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v3.22.4

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | $ 563.2 | $ 473.3 | $ 418.6
Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 553.5 | 466.1 | 411.9
Rate Adjustment Mechanism Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 9.7 | 7.2 | 6.7
Gas Segment |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 265.3 | 224.8 | 191.4
Gas Segment | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 263.3 | 217.6 | 185.2
Gas Segment | Rate Adjustment Mechanism Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 2.0 | 7.2 | 6.2
Electric |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 297.9 | 248.5 | 227.2
Electric | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 290.2 | 248.5 | 226.7
Electric | Rate Adjustment Mechanism Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 7.7 | 0.0 | 0.5
Residential | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 258.1 | 219.0 | 201.8
Residential | Gas Segment | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 98.2 | 83.9 | 73.1
Residential | Electric | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 159.9 | 135.1 | 128.7
C&I | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 266.4 | 227.4 | 195.9
C&I | Gas Segment | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 153.8 | 124.1 | 104.5
C&I | Electric | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 112.6 | 103.3 | 91.4
Other | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 29.0 | 19.7 | 14.2
Other | Gas Segment | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | 11.3 | 9.6 | 7.6
Other | Electric | Billed and Unbilled Revenue |  |  |
Operating Revenues [Line Items] |  |  |
Total Gas and Electric Operating Revenues | $ 17.7 | $ 10.1 | $ 6.6

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