Income Tax Level 4 Income tax expense (benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
Deferred Federal Income Tax Expense (Benefit)	$ 72	$ (6)	$ 523
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	2	36	(339)
Income Tax Expense (Benefit)	$ 74	$ 30	$ 184