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Investments Subject to Significant Influence and Equity Income (Equity Method) (Details) - Entity [Domain] - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	$ 1,346	$ 1,312
Equity Method Investment, Summarized Financial Information [Abstract]
Other long-term liabilities	781	764
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	12
Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	1,346	1,312
Income (loss) from equity investments and subsidiaries	149	154
Equity Method Investment, Summarized Financial Information [Abstract]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	12
NSPML | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	547	554
Income (loss) from equity investments and subsidiaries	$ 47	46
Percentage of Ownership	100.00%
LIL | Class B units
Schedule of Equity Method Investments [Line Items]
Percentage of Ownership	100.00%
LIL | Total Units Issued [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of Ownership	24.90%
LIL | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	$ 629	579
Income (loss) from equity investments and subsidiaries	$ 49	45
Percentage of Ownership	45.60%
M&NP | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	$ 129	138
Income (loss) from equity investments and subsidiaries	$ 20	22
Percentage of Ownership	12.90%
Lucelec | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	$ 41	41
Income (loss) from equity investments and subsidiaries	$ 4	3
Percentage of Ownership	19.50%
Bear Swamp
Equity Method Investment, Summarized Financial Information [Abstract]
Distribution received			$ 179
Other long-term liabilities	$ 118	137
Bear Swamp | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	0	0
Income (loss) from equity investments and subsidiaries	$ 29	35
Percentage of Ownership	50.00%
Other Investments | Equity Method Investee | Emera Inc.
Schedule of Equity Method Investments [Line Items]
Investments subject to significant influence	$ 0	0
Income (loss) from equity investments and subsidiaries	$ 0	$ 3
Maritime Link And LIL | Plan, subject to approval
Schedule of Equity Method Investments [Line Items]
Percentage of Ownership	49.00%

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Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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