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Commitments and Contingencies (Legal Proceedings) (Details) $ in Millions, $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 USD ($) | Dec. 31, 2018 | Dec. 31, 2019 CAD ($) | Dec. 31, 2019 USD ($)
Prime Rate [Member] | Tampa Electric |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  | $ 27 | $ 21
Prime Rate [Member] | TGH |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Litigation Settlement, Amount | $ 21 |  |  |
Litigation Settlement Variable Rate | 2.00% |  |  |
Prime Rate [Member] | Maximum | Emera Maine |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 10.41% |  |
ISO-New England Open Access Transmission Tariff-allowed | Emera Maine |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  |  | $ 4
ISO-New England Open Access Transmission Tariff-allowed | Prime Rate [Member] | Emera Maine |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 10.57% |  |
ISO-New England Open Access Transmission Tariff-allowed | Prime Rate [Member] | Maximum | Emera Maine |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 11.74% |  |

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- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14435-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14557-108349 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=118943654&loc=d3e12021-110248 + Details
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