Debt instrument, accrued and unpaid interest.

No definition available.

Name:	m_DebtInstrumentAccruedAndUnpaidInterest
Namespace Prefix:	m_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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+ Details

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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-Subparagraph (bbb)(2)
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+ Details

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

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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Balance Type:	credit
Period Type:	duration

- Definition

Reflects the difference between the fair value of payments made to legally extinguish a debt and its carrying value at that time. This item excludes the write-off of amounts previously capitalized as debt issuance costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 2
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Balance Type:	debit
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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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- Details

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Financing Activities (Narrative) (Details) - USD ($)			3 Months Ended				6 Months Ended
Financing Activities (Narrative) (Details) - USD ($)	Aug. 17, 2021	Mar. 17, 2021	Oct. 30, 2021	Jul. 31, 2021	May 01, 2021	Aug. 01, 2020	Jul. 31, 2021	Aug. 01, 2020
Gains (losses) on retirement of debt				$ (3,000,000)	$ (11,000,000)	$ 0	$ (14,000,000)	$ 0
Extinguishment of debt		$ 500,000,000
Debt Instrument, Repurchase Amount		$ 17,000,000
Secured Debt, Current [Member]
Face amount				$ 1,300,000,000			$ 1,300,000,000
5.875% Senior Notes due 2029 [Member]
Debt instrument interest rate, stated percentage		5.875%
Face amount		$ 500,000,000
Debt instrument, maturity date		Apr. 01, 2029
Forecast [Member]
Gains (losses) on retirement of debt			$ 185,000,000
Subsequent Event [Member] \| 8.375% Senior secured notes due 2025 [Member]
Debt instrument, redeemed in principal amount	$ 1,300,000,000
Debt instrument interest rate, stated percentage	8.375%
Debt instrument, redemption price, percentage of principal amount redeemed	100.00%
Debt instrument, accrued and unpaid interest	$ 19,000,000
Gain (loss) on early redemption of debt before write off	138,000,000
Unamortized deferred debt costs	$ 47,000,000