,186	40,930
Total current liabilities		3,063,960	3,225,136
Long-term debt		2,882,300	3,208,300
Other long-term liabilities		$ 364,099	370,579
Commitments and contingencies
Stockholders' deficit:
Preferred stock, authorized 1,000 shares; no shares issued		$ 0	0
Common stock, par value $.01 per share, authorized 200,000 shares; 43,819 shares issued and 42,611 shares outstanding as of February 12, 2011; 50,061 shares issued and 45,107 shares outstanding as of August 28, 2010		501	438
Additional paid-in capital		557,955	535,945
Retained deficit		(245,344)	(1,172,935)
Accumulated other comprehensive loss		(106,468)	(92,338)
Treasury stock, at cost		(945,409)	(309,522)
Total stockholders' deficit		(738,765)	(1,038,412)
Liabilities and Stockholders' Deficit		$ 5,571,594	$ 5,765,603

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands	Feb. 12, 2011	Aug. 28, 2010
Stockholders' deficit:
Preferred stock, shares authorized	1,000	1,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	43,819	50,061
Common stock, shares outstanding	42,611	45,107

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 12, 2011	Feb. 13, 2010	Feb. 12, 2011	Feb. 13, 2010
Condensed Consolidated Statements of Income [Abstract]
Net sales	$ 1,660,946	$ 1,506,225	$ 3,452,608	$ 3,095,469
Cost of sales, including warehouse and delivery expenses	815,335	752,489	1,699,249	1,541,809
Gross profit	845,611	753,736	1,753,359	1,553,660
Operating, selling, general and administrative expenses	573,863	523,355	1,175,491	1,062,850
Operating profit	271,748	230,381	577,868	490,810
Interest expense, net	39,576	36,309	76,829	72,650
Income before income taxes	232,172	194,072	501,039	418,160
Income taxes	84,116	70,739	180,908	151,527
Net income	$ 148,056	$ 123,333	$ 320,131	$ 266,633
Weighted average shares for basic earnings per share	43,399	49,436	44,034	49,775
Effect of dilutive stock equivalents	979	750	972	730
Adjusted weighted average shares for diluted earnings per share	44,378	50,186	45,006	50,505
Basic earnings per share	$ 3.41	$ 2.49	$ 7.27	$ 5.36
Diluted earnings per share	$ 3.34	$ 2.46	$ 7.11	$ 5.28

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Feb. 12, 2011	Feb. 13, 2010
Cash flows from operating activities:
Net income	$ 320,131	$ 266,633
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property and equipment	88,417	87,099
Amortization of debt origination fees	3,898	2,999
Income tax benefit from exercise of stock options	(15,847)	(7,061)
Deferred income taxes	(1,955)	(2,145)
Share-based compensation expense	12,119	8,867
Changes in operating assets and liabilities:
Accounts receivable	(13,903)	(20,849)
Merchandise inventories	(104,770)	(52,560)
Accounts payable and accrued expenses	65,957	9,965
Income taxes payable	75,513	46,532
Other, net	11,549	9,428
Net cash provided by operating activities	441,109	348,908
Cash flows from investing activities:
Capital expenditures	(108,357)	(111,128)
Purchase of marketable securities	(22,581)	(10,467)
Proceeds from sale of marketable securities	19,454	8,015
Disposal of capital assets	2,158	4,231
Net cash used in investing activities	(109,326)	(109,349)
Cash flows from financing activities:
Net proceeds from commercial paper	25,300	47,800
Net proceeds from short-term borrowings	12,493
Proceeds from issuance of debt	500,000
Repayment of debt	(199,300)
Net proceeds from sale of common stock	33,249	18,726
Purchase of treasury stock	(694,050)	(291,888)
Income tax benefit from exercise of stock options	15,847	7,061
Payments of capital lease obligations	(10,903)	(9,084)
Other, net	(5,450)
Net cash used in financing activities	(322,814)	(227,385)
Effect of exchange rate changes on cash	632	281
Net increase in cash and cash equivalents	9,601	12,455
Cash and cash equivalents at beginning of period	98,280	92,706
Cash and cash equivalents at end of period	$ 107,881	$ 105,161

General	6 Months Ended
General	Feb. 12, 2011
General [Abstract]
General	Note A — General The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information and with instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission’s (the “SEC”) rules and regulations. Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments, including normal recurring accruals, considered necessary for a fair presentation have been included. For further information, refer to the consolidated financial statements and related notes included in the AutoZone, Inc. (“AutoZone” or the “Company”) Annual Report on Form 10-K for the year ended August 28, 2010. Operating results for the twelve and twenty-four weeks ended February 12, 2011, are not necessarily indicative of the results that may be expected for the fiscal year ending August 27, 2011. Each of the first three quarters of AutoZone’s fiscal year consists of 12 weeks, and the fourth quarter consists of 16 or 17 weeks. The fourth quarters for fiscal 2010 and fiscal 2011 each have 16 weeks. Additionally, the Company’s business is somewhat seasonal in nature, with the highest sales generally occurring during the months of February through September and the lowest sales generally occurring in the months of December and January.

Share-Based Payments

6 Months Ended

Feb. 12, 2011

Share-Based Payments [Abstract]

Share-Based Payments

Note B — Share-Based Payments

AutoZone recognizes compensation expense for share-based payments based on the fair value of the awards at the grant date. Share-based payments include stock option grants, restricted stock grants, restricted stock unit grants and the discount on shares sold to employees under share purchase plans. Additionally, directors’ fees are paid in restricted stock units with value equivalent to the value of shares of common stock as of the grant date. The change in fair value of liability-based stock awards is also recognized in share-based compensation expense.

Total share-based compensation expense (a component of operating, selling, general and administrative expenses) was $7.0 million for the twelve week period ended February 12, 2011, and was $4.6 million for the comparable prior year period. Share-based compensation expense was $12.1 million for the twenty-four week period ended February 12, 2011, and was $8.9 million for the comparable prior year period.

