v3.21.1
Retirement-Related Benefits - Cost of Pension Plans (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Cost/(Income) of Pension Plans    
Total defined benefit and contribution pension plans cost recognized in the Consolidated Income Statement $ 672 $ 584
U.S. | Pension Plans    
Cost/(Income) of Pension Plans    
Interest cost $ 277 $ 375
Interest cost - income statement location Other (income) and expense Other (income) and expense
Expected return on plan assets $ (451) $ (542)
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ 4 $ 4
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 249 $ 207
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 80 $ 44
Cost of defined contribution plans 151 155
Total defined benefit and contribution pension plans cost recognized in the Consolidated Income Statement 231 199
Non-U.S. | Pension Plans    
Cost/(Income) of Pension Plans    
Service cost 92 95
Interest cost $ 111 $ 129
Interest cost - income statement location Other (income) and expense Other (income) and expense
Expected return on plan assets $ (291) $ (309)
Expected return on plan assets - income statement location Other (income) and expense Other (income) and expense
Amortization of prior service costs/(credits) $ (2) $ (5)
Amortization of prior service costs/(credits) - income statement location Other (income) and expense Other (income) and expense
Recognized actuarial losses $ 375 $ 342
Recognized actuarial losses - income statement location Other (income) and expense Other (income) and expense
Curtailments and settlements $ 17 $ 8
Curtailments and settlements - income statement location Other (income) and expense Other (income) and expense
Multi-employer plans $ 8 $ 7
Other costs/(credits) $ 11 $ 5
Other costs/(credits) - income statement location Other (income) and expense Other (income) and expense
Total net periodic pension / nonpension (income)/cost of defined benefit plans $ 322 $ 274
Cost of defined contribution plans 119 110
Total defined benefit and contribution pension plans cost recognized in the Consolidated Income Statement $ 441 $ 385