Related Party Transactions (Details) € in Millions, £ in Millions, $ in Millions			12 Months Ended
	Apr. 13, 2022 EUR (€) shares	Jan. 01, 2015 GBP (£)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 26, 2023
Related Party Transaction [Line Items]
Remaining lease term			6 years	6 years
Extended lease term			10 years
Revenue			$ 6,707	$ 6,426	$ 6,037
I2PO
Related Party Transaction [Line Items]
Business acquisition, number of shares acquired (in shares) | shares	900,000
Final purchase price | €	€ 9
Fair value of equity interests			7	8
Warner and Chappell Music Limited and WMG Acquisition Limited
Related Party Transaction [Line Items]
Extended lease term		5 years				5 years
Payments for rent | £		£ 3
Deezer | Streaming Service License
Related Party Transaction [Line Items]
Revenue			45	41	40
Deezer | PEDL And Latin America Licenses
Related Party Transaction [Line Items]
Revenue			2	$ 2	$ 2
Building
Related Party Transaction [Line Items]
Related party transactions, annual rent payments			$ 15
Remaining lease term			5 years
Extended lease term			10 years