Income Taxes - Change in Reserve for Uncertain Tax Positions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in reserve for uncertain tax positions, excluding related accrued interest and penalties
Beginning balance	$ 303	$ 301	$ 308
Additions for current year tax positions	15	16	23
Additions for prior year tax positions	20	3	32
Reductions for prior year tax positions	(46)	(13)	(45)
Cash settlements	(2)	(2)	(6)
Statute of limitations lapses	(4)	(2)	(11)
Ending balance	$ 286	$ 303	$ 301