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Commitments and Contingencies (Environmental Accruals) (Details) - CAD CAD in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Accrual for Environmental Loss Contingencies Disclosure [Abstract] |  |  |
Asset Retirement Obligation | CAD 170 | CAD 109 | CAD 106
Nova Scotia Power Inc. [Member] |  |  |
Accrual for Environmental Loss Contingencies Disclosure [Abstract] |  |  |
Accrual for Environmental Loss Contingencies, Undiscounted, Next Twelve Months | 41 |  |
Accrual for Environmental Loss Contingencies, Undiscounted, Second Year Through Fifth Year | CAD 41 |  |
Carbon Emission Reduction Targets [Abstract] |  |  |
Per cent non-emitting generation sources | 90.00% |  |
Canada's target per cent reduction under the Paris Agreement | 30.00% |  |
Polychlorinated Biphenyl (PCB) Regulations [Member] | Nova Scotia Power Inc. [Member] |  |  |
Accrual for Environmental Loss Contingencies Disclosure [Abstract] |  |  |
Accrual for Environmental Loss Contingencies | CAD 43 |  |
Accrual for Environmental Loss Contingencies, Payments | 28 | 20 |
Asset Retirement Obligation | CAD 11 | CAD 15 |

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- Definition Undiscounted amount of the accrual for environmental loss contingencies expected to be paid in the next two to five fiscal years following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References No definition available. + Details
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- Definition The targetted percentage of electrical generation from non-emitting sources under Paris Agreement. + References No definition available. + Details
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- Definition Target percentage reduction in carbon emissions under the Paris Agreement + References No definition available. + Details
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- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346 + Details
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- Definition Amount of cash outflow to settle environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.Y.Q2) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
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- Definition Undiscounted amount of the accrual for environmental loss contingencies expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
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- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190 + Details
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