Restructuring - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) Positions	Dec. 31, 2015 USD ($) Positions
Restructuring Plan, 2016
Restructuring Cost and Reserve [Line Items]
Workforce reduction, positions | Positions	230
Initial Charge Recorded	$ 30
Restructuring charges paid	7
Restructuring Plan, 2015
Restructuring Cost and Reserve [Line Items]
Workforce reduction, positions | Positions		550
Restructuring reserve reversed	7
Initial Charge Recorded	63	$ 63
Restructuring charges paid	40	13
Restructuring Plan, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring reserve reversed		$ 7
Initial Charge Recorded	$ 86