Revenue Recognition - Summary of Disaggregation of Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total Revenues	$ 1,250	$ 1,071	$ 2,585	$ 2,327
Intersegment eliminations
Disaggregation of Revenue [Line Items]
Total Revenues	(1)	(2)	(2)	(3)
Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenues	565	467	1,137	1,001
Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenues	686	606	1,450	1,329
Recorded Music
Disaggregation of Revenue [Line Items]
Total Revenues	1,059	907	2,220	1,991
Recorded Music | Operating Segments
Disaggregation of Revenue [Line Items]
Total Revenues	1,059	907	2,220	1,991
Recorded Music | Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenues	469	380	950	833
Recorded Music | Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenues	590	527	1,270	1,158
Recorded Music | Digital
Disaggregation of Revenue [Line Items]
Total Revenues	756	626	1,483	1,259
Recorded Music | Physical
Disaggregation of Revenue [Line Items]
Total Revenues	118	94	292	278
Recorded Music | Total Digital and Physical
Disaggregation of Revenue [Line Items]
Total Revenues	874	720	1,775	1,537
Recorded Music | Artist services and expanded-rights
Disaggregation of Revenue [Line Items]
Total Revenues	118	115	298	303
Recorded Music | Licensing
Disaggregation of Revenue [Line Items]
Total Revenues	67	72	147	151
Music Publishing
Disaggregation of Revenue [Line Items]
Total Revenues	192	166	367	339
Music Publishing | Operating Segments
Disaggregation of Revenue [Line Items]
Total Revenues	192	166	367	339
Music Publishing | Operating Segments | U.S.
Disaggregation of Revenue [Line Items]
Total Revenues	96	87	187	168
Music Publishing | Operating Segments | International
Disaggregation of Revenue [Line Items]
Total Revenues	96	79	180	171
Music Publishing | Digital
Disaggregation of Revenue [Line Items]
Total Revenues	104	74	203	147
Music Publishing | Performance
Disaggregation of Revenue [Line Items]
Total Revenues	35	41	65	87
Music Publishing | Mechanical
Disaggregation of Revenue [Line Items]
Total Revenues	12	15	23	30
Music Publishing | Synchronization
Disaggregation of Revenue [Line Items]
Total Revenues	38	34	71	70
Music Publishing | Other
Disaggregation of Revenue [Line Items]
Total Revenues	$ 3	$ 2	$ 5	$ 5