Federal Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Line Items]
Federal rate		35.00%
Deferred tax impact from the Tax Cut and Jobs Act		$ (1,322,000,000)
Dividends-received deduction		264,000,000	$ 182,000,000	$ 192,000,000
Valuation allowance		0
Unrecognized tax benefits, that, if recognized, would impact income tax expense and effective tax rate		11,000,000	1,000,000
Recognized interest and penalty expense related to uncertain tax positions		0	(3,000,000)	$ 0
Accrued interest and penalty expense related to unrecognized tax benefits		0	$ 0
Scenario, Forecast [Member]
Income Tax [Line Items]
Federal rate	21.00%
Alternative Minimum [Member]
Income Tax [Line Items]
Tax Credit Carryforward, Amount		73,000,000
Research And Development Credits [Member]
Income Tax [Line Items]
Tax Credit Carryforward, Amount		$ 3,000,000