Income Taxes (Components of income tax expense and reconciliation of effective tax rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
Federal	$ 47	$ 190	$ 186
Foreign	18	15	10
State and local	58	30	24
Current income tax expense	123	235	220
Deferred
Federal	243	(580)	119
Foreign	3	(2)	(1)
State and local	11	49	5
Deferred income tax expense (benefit)	257	(533)	123
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Computed tax at statutory tax rate	310	367	318
State income taxes, net of federal tax benefit	54	34	21
Non-deductible expenses and other	6	(3)	9
Enactment of the Tax Act	6	(689)	0
Foreign taxes	4	(7)	(5)
Total	$ 380	$ (298)	$ 343