Restructuring Programs - Restructuring and Related Costs (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) employee	Dec. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 6	$ 102
Restructuring payments	81	$ 93	$ 169
H C L Technologies
Restructuring Cost and Reserve [Line Items]
Number of employees transferred | employee		2,200
Restructuring payments	26	$ 65
Restructuring related costs	21	37
Retention Related Severance Bonuses
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	4	39
Contractual Severance Costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	(2)	43
Contractual Severance Costs | H C L Technologies
Restructuring Cost and Reserve [Line Items]
Related restructuring costs		38
Consulting and Other Costs
Restructuring Cost and Reserve [Line Items]
Related restructuring costs	$ 4	$ 20