Restructuring - Activities by Program (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 759
Expense	$ 150	$ 159	318	$ 346
(Payments) receipts, net			(491)
Non-cash activity			(92)
Restructuring reserve, ending balance	494		494
Separation Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			690
Expense	35	25	82	153
(Payments) receipts, net			(328)
Non-cash activity			0
Restructuring reserve, ending balance	444		444
Accelerated Depreciation
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			0
Expense	73	98	126	132
(Payments) receipts, net			0
Non-cash activity			(126)
Restructuring reserve, ending balance	0		0
Other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			69
Expense	42	$ 36	110	$ 61
(Payments) receipts, net			(163)
Non-cash activity			34
Restructuring reserve, ending balance	$ 50		$ 50