v3.26.1
Revenue from Contracts with Customers - MEC (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Operating revenue $ 6,686 $ 6,394 $ 13,358 $ 12,760
MEC        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 855 841 1,978 1,827
Other revenue 17 19 34 47
Operating revenue 872 860 2,012 1,874
MEC | Other customer revenue        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 1   4 3
Regulated | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 3,278 3,146 6,246 5,970
Regulated | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 119 127 488 485
Regulated | Wholesale        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 111 116 334 262
Regulated | Other customer revenue        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 40 36 86 63
Regulated | MEC | Retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 770 739 1,691 1,593
Regulated | MEC | Retail | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 248 244 646 627
Regulated | MEC | Retail | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 107 111 277 271
Regulated | MEC | Retail | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 362 330 664 590
Regulated | MEC | Retail | Natural gas transportation services        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 12 11 28 27
Regulated | MEC | Retail | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 41 43 76 78
Regulated | MEC | Wholesale        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 71 88 257 204
Regulated | MEC | Multi-value transmission projects | Multi-value transmission projects        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 13 13 26 27
Nonregulated | MEC | Other customer revenue        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue   1    
Electric | Regulated | MEC        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 743 724 1,473 1,363
Other revenue 17 19 34 47
Operating revenue 760 743 1,507 1,410
Electric | Regulated | MEC | Regulated retail electric        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 669 634 1,258 1,179
Electric | Regulated | MEC | Regulated retail electric | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 183 177 364 358
Electric | Regulated | MEC | Regulated retail electric | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 87 89 169 169
Electric | Regulated | MEC | Regulated retail electric | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 358 325 651 576
Electric | Regulated | MEC | Regulated retail electric | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 41 43 74 76
Electric | Regulated | MEC | Wholesale        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 61 77 189 157
Electric | Regulated | MEC | Multi-value transmission projects | Multi-value transmission projects        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 13 13 26 27
Natural Gas | Regulated | MEC        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 111 116 501 461
Other revenue 0 0 0 0
Operating revenue 111 116 501 461
Natural Gas | Regulated | MEC | Regulated retail gas        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 101 105 433 414
Natural Gas | Regulated | MEC | Regulated retail gas | Residential        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 65 67 282 269
Natural Gas | Regulated | MEC | Regulated retail gas | Commercial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 20 22 108 102
Natural Gas | Regulated | MEC | Regulated retail gas | Industrial        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 4 5 13 14
Natural Gas | Regulated | MEC | Regulated retail gas | Natural gas transportation services        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 12 11 28 27
Natural Gas | Regulated | MEC | Regulated retail gas | Other retail        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 0 0 2 2
Natural Gas | Regulated | MEC | Wholesale        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 10 11 68 47
Other | Nonregulated | MEC        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue 1 1 4 3
Other revenue 0 0 0 0
Operating revenue 1 1 4 3
Other | Nonregulated | MEC | Other customer revenue        
Disaggregation of Revenue [Line Items]        
Total Customer Revenue $ 1 $ 1 $ 4 $ 3