During the twenty-four week period ended February 12, 2011, 339,370 shares of stock options were exercised at a weighted average exercise price of $101.44. In the comparable prior year period, 262,059 shares of stock options were exercised at a weighted average exercise price of $72.30. The Company made stock option grants of 424,780 shares during the twenty-four week period ended February 12, 2011, and granted options to purchase 496,580 shares during the comparable prior year period. The weighted average fair value of the stock option awards granted during the twenty-four week periods ended February 12, 2011 and February 13, 2010, using the Black-Scholes-Merton multiple-option pricing valuation model, was $58.58 and $40.75 per share, respectively, using the following weighted average key assumptions:


	Twenty-Four Weeks Ended
	February 12,			February 13,
	2011			2010

Expected price volatility		31	%		31	%
Risk-free interest rate		1.0	%		1.8	%
Weighted average expected lives (in years)		4.3			4.3
Forfeiture rate		10.0	%		10.0	%
Dividend yield		0.0	%		0.0	%

See AutoZone’s Annual Report on Form 10-K for the year ended August 28, 2010 for a discussion of the methodology used in developing AutoZone’s assumptions to determine the fair value of the option awards.

For the twelve week period ended February 12, 2011, there were 1,260 anti-dilutive stock options excluded from the diluted earnings per share computation. For the comparable prior year period, 24,900 anti-dilutive shares were excluded. There were 1,260 anti-dilutive shares excluded from the diluted earnings per share computation for the twenty-four week period ended February 12, 2011, and 25,500 anti-dilutive shares excluded for the comparable prior year.

On December 15, 2010, the Company’s stockholders approved the 2011 Equity Incentive Award Plan (the “Plan”), allowing the Company to provide equity-based compensation to non-employee directors and employees for their service to AutoZone or its subsidiaries or affiliates. Under the Plan, participants may receive equity-based compensation in the form of stock options, stock appreciation rights, restricted stock, restricted stock units, dividend equivalents, deferred stock, stock payments, performance share awards and other incentive awards structured by the Company’s Board of Directors (the “Board”) and the Compensation Committee of the Board.

On December 15, 2010, the Company adopted the 2011 Director Compensation Program (the “Program”), which states that non-employee directors will receive their compensation in awards of restricted stock units under the Plan. The Program replaces the former 2003 Director Compensation Plan and the 2003 Director Stock Option Plan. Under the Program, restricted stock units are granted the first day of each calendar quarter. The number of restricted stock units granted each quarter is determined by dividing one-fourth of the amount of the annual retainer by the fair market value of the shares of common stock as of the grant date. The restricted stock units are fully vested on the date they are issued and are paid in shares of the Company’s common stock subsequent to the non-employee director ceasing to be a member of the Board. For the twelve weeks ended February 12, 2011, the Company recognized $466 thousand in share-based compensation expense related to the Program.

Fair Value Measurements

6 Months Ended

Feb. 12, 2011

Fair Value Measurements [Abstract]

Fair Value Measurements

Note C — Fair Value Measurements

The Company defines fair value as the price received to transfer an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company uses a hierarchy of valuation inputs to measure fair value.

The hierarchy prioritizes the inputs into three broad levels:

Level 1 inputs—unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. An active market for the asset or liability is one in which transactions for the asset or liability occur with sufficient frequency and volume to provide ongoing pricing information.

Level 2 inputs—inputs other than quoted market prices included in Level 1 that are observable, either directly or indirectly, for the asset or liability. Level 2 inputs include, but are not limited to, quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active and inputs other than quoted market prices that are observable for the asset or liability, such as interest rate curves and yield curves observable at commonly quoted intervals, volatilities, credit risk and default rates.

Level 3 inputs—unobservable inputs for the asset or liability.

The Company’s assets and liabilities measured at fair value on a recurring basis were as follows:


	February 12, 2011
(in thousands)	Level 1		Level 2		Level 3		Fair Value

Other current assets	$	5,955	$	60	$	—	$	6,015
Other long-term assets		62,812		6,385		—		69,197

	$	68,767	$	6,445	$	—	$	75,212


	August 28, 2010
(in thousands)	Level 1		Level 2			Level 3		Fair Value

Other current assets	$	11,307	$	4,996		$	—	$	16,303
Other long-term assets		47,725		8,673			—		56,398
Accrued expenses and other		—		(9,979	)		—		(9,979	)

	$	59,032	$	3,690		$	—	$	62,722

At February 12, 2011, the fair value measurement amounts for assets and liabilities recorded in the accompanying Condensed Consolidated Balance Sheet consisted of short-term marketable securities of $6.0 million, which are included within other current assets and long-term marketable securities of $69.2 million, which are included in other long-term assets. The Company’s marketable securities are typically valued at the closing price in the principal active market as of the last business day of the quarter or through the use of other market inputs relating to the securities, including benchmark yields and reported trades. The fair values of the marketable securities, by asset class, are described in “Note D — Marketable Securities”.

The carrying value of certain of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, prepaid assets and accounts payable, approximate fair value because of their short maturities. A discussion of the carrying values and fair values of the Company’s debt is included in “Note H — Financing”.

Marketable Securities

6 Months Ended

Feb. 12, 2011

Marketable Securities [Abstract]

Marketable Securities

Note D — Marketable Securities

The Company’s basis for determining the cost of a security sold is the “Specific Identification Model”. Unrealized gains (losses) on marketable securities are recorded in accumulated other comprehensive loss. The Company’s available-for-sale marketable securities consisted of the following:


	February 12, 2011
	Amortized		Gross		Gross
	Cost		Unrealized		Unrealized
(in thousands)	Basis		Gains		Losses			Fair Value

Corporate securities	$	24,394	$	232	$	(27	)	$	24,599
Government bonds		30,709		36		(104	)		30,641
Mortgage-backed securities		5,625		106		—			5,731
Asset-backed securities and other		14,099		158		(16	)		14,241

	$	74,827	$	532	$	(147	)	$	75,212


	August 28, 2010
	Amortized		Gross		Gross
	Cost		Unrealized		Unrealized
(in thousands)	Basis		Gains		Losses			Fair Value

Corporate securities	$	28,707	$	490	$	(1	)	$	29,196
Government bonds		24,560		283		—			24,843
Mortgage-backed securities		8,603		192		—			8,795
Asset-backed securities and other		9,831		47		(11	)		9,867

	$	71,701	$	1,012	$	(12	)	$	72,701

The marketable securities held at February 12, 2011 are primarily debt securities and have effective maturities ranging from less than one year to approximately 3 years. The Company did not realize any material gains or losses on its marketable securities during the twenty-four week period ended February 12, 2011.

