Restructuring Programs - Restructuring and Related Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 102
Number of employees transferred | employee	2,200
Payments for restructuring related costs	$ 65
Restructuring payments	93	$ 169	$ 220
Restructuring related costs	37
Retention Related Severance Bonuses
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	39
Contractual Severance Costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	43
Consulting and Other Costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 20