Revenue Recognition - Summary of Disaggregation of Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total Revenue	$ 1,058	$ 958	$ 3,351	$ 2,966
Amount of change in revenue	$ 100		$ 385
Percentage of change in revenue	10.00%		13.00%
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Total Revenue	$ (2)	(3)	$ (6)	(7)
Amount of change in revenue	$ 1		$ 1
Percentage of change in revenue	(33.00%)		(14.00%)
Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenue	$ 466	425	$ 1,455	1,281
Amount of change in revenue	$ 41		$ 174
Percentage of change in revenue	10.00%		14.00%
Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenue	$ 594	536	$ 1,902	1,692
Amount of change in revenue	$ 58		$ 210
Percentage of change in revenue	11.00%		12.00%
Recorded Music
Disaggregation of Revenue [Line Items]
Total Revenue	$ 913	802	$ 2,887	2,497
Amount of change in revenue	$ 111		$ 390
Percentage of change in revenue	14.00%		16.00%
Recorded Music | Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenue	$ 395	356	$ 1,236	1,061
Amount of change in revenue	$ 39		$ 175
Percentage of change in revenue	11.00%		16.00%
Recorded Music | Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenue	$ 518	446	$ 1,651	1,436
Amount of change in revenue	$ 72		$ 215
Percentage of change in revenue	16.00%		15.00%
Recorded Music | Digital
Disaggregation of Revenue [Line Items]
Total Revenue	$ 584	519	$ 1,744	1,491
Amount of change in revenue	$ 65		$ 253
Percentage of change in revenue	13.00%		17.00%
Recorded Music | Physical
Disaggregation of Revenue [Line Items]
Total Revenue	$ 95	130	$ 456	500
Amount of change in revenue	$ (35)		$ (44)
Percentage of change in revenue	(27.00%)		(9.00%)
Recorded Music | Total Digital and Physical
Disaggregation of Revenue [Line Items]
Total Revenue	$ 679	649	$ 2,200	1,991
Amount of change in revenue	$ 30		$ 209
Percentage of change in revenue	5.00%		10.00%
Recorded Music | Artist Services and Expanded-Rights
Disaggregation of Revenue [Line Items]
Total Revenue	$ 158	85	$ 458	264
Amount of change in revenue	$ 73		$ 194
Percentage of change in revenue	86.00%		73.00%
Recorded Music | Licensing
Disaggregation of Revenue [Line Items]
Total Revenue	$ 76	68	$ 229	242
Amount of change in revenue	$ 8		$ (13)
Percentage of change in revenue	12.00%		(5.00%)
Music Publishing
Disaggregation of Revenue [Line Items]
Total Revenue	$ 147	159	$ 470	476
Amount of change in revenue	$ (12)		$ (6)
Percentage of change in revenue	(8.00%)		(1.00%)
Music Publishing | Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenue	$ 71	69	$ 219	220
Amount of change in revenue	$ 2		$ (1)
Percentage of change in revenue	3.00%		0.00%
Music Publishing | Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenue	$ 76	90	$ 251	256
Amount of change in revenue	$ (14)		$ (5)
Percentage of change in revenue	(16.00%)		(2.00%)
Music Publishing | Performance
Disaggregation of Revenue [Line Items]
Total Revenue	$ 36	51	$ 135	153
Amount of change in revenue	$ (15)		$ (18)
Percentage of change in revenue	(29.00%)		(12.00%)
Music Publishing | Digital
Disaggregation of Revenue [Line Items]
Total Revenue	$ 65	59	$ 195	169
Amount of change in revenue	$ 6		$ 26
Percentage of change in revenue	10.00%		15.00%
Music Publishing | Mechanical
Disaggregation of Revenue [Line Items]
Total Revenue	$ 13	17	$ 41	55
Amount of change in revenue	$ (4)		$ (14)
Percentage of change in revenue	(24.00%)		(25.00%)
Music Publishing | Synchronization
Disaggregation of Revenue [Line Items]
Total Revenue	$ 29	28	$ 89	90
Amount of change in revenue	$ 1		$ (1)
Percentage of change in revenue	4.00%		(1.00%)
Music Publishing | Other
Disaggregation of Revenue [Line Items]
Total Revenue	$ 4	$ 4	$ 10	$ 9
Amount of change in revenue	$ 0		$ 1
Percentage of change in revenue	0.00%		11.00%