Company Restructuring - Changes in the restructuring liability (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Restructuring Reserve
Restructuring liability as of December 31, 2018	$ 44
Expense incurred	50
Adjustments to liability	(9)
Payments and non-cash pension settlements	(63)
Restructuring liability as of December 31, 2019	22
Employee costs
Restructuring Reserve
Restructuring liability as of December 31, 2018	29
Expense incurred	43
Adjustments to liability	(9)
Payments and non-cash pension settlements	(49)
Restructuring liability as of December 31, 2019	14
Exit costs
Restructuring Reserve
Restructuring liability as of December 31, 2018	15
Expense incurred	7
Adjustments to liability	0
Payments and non-cash pension settlements	(14)
Restructuring liability as of December 31, 2019	$ 8