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Organization, Summary of Significant Accounting Policies and Recent Developments (Tables) | 12 Months Ended
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Dec. 31, 2016
Organization Summary Of Significant Accounting Policies And Recent Developments [Abstract] |
Range of depreciation rates |
Source of Supply | 1.15% - 3.44% | Transmission and Distribution (T&D):
Pumping | 2.00% - 5.39% | T&D – Mains | 1.10% - 3.13%
Water Treatment | 1.65% - 7.09% | T&D – Services | 2.12% - 3.16%
General Plant | 2.08% - 17.84% | T&D – Other | 1.61% - 4.63%
Wastewater Collection | 1.42% - 1.81% |  |
Allowance for Funds Used During Construction Rates |
|  | 2016 |  |  | 2015 |  |  | 2014 |
Middlesex |  |  | 6.73% |  |  |  | 6.72% |  |  |  | 7.03% |
Tidewater |  |  | 7.92% |  |  |  | 7.92% |  |  |  | 7.91% |

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