Retirement Benefits - Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Plan Contributions [Abstract]
Payment for Pension and Other Postretirement Benefits	$ 773
Pension and Other Postretirement Benefit Contributions Unfunded Plans	387
Pension And Other Postretirement Expected Benefit Contributions Unfunded Plans	390
Pension Plan | Minimum
Plan Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	600
Pension Plan | Maximum
Plan Contributions [Abstract]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	800
Pension Plan | U.S. Plans
Change in Benefit Obligation
Benefit obligation at January 1	49,020	$ 45,672
Service cost	526	520	$ 474
Interest cost	928	1,291	1,570
Amendments	0	0
Separation programs/other	(25)	(10)
Curtailments	0	0
Settlements	(1,297)	(25)
Plan participant contributions	20	23
Benefits paid	(2,522)	(3,055)
Foreign exchange translation	0	0
Actuarial (gain)/loss	(1,762)	4,604
Benefit obligation at December 31	44,888	49,020	45,672
Change in Plan Assets
Fair value of plan assets at January 1	48,355	44,253
Actual return on plan assets	1,150	7,018
Company contributions	247	186
Plan participant contributions	20	23
Benefits paid	(2,522)	(3,055)
Settlements	(1,297)	(25)
Foreign exchange translation	0	0
Defined Benefit Plan Other Increase Decrease Plan Assets	(44)	(45)
Fair value of plan assets at December 31	45,909	48,355	44,253
Funded status at December 31	1,021	(665)
Amounts Recognized on the Balance Sheet
Prepaid assets	3,130	1,578
Accrued liabilities	(2,109)	(2,243)
Total	1,021	(665)
Amounts Recognized in Accumulated Other Comprehensive Loss (pre-tax)
Unamortized prior service costs/(credits)	2	4
Pension Plans in which Accumulated Benefit Obligation Exceeds Plan Assets at December 31
Accumulated benefit obligation	2,192	2,295
Fair value of plan assets	140	145
Accumulated Benefit Obligation at December 31	43,879	47,848
Pension Plans in which Projected Benefit Obligation Exceeds Plan Assets at December 31
Projected benefit obligation	2,249	2,389
Fair value of plan assets	140	145
Expected Future Benefit Payments and Amortization
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	2,700
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	2,670
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	2,680
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	2,680
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	2,650
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Year Thereafter	12,805
Pension Plan | U.S. Plans | Alternatives
Change in Plan Assets
Fair value of plan assets at January 1	6,337
Fair value of plan assets at December 31	6,690	6,337
Pension Plan | U.S. Plans | Hedge Funds
Change in Plan Assets
Fair value of plan assets at January 1	3,258
Fair value of plan assets at December 31	3,390	3,258
Pension Plan | U.S. Plans | Private Equity Funds
Change in Plan Assets
Fair value of plan assets at January 1	1,859
Fair value of plan assets at December 31	1,977	1,859
Pension Plan | Non-U.S. Plans
Change in Benefit Obligation
Benefit obligation at January 1	39,835	35,373
Service cost	557	529	506
Interest cost	420	514	691
Amendments	4	0
Separation programs/other	185	219
Curtailments	(4)	0
Settlements	0	(189)
Plan participant contributions	13	14
Benefits paid	(1,565)	(1,394)
Foreign exchange translation	(1,432)	1,131
Actuarial (gain)/loss	(3,581)	3,638
Benefit obligation at December 31	34,432	39,835	35,373
Change in Plan Assets
Fair value of plan assets at January 1	33,820	29,958
Actual return on plan assets	788	4,149
Company contributions	912	744
Plan participant contributions	13	14
Benefits paid	(1,565)	(1,394)
Settlements	0	(189)
Foreign exchange translation	(855)	547
Defined Benefit Plan Other Increase Decrease Plan Assets	(28)	(9)
Fair value of plan assets at December 31	33,085	33,820	29,958
Funded status at December 31	(1,347)	(6,015)
Amounts Recognized on the Balance Sheet
Prepaid assets	5,404	2,673
Accrued liabilities	(6,751)	(8,688)
Total	(1,347)	(6,015)
Amounts Recognized in Accumulated Other Comprehensive Loss (pre-tax)
Unamortized prior service costs/(credits)	170	206
Pension Plans in which Accumulated Benefit Obligation Exceeds Plan Assets at December 31
Accumulated benefit obligation	12,586	14,595
Fair value of plan assets	6,835	7,203
Accumulated Benefit Obligation at December 31	31,850	36,272
Pension Plans in which Projected Benefit Obligation Exceeds Plan Assets at December 31
Projected benefit obligation	13,651	15,951
Fair value of plan assets	6,900	7,264
Expected Future Benefit Payments and Amortization
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	1,490
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	1,350
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	1,360
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	1,380
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1,380
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Year Thereafter	7,035
Pension Plan | Non-U.S. Plans | Alternatives
Change in Plan Assets
Fair value of plan assets at January 1	2,311
Fair value of plan assets at December 31	2,363	2,311
Pension Plan | Non-U.S. Plans | Hedge Funds
Change in Plan Assets
Fair value of plan assets at January 1	1,259
Fair value of plan assets at December 31	1,221	1,259
Pension Plan | Non-U.S. Plans | Private Equity Funds
Change in Plan Assets
Fair value of plan assets at January 1	729
Fair value of plan assets at December 31	756	729
Worldwide OPEB
Change in Benefit Obligation
Benefit obligation at January 1	6,575	6,072
Service cost	49	47	43
Interest cost	127	169	211
Amendments	0	21
Separation programs/other	0	0
Curtailments	0	0
Settlements	0	0
Plan participant contributions	21	21
Benefits paid	(356)	(339)
Foreign exchange translation	0	28
Actuarial (gain)/loss	(376)	556
Benefit obligation at December 31	6,040	6,575	6,072
Change in Plan Assets
Fair value of plan assets at January 1	0	0
Actual return on plan assets	0	0
Company contributions	0	0
Plan participant contributions - Worldwide OPEB	0	0
Benefits paid - Worldwide OPEB	0	0
Settlements	0	0
Foreign exchange translation	0	0
Defined Benefit Plan Other Increase Decrease Plan Assets	0	0
Fair value of plan assets at December 31	0	0	$ 0
Funded status at December 31	(6,040)	(6,575)
Amounts Recognized on the Balance Sheet
Prepaid assets	0	0
Accrued liabilities	(6,040)	(6,575)
Total	(6,040)	(6,575)
Amounts Recognized in Accumulated Other Comprehensive Loss (pre-tax)
Unamortized prior service costs/(credits)	22	$ (11)
Expected Future Benefit Payments and Amortization
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	335
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	330
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	330
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	330
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	330
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Year Thereafter	$ 1,620