Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	5 Months Ended	6 Months Ended
	Jun. 30, 2018	May 31, 2018	Jun. 30, 2017	May 31, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 57	$ (31)	$ 112	$ 94	$ 187
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent		(126)	162	(430)	206
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	0	0	(2)	(18)	(9)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		0	0	1	0
OCI, net of tax		(126)	160	(447)	197
Comprehensive income	$ (16)	$ (157)	$ 272	$ (353)	$ 384