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Commitments and Contingencies (Guarantees and Letters of Credit) (Details) $ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 CAD ($)	Dec. 31, 2017 CAD ($)	Dec. 31, 2018 USD ($)
Nova Scotia Power Inc. [Member] | Jointly Owned Electricity Generation Plant [Member]
Guarantor Obligations [Line Items]
Utilities Operating Expense, Maintenance and Operations	$ 2	$ 3
Utilities Operating Expense, Purchased Power	19	$ 18
Payment Guarantee [Member] | SeaCoast Gas Transmission LLC [Member]
Guarantor Obligations [Line Items]
Guaranty Liabilities			$ 45
Letters of Credit Outstanding, Amount			27
Pension plan [Member] | Nova Scotia Power Inc. [Member]
Guarantor Obligations [Line Items]
Letters of Credit Outstanding, Amount	$ 49
Reinsurance agreements [Member] | Emera Reinsurance Limited [Member]
Guarantor Obligations [Line Items]
Letters of Credit Outstanding, Amount			6
Surety bonds
Guarantor Obligations [Line Items]
Letters of Credit Outstanding, Amount			$ 67

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

This item represents a non-contingent liability for the fair value of an obligation to stand ready to perform over the term of a guaranty issued in the event that specified triggering events or conditions occur.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 25
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82913062&loc=d3e11049-110243

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82913062&loc=d3e11019-110243

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Amount of operating expense for routine plant maintenance, repairs and operations of regulated operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(b))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Amount of operating expense for purchased power of regulated operation.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(b))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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