Changes in Accumulated Other Comprehensive Income Level 4 (Details) - Summary of Changes in Accumulated Other Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (8)	$ (39)
Beginning Balance Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, After Tax	1	3
Beginning Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(9)	(42)
Other comprehensive income before reclassifications, net of tax	14	6
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	14	6
Ending Balance Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, After Tax	1	3
Ending Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	5	(36)
Ending Balance	$ 6	$ (33)