v3.22.4
Accumulated Other Comprehensive (Loss) Income​​ (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period $ 1,559 $ 1,447 $ 2,973
Other comprehensive income:      
Total Other comprehensive income, net of tax 174 650 146
Balance at end of period 1,357 1,559 1,447
Amount related to settlement of certain employee retirement benefits 47 584 199
Accumulated other comprehensive loss      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period (1,111) (1,761) 295
Other comprehensive income:      
Total Other comprehensive income, net of tax 174 650 146
Balance at end of period (937) (1,111) (1,761)
Pension and other postretirement benefits      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period (1,121) (1,791) (43)
Establishment of additional defined benefit plans 0 0 (1,752)
Separation-related adjustments 0 0 (50)
Other comprehensive income:      
Unrecognized net actuarial loss and prior service benefit / Net change from periodic revaluations 176 190 (259)
Tax (expense) benefit (41) (43) 62
Total Other comprehensive income (loss) before reclassifications, net of tax 135 147 (197)
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings 124 680 326
Tax expense (30) (157) (75)
Total amount reclassified from Accumulated other comprehensive loss, net of tax 94 523 251
Total Other comprehensive income, net of tax 229 670 54
Balance at end of period (892) (1,121) (1,791)
Foreign currency translation      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period 25 29 338
Separation-related adjustments 0 0 (396)
Other comprehensive income:      
Total Other comprehensive income (loss) before reclassifications, net of tax (76) (4) 65
Total amount reclassified from Accumulated other comprehensive loss, net of tax 0 0 22
Total Other comprehensive income, net of tax (76) (4) 87
Balance at end of period (51) 25 29
Cash flow hedges      
AOCI Attributable to Parent [Abstract]      
Balance at beginning of period (15) 1 0
Separation-related adjustments 0 0 (4)
Other comprehensive income:      
Unrecognized net actuarial loss and prior service benefit / Net change from periodic revaluations 95 (161) (2)
Tax (expense) benefit (22) 37 1
Total Other comprehensive income (loss) before reclassifications, net of tax 73 (124) (1)
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings (67) 140 8
Tax expense 15 (32) (2)
Total amount reclassified from Accumulated other comprehensive loss, net of tax (52) 108 6
Total Other comprehensive income, net of tax 21 (16) 5
Balance at end of period 6 (15) 1
Cash flow hedges | Aluminum Contract      
Other comprehensive income:      
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings 48 (142) (8)
Cash flow hedges | Energy Related Derivative      
Other comprehensive income:      
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings 20 0 0
Cash flow hedges | Commodity Contract      
Other comprehensive income:      
Amortization of net actuarial loss and prior service benefit / Net amount reclassified to earnings $ (1) $ 2 $ 0