Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Unrecognized tax benefits:
Balance, January 1		$ 298	$ 245	$ 227
Increases as a result of tax positions taken during the current year		73	32	26
Decreases of tax positions taken during prior years	$ (22)	(61)	(21)	(20)
Increases of tax positions taken during prior years		6	46	40
Decreases as a result of settlements with taxing authorities and the expiration of statutes of limitations		(2)	(2)	(23)
Effect of foreign currency rate movements		0	(2)	(5)
Balance, December 31		$ 314	$ 298	$ 245