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Capitalization (Narrative) (Details) - USD ($) $ in Millions | 1 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
May 31, 2022 | Jun. 30, 2022 | Jun. 30, 2021 | Dec. 31, 2021 | Nov. 30, 2021
Schedule of Capitalization [Line Items] |  |  |  |  |
Other long term debt |  | $ 1,606.0 |  | $ 2,123.0 |
Customer advances for construction |  | $ 229.0 |  | 23.5 |
Common Stock [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Issuance of common stock |  | 76,550 | 7,787 |  |
Proceeds amount |  | $ 7.0 | $ 0.6 |  |
Delaware SRF Program [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Maximum borrowing capacity, construction loan |  |  |  |  | $ 50.0
First Mortgage Bonds [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Other long term debt | $ 52.2 |  |  |  |
Maturity date | Aug. 01, 2056 |  |  |  |
First Mortgage Bonds [Member] | Series 2022A [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Other long term debt | $ 16.2 |  |  |  |
Interest rate | 2.70% |  |  |  |
First Mortgage Bonds [Member] | Series 2022B [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Other long term debt | $ 360.0 |  |  |  |
Interest rate | 3.00% |  |  |  |
Tidewater [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Maximum borrowing capacity, construction loan |  | $ 2.2 |  | $ 50.0 |
Interest rate |  |  |  | 2.00% |
Dividend Reinvestment and Common Stock Purchase Plan [Member] |  |  |  |  |
Schedule of Capitalization [Line Items] |  |  |  |  |
Percentage of discount purchase of common stock in investment plan |  | 3.00% |  |  |
Number of shares offering for discount |  | 200,000 |  |  |
Remaing shares available |  | 93,000 |  |  |

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