Restructuring of Operations - Additional Information (Details) $ in Millions		3 Months Ended		9 Months Ended
	Sep. 30, 2015 employee	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 1	$ 2	$ 13	$ 14
Estimated reduction of employees | employee	100
Restructuring and related activities, completion date period	2 years
Employee Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			1	11	9
Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 1	$ 1	$ 2	$ 5