The Company holds twenty-four securities that are in an unrealized loss position of approximately $147 thousand at February 12, 2011. The Company has the intent and ability to hold these investments until recovery of fair value or maturity, and does not deem the investments to be impaired on an other than temporary basis. In evaluating whether the securities are deemed to be impaired on an other than temporary basis, the Company considers factors such as the duration and severity of the loss position, the credit worthiness of the investee, the term to maturity and our intent and ability to hold the investments until maturity or until recovery of fair value.

Derivative Financial Instruments	6 Months Ended
Derivative Financial Instruments	Feb. 12, 2011
Derivative Financial Instruments [Abstract]
Derivative Financial Instruments	Note E — Derivative Financial Instruments During the first quarter of fiscal 2011, the Company was party to three forward starting swaps. These agreements were designated as cash flow hedges and were used to hedge the exposure to variability in future cash flows resulting from changes in variable interest rates related to the $500 million Senior Note debt issuance during the first quarter of fiscal 2011. The swaps had notional amounts of $150 million, $150 million and $100 million with associated fixed rates of 3.15%, 3.13%, and 2.57%, respectively. The swaps were benchmarked based on the 3-month London InterBank Offered Rate. These swaps expired in November 2010 and resulted in a loss of $7.4 million, net of tax, that will be deferred in accumulated other comprehensive loss and reclassified to interest expense over the life of the underlying debt. The hedges remained highly effective until they expired; therefore, no ineffectiveness was recognized in earnings. At February 12, 2011, the Company had $8.0 million recorded in accumulated other comprehensive loss related to net realized losses associated with terminated interest derivatives which were designated as hedges. Net losses are amortized into interest expense over the remaining life of the associated debt. During the twenty-four week period ended February 12, 2011, the Company reclassified $453 thousand of net losses from accumulated other comprehensive loss to interest expense. In the comparable prior year period, the Company reclassified $282 thousand of net gains from accumulated other comprehensive loss to interest expense.

Merchandise Inventories	6 Months Ended
Merchandise Inventories	Feb. 12, 2011
Merchandise Inventories [Abstract]
Merchandise Inventories	Note F — Merchandise Inventories Inventories are stated at the lower of cost or market using the last-in, first-out (“LIFO”) method for domestic inventories and the first-in, first-out (“FIFO”) method for Mexico inventories. Included in inventories are related purchasing, storage and handling costs. Due to price deflation on the Company’s merchandise purchases, the Company’s domestic inventory balances are effectively maintained under the FIFO method. The Company’s policy is not to write up inventory in excess of replacement cost. The cumulative balance of this unrecorded adjustment, which will be reduced upon experiencing price inflation on the Company’s merchandise purchases, was $255.6 million at February 12, 2011, and $247.3 million at August 28, 2010.

Pension and Savings Plans

6 Months Ended

Feb. 12, 2011

Pension and Savings Plans [Abstract]

Pension and Savings Plans

Note G — Pension and Savings Plans

The components of net periodic pension expense related to the Company’s pension plans consisted of the following:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Interest cost	$	2,570		$	2,611		$	5,139		$	5,222
Expected return on plan assets		(2,152	)		(2,087	)		(4,304	)		(4,175	)
Amortization of net loss		2,170			1,877			4,341			3,755

Net periodic pension expense	$	2,588		$	2,401		$	5,176		$	4,802

The Company makes contributions in amounts at least equal to the minimum funding requirements of the Employee Retirement Income Security Act of 1974, as amended by the Pension Protection Act of 2006. During the twenty-four week period ended February 12, 2011, the Company made contributions to its funded plan in the amount of $3.2 million. The Company expects to contribute approximately $2.6 million to the plan during the remainder of fiscal 2011; however, a change to the expected cash funding may be impacted by a change in interest rates or a change in the actual or expected return on plan assets.

Financing

6 Months Ended

Feb. 12, 2011

Financing [Abstract]

Financing

Note H — Financing

The Company’s long-term debt consisted of the following:


	February 12,		August 28,
(in thousands)	2011		2010

4.75% Senior Notes due November 2010, effective interest rate of 4.17%	$	—	$	199,300
5.875% Senior Notes due October 2012, effective interest rate of 6.33%		300,000		300,000
4.375% Senior Notes due June 2013, effective interest rate of 5.65%		200,000		200,000
6.5% Senior Notes due January 2014, effective interest rate of 6.63%		500,000		500,000
5.75% Senior Notes due January 2015, effective interest rate of 5.89%		500,000		500,000
5.5% Senior Notes due November 2015, effective interest rate of 4.86%		300,000		300,000
6.95% Senior Notes due June 2016, effective interest rate of 7.09%		200,000		200,000
7.125% Senior Notes due August 2018, effective interest rate of 7.28%		250,000		250,000
4.000% Senior Notes due November 2020, effective interest rate of 4.43%		500,000		—
Commercial paper, weighted average interest rate of 0.37% and 0.41% at February 12, 2011 and August 28, 2010, respectively		458,300		433,000

	$	3,208,300	$	2,882,300

As of February 12, 2011, the commercial paper borrowings mature in the next twelve months, but are classified as long-term in the accompanying Condensed Consolidated Balance Sheets as the Company has the ability and intent to refinance them on a long-term basis. Before considering the effect of commercial paper borrowings, the Company had $796.0 million of availability under its $800 million revolving credit facility, expiring in July 2012, which would allow it to replace these short-term obligations with long-term financing.

In addition to the long-term debt discussed above, as of February 12, 2011, the Company has $40.9 million of short-term borrowings that are scheduled to mature in the next 12 months. The short-term borrowings are unsecured, peso-denominated borrowings and accrue interest at 5.1% as of February 12, 2011.

On November 15, 2010, the Company issued $500 million in 4.000% Senior Notes due 2020 under the Company’s shelf registration statement filed with the SEC on July 29, 2008 (the “Shelf Registration”). The Shelf Registration allows the Company to sell an indeterminate amount in debt securities to fund general corporate purposes, including repaying, redeeming or repurchasing outstanding debt and for working capital, capital expenditures, new store openings, stock repurchases and acquisitions. The Company used the proceeds from the issuance of debt to repay the principal due relating to the 4.75% Senior Notes that matured on November 15, 2010, to repay a portion of the commercial paper borrowings and for general corporate purposes.

The fair value of the Company’s debt was estimated at $3.425 billion as of February 12, 2011, and $3.182 billion as of August 28, 2010, based on the quoted market prices for the same or similar issues or on the current rates available to the Company for debt of the same terms. Such fair value is greater than the carrying value of debt by $175.5 million at February 12, 2011, and $273.5 million at August 28, 2010.

