Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Total gross intangible asset subject to amortization	$ 3,371	$ 3,360
Accumulated amortization	(1,326)	(1,270)
Total net intangible assets subject to amortization	2,045	2,090
Intangible assets not subject to amortization	117	117
Total net intangible assets	2,162	2,207
Trademarks and tradenames
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization	$ 117	117
Recorded music catalog
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	10 years
Total gross intangible asset subject to amortization	$ 901	898
Music publishing copyrights
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	27 years
Total gross intangible asset subject to amortization	$ 1,540	1,534
Artist and songwriter contracts
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	13 years
Total gross intangible asset subject to amortization	$ 906	904
Trademarks
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	6 years
Total gross intangible asset subject to amortization	$ 14	14
Other Intangible Assets
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	7 years
Total gross intangible asset subject to amortization	$ 10	$ 10