Income Taxes Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Total Current Provision	$ 162	$ 115	$ 303
Total Deferred (Provision) Benefit	25	(381)	448
(Provision) Benefit for Income Taxes	$ (137)	$ (496)	$ 145