Taxes on Income - Current and Deferred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure
Federal	$ 8	$ 21	$ 258
State	0	0	32
Current Income Tax Expense (Benefit)	8	21	290
Federal	(11)	17	(130)
State	(10)	14	22
Deferred income taxes	(21)	31	(108)
Total income tax expense	$ (13)	$ 52	$ 182