Revenue Recognition - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,864	$ 1,689	$ 5,436	$ 4,839
Operating Segments \| U.S.
Disaggregation of Revenue [Line Items]
Total revenues	781	722	2,291	2,085
Operating Segments \| International
Disaggregation of Revenue [Line Items]
Total revenues	1,084	968	3,149	2,758
Intersegment eliminations
Disaggregation of Revenue [Line Items]
Total revenues	(1)	(1)	(4)	(4)
Recorded Music \| Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	1,488	1,354	4,348	3,874
Recorded Music \| Operating Segments \| U.S.
Disaggregation of Revenue [Line Items]
Total revenues	587	536	1,729	1,565
Recorded Music \| Operating Segments \| International
Disaggregation of Revenue [Line Items]
Total revenues	901	818	2,619	2,309
Recorded Music \| Operating Segments \| Total digital and physical
Disaggregation of Revenue [Line Items]
Total revenues	1,153	1,048	3,393	3,040
Recorded Music \| Operating Segments \| Digital
Disaggregation of Revenue [Line Items]
Total revenues	1,016	929	2,967	2,643
Recorded Music \| Operating Segments \| Physical
Disaggregation of Revenue [Line Items]
Total revenues	137	119	426	397
Recorded Music \| Operating Segments \| Artist services and expanded-rights
Disaggregation of Revenue [Line Items]
Total revenues	224	195	619	508
Recorded Music \| Operating Segments \| Licensing
Disaggregation of Revenue [Line Items]
Total revenues	111	111	336	326
Music Publishing \| Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	377	336	1,092	969
Music Publishing \| Operating Segments \| U.S.
Disaggregation of Revenue [Line Items]
Total revenues	194	186	562	520
Music Publishing \| Operating Segments \| International
Disaggregation of Revenue [Line Items]
Total revenues	183	150	530	449
Music Publishing \| Operating Segments \| Digital
Disaggregation of Revenue [Line Items]
Total revenues	235	204	674	599
Music Publishing \| Operating Segments \| Performance
Disaggregation of Revenue [Line Items]
Total revenues	59	58	181	167
Music Publishing \| Operating Segments \| Mechanical
Disaggregation of Revenue [Line Items]
Total revenues	19	16	54	46
Music Publishing \| Operating Segments \| Synchronization
Disaggregation of Revenue [Line Items]
Total revenues	60	54	170	142
Music Publishing \| Operating Segments \| Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 4	$ 4	$ 13	$ 15