v3.22.0.1
Accumulated Other Comprehensive (Loss) Income​​ (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period $ 1,447 $ 2,973 $ 2,969
Other comprehensive income (loss):      
Total Other comprehensive income, net of tax 650 146 45
Balance at end of period 1,559 1,447 2,973
Amount related to settlement of certain employee retirement benefits 584 199 0
Accumulated other comprehensive (loss) income      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period (1,761) 295 250
Other comprehensive income (loss):      
Total Other comprehensive income, net of tax 650 146 45
Balance at end of period (1,111) (1,761) 295
Pension and other postretirement benefits      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period (1,791) (43) (32)
Establishment of additional defined benefit plans 0 (1,752) 0
Separation-related adjustments 0 (50) 0
Other comprehensive income (loss):      
Unrecognized net actuarial loss and prior service benefit / Net change from periodic revaluations 190 (259) (16)
Tax (expense) benefit (43) 62 3
Total Other comprehensive income (loss) before reclassifications, net of tax 147 (197) (13)
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings 680 326 3
Tax expense (157) (75) (1)
Total amount reclassified from Accumulated other comprehensive loss, net of tax 523 251 2
Total Other comprehensive income, net of tax 670 54 (11)
Balance at end of period (1,121) (1,791) (43)
Foreign currency translation      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period 29 338 282
Separation-related adjustments 0 (396) 0
Other comprehensive income (loss):      
Total Other comprehensive income (loss) before reclassifications, net of tax (4) 65 56
Total amount reclassified from Accumulated other comprehensive loss, net of tax 0 22 0
Total Other comprehensive income, net of tax (4) 87 56
Balance at end of period 25 29 338
Cash flow hedges      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period 1 0  
Separation-related adjustments 0 (4)  
Other comprehensive income (loss):      
Unrecognized net actuarial loss and prior service benefit / Net change from periodic revaluations (161) (2)  
Tax (expense) benefit 37 1  
Total Other comprehensive income (loss) before reclassifications, net of tax (124) (1)  
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings 140 8  
Tax expense (32) (2)  
Total amount reclassified from Accumulated other comprehensive loss, net of tax 108 6  
Total Other comprehensive income, net of tax (16) 5  
Balance at end of period $ (15) $ 1 $ 0