Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary of unrecognized income tax benefits
Unrecognized tax benefits balance at beginning of year	$ 38	$ 37	$ 54
Additions for tax positions of current year	10	6	8
Additions for tax positions of prior years	0	1	0
Reductions for tax positions of prior years	(2)	0	(3)
Reductions for settlements of tax positions	0	0	(2)
Reductions for lapses in statutes of limitations	(6)	(6)	(20)
Unrecognized tax benefits balance at end of year	$ 40	$ 38	$ 37