v3.22.0.1
Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 1 Months Ended 12 Months Ended
Apr. 30, 2021
Dec. 31, 2020
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Settlements     $ 584 $ 199 $ 0
Pension benefits​          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Service cost     21 21 3
Interest cost     63 108 4
Expected return on plan assets     (110) (170) (5)
Amortization of net actuarial loss     94 123 3
Amortization of prior service benefit     0 0 0
Settlements     584 199 0
Net periodic benefit cost     652 281 $ 5
Settlements     1,051 542  
Pension benefits​ | United States          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Settlements     (549)    
Net periodic benefit cost     653 220  
Settlements $ (995) $ (240)      
Defined benefit plan, plan assets, transfer of plan assets $ (1,007) $ (245)      
Defined Benefit Plan, Net Periodic Benefit Cost Lump Sum Benefits     35    
Other postretirement benefits          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Service cost     6 5  
Interest cost     11 13  
Expected return on plan assets     0 0  
Amortization of net actuarial loss     8 8  
Amortization of prior service benefit     (6) (4)  
Settlements     0 0  
Net periodic benefit cost     19 22  
Settlements     $ 0 $ 0