Restructuring Actions - Roll Forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
2019 Restructuring Actions
Restructuring Reserve Roll Forward
Expenses incurred	$ 282
Non-cash changes	(76)
Cash payments	(52)
Adjustments	(14)
Restructuring actions balances, Ending Balance	140
2018 Restructuring Actions
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance	84
Expenses incurred		$ 137
Non-cash changes		(12)
Cash payments	(76)	(24)
Adjustments	(5)	(17)
Restructuring actions balances, Ending Balance	3	84
Employee-Related | 2019 Restructuring Actions
Restructuring Reserve Roll Forward
Expenses incurred	242
Non-cash changes	(36)
Cash payments	(52)
Adjustments	(14)
Restructuring actions balances, Ending Balance	140
Employee-Related | 2018 Restructuring Actions
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance	84
Expenses incurred		125
Cash payments	(76)	(24)
Adjustments	(5)	(17)
Restructuring actions balances, Ending Balance	3	84
Employee-Related | 2017 Restructuring Actions
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance	40	88
Expenses incurred			$ 99
Cash payments	(21)	(20)	(8)
Adjustments	1	(28)	(3)
Restructuring actions balances, Ending Balance	20	40	$ 88
Asset-Related | 2019 Restructuring Actions
Restructuring Reserve Roll Forward
Expenses incurred	40
Non-cash changes	$ (40)
Asset-Related | 2018 Restructuring Actions
Restructuring Reserve Roll Forward
Expenses incurred		12
Non-cash changes		$ (12)