Restructuring Programs - Certain Related Costs Incurred in Connection with Restructuring Programs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ (4)	$ 12
Retention related severance/bonuses
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	(4)	7
Contractual severance costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	0	4
Consulting and other costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 0	$ 1