Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Unrecognized tax benefits:
Balance, January 1		$ 314	$ 298	$ 245
Increases as a result of tax positions taken during the current year		37	73	32
Decreases of tax positions taken during prior years	$ (22)	(53)	(61)	(21)
Increases of tax positions taken during prior years		10	6	46
Decreases as a result of settlements with taxing authorities and the expiration of statutes of limitations		(3)	(2)	(2)
Effect of foreign currency rate movements		(9)	0	(2)
Balance, December 31		$ 296	$ 314	$ 298