Restructuring - Narrative (Details) - Organizational restructuring - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 37		$ 56
Minimum
Restructuring Cost and Reserve [Line Items]
Expected costs	250		250
Maximum
Restructuring Cost and Reserve [Line Items]
Expected costs	300		300
Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 21	$ 55	$ 36	$ 138