Income Taxes, Change in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized Tax Benefits [Roll Forward]
Balance as of beginning of year	$ 847	$ 897	$ 970
Additions for tax positions related to the current year	3	5	19
Additions for tax positions related to prior years	13	9	30
Reductions for tax positions related to prior years	(25)	(20)	(101)
Reductions for tax positions related to the lapse of applicable statute of limitations	0	(44)	(14)
Settlements	(22)	0	(7)
Balance as of end of year	$ 816	$ 847	$ 897