Pensions And Other Postretirement Benefits - Accumulated Benefit Obligations and Projected Benefit Obligations (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
U.S.
ABO and PBO [Line Items]
ABO	$ 66,448	$ 64,669
Plans with ABO in Excess of Plan Assets [Abstract]
ABO	66,448	64,669
Fair Value of Plan Assets	61,077	59,239
Plans with PBO in Excess of Plan Assets [Abstract]
PBO	66,468	64,684
Fair Value of Plan Assets	61,077	59,239
Non-U.S.
ABO and PBO [Line Items]
ABO	20,721	21,319
Plans with ABO in Excess of Plan Assets [Abstract]
ABO	12,042	10,996
Fair Value of Plan Assets	4,185	3,940
Plans with PBO in Excess of Plan Assets [Abstract]
PBO	12,128	11,079
Fair Value of Plan Assets	$ 4,186	$ 3,940

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Section 50
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Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

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