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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 835
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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
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- 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.

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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
-SubTopic 50
-Section 40
-Paragraph 4
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Balance Type:	credit
Period Type:	duration

- Definition

Debt instrument maturity year.

+ References

No definition available.

+ Details

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Namespace Prefix:	wmg_
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Balance Type:	na
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- Definition

Debt instrument remaining outstanding amount.

+ References

No definition available.

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

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Period Type:

Debt - Open Market Purchase - Additional Information (Detail) - USD ($)		3 Months Ended
	Oct. 09, 2018	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ 0	$ 3,000,000
Acquisition Corp.
Debt Instrument [Line Items]
Aggregate principal amount of debt instrument		$ 3,010,000,000.000		$ 2,998,000,000
4.875% Senior Secured Notes due 2024
Debt Instrument [Line Items]
Interest rate		4.875%	4.875%
4.875% Senior Secured Notes due 2024 \| Acquisition Corp.
Debt Instrument [Line Items]
Aggregate principal amount of debt instrument	$ 30,000,000	$ 220,000,000		$ 220,000,000
Due date of senior secured notes	2024	2024
Interest rate	4.875%	4.875%
Debt instrument remaining outstanding amount	$ 220,000,000
Loss on extinguishment of debt	$ 1,000,000