v3.26.1
Fair Value Measurements - SPPC - Debt (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value $ 61,485 $ 57,259
Level 2 | Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value 55,882 52,665
SPPC | Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value 2,566 1,972
SPPC | Level 2 | Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-term debt, fair value $ 2,545 $ 1,967