Segment Information (Reportable Segments) (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	$ 6,524.0	$ 6,226.0
Allowance for Funds Used During Construction, Investing Activities	30.0	16.0
Regulated Fuel Adjustment	(46.0)	59.0
Depreciation, Depletion and Amortization	916.0	856.0
Interest Expense	724.0	705.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	154.0	124.0
Income tax expense (recovery)	69.0	520.0
Net income attributable to common shareholders	709.6	266.1
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	2,151.0	1,522.0
Assets, Total	32,314.0	28,806.0
Goodwill	6,313.0	5,805.0	$ 6,213.0
Investments subject to significant influence	1,316.0	1,215.0
All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	6,525.0	6,226.0
Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	(1.0)	0.0
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	(54.0)	(58.0)
Allowance for Funds Used During Construction, Investing Activities	0.0	0.0
Regulated Fuel Adjustment	0.0	0.0
Depreciation, Depletion and Amortization	0.0	0.0
Interest Expense	0.0	0.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	0.0	0.0
Income tax expense (recovery)	0.0	0.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	0.0	0.0
Assets, Total	(34.0)	(86.0)
Goodwill	0.0	0.0
Investments subject to significant influence	0.0	0.0
Intersegment Eliminations [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	0.0	0.0
Intersegment Eliminations [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	(54.0)	(58.0)
Emera Florida And New Mexico Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	3,675.0	3,623.0
Allowance for Funds Used During Construction, Investing Activities	21.0	5.0
Regulated Fuel Adjustment	0.0	0.0
Depreciation, Depletion and Amortization	534.0	500.0
Interest Expense	238.0	248.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	0.0	0.0
Income tax expense (recovery)	101.0	529.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	1,548.0	910.0
Assets, Total	20,051.0	17,216.0
Goodwill	6,053.0	5,566.0
Investments subject to significant influence	0.0	0.0
Emera Florida And New Mexico Segment [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	3,675.0	3,623.0
Emera Florida And New Mexico Segment [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	0.0	0.0
Nova Scotia Power Inc Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	1,440.0	1,338.0
Allowance for Funds Used During Construction, Investing Activities	6.0	8.0
Regulated Fuel Adjustment	(46.0)	59.0
Depreciation, Depletion and Amortization	219.0	207.0
Interest Expense	142.0	134.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	0.0	0.0
Income tax expense (recovery)	8.0	0.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	345.0	385.0
Assets, Total	5,143.0	4,979.0
Goodwill	0.0	0.0
Investments subject to significant influence	0.0	0.0
Nova Scotia Power Inc Segment [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	1,437.0	1,335.0
Nova Scotia Power Inc Segment [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	3.0	3.0
Emera Maine Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	278.0	297.0
Allowance for Funds Used During Construction, Investing Activities	3.0	3.0
Regulated Fuel Adjustment	0.0	0.0
Depreciation, Depletion and Amortization	64.0	47.0
Interest Expense	22.0	20.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	3.0	1.0
Income tax expense (recovery)	11.0	27.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	100.0	82.0
Assets, Total	1,721.0	1,540.0
Goodwill	156.0	143.0
Investments subject to significant influence	35.0	13.0
Emera Maine Segment [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	278.0	297.0
Emera Maine Segment [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	0.0	0.0
Emera Caribbean Segment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	467.0	434.0
Allowance for Funds Used During Construction, Investing Activities	0.0	0.0
Regulated Fuel Adjustment	0.0	0.0
Depreciation, Depletion and Amortization	50.0	51.0
Interest Expense	27.0	25.0
Internally Allocated Interest	0.0	0.0
Income (Loss) from Equity Method Investments	3.0	3.0
Income tax expense (recovery)	(2.0)	0.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	87.0	72.0
Assets, Total	1,373.0	1,251.0
Goodwill	104.0	96.0
Investments subject to significant influence	42.0	39.0
Emera Caribbean Segment [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	467.0	434.0
Emera Caribbean Segment [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	0.0	0.0
NEGG [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total		465.0
Allowance for Funds Used During Construction, Investing Activities		0.0
Regulated Fuel Adjustment		0.0
Depreciation, Depletion and Amortization		48.0
Interest Expense		2.0
Internally Allocated Interest		(24.0)
Income (Loss) from Equity Method Investments		24.0
Income tax expense (recovery)		18.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures		47.0
Corporate and Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	104.0	127.0
Allowance for Funds Used During Construction, Investing Activities	0.0	0.0
Regulated Fuel Adjustment	0.0	0.0
Depreciation, Depletion and Amortization	3.0	3.0
Interest Expense	290.0	276.0
Internally Allocated Interest	24.0	24.0
Income (Loss) from Equity Method Investments	110.0	96.0
Income tax expense (recovery)	(115.0)	(54.0)
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	38.0	26.0
Assets, Total	2,275.0	2,331.0
Goodwill	0.0	0.0
Investments subject to significant influence	1,239.0	1,163.0
Amortization Related to Unregulated Long Term Debt	12.0	24.0
Corporate and Other [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	68.0	86.0
Corporate and Other [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	36.0	41.0
Emera Energy Services [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	614.0
Allowance for Funds Used During Construction, Investing Activities	0.0
Regulated Fuel Adjustment	0.0
Depreciation, Depletion and Amortization	46.0
Interest Expense	5.0
Internally Allocated Interest	(24.0)
Income (Loss) from Equity Method Investments	38.0
Income tax expense (recovery)	66.0
Segment Reporting Information, Additional Information [Abstract]
Capital expenditures	33.0
Assets, Total	1,785.0	1,575.0
Goodwill	0.0	0.0
Investments subject to significant influence	0.0	0.0
Emera Energy Services [Member] \| All External Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	600.0	451.0
Emera Energy Services [Member] \| Internal Customers [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Revenues, Total	$ 14.0	$ 14.0

Amortization Related to Unregulated Long Term Debt.

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Amount of interest expense allocated between segments.

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The regulated fuel adjustment related to the fuel adjustment mechanism ("FAM").

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Cash inflow due to change during the period in the allowance for other funds used during construction classified as an investing activity.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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