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Regulatory Assets and Liabilities (Unamortized Defeance Costs and Standard Cost Recovery) (Details) $ in Thousands, $ in Billions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2017 CAD ($)	Dec. 31, 2016 CAD ($)
Nova Scotia Power Inc. [Member] | Defeased Debt [Member]
Public Utilities, General Disclosures [Line Items]
Long-term Debt		$ 0.7	$ 0.8
Grand Bahama Power Company Limited [Member] | Steam Plant [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Amount of Loss (Recovery) on Plant Abandonment	$ 21,000

X

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: 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(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: 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(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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+ References

No definition available.

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Amount of loss (recovery of loss) related to a plant abandonment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 10.E)
-URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e660019-123033

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section 35
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45741-110387

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