Stock Repurchase Program	6 Months Ended
Stock Repurchase Program	Feb. 12, 2011
Stock Repurchase Program [Abstract]
Stock Repurchase Program	Note I — Stock Repurchase Program From January 1, 1998 to February 12, 2011, the Company has repurchased a total of 124.6 million shares at an aggregate cost of $9.4 billion, including 2,831,300 shares of its common stock at an aggregate cost of $694.1 million during the twenty-four week period ended February 12, 2011. On December 15, 2010, the Board voted to increase the authorization by $500 million to raise the cumulative share repurchase authorization from $9.4 billion to $9.9 billion. Considering cumulative repurchases as of February 12, 2011, the Company had $491.4 million remaining under the Board’s authorization to repurchase its common stock. Subsequent to February 12, 2011, the Company has repurchased 525,119 shares of its common stock at an aggregate cost of $136.7 million. During the twenty-four week period ended February 12, 2011, the Company retired 6.6 million shares of treasury stock which had previously been repurchased under the Company’s share repurchase program. The retirement increased retained deficit by $1,247.7 million and decreased additional paid-in capital by $82.2 million.

Comprehensive Income

6 Months Ended

Feb. 12, 2011

Comprehensive Income [Abstract]

Comprehensive Income

Note J — Comprehensive Income

Comprehensive income includes foreign currency translation adjustments; the impact from certain derivative financial instruments designated and effective as cash flow hedges, including changes in fair value, as applicable; the reclassification of gains and/or losses from accumulated other comprehensive loss to net income to offset the earnings impact of the underlying items being hedged; pension liability adjustments and changes in the fair value of certain investments classified as available-for-sale.

Comprehensive income consisted of the following:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Net income	$	148,056		$	123,333		$	320,131		$	266,633
Foreign currency translation adjustments		3,614			(1,554	)		16,282			(66	)
Net impact from derivative instruments		(3,939	)		(141	)		(4,998	)		(282	)
Pension liability adjustments		1,620			2,461			3,243			2,461
Unrealized (losses) gains from marketable securities		(327	)		(84	)		(400	)		99

Comprehensive income	$	149,024		$	124,015		$	334,258		$	268,845

Litigation	6 Months Ended
Litigation	Feb. 12, 2011
Litigation [Abstract]
Litigation	Note K — Litigation AutoZone, Inc. is a defendant in a lawsuit entitled “Coalition for a Level Playing Field, L.L.C., et al., v. AutoZone, Inc. et al.,” filed in the U.S. District Court for the Southern District of New York in October 2004. The case was filed by more than 200 plaintiffs, which are principally automotive aftermarket warehouse distributors and jobbers, against a number of defendants, including automotive aftermarket retailers and aftermarket automotive parts manufacturers. In the amended complaint, the plaintiffs allege, inter alia, that some or all of the automotive aftermarket retailer defendants have knowingly received, in violation of the Robinson-Patman Act (the “Act”), from various of the manufacturer defendants benefits such as volume discounts, rebates, early buy allowances and other allowances, fees, inventory without payment, sham advertising and promotional payments, a share in the manufacturers’ profits, benefits of pay-on-scan purchases, implementation of radio frequency identification technology, and excessive payments for services purportedly performed for the manufacturers. Additionally, a subset of plaintiffs alleges a claim of fraud against the automotive aftermarket retailer defendants based on discovery issues in a prior litigation involving similar claims under the Act. In the prior litigation, the discovery dispute, as well as the underlying claims, was decided in favor of AutoZone and the other automotive aftermarket retailer defendants who proceeded to trial, pursuant to a unanimous jury verdict which was affirmed by the Second Circuit Court of Appeals. In the current litigation, plaintiffs seek an unspecified amount of damages (including statutory trebling), attorneys’ fees, and a permanent injunction prohibiting the aftermarket retailer defendants from inducing and/or knowingly receiving discriminatory prices from any of the aftermarket manufacturer defendants and from opening up any further stores to compete with plaintiffs as long as defendants allegedly continue to violate the Act. In an order dated September 7, 2010 and issued on September 16, 2010, the court granted motions to dismiss all claims against AutoZone and its co-defendant competitors and suppliers. Based on the record in the prior litigation, the court dismissed with prejudice all overlapping claims — that is, those covering the same time periods covered by the prior litigation and brought by the judgment plaintiffs in the prior litigation. The court also dismissed with prejudice the plaintiffs’ attempt to revisit discovery disputes from the prior litigation. Further, with respect to the other claims under the Act, the Court found that the factual statements contained in the complaint fall short of what would be necessary to support a plausible inference of unlawful price discrimination. Finally, the court held that the AutoZone pay-on-scan program is a difference in non-price terms that are not governed by the Act. The court ordered the case closed, but also stated that “in an abundance of caution the Court [was] defer[ring] decision on whether to grant leave to amend to allow plaintiff an opportunity to propose curative amendments.” The plaintiffs filed a motion for leave to amend their complaint and attached a proposed Third Amended and Supplemental Complaint (the “Third Amended Complaint”) on behalf of four plaintiffs. The Third Amended Complaint repeats and expands certain allegations from previous complaints, asserting two claims under the Act, but states that all other plaintiffs have withdrawn their claims, and that, inter alia, Chief Auto Parts, Inc. has been dismissed as a defendant. AutoZone and the co-defendants have filed an opposition to the motion seeking leave to amend which is before the court for decision. The Company believes this suit to be without merit and is vigorously defending against it. The Company is unable to estimate a loss or possible range of loss. In 2004, the Company acquired a store site in Mount Ephraim, New Jersey that had previously been the site of a gasoline service station and contained evidence of groundwater contamination. Upon acquisition, the Company voluntarily reported the groundwater contamination issue to the New Jersey Department of Environmental Protection and entered into a Voluntary Remediation Agreement providing for the remediation of the contamination associated with the property. The Company has conducted and paid for (at an immaterial cost to the Company) remediation of visible contamination on the property and is investigating and will be addressing potential vapor intrusion impacts in downgradient residences and businesses. Pursuant to the Voluntary Remediation Agreement, upon completion of all remediation required by the agreement, the Company is eligible to be reimbursed up to 75 percent of its remediation costs by the State of New Jersey. Although the aggregate amount of additional costs that the Company may incur pursuant to the Voluntary Remediation Agreement cannot currently be ascertained, the Company does not currently believe that fulfillment of its obligations under the agreement will result in costs that are material to its financial condition, results of operations or cash flow. The Company is involved in various other legal proceedings incidental to the conduct of its business, including several lawsuits containing class-action allegations in which the plaintiffs are current and former hourly and salaried employees who allege various wage and hour violations and unlawful termination practices. The Company does not currently believe that, in the aggregate, these matters will result in liabilities material to the Company’s financial condition, results of operations, or cash flows.

