v3.25.1
Shareholders' Equity - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance $ 10,332 $ 9,797
Other comprehensive income (loss) before reclassifications (6) 18
Amounts reclassified from accumulated other comprehensive income (loss) (4)  
Net other comprehensive (loss) income (10) 18
Ending balance 10,534 10,007
Employee Benefit Plan Funded Status    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance (95) (96)
Other comprehensive income (loss) before reclassifications 0 0
Amounts reclassified from accumulated other comprehensive income (loss) 0  
Net other comprehensive (loss) income 0 0
Ending balance (95) (96)
Amortization of Prior Service Cost    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 1 1
Other comprehensive income (loss) before reclassifications 0 0
Amounts reclassified from accumulated other comprehensive income (loss) 0  
Net other comprehensive (loss) income 0 0
Ending balance 1 1
Amortization of Actuarial Loss    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 74 74
Other comprehensive income (loss) before reclassifications 0 0
Amounts reclassified from accumulated other comprehensive income (loss) 0  
Net other comprehensive (loss) income 0 0
Ending balance 74 74
Gain (Loss) on Cash Flow Hedges    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 30 (9)
Other comprehensive income (loss) before reclassifications (8) 19
Amounts reclassified from accumulated other comprehensive income (loss) 0  
Net other comprehensive (loss) income (8) 19
Ending balance 22 10
Gain (Loss) on Fixed-Income Securities    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 2 4
Other comprehensive income (loss) before reclassifications 2 (1)
Amounts reclassified from accumulated other comprehensive income (loss) (4)  
Net other comprehensive (loss) income (2) (1)
Ending balance 0 3
Accumulated Other Comprehensive Income (Loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 12 (26)
Net other comprehensive (loss) income (10) 18
Ending balance $ 2 $ (8)