Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unfavorable impact in tax provision from change in tax law	$ 0	$ 0	$ 119
Deferred tax asset amount related to accumulated other comprehensive income	1,200	1,000
Investment of U.S. government accounts receivable in the CCF	340	$ 483
Net operating loss carryforwards	989
Tax credit carryforwards	$ 68
Possible chance of tax position sustainable, percentage	50.00%
Tax positions for which it is reasonably possible that the unrecognized tax benefits will significantly increase or decrease	$ 0