Investment Holding Level 4 Repurchase Agreements, Dollar Roll Transactions and Other (Details) - USD ($) $ in Millions	3 Months Ended	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2016	May 31, 2018	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 01, 2018
Assets Sold under Agreements to Repurchase [Line Items]
Securities Loaned, Gross			$ 277	$ 277	$ 674
Securities Loaned, Collateral, Obligation to Return			284	284	689
Securities Sold under Agreements to Repurchase, Gross			186	186	202
Securities Sold Under Agreements to Repurchase, Collateral, Obligation to Return			190	190	206
Securities Sold under Agreements to Repurchase, Fair Value of Collateral			25	25	0
Securities Received as Collateral			76	76
Interest-bearing Deposit Liabilities, Domestic			23	23	22
Equity Method Investments			894	$ 894
Aggregate Investment Loss Percentage of Company's Pre Tax Consolidated Net Income Minimum				10.00%
Assets			150,146	$ 150,146	168,732		$ 162,284
Liabilities			148,141	148,141	162,052		$ 160,517
Net Investment Income		$ 520	509		1,281	$ 1,373
Net Income (Loss) Attributable to Parent		$ 94	409		(46)	282
Limited Partner [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Outstanding Commitments to Fund Limited Partnership and Other Alternative Investments			478	478
Assets			132,700	132,700	161,100
Liabilities			28,600	28,600	46,500
Net Investment Income				653	1,800	$ 900
Net Income (Loss) Attributable to Parent	$ 7,400			8,900	8,100
Excluded from Balance Sheet [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Received as Collateral			$ 1	$ 1	$ 1