Income Taxes and Accounting for Uncertainty in Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes and Accounting for Uncertainty in Income Taxes
Unrecognized tax benefits if recognized, could favorably affect our effective tax rate	$ 349
Additional uncertain tax benefits			$ 274
Interest and penalty (credit) expense	16	$ 13	$ 22
Accrued interest and penalties	$ 104	$ 88