Amount awarded from other party in judgment or settlement of litigation.

No definition available.

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

- Definition

Cash received for the settlement of litigation during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Commitments and contingencies.

+ References

No definition available.

+ Details

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Namespace Prefix:	wmg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Jul. 29, 2015	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017	Sep. 30, 2016
Commitments And Contingencies [Line Items]
Revenues		$ 1,045	$ 917
Sirius XM \| Settled Litigation
Commitments And Contingencies [Line Items]
Receipts from plaintiff	$ 210
Cash distribution					$ 33
Revenues		$ 1		$ 4	$ 28