Other Intangible Assets Level 4 - Other Intangible Assets Gross/Net (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	May 31, 2018	Sep. 30, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-Lived Intangible Assets, Gross	$ 29		$ 29		$ 29
Finite-Lived Intangible Assets, Accumulated Amortization	2		2		2
Finite-Lived Intangible Assets, Net	27		27		$ 27
Finite-Lived Intangible Asset, Useful Life					5 years
Indefinite-lived Intangible Assets (Excluding Goodwill)	26		26		$ 26
Intangible Assets, Gross (Excluding Goodwill)	55		55		55
Amortization of Intangible Assets	2	$ 0	2	$ 0		$ 0
Other Intangible Assets, Net	$ 53		$ 53		$ 53