v3.26.1
Segment Information - SPPC (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2026
USD ($)
reportableSegment
operatingSegment
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Segment Reporting Information [Line Items]      
Number of reportable segments | operatingSegment 8    
Revenues $ 6,672 $ 6,366  
Cost of sales 1,670 1,531  
Interest expense 746 686  
Interest and dividend income 54 62  
Income tax expense (benefit) (430) (399)  
Other segment items (191) (82)  
Net income (loss) attributable to parent 1,114 1,187  
Capital expenditures 2,418 2,128  
Assets $ 152,029   $ 148,327
SPPC      
Segment Reporting Information [Line Items]      
Number of reportable segments | reportableSegment 2    
Revenues $ 272 285  
Cost of sales 131 143  
Operations and maintenance 71 60  
Depreciation and amortization 45 40  
Interest expense 31 24  
Interest and dividend income 4 3  
Income tax expense (benefit) 1 3  
Other segment items 30 9  
Net income (loss) attributable to parent 27 27  
Capital expenditures 251 173  
Assets 8,123   7,045
SPPC | Regulated common assets      
Segment Reporting Information [Line Items]      
Assets 514   19
SPPC | Electric      
Segment Reporting Information [Line Items]      
Revenues 235 236  
SPPC | Electric | Operating segments      
Segment Reporting Information [Line Items]      
Revenues 235 236  
Cost of sales 113 115  
Operations and maintenance 67 54  
Depreciation and amortization 40 35  
Interest expense 28 22  
Interest and dividend income 4 3  
Income tax expense (benefit) 0 2  
Other segment items 29 9  
Net income (loss) attributable to parent 20 20  
Capital expenditures 235 159  
Assets 7,030   6,541
SPPC | Natural Gas      
Segment Reporting Information [Line Items]      
Revenues 37 49  
SPPC | Natural Gas | Operating segments      
Segment Reporting Information [Line Items]      
Revenues 37 49  
Cost of sales 18 28  
Operations and maintenance 4 6  
Depreciation and amortization 5 5  
Interest expense 3 2  
Interest and dividend income 0 0  
Income tax expense (benefit) 1 1  
Other segment items 1 0  
Net income (loss) attributable to parent 7 7  
Capital expenditures 16 $ 14  
Assets $ 579   $ 485