Income Taxes - Income Tax Provision (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current income tax expense
U.S. federal		$ 0	$ (1)	$ 13
U.S. state and local		(4)	0	(5)
Non-U.S.		73	98	58
Total current		69	97	66
Deferred income tax expense
U.S. federal		(16)	(1)	115
U.S. state and local		31	13	6
Non-U.S.		27	(4)	7
Total deferred		42	8	128
Total income tax provision	$ (240)	$ 111	$ 105	$ 194