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Commitments and Contingencies (Legal Proceedings) (Details) CAD in Millions, $ in Millions |  |  |  |  |  | 6 Months Ended | 15 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 29, 2016 | Mar. 22, 2016 | Jun. 19, 2014 | Dec. 19, 2013 USD ($) | Sep. 30, 2011 | Jun. 30, 2016 | Mar. 31, 2014 | Dec. 31, 2012 | Sep. 30, 2016 CAD | Sep. 30, 2016 USD ($) | Dec. 31, 2015 CAD | Dec. 31, 2015 USD ($)
Tampa Electric And Peoples Gas Division [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  |  |  |  |  |  |  | CAD 43 | $ 32 |  |
Emera Maine [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  |  | 10.57% |  | 11.14% | 10.57% | 10.57% | 11.74% |  |  |  |
Emera Maine [Member] | ENE Case [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  |  |  |  |  |  |  |  |  | CAD 5 | $ 4
Public Utilities, Approved Return on Equity, Percentage |  | 9.59% |  |  |  |  |  |  |  |  |  |
Emera Maine [Member] | ENE Case [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 10.42% |  |  |  |  |  |  |  |  |  |
Emera Maine [Member] | MA AG II Case [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingency, Estimate of Possible Loss |  |  |  |  |  |  |  |  |  |  | CAD 7 | $ 5
Public Utilities, Approved Return on Equity, Percentage |  | 10.90% |  |  |  |  |  |  |  |  |  |
Emera Maine [Member] | MA AG II Case [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 12.19% |  |  |  |  |  |  |  |  |  |
Emera Maine [Member] | Eastern Massachusetts Consumer Owned Systems [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage | 8.61% |  |  |  |  |  |  |  |  |  |  |
Emera Maine [Member] | Eastern Massachusetts Consumer Owned Systems [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage | 11.24% |  |  |  |  |  |  |  |  |  |  |
TECO Guatemala Holdings [Member] | Prime Rate [Member] |  |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Amount |  |  |  | $ 21 |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  |  |  | 2.00% |  |  |  |  |  |  |  |

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