Income Taxes - Reconciliation of Change in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gross Unrecognized Tax Benefits
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 451	$ 431	$ 440
Additions for tax positions related to the current year		33	23
Additions for tax positions related to prior years	1	3	12
Reductions for tax positions related to prior years due to IRS and other settlements	(47)	(16)	(44)
Ending balance	405	451	431
Portion of balance at December 31, that, if recognized, would impact the effective income tax rate	143
Accrued Interest and Penalties
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	46	31	35
Additions for tax positions related to the current year		0	17
Additions for tax positions related to prior years	4	21	4
Reductions for tax positions related to prior years due to IRS and other settlements	(36)	(6)	(25)
Ending balance	14	46	31
Portion of balance at December 31, that, if recognized, would impact the effective income tax rate	10
Gross Tax, Interest and Penalties
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	497	462	475
Additions for tax positions related to the current year		33	40
Additions for tax positions related to prior years	5	24	16
Reductions for tax positions related to prior years due to IRS and other settlements	(83)	(22)	(69)
Ending balance	419	$ 497	$ 462
Portion of balance at December 31, that, if recognized, would impact the effective income tax rate	$ 153