Income Taxes (Provision (Benefit) For Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 1	$ 11	$ (12)
State	(3)	10	1
Total	(2)	21	(11)
Deferred:
Federal	(1,697)	501	408
State	(304)	2	88
Foreign	(2)	1	1
Total	(2,003)	504	497
Provision (Benefit) for Income Taxes	$ (2,005)	$ 525	$ 486