Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns
Balance at beginning of year	$ 49	$ 48
Change in tax positions of prior years	3	1
Change in tax positions of current year	0	0
Reduction in tax positions for statute expirations	0	0
Reduction in tax positions for audit settlements	0	0
Balance at end of year	$ 52	$ 49