Income Tax Level 4 Effective Income Tax Rate Reconciliation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 23,000,000	$ 40,000,000
Tax Adjustments, Settlements, and Unusual Provisions	3
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	132,000,000	125,000,000	$ 186,000,000
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	102,000,000	76,000,000	152,000,000
Income Tax Reconciliation, Deductions, Foreign Investments	7,000,000	7,000,000	3,000,000
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	3,000,000	1,000,000	(1,000,000)
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Amount	396,000,000	0	0
Income Tax Expense (Benefit)	422,000,000	74,000,000	30,000,000
Loss Contingency Accrual, Insurance-related Assessment, Premium Tax Offset	11,000,000	15,000,000
Guaranty Liabilities	8,000,000	8,000,000
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	$ 0	$ 31,000,000	$ 0