v3.22.1
Accumulated Other Comprehensive Income​ (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2022
Mar. 31, 2021
AOCI Attributable to Parent [Abstract]    
Balance at beginning of period $ 1,559 $ 1,447
Other comprehensive income:    
Total Other comprehensive loss, net of tax (19) (4)
Balance at end of period 1,561 1,490
Pension and other postretirement benefits    
AOCI Attributable to Parent [Abstract]    
Balance at beginning of period (1,121) (1,791)
Other comprehensive income:    
Other Comprehensive Income (Loss), before Reclassifications, before Tax 55 (1)
Other Comprehensive Income (Loss) before Reclassifications, Tax (12) 0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax 43 (1)
Amortization of net actuarial loss and prior service cost 20 33
Tax expense (5) (7)
Total amount reclassified from Accumulated other comprehensive loss, net of tax 15 26
Total Other comprehensive loss, net of tax 58 25
Balance at end of period (1,063) (1,766)
Foreign currency translation    
AOCI Attributable to Parent [Abstract]    
Balance at beginning of period 25 29
Other comprehensive income:    
Total Other comprehensive loss, net of tax (7) (7)
Balance at end of period 18 22
Cash flow hedges    
AOCI Attributable to Parent [Abstract]    
Balance at beginning of period (15) 1
Other comprehensive income:    
Other Comprehensive Income (Loss), before Reclassifications, before Tax (143) (35)
Other Comprehensive Income (Loss) before Reclassifications, Tax 33 8
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax (110) (27)
Amortization of net actuarial loss and prior service cost 53 7
Tax expense (13) (2)
Total amount reclassified from Accumulated other comprehensive loss, net of tax 40 5
Total Other comprehensive loss, net of tax (70) (22)
Balance at end of period (85) (21)
Accumulated other comprehensive loss    
AOCI Attributable to Parent [Abstract]    
Balance at beginning of period (1,111) (1,761)
Other comprehensive income:    
Total Other comprehensive loss, net of tax (19) (4)
Balance at end of period $ (1,130) $ (1,765)