Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Total gross intangible asset subject to amortization	$ 3,312	$ 3,360
Accumulated amortization	(1,461)	(1,270)
Total net intangible assets subject to amortization	1,851	2,090
Intangible assets not subject to amortization	154	117
Total net other intangible assets	2,005	2,207
Trademarks and tradenames
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization	$ 154	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	$ 870	898
Music publishing copyrights
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	26 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	$ 864	904
Trademarks
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	6 years
Total gross intangible asset subject to amortization	$ 12	14
Other Intangible Assets
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, Useful Life	5 years
Total gross intangible asset subject to amortization	$ 26	$ 10