Long Term Debt (Revolving credit facilities, outstanding borrowings and available capacity) (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 3,155	$ 2,729
Use of available facilities	1,408	894
Available capacity under existing agreements	420	990
Revolving credit facility
Debt Instrument [Line Items]
Available capacity under existing agreements	2,219	1,527
Available capacity under existing agreements	811	633
Advances on the revolving credit facility	50
Revolving credit facility \| Emera
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 900	900
Maturity	June 2027
Revolving credit facility \| NSPI
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 800	600
Maturity	December 2027
Revolving credit facility \| ECI
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 11	27
Maturity	2023-2032
Non-revolving credit facility \| NSPI
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 400	0
Maturity	July 2024
Non-revolving credit facility \| NMGC
Debt Instrument [Line Items]
Available capacity under existing agreements	$ 108	0
Maturity	March 2024
Borrowings under credit facilities
Debt Instrument [Line Items]
Use of available facilities	$ 1,396	770
Letters of credit issued within the credit facilities
Debt Instrument [Line Items]
Use of available facilities	$ 12	$ 124

Advances against the line of credit facility which can be made by way of overdraft.

No definition available.

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Namespace Prefix:	ema_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

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- Definition

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

+ References

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI https://asc.fasb.org/extlink&oid=99376301&loc=d3e1336-112600

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=99376301&loc=d3e1314-112600

+ Details

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