| Operating revenues | — | — | — |
| Utility revenues | 696.81a | 941.78a | 897.92a |
| Exploration and production and other revenues | 961.08a | 958.46a | 1,010.63a |
| Pipeline and storage and gathering revenues | 286.93a | 273.54a | 277.5a |
| Operating expenses | — | — | — |
| Purchased gas | -150.06a | -437.6a | -392.09a |
| Operation and maintenance | — | — | — |
| Utility | -218.39a | -205.24a | -193.06a |
| Exploration and production and other | -141.31a | -124.27a | -191.57a |
| Pipeline and storage and gathering | -160.32a | -149.25a | -136.57a |
| Property, franchise and other taxes | -88.85a | -92.7a | -101.18a |
| Depreciation, depletion and amortization | -457.03a | -409.57a | -369.79a |
| Impairment of assets | -519.13a | | |
| Gain on sale of assets | | | 12.74a |
| Operating income | 209.72a | 755.15a | 814.52a |
| Other income (expense) | — | — | — |
| Other income (deductions) | 16.23a | 18.14a | -1.51a |
| Interest expense on long-term debt | -122.8a | -111.95a | -120.51a |
| Other interest expense | -15.9a | -19.94a | -9.85a |
| Income before income taxes | 87.26a | 641.4a | 682.65a |
| Income tax expense | -9.74a | -164.53a | -116.63a |
| Net income available for common stock | 77.51a | 476.87a | 566.02a |