Restructuring Programs - Certain Related Costs Incurred in Connection with Restructuring Programs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 12	$ 58
Retention related severance/bonuses
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	7	9
Contractual severance costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	4	38
Consulting and other costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 1	$ 11