Goodwill and Other Intangible Assets - Amortization Expense Related to Amortizable Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Charged to cost of sales	$ 0	$ 0	$ 1	$ 1
Charged to amortization of intangibles	2	3	4	5
Total amortization	$ 2	$ 3	$ 5	$ 6