Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Federal, current	$ 773	$ 454	$ 871
State, current	176	51	71
Total current	949	505	942
Federal, deferred	123	(474)	301
State, deferred	10	71	25
Total deferred	133	(403)	326
Income Tax Expense (Benefit), Total	$ 1,082	$ 102	$ 1,268