Restructuring Reserve (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020		Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	$ 291	[1]	$ 141
Adjustments	19
Cash payments	(169)		(82)
Restructuring reserve, ending balance	141		59
Employee separation costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	158		38
Adjustments	14
Cash payments	(134)		(38)
Restructuring reserve, ending balance	38		0
Exit and disposal costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	133		103
Adjustments	5
Cash payments	(35)		(44)
Restructuring reserve, ending balance	$ 103		$ 59

[1] The restructuring reserve was zero until the third quarter of 2020.