Maturity date (by month and year) for debt instrument.

No definition available.

Name:	azo_DebtInstrumentMaturityMonthAndYear
Namespace Prefix:	azo_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of days prior to the expiration date, required to extend or modify the line of credit facility.

+ References

No definition available.

+ Details

Name:	azo_LineOfCreditFacilityTermPriorToExpirationPeriod
Namespace Prefix:	azo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Penalty percentage assessed from extending expiration period.

+ References

No definition available.

+ Details

Name:	azo_PercentageOfPenaltyForExtendingExpirationPeriod
Namespace Prefix:	azo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The term prior to the expiration date, required to extend or modify term-loan.

+ References

No definition available.

+ Details

Name:	azo_TermLoanMaturityPeriod
Namespace Prefix:	azo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ 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=77997519&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=77997519&loc=d3e13476-108611

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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 Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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(22))
-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 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: 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(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_LineOfCredit
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

+ Details

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

- Definition

Description of the terms of a credit facility arrangement. Terms typically include interest rate, collateral required, guarantees required, repayment requirements, and restrictions on use of assets and activities of the entity.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

- 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=98514028&loc=d3e3255-108585

+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=azo_NewMultiYearRevolvingCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=azo_MultiYearRevolvingCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=azo_NewThreeSixtyFourDayRevolvingCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=azo_ThreeSixtyFourDayRevolvingCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=azo_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=azo_SeniorNotesEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=azo_ThreePointOnetwoFiveSeniorNotesDueAprilTwoThousandTwentySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=azo_OnePointSixTwoFiveSeniorNotesDueAprilTwoThousandNintheenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financing - Additional Information (Detail) - USD ($)				3 Months Ended	8 Months Ended		12 Months Ended
Financing - Additional Information (Detail) - USD ($)	Apr. 18, 2017	Nov. 18, 2016	Apr. 21, 2016	Nov. 18, 2016	May 06, 2017	May 07, 2016	Aug. 27, 2016
Debt Instrument [Line Items]
Remaining borrowing capacity under revolving credit facility					$ 1,997,000,000
Amount available under credit facility					2,000,000,000
Proceeds from issuance of debt					600,000,000	$ 650,000,000
Fair value of the Company's debt					5,222,000,000		$ 5,117,000,000
Excess (shortfall) of fair value of debt over (from) carrying value					$ 69,100,000		$ 192,700,000
New Multi-Year Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Amount available under credit facility		$ 1,600,000,000		$ 1,600,000,000
Extended expiration of credit facility		2 years
Maximum amount available under credit facility		$ 2,100,000,000		2,100,000,000
Interest accrual on foreign currency loans the basis points					Interest accrues on Eurodollar loans at a defined Eurodollar rate, defined as LIBOR plus the applicable percentage, as defined in the revolving credit facility, depending upon the Company's senior, unsecured, (non-credit enhanced) long-term debt rating. Interest accrues on base rate loans as defined in the credit facility.
Credit facility expiration date					Nov. 18, 2021
Credit Agreement description					This credit facility is available to primarily support commercial paper borrowings, letters of credit and other short-term unsecured bank loans. The capacity of the credit facility may be increased to $2.1 billion prior to the maturity date at the Company’s election and subject to bank credit capacity and approval, and may include up to $200 million in letters of credit. Under the revolving credit facility, the Company may borrow funds consisting of Eurodollar loans, base rate loans or a combination of both. The Company also has the option to borrow funds under the terms of a swingline loan subfacility. The revolving credit facility expires on November 18, 2021, but the Company may, by notice to the administrative agent, make up to two requests to extend the termination date for an additional period of one year. The first such request must be made no earlier than 60 days, and no later than 45 days, prior to November 18, 2017, while the second request must be made no earlier than 60 days, and no later than 45 days, prior to November 18, 2018.
Borrowings, outstanding					$ 0
Letters of credit, outstanding					$ 3,300,000
New Multi-Year Revolving Credit Agreement [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Maximum amount available under credit facility		200,000,000		200,000,000
Multi Year Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Amount available under credit facility		1,250,000,000		$ 1,250,000,000
New 364-Day Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Extended expiration of credit facility				1 year
Maximum amount available under credit facility		400,000,000		$ 400,000,000
Credit facility expiration date					Nov. 17, 2017
Credit Agreement description					The credit facility is available to primarily support commercial paper borrowings and other short-term unsecured bank loans. Under the credit facility, the Company may borrow funds consisting of Eurodollar loans, base rate loans or a combination of both.The New 364-Day Credit Agreement expires on November 17, 2017, but the Company may request an extension of the termination date for 364 days no later than 45 days prior to November 17, 2017, subject to bank approval. In addition, at least 15 days prior to November 17, 2017, the Company has the right to convert the credit facility to a term loan for up to one year from the termination date, subject to a 1% penalty.
Credit facility interest rate description					Interest accrues on Eurodollar loans at a defined Eurodollar rate, defined as LIBOR plus the applicable margin, as defined in the revolving credit facility, depending upon the Company's senior, unsecured, (non-credit enhanced) long-term debt rating. Interest accrues on base rate loans as defined in the credit facility.
Borrowings, outstanding					$ 0
New 364-Day Revolving Credit Agreement [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Term Loan Maturity Period					1 year
364-Day Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum amount available under credit facility		$ 500,000,000		$ 500,000,000
Term Loan [Member] \| New 364-Day Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Percentage of penalty for extending expiration period					1.00%
Term Loan [Member] \| New 364-Day Revolving Credit Agreement [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Line of credit facility extension or modification period prior to expiration					15 days
3.750% Senior Notes due June 2027, effective interest rate of 3.83% [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 600,000,000
Debt instrument maturity, month and year	2027-06				2027-06		2027-06
Stated interest rate percentage	3.75%				3.75%		3.75%
Three Point OneTwo Five Senior Notes due April Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt			$ 400,000,000
Debt instrument maturity, month and year			2026-04
Stated interest rate percentage			3.125%
One Point Six Two Five Senior Notes due April Two Thousand nintheen [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt			$ 250,000,000
Debt instrument maturity, month and year			2019-04
Stated interest rate percentage			1.625%