Income Taxes (Schedule Of The Provision For (Benefit From) Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ 231	$ 8	$ 225
State	18	9	24
Foreign	27	20	9
Total Current	276	37	258
Deferred
Federal	(557)	136	30
State	25	(33)	3
Foreign	(2)	(2)	7
Total Deferred	(534)	101	40
Provision for (benefit from) income taxes	$ (258)	$ 138	$ 298