Federal Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective tax rate	18.00%	19.00%	24.00%
Federal rate	35.00%
Dividends-received deduction	$ 182	$ 192	$ 163
Unrecognized tax benefits, that, if recognized, would impact income tax expense and effective tax rate	1	13
Recognized interest and penalty expense related to uncertain tax positions	(3)		$ (10)
Accrued interest and penalty expense related to unrecognized tax benefits		$ 3
Alternative Minimum [Member]
Tax Credit Carryforward, Amount	$ 85