v3.25.1
Accumulated Other Comprehensive Income (Loss), Net of Tax - Schedule of Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning Balance $ 16,114 $ 15,477 $ 15,477
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 2 2  
Other Comprehensive Income (Loss), net of tax (3) 10  
Ending Balance 16,370 15,718 16,114
Cash Flow Hedges [Member]      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning Balance 36 3 3
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax (20) 20 42
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 0 (2) (9)
Other Comprehensive Income (Loss), net of tax (20) 18  
Ending Balance 16 21 36
Pension and OPEB Plans [Member]      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning Balance (76) (102) (102)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax 0 0  
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 1 2  
Other Comprehensive Income (Loss), net of tax 1 2  
Ending Balance (75) (100) (76)
Available-for-Sale Securities [Member]      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning Balance (93) (80) (80)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax 15 (12)  
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 1 2  
Other Comprehensive Income (Loss), net of tax 16 (10)  
Ending Balance (77) (90) (93)
AOCI Attributable to Parent [Member]      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning Balance (133) (179) (179)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax (5) 8  
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 2 2  
Other Comprehensive Income (Loss), net of tax (3) 10  
Ending Balance $ (136) $ (169) $ (133)