Segment Reporting

6 Months Ended

Feb. 12, 2011

Segment Reporting [Abstract]

Segment Reporting

Note L — Segment Reporting

The Company’s two operating segments (Domestic Auto Parts and Mexico) are aggregated as one reportable segment: Auto Parts Stores. The criteria the Company used to identify the reportable segment are primarily the nature of the products the Company sells and the operating results that are regularly reviewed by the Company’s chief operating decision maker to make decisions about the resources to be allocated to the business units and to assess performance. The accounting policies of the Company’s reportable segment are the same as those described in Note A in its Annual Report on Form 10-K for the year ended August 28, 2010.

The Auto Parts Stores segment is a retailer and distributor of automotive parts and accessories through the Company’s 4,674 stores in the United States, including Puerto Rico, and Mexico. Each store carries an extensive product line for cars, sport utility vehicles, vans and light trucks, including new and remanufactured automotive hard parts, maintenance items, accessories and non-automotive products.

The Other category reflects business activities that are not separately reportable, including ALLDATA, which produces, sells and maintains diagnostic and repair information software used in the automotive repair industry, and E-commerce, which includes direct sales to customers through www.autozone.com.

The Company evaluates its reportable segment primarily on the basis of net sales and segment profit, which is defined as gross profit. Segment results for the periods presented were as follows:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Net Sales
Auto Parts Stores	$	1,623,949		$	1,472,958		$	3,378,936		$	3,029,218
Other		36,997			33,267			73,672			66,251

Total	$	1,660,946		$	1,506,225		$	3,452,608		$	3,095,469


Segment Profit
Auto Parts Stores	$	816,692		$	726,797		$	1,695,558		$	1,499,795
Other		28,919			26,939			57,801			53,865

Gross profit		845,611			753,736			1,753,359			1,553,660
Operating, selling, general and administrative expenses		(573,863	)		(523,355	)		(1,175,491	)		(1,062,850	)
Interest expense, net		(39,576	)		(36,309	)		(76,829	)		(72,650	)

Income before income taxes	$	232,172		$	194,072		$	501,039		$	418,160

Share-Based Payments (Tables)

6 Months Ended

Feb. 12, 2011

Share-Based Payments (Tables) [Abstract]

Weighted average fair value of the stock option awards granted, weighted average key assumptions:

The weighted average fair value of the stock option awards granted during the twenty-four week periods ended February 12, 2011 and February 13, 2010, using the Black-Scholes-Merton multiple-option pricing valuation model, was $58.58 and $40.75 per share, respectively, using the following weighted average key assumptions:


	Twenty-Four Weeks Ended
	February 12,			February 13,
	2011			2010

Expected price volatility		31	%		31	%
Risk-free interest rate		1.0	%		1.8	%
Weighted average expected lives (in years)		4.3			4.3
Forfeiture rate		10.0	%		10.0	%
Dividend yield		0.0	%		0.0	%

Fair Value Measurements (Tables)

6 Months Ended

Feb. 12, 2011

Fair Value Measurements (Tables) [Abstract]

Company's assets and liabilities measured at fair value on a recurring basis

The Company’s assets and liabilities measured at fair value on a recurring basis were as follows:


	February 12, 2011
(in thousands)	Level 1		Level 2		Level 3		Fair Value

Other current assets	$	5,955	$	60	$	—	$	6,015
Other long-term assets		62,812		6,385		—		69,197

	$	68,767	$	6,445	$	—	$	75,212


	August 28, 2010
(in thousands)	Level 1		Level 2			Level 3		Fair Value

Other current assets	$	11,307	$	4,996		$	—	$	16,303
Other long-term assets		47,725		8,673			—		56,398
Accrued expenses and other		—		(9,979	)		—		(9,979	)

	$	59,032	$	3,690		$	—	$	62,722

Marketable Securities (Tables)

6 Months Ended

Feb. 12, 2011

Marketable Securities (Tables) [Abstract]

Available-for-sale marketable securities

The Company’s available-for-sale marketable securities consisted of the following:


	February 12, 2011
	Amortized		Gross		Gross
	Cost		Unrealized		Unrealized
(in thousands)	Basis		Gains		Losses			Fair Value

Corporate securities	$	24,394	$	232	$	(27	)	$	24,599
Government bonds		30,709		36		(104	)		30,641
Mortgage-backed securities		5,625		106		—			5,731
Asset-backed securities and other		14,099		158		(16	)		14,241

	$	74,827	$	532	$	(147	)	$	75,212


	August 28, 2010
	Amortized		Gross		Gross
	Cost		Unrealized		Unrealized
(in thousands)	Basis		Gains		Losses			Fair Value

Corporate securities	$	28,707	$	490	$	(1	)	$	29,196
Government bonds		24,560		283		—			24,843
Mortgage-backed securities		8,603		192		—			8,795
Asset-backed securities and other		9,831		47		(11	)		9,867

	$	71,701	$	1,012	$	(12	)	$	72,701

Pension and Savings Plans (Tables)

6 Months Ended

Feb. 12, 2011

Pension and Savings Plans (Tables) [Abstract]

The components of net periodic pension expense related to the Company's pension plans consisted of the following:

The components of net periodic pension expense related to the Company’s pension plans consisted of the following:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Interest cost	$	2,570		$	2,611		$	5,139		$	5,222
Expected return on plan assets		(2,152	)		(2,087	)		(4,304	)		(4,175	)
Amortization of net loss		2,170			1,877			4,341			3,755

Net periodic pension expense	$	2,588		$	2,401		$	5,176		$	4,802

Financing (Tables)

6 Months Ended

Feb. 12, 2011

Financing (Tables) [Abstract]

Components of Company's long-term debt

The Company’s long-term debt consisted of the following:


