Restructuring Plan Employee Severance and Other Exit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 0	$ 2	$ 0
Restructuring Reserve, Period Increase (Decrease)	3	13
Payments for Restructuring	$ 5	$ 11