Additional Financial Information (Details) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2025 USD ($) $ / shares	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2025 USD ($) $ / shares	Mar. 31, 2024 USD ($) $ / shares
Dividends Payable [Line Items]
Interest payments	$ 53	$ 57	$ 71	$ 90
Income and withholding taxes paid	58	33	101	72
Noncash acquisition activities			34	18
Net gain on divestitures	$ 0	$ 14	0	$ 31
Pre-tax realized net gain on sale of an investment			$ 29
Debt instrument, covenant, total indebtedness to EBITDA ratio	3.50		3.50
Dividends (in dollars per share) \| $ / shares	$ 0.18	$ 0.17	$ 0.36	$ 0.34
Dividends paid	$ 95		$ 189	$ 178
Dividends paid (in dollars per share) \| $ / shares	$ 0.18		$ 0.36
Class A Common Stock
Dividends Payable [Line Items]
Dividends (in dollars per share) \| $ / shares	0.18
Class B Common Stock
Dividends Payable [Line Items]
Dividends (in dollars per share) \| $ / shares	$ 0.18

Aggregate dividends paid during the period for each share of common stock outstanding.

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