v3.22.0.1
Retirement-Related Benefits - Net Periodic Cost (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 1,438 $ 1,235 $ 700
Nonpension Postretirement Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Total net periodic pension / nonpension (income)/cost of defined benefit plans 172 202 218
U.S. | Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Interest cost $ 1,109 $ 1,501 $ 1,882
Interest cost - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Expected return on plan assets $ (1,802) $ (2,169) $ (2,599)
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of transition assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ 16 $ 16 $ 16
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 996 $ 829 $ 559
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Curtailments and settlements - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 319 $ 178 $ (142)
U.S. | Nonpension Postretirement Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Service cost 7 9 10
Interest cost $ 65 $ 103 $ 145
Interest cost - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of transition assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ 4 $ 4 $ (2)
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 52 $ 29 $ 1
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Curtailments and settlements - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 127 $ 145 $ 154
Non-U.S. | Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Service cost 300 328 304
Interest cost $ 424 $ 541 $ 814
Interest cost - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Expected return on plan assets $ (1,115) $ (1,229) $ (1,530)
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of transition assets     $ 0
Amortization of transition assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ (12) $ (9) $ (25)
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 1,392 $ 1,336 $ 1,190
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Curtailments and settlements $ 94 $ 49 $ 38
Curtailments and settlements - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Multi-employer plans $ 17 $ 23 $ 23
Other costs/(credits) 18 18 28
Total net periodic pension / nonpension (income)/cost of defined benefit plans 1,119 1,057 842
Non-U.S. | Nonpension Postretirement Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Service cost 4 4 4
Interest cost $ 27 $ 35 $ 54
Interest cost - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Expected return on plan assets $ (3) $ (4) $ (5)
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of transition assets - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ 0 $ 0 $ 0
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 15 $ 21 $ 10
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Curtailments and settlements $ 0 $ 0 $ 0
Curtailments and settlements - income statement location Other (income) and expense Other (income) and expense Other (income) and expense
Other costs/(credits) $ 0 $ 0  
Total net periodic pension / nonpension (income)/cost of defined benefit plans 44 57 $ 64
Personal Pension Plan (PPP) | Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Total net periodic pension / nonpension (income)/cost of defined benefit plans 1,422 1,224 689
Personal Pension Plan (PPP) | U.S. | Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Total net periodic pension / nonpension (income)/cost of defined benefit plans 303 167 (153)
Personal Pension Plan (PPP) | Non-U.S. | Pension Plans      
Components of net periodic (income)/cost of the retirement-related benefit plans      
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 1,119 $ 1,057 $ 842