Restructuring Charges - Change in Restructuring Liability (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 77
Charge to Earnings	$ 63	$ 56	186	$ 142
Cash Paid			(143)
Non-cash and Other			2
Restructuring reserve, ending balance	122		122
Employee termination costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			57
Charge to Earnings			163
Cash Paid			(126)
Non-cash and Other			0
Restructuring reserve, ending balance	94		94
Asset impairment costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			8
Charge to Earnings			1
Cash Paid			0
Non-cash and Other			0
Restructuring reserve, ending balance	9		9
Facility exit costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			0
Charge to Earnings			2
Cash Paid			(2)
Non-cash and Other			0
Restructuring reserve, ending balance	0		0
Other costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			12
Charge to Earnings			20
Cash Paid			(15)
Non-cash and Other			2
Restructuring reserve, ending balance	$ 19		$ 19