Guarantor and Non-Guarantor Subsidiaries Financial Information - Consolidating Statement of Operations (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Jul. 27, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements Captions [Line Items]
Revenues		$ 841	$ 811	$ 745	$ 849	$ 750	$ 710	$ 677	$ 829	$ 3,246	$ 2,966	$ 3,027
Costs and expenses:
Cost of revenue		(436)	(448)	(374)	(449)	(375)	(373)	(318)	(445)	(1,707)	(1,511)	(1,570)
Selling, general and administrative expenses										(1,082)	(1,073)	(1,172)
Amortization expense		(55)	(63)	(63)	(62)	(64)	(63)	(63)	(65)	(243)	(255)	(266)
Total costs and expenses		(786)	(766)	(693)	(787)	(713)	(687)	(633)	(806)	(3,032)	(2,839)	(3,008)
Operating income		55	45	52	62	37	23	44	23	214	127	19
Loss on extinguishment of debt		(14)		(4)						(18)		(141)
Interest income (expense), net		(42)	(43)	(43)	(45)	(45)	(45)	(45)	(46)	(173)	(181)	(203)
Other income (expense), net										18	(21)	(4)
Income (loss) before income taxes		(8)	(3)	27	25	(17)	(39)	13	(32)	41	(75)	(329)
Income tax (expense) benefit		5	(4)	(15)	3	(6)	(4)	6	(9)	(11)	(13)	26
Net income (loss)										30	(88)	(303)
Less: Income attributable to noncontrolling interest		(1)	(2)	(1)	(1)		(1)	(1)	(1)	(5)	(3)	(5)
Net income (loss) attributable to Warner Music Group Corp.		$ (4)	$ (9)	$ 11	$ 27	$ (23)	$ (44)	$ 18	$ (42)	25	(91)	(308)
Eliminations
Condensed Income Statements Captions [Line Items]
Revenues										(309)	(254)	(275)
Costs and expenses:
Cost of revenue										188	143	158
Selling, general and administrative expenses										121	110	117
Total costs and expenses										309	253	275
Operating income											(1)
Interest income (expense), net										1
Equity gains (losses) from consolidated subsidiaries										(236)	32	(33)
Income (loss) before income taxes										(235)	31	(33)
Income tax (expense) benefit										19	29	(17)
Net income (loss)										(216)	60	(50)
Net income (loss) attributable to Warner Music Group Corp.										(216)	60	(50)
Eliminations
Costs and expenses:
Equity gains (losses) from consolidated subsidiaries										(78)	160	594
Income (loss) before income taxes										(78)	160	594
Net income (loss)										(78)	160	594
Net income (loss) attributable to Warner Music Group Corp.										(78)	160	594
WMG Acquisition Corp.
Costs and expenses:
Loss on extinguishment of debt	$ 4
WMG Acquisition Corp. | Reportable Legal Entities
Costs and expenses:
Selling, general and administrative expenses											1	(1)
Total costs and expenses											1	(1)
Operating income											1	(1)
Loss on extinguishment of debt										(4)		(141)
Interest income (expense), net										(84)	(82)	(102)
Equity gains (losses) from consolidated subsidiaries										162	35	(80)
Other income (expense), net										(10)	(10)	12
Income (loss) before income taxes										64	(56)	(312)
Income tax (expense) benefit										(11)	(13)	26
Net income (loss)										53	(69)	(286)
Net income (loss) attributable to Warner Music Group Corp.										53	(69)	(286)
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements Captions [Line Items]
Revenues										1,668	1,632	1,498
Costs and expenses:
Cost of revenue										(703)	(788)	(639)
Selling, general and administrative expenses										(739)	(675)	(633)
Amortization expense										(118)	(122)	(120)
Total costs and expenses										(1,560)	(1,585)	(1,392)
Operating income										108	47	106
Interest income (expense), net										3	6	9
Equity gains (losses) from consolidated subsidiaries										74	(67)	113
Other income (expense), net										2	1	(18)
Income (loss) before income taxes										187	(13)	210
Income tax (expense) benefit										(20)	(29)	(9)
Net income (loss)										167	(42)	201
Less: Income attributable to noncontrolling interest										(1)	(1)	(1)
Net income (loss) attributable to Warner Music Group Corp.										166	(43)	200
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Income Statements Captions [Line Items]
Revenues										1,887	1,588	1,804
Costs and expenses:
Cost of revenue										(1,192)	(866)	(1,089)
Selling, general and administrative expenses										(464)	(509)	(655)
Amortization expense										(125)	(133)	(146)
Total costs and expenses										(1,781)	(1,508)	(1,890)
Operating income										106	80	(86)
Interest income (expense), net										(79)	(83)	(88)
Other income (expense), net										26	(12)	2
Income (loss) before income taxes										53	(15)	(172)
Income tax (expense) benefit										1		26
Net income (loss)										54	(15)	(146)
Less: Income attributable to noncontrolling interest										(4)	(2)	(4)
Net income (loss) attributable to Warner Music Group Corp.										50	(17)	(150)
WMG Acquisition Corp. Consolidated | Reportable Legal Entities
Condensed Income Statements Captions [Line Items]
Revenues										3,246	2,966	3,027
Costs and expenses:
Cost of revenue										(1,707)	(1,511)	(1,570)
Selling, general and administrative expenses										(1,082)	(1,073)	(1,172)
Amortization expense										(243)	(255)	(266)
Total costs and expenses										(3,032)	(2,839)	(3,008)
Operating income										214	127	19
Loss on extinguishment of debt										(4)		(141)
Interest income (expense), net										(159)	(159)	(181)
Other income (expense), net										18	(21)	(4)
Income (loss) before income taxes										69	(53)	(307)
Income tax (expense) benefit										(11)	(13)	26
Net income (loss)										58	(66)	(281)
Less: Income attributable to noncontrolling interest										(5)	(3)	(5)
Net income (loss) attributable to Warner Music Group Corp.										53	(69)	(286)
WMG Holdings Corp. | Reportable Legal Entities
Costs and expenses:
Loss on extinguishment of debt										(14)
Interest income (expense), net										(14)	(22)	(22)
Equity gains (losses) from consolidated subsidiaries										53	(69)	(286)
Income (loss) before income taxes										25	(91)	(308)
Net income (loss)										25	(91)	(308)
Net income (loss) attributable to Warner Music Group Corp.										25	(91)	(308)
Warner Music Group Corp. | Reportable Legal Entities
Costs and expenses:
Equity gains (losses) from consolidated subsidiaries										25	(91)	(308)
Income (loss) before income taxes										25	(91)	(308)
Net income (loss)										25	(91)	(308)
Net income (loss) attributable to Warner Music Group Corp.										$ 25	$ (91)	$ (308)