| Operating revenues | 5,124.92a | 4,695.99a | 4,324.39a |
| Operating expenses | — | — | — |
| Fuel and purchased power | -1,822.57a | -1,792.66a | -1,629.34a |
| Operations and maintenance | -1,165.16a | -1,058.73a | -987.07a |
| Depreciation and amortization | -895.35a | -794.04a | -753.2a |
| Taxes other than income taxes | -227.4a | -224.01a | -220.37a |
| Other expense | -2.39a | -1.91a | -2.49a |
| Total | -4,112.85a | -3,871.35a | -3,592.47a |
| Operating income | 1,012.06a | 824.64a | 731.91a |
| Other income (deductions) | — | — | — |
| Allowance for equity funds used during construction | 38.62a | 53.12a | 45.26a |
| Pension and other postretirement non-service credits, net | 48.87a | 40.65a | 98.49a |
| Other income | 48.61a | 33.67a | 7.92a |
| Other expense | -34.14a | -25.06a | -52.39a |
| Total | 101.97a | 102.38a | 99.28a |
| Interest expense | — | — | — |
| Interest charges | -425.74a | -374.89a | -283.57a |
| Allowance for borrowed funds used during construction | -48.27a | -43.56a | -28.03a |
| Total | -377.47a | -331.32a | -255.54a |
| Income before income taxes | 736.56a | 595.69a | 575.65a |
| Income taxes | -110.53a | -76.91a | -74.83a |
| Net income | 626.03a | 518.78a | 500.83a |
| Less: net income attributable to noncontrolling interests | 17.22a | 17.22a | 17.22a |
| Net income attributable to common shareholders | 608.81a | 501.56a | 483.6a |