Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits, January 1	$ 1,879	$ 1,422	$ 1,543
Additions based on tax positions related to the current year	352	436	230
Additions based on tax positions related to prior years	111	152	133
Reductions for tax positions of prior years	(181)	(31)	(344)
Reductions due to expiration of statutes of limitations	(107)	(76)	(117)
Settlements with tax authorities and other	(12)	(24)	(23)
Gross unrecognized tax benefits, December 31	$ 2,042	$ 1,879	$ 1,422