	February 12,		August 28,
(in thousands)	2011		2010

4.75% Senior Notes due November 2010, effective interest rate of 4.17%	$	—	$	199,300
5.875% Senior Notes due October 2012, effective interest rate of 6.33%		300,000		300,000
4.375% Senior Notes due June 2013, effective interest rate of 5.65%		200,000		200,000
6.5% Senior Notes due January 2014, effective interest rate of 6.63%		500,000		500,000
5.75% Senior Notes due January 2015, effective interest rate of 5.89%		500,000		500,000
5.5% Senior Notes due November 2015, effective interest rate of 4.86%		300,000		300,000
6.95% Senior Notes due June 2016, effective interest rate of 7.09%		200,000		200,000
7.125% Senior Notes due August 2018, effective interest rate of 7.28%		250,000		250,000
4.000% Senior Notes due November 2020, effective interest rate of 4.43%		500,000		—
Commercial paper, weighted average interest rate of 0.37% and 0.41% at February 12, 2011 and August 28, 2010, respectively		458,300		433,000

	$	3,208,300	$	2,882,300

Comprehensive Income (Tables)

6 Months Ended

Feb. 12, 2011

Comprehensive Income (Tables) [Abstract]

Comprehensive income

Comprehensive income consisted of the following:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Net income	$	148,056		$	123,333		$	320,131		$	266,633
Foreign currency translation adjustments		3,614			(1,554	)		16,282			(66	)
Net impact from derivative instruments		(3,939	)		(141	)		(4,998	)		(282	)
Pension liability adjustments		1,620			2,461			3,243			2,461
Unrealized (losses) gains from marketable securities		(327	)		(84	)		(400	)		99

Comprehensive income	$	149,024		$	124,015		$	334,258		$	268,845

Segment Reporting (Tables)

6 Months Ended

Feb. 12, 2011

Segment Reporting (Tables) [Abstract]

Segment results

Segment results for the periods presented were as follows:


	Twelve Weeks Ended						Twenty-Four Weeks Ended
	February 12,			February 13,			February 12,			February 13,
(in thousands)	2011			2010			2011			2010

Net Sales
Auto Parts Stores	$	1,623,949		$	1,472,958		$	3,378,936		$	3,029,218
Other		36,997			33,267			73,672			66,251

Total	$	1,660,946		$	1,506,225		$	3,452,608		$	3,095,469


Segment Profit
Auto Parts Stores	$	816,692		$	726,797		$	1,695,558		$	1,499,795
Other		28,919			26,939			57,801			53,865

Gross profit		845,611			753,736			1,753,359			1,553,660
Operating, selling, general and administrative expenses		(573,863	)		(523,355	)		(1,175,491	)		(1,062,850	)
Interest expense, net		(39,576	)		(36,309	)		(76,829	)		(72,650	)

Income before income taxes	$	232,172		$	194,072		$	501,039		$	418,160

General (Details)	3 Months Ended
General (Details)	Feb. 12, 2011
General (Textuals)
Description of reporting periods	Operating results for the twelve and twenty-four weeks ended February 12, 2011, are not necessarily indicative of the results that may be expected for the fiscal year ending August 27, 2011. Each of the first three quarters of AutoZone's fiscal year consists of 12 weeks, and the fourth quarter consists of 16 or 17 weeks. The fourth quarters for fiscal 2010 and fiscal 2011 each have 16 weeks. Additionally, the Company's business is somewhat seasonal in nature, with the highest sales generally occurring during the months of February through September and the lowest sales generally occurring in the months of December and January.

Share-Based Payments (Details) - USD ($)	3 Months Ended		6 Months Ended
Share-Based Payments (Details) - USD ($)	Feb. 12, 2011	Feb. 13, 2010	Feb. 12, 2011	Feb. 13, 2010
Weighted average fair value of the stock option awards granted, weighted average key assumptions:
Expected price volatility			31.00%	31.00%
Risk-free interest rate			1.00%	1.80%
Weighted average expected lives (in years)			4.3	4.3
Forfeiture rate			10.00%	10.00%
Dividend yield			0.00%	0.00%
Share-Based Payments (Textuals)
Total share-based expense related to stock options and share purchase plans	$ 7,000,000	$ 4,600,000	$ 12,100,000	$ 8,900,000
Stock options granted			424,780	496,580
Weighted average grant date fair value of options granted			$ 58.58	$ 40.75
Anti-dilutive shares excluded from the computation of earnings per share	1,260	24,900	1,260	25,500
Restricted stock units granted under Director Compensation Program, description			Under the Program, restricted stock units are granted the first day of each calendar quarter. The number of restricted stock units granted each quarter is determined by dividing one-fourth of the amount of the annual retainer by the fair market value of the shares of common stock as of the grant date.
Stock options exercised - shares			339,370	262,059
Stock options exercised, weighted average exercise price	$ 101.44	$ 72.30	$ 101.44	$ 72.30
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based expense related to stock options and share purchase plans	$ 466,000

Fair Value Measurements (Details) - USD ($) $ in Thousands	Feb. 12, 2011	Aug. 28, 2010
Company's assets and liabilities measured at fair value on a recurring basis
Other current assets	$ 6,015	$ 16,303
Other long-term assets	69,197	56,398
Accrued expenses and other		(9,979)
Total	75,212	62,722
Level 1 [Member]
Company's assets and liabilities measured at fair value on a recurring basis
Other current assets	5,955	11,307
Other long-term assets	62,812	47,725
Accrued expenses and other		0
Total	68,767	59,032
Level 2 [Member]
Company's assets and liabilities measured at fair value on a recurring basis
Other current assets	60	4,996
Other long-term assets	6,385	8,673
Accrued expenses and other		(9,979)
Total	6,445	3,690
Level 3 [Member]
Company's assets and liabilities measured at fair value on a recurring basis
Other current assets	0	0
Other long-term assets	0	0
Accrued expenses and other		0
Total	$ 0	$ 0

Fair Value Measurements (Details Textuals) $ in Millions	Feb. 12, 2011 USD ($)
Fair Value Measurements (Textuals) [Abstract]
Short-term marketable securities	$ 6.0
Long term marketable securities	$ 69.2

