v3.26.3
Shareholders' Equity - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Jun. 30, 2025
Mar. 31, 2025
Sep. 30, 2026
Sep. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance $ 11,665 $ 10,837 $ 10,682 $ 10,534 $ 10,332 $ 10,837 $ 10,332
Other comprehensive (loss) income before reclassifications 3   (1)     5 (5)
Amounts reclassified from accumulated other comprehensive income (loss) 1         1 (3)
Net other comprehensive income (loss) 4 2 (1) 3 (10) 6 (8)
Ending balance 11,931 11,037 10,907 10,682 10,534 11,931 10,907
Employee Benefit Plan Funded Status              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance (95) (95) (95)   (95) (95) (95)
Other comprehensive (loss) income before reclassifications 0   0     0 0
Amounts reclassified from accumulated other comprehensive income (loss) 0         0 0
Net other comprehensive income (loss) 0   0     0 0
Ending balance (95)   (95) (95)   (95) (95)
Amortization of Prior Service Cost              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance 1 1 1   1 1 1
Other comprehensive (loss) income before reclassifications 0   0     0 0
Amounts reclassified from accumulated other comprehensive income (loss) 0         0 0
Net other comprehensive income (loss) 0   0     0 0
Ending balance 1   1 1   1 1
Amortization of Actuarial Loss              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance 75 75 75   74 75 74
Other comprehensive (loss) income before reclassifications 0   0     0 0
Amounts reclassified from accumulated other comprehensive income (loss) 1         1 1
Net other comprehensive income (loss) 1   0     1 1
Ending balance 76   75 75   76 75
Gain (Loss) on Cash Flow Hedges              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance 27 26 25   30 26 30
Other comprehensive (loss) income before reclassifications 3   (1)     5 (6)
Amounts reclassified from accumulated other comprehensive income (loss) 0         (1) 0
Net other comprehensive income (loss) 3   (1)     4 (6)
Ending balance 30   24 25   30 24
Gain (Loss) on Fixed-Income Securities              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance 0 (1) (1)   2 (1) 2
Other comprehensive (loss) income before reclassifications 0   0     0 1
Amounts reclassified from accumulated other comprehensive income (loss) 0         1 (4)
Net other comprehensive income (loss) 0   0     1 (3)
Ending balance 0   (1) (1)   0 (1)
Accumulated Other Comprehensive Income (Loss)              
AOCI Attributable to Parent, Net of Tax [Roll Forward]              
Beginning balance 8 6 5 2 12 6 12
Net other comprehensive income (loss) 4 2 (1) 3 (10)    
Ending balance $ 12 $ 8 $ 4 $ 5 $ 2 $ 12 $ 4