Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 552	$ 873	$ 1,061	$ 1,439
Effective tax rate	23.50%	27.70%	23.40%	27.50%
Income taxes receivable	$ 156		$ 156		$ 262