Additional Financial Information - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Nov. 09, 2023 $ / shares
Supplemental Cash Flow Information [Line Items]
Interest payments	$ 157	$ 122	$ 137
Foreign income and withholding taxes	219	141	124
Net gain on divestiture	41	0	0
Dividends paid	$ 340	318	$ 265
Noncash investing activities related to acquisition of music publishing rights and music catalogs		$ 125
Class A Common Stock | Subsequent Event
Supplemental Cash Flow Information [Line Items]
Dividends payable, amount per share (in dollars per share) | $ / shares				$ 0.17
Common Class B | Subsequent Event
Supplemental Cash Flow Information [Line Items]
Dividends payable, amount per share (in dollars per share) | $ / shares				$ 0.17
Revolving Credit Facility | Line of Credit
Supplemental Cash Flow Information [Line Items]
Debt instrument, covenant, total indebtedness to EBITDA ratio	3.50