Debt instrument remaining term

Name:	azo_DebtInstrumentRemainingTerm
Namespace Prefix:	azo
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing.

+ Details

Name:	azo_FinancingTextualsAbstract
Namespace Prefix:	azo
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Long Term Debt Weighted Average Interest Rate.

+ Details

Name:	azo_LongTermDebtWeightedAverageInterestRate
Namespace Prefix:	azo
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13476-108611

+ Details

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Interest rate stated in the contractual debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of long-term debt instruments that have contractual principal amounts and for which the fair value option has been elected.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph d(2)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

+ Details

Name:	us-gaap_FairValueOptionAggregateDifferencesLongTermDebtInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate
Namespace Prefix:	us-gaap
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongTermDebtAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year (current maturities) or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

+ References

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 18
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 19
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19
-Subparagraph a
-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.(a),16(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 13
-Article 9
-Subparagraph 2, 3

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 7
-Section 03
-Paragraph 16
-Subparagraph a(1)

+ Details

Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of the carrying amount of short-term borrowings outstanding as of the balance sheet date which accrues interest at a set, unchanging rate.

+ Details

Name:	us-gaap_ShortTermDebtPercentageBearingFixedInterestRate
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Financing (Details) (USD $)	3 Months Ended	9 Months Ended
Financing (Details) (USD $)	Nov. 20, 2010	May 07, 2011	Aug. 28, 2010
Components of Company's long-term debt
Long-term debt		$ 3,171,100,000	$ 2,882,300,000
Financing (Textuals)
Amount available under credit facility		800,000,000
Remaining borrowing capacity under revolving credit facility		796,000,000
Expiration of credit facility		July 2012
Short-term borrowings		49,686,000	26,186,000
Interest rate on short-term borrowings		5.00%
Proceeds from issuance of debt	500,000,000	500,000,000
Fair value of the Company's debt		3,454,000,000	3,182,000,000
Fair value option aggregate differences long term debt instruments		232,900,000	273,500,000
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	199,300,000
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		300,000,000	300,000,000
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		200,000,000	200,000,000
Stated interest rate percentage		4.375%
Effective interest rate		5.65%
6.500% Senior Notes due January 2014, effective interest rate of 6.63% [Member]
Components of Company's long-term debt
Long-term debt		500,000,000	500,000,000
Stated interest rate percentage		6.50%
Effective interest rate		6.63%
5.750% Senior Notes due January 2015, effective interest rate of 5.89% [Member]
Components of Company's long-term debt
Long-term debt		500,000,000	500,000,000
Stated interest rate percentage		5.75%
Effective interest rate		5.89%
5.50% Senior Notes due November 2015, effective interest rate of 4.86% [Member]
Components of Company's long-term debt
Long-term debt		300,000,000	300,000,000
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		200,000,000	200,000,000
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		250,000,000	250,000,000
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		500,000,000	0
Stated interest rate percentage		4.00%
Effective interest rate		4.43%
Financing (Textuals)
Proceeds from issuance of debt	500,000,000
Commercial paper, weighted average interest rate of 0.35% and 0.41% [Member]
Components of Company's long-term debt
Long-term debt		$ 421,100,000	$ 433,000,000
Weighted average interest rate of commercial paper	0.35%		0.41%
Commercial paper borrowings, maturity period (in months)		12