v3.25.3
Reportable Segments - Schedule of Financial Data (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Segment Reporting Information [Line Items]          
Revenues from external customers $ 1,988 $ 1,856 $ 6,852 $ 6,381  
Intersegment revenues     0    
Utility natural gas, fuel and purchased power 219 197 1,525 1,217  
Non-utility cost of revenues, including natural gas 1 1 4 2  
Operation and maintenance expenses 741 775 2,203 2,162  
Depreciation and amortization 392 334 1,125 1,083  
Taxes other than income taxes 133 125 427 410  
Interest expense and other finance charges 243 195 676 616  
Income tax expense (benefit) (7) 52 129 163  
Interest income 0 0 0 0  
Other expense (income), net (27) (16) (25) (43)  
Net income (loss) 293 193 788 771  
Interest income from securitization bonds (less than for 2025) 1 1 1 3  
Expenditures for Long-lived Assets     3,730 2,766  
Total Assets 45,049   45,049   $ 43,768
Natural Gas          
Segment Reporting Information [Line Items]          
Revenues from external customers 622 611 3,224 2,876  
Corporate and Other          
Segment Reporting Information [Line Items]          
Revenues from external customers 1 2 6 6  
Corporate and Other | Pension and Other Postretirement Plans Costs          
Segment Reporting Information [Line Items]          
Regulatory assets 365   365   384
Operating Segments          
Segment Reporting Information [Line Items]          
Revenues from external customers 1,988 1,856 6,852 6,381  
Intersegment revenues     2    
Utility natural gas, fuel and purchased power 219 197 1,527 1,217  
Non-utility cost of revenues, including natural gas 1 1 4 2  
Operation and maintenance expenses 741 775 2,203 2,162  
Depreciation and amortization 392 334 1,125 1,083  
Taxes other than income taxes 133 125 427 410  
Interest expense and other finance charges 249 202 703 640  
Income tax expense (benefit) (7) 52 129 163  
Interest income (6) (7) (27) (24)  
Other expense (income), net (27) (16) (25) (43)  
Net income (loss) 293 193 788 771  
Operating Segments | Electric          
Segment Reporting Information [Line Items]          
Revenues from external customers 1,365 1,243 3,622 3,499  
Intersegment revenues     0    
Utility natural gas, fuel and purchased power 72 58 211 151  
Non-utility cost of revenues, including natural gas 0 0 0 0  
Operation and maintenance expenses 520 560 1,527 1,532  
Depreciation and amortization 247 201 687 664  
Taxes other than income taxes 82 73 240 228  
Interest expense and other finance charges 116 88 323 276  
Income tax expense (benefit) 56 53 122 131  
Interest income (1) (4) (12) (15)  
Other expense (income), net (20) (12) (48) (30)  
Net income (loss) 293 226 572 562  
Expenditures for Long-lived Assets     2,534 1,643  
Total Assets 26,338   26,338   23,936
Operating Segments | Natural Gas          
Segment Reporting Information [Line Items]          
Revenues from external customers 622 611 3,224 2,876  
Intersegment revenues     2    
Utility natural gas, fuel and purchased power 147 139 1,316 1,066  
Non-utility cost of revenues, including natural gas 1 2 4 3  
Operation and maintenance expenses 219 214 679 637  
Depreciation and amortization 139 129 423 403  
Taxes other than income taxes 53 51 183 177  
Interest expense and other finance charges 52 40 154 152  
Income tax expense (benefit) (54) 9 62 88  
Interest income 0 (1) (10) (2)  
Other expense (income), net (6) (2) 30 (8)  
Net income (loss) 71 30 385 360  
Expenditures for Long-lived Assets     1,164 1,115  
Total Assets 17,553   17,553   18,583
Operating Segments | Corporate and Other          
Segment Reporting Information [Line Items]          
Revenues from external customers 1 2 6 6  
Intersegment revenues     0    
Utility natural gas, fuel and purchased power 0 0 0 0  
Non-utility cost of revenues, including natural gas 0 (1) 0 (1)  
Operation and maintenance expenses 2 1 (3) (7)  
Depreciation and amortization 6 4 15 16  
Taxes other than income taxes (2) 1 4 5  
Interest expense and other finance charges 81 74 226 212  
Income tax expense (benefit) (9) (10) (55) (56)  
Interest income (5) (2) (5) (7)  
Other expense (income), net (1) (2) (7) (5)  
Net income (loss) (71) (63) (169) (151)  
Expenditures for Long-lived Assets     32 8  
Total Assets 1,158   1,158   $ 1,249
Eliminations          
Segment Reporting Information [Line Items]          
Revenues from external customers 0 0 0 0  
Intersegment revenues     (2)    
Utility natural gas, fuel and purchased power 0 0 (2) 0  
Non-utility cost of revenues, including natural gas 0 0 0 0  
Operation and maintenance expenses 0 0 0 0  
Depreciation and amortization 0 0 0 0  
Taxes other than income taxes 0 0 0 0  
Interest expense and other finance charges (6) (7) (27) (24)  
Income tax expense (benefit) 0 0 0 0  
Interest income (6) (7) (27) (24)  
Other expense (income), net 0 0 0 0  
Net income (loss) $ 0 $ 0 $ 0 $ 0