v3.26.1
Stockholders' Equity - Components of AOCI (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total Equity $ 1,639 $ 1,073 $ 1,093 $ 1,246 $ 1,180 $ 1,387
Accumulated other comprehensive income (loss)            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total Equity (12) $ (11) $ (4) (9) $ (10) $ (12)
Available-for-sale securities unrealized gain (loss), net            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total Equity (4)     1    
Postretirement benefit prior service credits (costs), net            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total Equity 10     13    
Postretirement benefit actuarial gain (loss), net            
Accumulated Other Comprehensive Income (Loss) [Line Items]            
Total Equity $ (18)     $ (23)