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Collaborative Arrangements (Details) - Nova Scotia Power Inc. [Member] - Jointly Owned Electricity Generation Plant [Member] - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangements [Line Items]
Utilities Operating Expense, Purchased Power	$ 19	$ 18
Utilities Operating Expense, Maintenance and Operations	$ 2	$ 3

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- Definition

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+ References

No definition available.

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- Definition

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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- Definition

Amount of operating expense for purchased power 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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