Income Tax Level 4 Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	May 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		$ 6	$ 23
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 21	98	132	$ 125
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	(12)	(37)	(102)	(76)
Income Tax Reconciliation, Deductions, Foreign Investments	(3)	(4)	(7)	(7)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	3	2	3	1
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	0	0	0	31
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act of 2017, Amount	(2)	0	396	0
Income Tax Expense (Benefit)	$ 7	59	422	$ 74
Loss Contingency Accrual, Insurance-related Assessment, Premium Tax Offset		4	11
Guaranty Liabilities		$ 8	$ 8