Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax expense	$ 873	$ 314	$ 1,439	$ 708
Effective tax rate	27.70%	21.60%	27.50%	20.80%
Income taxes payable	$ (978)		$ (978)
Income taxes receivable					$ 335