| Operating revenues | — | — | — |
| Revenues from contracts with customers | 2,916.6a | 2,607.3a | 3,304.2a |
| Other revenues | 68.7a | 67a | 71.5a |
| Operating revenues | 2,985.3a | 2,674.3a | 3,375.7a |
| Fuel, purchased power and direct transmission expense | -1,076.4a | -911.7a | -1,662.4a |
| Operating expenses | — | — | — |
| Other operation and maintenance | -514.4a | -502.6a | -501.4a |
| Depreciation and amortization | -539.5a | -506.6a | -460.9a |
| Taxes other than income | -109.7a | -103.2a | -101.5a |
| Operating expenses | -1,163.6a | -1,112.4a | -1,063.8a |
| Operating income | 745.3a | 650.2a | 649.5a |
| Other income (expense) | — | — | — |
| Allowance for equity funds used during construction | 25.5a | 19.4a | 6.9a |
| Other net periodic benefit income (expense) | -2.2a | 5.6a | -12.9a |
| Gain on equity securities | 0a | 0a | 282.1a |
| Other income | 30.6a | 48.2a | 74.6a |
| Other expense | -24.1a | -29a | -44.6a |
| Net other income | 29.8a | 44.2a | 306.1a |
| Interest expense | — | — | — |
| Interest on long-term debt | -228.3a | -205a | -162.1a |
| Allowance for borrowed funds used during construction | -14.6a | -7.1a | -4a |
| Interest on short-term debt and other interest charges | -40.8a | -23.5a | -8.2a |
| Interest expense | -254.5a | -221.4a | -166.3a |
| Income before taxes | 520.6a | 473a | 789.3a |
| Income tax expense | -79.1a | -56.2a | -123.6a |
| Net income | 441.5a | 416.8a | 665.7a |