Pension Plans and Other Post Employment Benefit Plans Change in Projected Benefit Obligations, Plan Assets and Funded Status (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 01, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan					$ 5,800
Defined Benefit Plan, Accumulated Benefit Obligation		$ 21,600	$ 21,000
Trust Agreement [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period		294
Benefit obligation at end of the period		249	294
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period		21,004	23,532
Service Cost		26	41	$ 136
Interest Cost		559	769	755
Plan participants' contributions		2	2
Actuarial (gain) loss		1,659	2,469
Benefits Paid		(1,538)	(1,635)
Plan amendments		(3)	(76)
Net effects of acquisitions / divestitures / other		0	(1)
Effect of foreign exchange rates		(27)	(60)
Change in Benefit Obligation - Impact of Internal Reorganizations		0	(4,037)
Benefit obligation at end of the period		21,682	21,004	23,532
Fair value of plan assets at beginning of period		16,941	18,951
Actual return on plan assets		2,404	2,552
Employer contributions		62	121
Plan participants' contributions		2	2
Benefits paid		(1,538)	(1,635)
Net effects of acquisitions / divestitures / other		0	(6)
Effect of foreign exchange rates		(36)	(38)
Change in Plan Assets - Impact of Internal Reorganizations		0	(3,006)
Fair value of plan assets at end of period		17,835	16,941	18,951
Funded (unfunded) status of plan		(3,847)	(4,063)
Pension Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		(3,301)	(3,535)
Pension Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		(98)	(90)
Pension Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan	[1],[2]	(448)	(438)
Other Post Employment Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at beginning of the period		2,591	2,514
Service Cost		2	4	9
Interest Cost		66	84	85
Plan participants' contributions		34	37
Actuarial (gain) loss		59	211
Benefits Paid		(241)	(239)
Plan amendments		(939)	0
Net effects of acquisitions / divestitures / other		0	0
Effect of foreign exchange rates		(1)	0
Change in Benefit Obligation - Impact of Internal Reorganizations		0	(20)
Benefit obligation at end of the period		1,571	2,591	2,514
Fair value of plan assets at beginning of period		0	0
Actual return on plan assets		0	0
Employer contributions		207	202
Plan participants' contributions		34	37
Benefits paid		(241)	(239)
Net effects of acquisitions / divestitures / other		0	0
Effect of foreign exchange rates		0	0
Change in Plan Assets - Impact of Internal Reorganizations		0	0
Fair value of plan assets at end of period		0	0	$ 0
Funded (unfunded) status of plan		(1,571)	(2,591)
Other Post Employment Benefits Plan | U.S. Plans with Plan Assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		0	0
Other Post Employment Benefits Plan | Non-U.S. plans with plan assets [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan		0	0
Other Post Employment Benefits Plan | All other plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan	[1],[2]	$ (1,571)	$ (2,591)

[1] As of December 31, 2020, and December 31, 2019, $249 million and $294 million, respectively, of the benefit obligations are supported by funding under the Trust agreement, defined in the "Trust Assets" section below.

[2] Includes pension plans maintained around the world where funding is not customary.