Marketable Securities (Details) $ in Thousands	6 Months Ended	12 Months Ended
Marketable Securities (Details) $ in Thousands	Feb. 12, 2011 USD ($)	Aug. 28, 2010 USD ($)
Available-for-sale marketable securities
Available-For-Sale Marketable Securities, Amortized Cost Basis	$ 74,827	$ 71,701
Available-For-Sale Marketable Securities, Gross Unrealized Gains	532	1,012
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(147)	(12)
Available-For-Sale Marketable Securities, Fair Value	$ 75,212	72,701
Marketable Securities (Textuals) [Abstract]
Available for sale securities debt maturity period range	Less than one year to approximately 3 years
Held to maturity securities in continuous unrealized loss position amount	$ 147
Number of securities held in unrealized loss position	24
Corporate securities [Member]
Available-for-sale marketable securities
Available-For-Sale Marketable Securities, Amortized Cost Basis	$ 24,394	28,707
Available-For-Sale Marketable Securities, Gross Unrealized Gains	232	490
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(27)	(1)
Available-For-Sale Marketable Securities, Fair Value	24,599	29,196
Government bonds [Member]
Available-for-sale marketable securities
Available-For-Sale Marketable Securities, Amortized Cost Basis	30,709	24,560
Available-For-Sale Marketable Securities, Gross Unrealized Gains	36	283
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(104)	0
Available-For-Sale Marketable Securities, Fair Value	30,641	24,843
Mortgage-backed securities [Member]
Available-for-sale marketable securities
Available-For-Sale Marketable Securities, Amortized Cost Basis	5,625	8,603
Available-For-Sale Marketable Securities, Gross Unrealized Gains	106	192
Available-For-Sale Marketable Securities, Gross Unrealized Losses	0	0
Available-For-Sale Marketable Securities, Fair Value	5,731	8,795
Asset-Backed securities and other [Member]
Available-for-sale marketable securities
Available-For-Sale Marketable Securities, Amortized Cost Basis	14,099	9,831
Available-For-Sale Marketable Securities, Gross Unrealized Gains	158	47
Available-For-Sale Marketable Securities, Gross Unrealized Losses	(16)	(11)
Available-For-Sale Marketable Securities, Fair Value	$ 14,241	$ 9,867

Derivative Financial Instruments (Details) $ in Thousands	3 Months Ended	6 Months Ended
Derivative Financial Instruments (Details) $ in Thousands	Nov. 20, 2010 USD ($)	Feb. 12, 2011 USD ($)	Feb. 13, 2010 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 500,000	$ 500,000
Derivative Financial Instruments (Textuals) [Abstract]
Number of forward starting swaps company was party to during period	3
Derivative description of terms	The swaps were benchmarked based on the 3-month London InterBank Offered Rate.
Accumulated other comprehensive gain (loss) related to net unrealized gain (loss), net of tax		(8,000)
Change in AOCI derivative balance, net of tax	$ (7,400)
Gain (loss) on cash flow hedge ineffectiveness, net	0
Cash flow hedge gain (loss) reclassified to interest expense, net		$ 453	$ 282
Forward Starting Swap, One [Member]
Derivative [Line Items]
Notional amount of forward swaps	$ 150,000
Fixed rates of the hedges based on LIBOR	3.15%
Forward Starting Swap, Two [Member]
Derivative [Line Items]
Notional amount of forward swaps	$ 150,000
Fixed rates of the hedges based on LIBOR	3.13%
Forward Starting Swap, Three [Member]
Derivative [Line Items]
Notional amount of forward swaps	$ 100,000
Fixed rates of the hedges based on LIBOR	2.57%
4.000% Senior Notes due November 2020, effective interest rate of 4.43% [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 500,000

Merchandise Inventories (Details) - USD ($) $ in Millions	Feb. 12, 2011	Aug. 28, 2010
Merchandise Inventories (Textuals) [Abstract]
Unrecorded adjustment for LIFO value in excess of replacement value	$ 255.6	$ 247.3

Pension and Savings Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 12, 2011	Feb. 13, 2010	Feb. 12, 2011	Feb. 13, 2010
The components of net periodic pension expense related to the Company's pension plans consisted of the following:
Interest cost	$ 2,570	$ 2,611	$ 5,139	$ 5,222
Expected return on plan assets	(2,152)	(2,087)	(4,304)	(4,175)
Amortization of net loss	2,170	1,877	4,341	3,755
Net periodic pension expense	2,588	$ 2,401	5,176	$ 4,802
Pension and Savings Plans (Textuals) [Abstract]
Annual contributions by the Company to pension plans			3,200
Expected contributions to the plan during the remainder of fiscal 2011	$ 2,600		$ 2,600

Financing (Details) $ in Thousands	3 Months Ended	6 Months Ended
Financing (Details) $ in Thousands	Nov. 20, 2010 USD ($)	Feb. 12, 2011 USD ($)	Aug. 28, 2010 USD ($)
Components of Company's long-term debt
Long-term debt		$ 3,208,300	$ 2,882,300
Financing (Textuals)
Amount available under credit facility		800,000
Remaining borrowing capacity under revolving credit facility		$ 796,000
Expiration of credit facility		July 2012
Short-term borrowings		$ 40,930	26,186
Interest rate on short-term borrowings		5.10%
Proceeds from issuance of debt	$ 500,000	$ 500,000
Fair value of the Company's debt		3,425,000	3,182,000
Fair value option aggregate differences long term debt instruments		175,500	273,500
4.75% Senior Notes due November 2010, effective interest rate of 4.17% [Member]
Components of Company's long-term debt
Long-term debt		$ 0	199,300
Stated interest rate percentage		4.75%
Effective interest rate		4.17%
5.875% Senior Notes due October 2012, effective interest rate of 6.33% [Member]
Components of Company's long-term debt
Long-term debt		$ 300,000	300,000
Stated interest rate percentage		5.875%
Effective interest rate		6.33%
4.375% Senior Notes due June 2013, effective interest rate of 5.65% [Member]
Components of Company's long-term debt
Long-term debt		$ 200,000	200,000
Stated interest rate percentage		4.375%
Effective interest rate		5.65%
6.5% Senior Notes due January 2014, effective interest rate of 6.63% [Member]
Components of Company's long-term debt
Long-term debt		$ 500,000	500,000
Stated interest rate percentage		6.50%
Effective interest rate		6.63%
5.75% Senior Notes due January 2015, effective interest rate of 5.89% [Member]
Components of Company's long-term debt
Long-term debt		$ 500,000	500,000
Stated interest rate percentage		5.75%
Effective interest rate		5.89%
5.5% Senior Notes due November 2015, effective interest rate of 4.86% [Member]
Components of Company's long-term debt
Long-term debt		$ 300,000	300,000
Stated interest rate percentage		5.50%
Effective interest rate		4.86%
6.95% Senior Notes due June 2016, effective interest rate of 7.09% [Member]
Components of Company's long-term debt
Long-term debt		$ 200,000	200,000
Stated interest rate percentage		6.95%
Effective interest rate		7.09%
7.125% Senior Notes due August 2018, effective interest rate of 7.28% [Member]
Components of Company's long-term debt
Long-term debt		$ 250,000	250,000
Stated interest rate percentage		7.125%
Effective interest rate		7.28%
4.000% Senior Notes due November 2020, effective interest rate of 4.43% [Member]
Components of Company's long-term debt
Long-term debt		$ 500,000	0
Stated interest rate percentage		4.00%
Effective interest rate		4.43%
Financing (Textuals)
Proceeds from issuance of debt	$ 500,000
Commercial paper [Member]
Components of Company's long-term debt
Long-term debt		$ 458,300	$ 433,000
Weighted average interest rate of commercial paper	0.37%		0.41%
Commercial paper borrowings, maturity period (in months)		12

