Federal Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax [Line Items]
Federal rate	21.00%	35.00%
Dividends-received deduction	$ 84	$ 264	$ 175
Deferred tax impact from the Tax Cut and Jobs Act	(3)	1,526
Tax credit carryforward, valuation allowance	0
Unrecognized tax benefits, that, if recognized, would impact income tax expense and effective tax rate	12	11
Recognized interest and penalty expense related to uncertain tax positions	$ 0	$ 0	$ (2)
Scenario, Plan [Member]
Income Tax [Line Items]
Federal rate	21.00%
Research Tax Credit Carryforward [Member]
Income Tax [Line Items]
Tax credit carryforward	$ 1,300