| Revenues | — | — | — |
| electric | 1,200.7a | 1,068.83a | 1,106.57a |
| gas | 313.2a | 353.31a | 371.27a |
| Total revenues | 1,513.9a | 1,422.14a | 1,477.84a |
| Operating expenses | — | — | — |
| Fuel, purchased supply and direct transmission expense | -433.82a | -420.26a | -492.01a |
| Operating and maintenance | -227.84a | -220.52a | -221.43a |
| Administrative and general | -137.44a | -117.36a | -113.78a |
| Property and other taxes | -163.85a | -153.07a | -192.52a |
| Depreciation and depletion | -227.64a | -210.47a | -195.02a |
| Total operating expenses | -1,190.58a | -1,121.69a | -1,214.76a |
| Operating income | 323.32a | 300.46a | 263.08a |
| Interest expense, net | -131.67a | -114.62a | -100.11a |
| Other income, net | 23.02a | 15.83a | 19.43a |
| Income before income taxes | 214.67a | 201.67a | 182.4a |
| Income tax benefit (expense) | 9.44a | -7.54a | 0.61a |
| Net income | 224.11a | 194.13a | 183.01a |