Restructuring of Operations - Additional Information (Details) $ in Millions		12 Months Ended
	Dec. 31, 2015 employee	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 15	$ 21	$ 24
Discontinued operations charges				1
Estimated reduction of employees | employee	100
Employee Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		12	15	$ 14
Discontinued operations charges
Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 3	$ 6	$ 10
Discontinued operations charges				$ 1