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v3.19.3

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | $ 85.3 | $ 87.1 | $ 320.9 | $ 315.0
Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 77.8 | 80.5 | 332.8 | 327.3
Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 7.5 | 6.6 | (11.9) | (12.3)
Gas Segment |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 24.9 | 25.7 | 143.9 | 147.4
Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 20.5 | 19.6 | 160.0 | 151.1
Gas Segment | Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 4.4 | 6.1 | (16.1) | (3.7)
Electric |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 60.4 | 61.4 | 177.0 | 167.6
Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 57.3 | 60.9 | 172.8 | 176.2
Electric | Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 3.1 | 0.5 | 4.2 | (8.6)
Residential | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 38.2 | 40.2 | 156.2 | 153.9
Residential | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 6.9 | 6.6 | 61.4 | 58.3
Residential | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 31.3 | 33.6 | 94.8 | 95.6
C&I | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 37.0 | 37.2 | 161.7 | 158.8
C&I | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 12.5 | 11.9 | 89.5 | 84.7
C&I | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 24.5 | 25.3 | 72.2 | 74.1
Other | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 2.6 | 3.1 | 14.9 | 14.6
Other | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 1.1 | 1.1 | 9.1 | 8.1
Other | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | $ 1.5 | $ 2.0 | $ 5.8 | $ 6.5

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