Restructuring - Narrative (Details) $ in Millions		12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) Positions	Dec. 31, 2018 USD ($) Positions	Dec. 31, 2017 USD ($)
Restructuring Plan, 2019
Restructuring Cost and Reserve [Line Items]
Workforce reduction, positions | Positions		300
Restructuring charges paid		$ 7
Restructuring Plan, 2018
Restructuring Cost and Reserve [Line Items]
Workforce reduction, positions | Positions			160
Restructuring reserves	$ 3		$ 3
Restructuring charges paid	$ 25	22	$ 1
Restructuring Plan, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring reserves				$ 6
Restructuring charges paid		$ 44