Accumulated Other Comprehensive Income Level 4 AOCI Rollforward (Details) - USD ($) $ in Millions		5 Months Ended	7 Months Ended	12 Months Ended
	Jan. 01, 2018	May 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 01, 2018	Dec. 31, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent		$ 5,810	$ 2,005	$ 6,680	$ 7,821	$ 1,767	$ 8,162
OCI, before Reclassifications, Net of Tax, Attributable to Parent			(196)	423	203
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent					(74)
Stockholders' Equity Attributable to Parent		5,810	2,005	6,680	7,821	1,767	8,162
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				182
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance				1,204
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent		774	(173)	1,022	693	0	539
OCI, before Reclassifications, Net of Tax, Attributable to Parent	$ 11	(432)	(198)	428	212
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent		2	25	(99)	(58)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(430)	(173)	329	154
Stockholders' Equity Attributable to Parent		774	(173)	1,022	693	0	539
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance				4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent		(14)	0	4	32	0	57
OCI, before Reclassifications, Net of Tax, Attributable to Parent		(13)	0	(5)	(9)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent		(5)	0	(23)	(16)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(18)	0	(28)	(25)
Stockholders' Equity Attributable to Parent		(14)	0	4	32	0	57
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance				(3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent		(2)	2	(3)	(3)	0	(3)
OCI, before Reclassifications, Net of Tax, Attributable to Parent		1	2	0	0
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent		0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		1	2	0	0
Stockholders' Equity Attributable to Parent		(2)	2	(3)	(3)	0	(3)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				182
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance				1,205
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent		758	(171)	1,023	722	0	593
OCI, before Reclassifications, Net of Tax, Attributable to Parent		(444)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent		3	25	(122)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(447)	(171)	301	129
Stockholders' Equity Attributable to Parent		$ 758	$ (171)	$ 1,023	$ 722	$ 0	$ 593