Restructuring Programs - Certain Related Costs Incurred in Connection with Restructuring Programs (Details) - 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]
Related restructuring costs	$ 5	$ 19	$ 17	$ 77
Retention related severance/bonuses
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	4	11	11	20
Contractual severance costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	0	0	4	38
Consulting and other costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 1	$ 8	$ 2	$ 19