Company Restructuring - Changes in the restructuring liability (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
Restructuring Reserve
Restructuring liability as of December 31, 2020	$ 72
Expense incurred	145
Adjustments to liability	(23)
Payments and non-cash charges	(130)
Restructuring liability as of June 30, 2021	64
Employee costs
Restructuring Reserve
Restructuring liability as of December 31, 2020	72
Expense incurred	50
Adjustments to liability	(23)
Payments and non-cash charges	(35)
Restructuring liability as of June 30, 2021	64
Exit costs
Restructuring Reserve
Restructuring liability as of December 31, 2020	0
Expense incurred	95
Adjustments to liability	0
Payments and non-cash charges	(95)
Restructuring liability as of June 30, 2021	$ 0