Segment Information - Schedule of Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,090	$ 963	$ 2,293	$ 2,008
Operating income	122	83	269	173
Amortization of intangible assets	55	55	109	108
Depreciation of property, plant and equipment	14	14	28	26
OIBDA	191	152	406	307
Operating Segments | Recorded Music
Segment Reporting Information [Line Items]
Revenues	933	791	1,974	1,695
Operating income	134	80	297	209
Amortization of intangible assets	37	38	75	74
Depreciation of property, plant and equipment	9	9	19	17
OIBDA	180	127	391	300
Operating Segments | Music Publishing
Segment Reporting Information [Line Items]
Revenues	158	174	323	317
Operating income	27	41	49	40
Amortization of intangible assets	18	17	34	34
Depreciation of property, plant and equipment	2	2	3	3
OIBDA	47	60	86	77
Corporate Expenses and Eliminations
Segment Reporting Information [Line Items]
Revenues	(1)	(2)	(4)	(4)
Operating income	(39)	(38)	(77)	(76)
Depreciation of property, plant and equipment	3	3	6	6
OIBDA	$ (36)	$ (35)	$ (71)	$ (70)