Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Cumulative costs since program inception	$ 1,200		$ 1,200
Estimate of cumulative pre tax costs that will result in cash outlays			60.00%
Estimate of cumulative pre tax costs that will be noncash			40.00%
Expected restructuring and related cost	2,500		$ 2,500
Total pretax restructuring costs	$ 150	$ 159	$ 318	$ 346
Forecast
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related cost					$ 800