Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of the deferred income tax assets and liabilities
Unrecognized tax benefits		$ 2	$ 14	$ 2	$ 1	$ 1
Unrecognized tax benefits is reasonably possible			$ 2
Unrecognized tax benefits, income tax penalties and interest accrued				0	$ 0
Tax Cuts And Jobs Act Of 2017, Deferred tax asset, provisional income tax benefit	$ 53	514		$ 514
Statutory federal income tax rate expense			21.00%	35.00%	35.00%
Tax Legislation benefit			14.00%	71.80%	(0.00%)
Change in tax rate income tax benefit			$ 53
Deferred tax assets
Deferred reinsurance gain		8	7	$ 8
Other assets		2	1	2
Total deferred tax assets		10	8	10
Deferred tax liabilities
Life and annuity reserves		(269)	(223)	(269)
DAC		(221)	(201)	(221)
Investments		(79)	(131)	(79)
Unrealized net capital gains		(223)	(65)	(223)
Other liabilities		(54)	(51)	(54)
Total deferred tax liabilities		(846)	(671)	(846)
Net deferred tax liability		(836)	(663)	(836)
Components of income tax expense
Current			116	104	$ 24
Deferred			(99)	(382)	120
Total income tax expense (benefit)			17	(278)	144
Income taxes paid			30
Income tax refunds received				1	$ 22
Current income tax receivable		$ 56	$ 78	$ 56
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation
Statutory federal income tax rate - expense			21.00%	35.00%	35.00%
Tax Legislation benefit			14.00%	71.80%	(0.00%)
Tax credits			(3.20%)	(1.70%)	(3.30%)
Dividends received deduction			(0.70%)	(0.60%)	(1.30%)
Adjustments to prior year tax liabilities			(0.30%)	(0.30%)	(0.00%)
State income taxes			1.50%	0.60%	0.30%
Non-deductible expenses			0.00%	0.10%	0.20%
Other			0.10%	0.00%	0.10%
Effective income tax rate expense (benefit)			(4.40%)	38.70%	(31.00%)