v3.26.1
Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Stockholders' Equity Attributable to Parent $ 7,292 $ 7,047 $ 7,360 $ 7,004
Accumulated Defined Benefit Plans Adjustment        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Stockholders' Equity Attributable to Parent 6 (5) 6 (5)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 0 0    
Accumulated Other Comprehensive Income/(Loss)        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Stockholders' Equity Attributable to Parent 156 82 146 63
Net change in fair value 10 19    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 10 19    
Available-for-sale Securities | AOCI Unrealized gain/loss, Available-for-sale        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Stockholders' Equity Attributable to Parent 150 87 $ 140 $ 68
AFS Unrealized Gain/(Loss) on AFS Securities 10 19    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent $ 10 $ 19