Income Taxes Level 4 (Details) - Components of Income Tax Expense - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current [Abstract]
State and local	$ 2	$ 2	$ 2
Foreign	19	34	25
Total current	21	36	27
Deferred [Abstract]
Federal	(5)	0	0
State and local	0	(1)	0
Foreign	2	3	7
Total deferred	(3)	2	7
Income tax expense	$ 18	$ 38	$ 34
Federal Statutory Income Tax Rate	35.00%