Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of period	$ 923	$ 952
Tax positions of prior periods netted against deferred tax assets	(49)	(32)
Increase in tax positions taken in the prior period	0	0
Increase in tax positions taken in the current period	4	4
Decrease due to settlement/payments	(2)	(1)
Decrease from the lapse of statute of limitations	0	0
Unrecognized tax benefits at end of period	$ 876	$ 923