Costs Associated with Exit and Restructuring - Liabilities Related to Exit and Restructuring Activities Included in the Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 8	$ 10	$ 15
Accrued liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	6	7
Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 2	$ 3