Stock Repurchase Program (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended	157 Months Ended
Stock Repurchase Program (Details) - USD ($) $ in Millions	Mar. 17, 2011	Feb. 12, 2011	Feb. 12, 2011	Dec. 15, 2010	Nov. 20, 2010
Stock Repurchase Program (Textuals) [Abstract]
Shares	525,119	2,831,300	124,600,000
Amount	$ 136.7	$ 694.1	$ 9,400.0
Stock repurchased, value				$ 9,900.0	$ 9,400.0
Stock repurchase authorized during the period, value				$ 500.0
Remaining value authorized for share repurchases		$ 491.4	$ 491.4
Treasury stock acquired repurchase authorization		From January 1, 1998 to February 12, 2011, the Company has repurchased a total of 124.6 million shares at an aggregate cost of $9.4 billion, including 2,831,300 shares of its common stock at an aggregate cost of $694.1 million during the twenty-four week period ended February 12, 2011. On December 15, 2010, the Board voted to increase the authorization by $500 million to raise the cumulative share repurchase authorization from $9.4 billion to $9.9 billion. Considering cumulative repurchases as of February 12, 2011, the Company had $491.4 million remaining under the Board’s authorization to repurchase its common stock. Subsequent to February 12, 2011, the Company has repurchased 525,119 shares of its common stock at an aggregate cost of $136.7 million. During the twenty-four week period ended February 12, 2011, the Company retired 6.6 million shares of treasury stock which had previously been repurchased under the Company’s share repurchase program. The retirement increased retained deficit by $1,247.7 million and decreased additional paid-in capital by $82.2 million.
Shares of treasury stock retired		6,600,000
Retained Deficit [Member]
Statement [Line Items]
Treasury stock value retired, cost method		$ (1,247.7)
Additional Paid-In Capital [Member]
Statement [Line Items]
Treasury stock value retired, cost method		$ (82.2)

Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Comprehensive Income (Details) - USD ($) $ in Thousands	Feb. 12, 2011	Feb. 13, 2010	Feb. 12, 2011	Feb. 13, 2010
Comprehensive Income (Details) [Abstract]
Net income	$ 148,056	$ 123,333	$ 320,131	$ 266,633
Foreign currency translation adjustments	3,614	(1,554)	16,282	(66)
Net impact from derivative instruments	(3,939)	(141)	(4,998)	(282)
Pension liability adjustments	1,620	2,461	3,243	2,461
Unrealized (losses) gains from marketable securities	(327)	(84)	(400)	99
Comprehensive income	$ 149,024	$ 124,015	$ 334,258	$ 268,845

Litigation (Details)	6 Months Ended	12 Months Ended
Litigation (Details)	Feb. 12, 2011	Aug. 28, 2010
Litigation (Textuals) [Abstract]
Number of plaintiffs in lawsuit entitled Coalition for a Level Playing Field, L.L.C., et al., v. AutoZone, Inc. et al.	More than 200
Number of plaintiffs who filed motions for leave and to amend their complaint		4
Number of claims asserted under the Robinson-Patman Act	2
Site contingency, recovery from third party of environmental remediation cost	In 2004, the Company acquired a store site in Mount Ephraim, New Jersey that had previously been the site of a gasoline service station and contained evidence of groundwater contamination. Upon acquisition, the Company voluntarily reported the groundwater contamination issue to the New Jersey Department of Environmental Protection and entered into a Voluntary Remediation Agreement providing for the remediation of the contamination associated with the property. The Company has conducted and paid for (at an immaterial cost to the Company) remediation of visible contamination on the property and is investigating and will be addressing potential vapor intrusion impacts in downgradient residences and businesses. Pursuant to the Voluntary Remediation Agreement, upon completion of all remediation required by the agreement, the Company is eligible to be reimbursed up to 75 percent of its remediation costs by the State of New Jersey. Although the aggregate amount of additional costs that the Company may incur pursuant to the Voluntary Remediation Agreement cannot currently be ascertained, the Company does not currently believe that fulfillment of its obligations under the agreement will result in costs that are material to its financial condition, results of operations or cash flow.
Reimbursable remediation costs	75.00%

Segment Reporting (Details) $ in Thousands	3 Months Ended		6 Months Ended
Segment Reporting (Details) $ in Thousands	Feb. 12, 2011 USD ($)	Feb. 13, 2010 USD ($)	Feb. 12, 2011 USD ($)	Feb. 13, 2010 USD ($)
Net Sales
Net sales	$ 1,660,946	$ 1,506,225	$ 3,452,608	$ 3,095,469
Segment Profit
Gross profit	845,611	753,736	1,753,359	1,553,660
Operating, selling, general and administrative	(573,863)	(523,355)	(1,175,491)	(1,062,850)
Interest expense, net	(39,576)	(36,309)	(76,829)	(72,650)
Income before income taxes	232,172	194,072	$ 501,039	418,160
Segment Reporting (Textuals) [Abstract]
Number of operating segments			2
Number of reportable segments			1
Number of automotive parts and accessories stores in the United States, including Puerto Rico and Mexico			4,674
Auto Parts Stores [Member]
Net Sales
Net sales	1,623,949	1,472,958	$ 3,378,936	3,029,218
Segment Profit
Gross profit	816,692	726,797	1,695,558	1,499,795
Other [Member]
Net Sales
Net sales	36,997	33,267	73,672	66,251
Segment Profit
Gross profit	$ 28,919	$ 26,939	$ 57,801	$ 53,865