Retirement Benefits - Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Plan | Global Redesign
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Cost (Credit)		$ 156	$ 268
Worldwide OPEB
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 42	49	47
Interest cost	146	127	169
Expected return on assets	0	0	0
Amortization of prior service costs/(credits)	(3)	(12)	(16)
Net remeasurement (gain)/loss	(1,314)	(376)	556
Defined Benefit Plan, Other Cost (Credit)	0	0	0
Settlements and curtailments	(1)	0	(2)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(1,130)	(212)	754
Non-U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	416	557	529
Interest cost	504	420	514
Expected return on assets	(1,006)	(1,130)	(1,067)
Amortization of prior service costs/(credits)	22	24	32
Net remeasurement (gain)/loss	(436)	(3,241)	499
Defined Benefit Plan, Other Cost (Credit)	63	156	226
Settlements and curtailments	(2)	(2)	103
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(439)	(3,216)	836
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement			(61)
Non-U.S. Plans | Pension Plan | Global Redesign
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain(Loss) Due to Curtailments and Other	57
U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	500	526	520
Interest cost	1,054	928	1,291
Expected return on assets	(2,569)	(2,728)	(2,795)
Amortization of prior service costs/(credits)	2	2	4
Net remeasurement (gain)/loss	1,720	(254)	377
Defined Benefit Plan, Other Cost (Credit)	46	19	35
Settlements and curtailments	438	70	5
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	1,191	(1,437)	$ (563)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	$ (438)	$ (70)