Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Consolidated Statements of Deficit (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Oct. 01, 2019	Oct. 01, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	1,060
Beginning balance	$ (269)	$ (320)
Net income	122	86
Other comprehensive income (loss), net of tax	10	(22)
Dividends	(38)	(31)
Distribution to noncontrolling interest holders	(1)	(2)
Other	$ 0	0
Ending balance (in shares)	1,069
Ending balance	$ (169)	$ (139)
ASC 842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption			$ 7
ASC 606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption				$ 150
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	1,060	1,052
Beginning balance	$ 0	$ 0
Other (in shares)	9	8
Ending balance (in shares)	1,069	1,060
Ending balance	$ 0	$ 0
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,128	1,128
Ending balance	1,128	1,128
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,177)	(1,272)
Net income	120	86
Dividends	(38)	(31)
Ending balance	(1,088)	(1,078)
Accumulated Deficit \| ASC 842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption			7
Accumulated Deficit \| ASC 606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption				139
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(240)	(190)
Other comprehensive income (loss), net of tax	10	(22)
Ending balance	(230)	(212)
Total Warner Music Group Corp. Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(289)	(334)
Net income	120	86
Other comprehensive income (loss), net of tax	10	(22)
Dividends	(38)	(31)
Ending balance	(190)	(162)
Total Warner Music Group Corp. Deficit \| ASC 842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption			$ 7
Total Warner Music Group Corp. Deficit \| ASC 606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption				139
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	20	14
Net income	2
Distribution to noncontrolling interest holders	(1)	(2)
Ending balance	$ 21	$ 23
Noncontrolling Interest \| ASC 606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of ASC adoption				$ 11