Restructuring Reserve (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring reserve - beginning balance	$ 141
Cash payments	(78)
Restructuring reserve - ending balance	63
Employee separation costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve - beginning balance	38
Cash payments	(37)
Restructuring reserve - ending balance	1
Exit and disposal costs
Restructuring Cost and Reserve [Line Items]
Restructuring reserve - beginning balance	103
Cash payments	(41)
Restructuring reserve - ending balance	$ 62