Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Date the credit facility terminates, in CCYY-MM-DD format.

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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.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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Long Term Debt (Narrative) (Details) $ in Millions, $ in Millions, $ in Millions, $ in Millions					12 Months Ended
	Feb. 05, 2021 USD ($)	May 20, 2020 USD ($)	Apr. 24, 2020 CAD ($)	Mar. 13, 2020 USD ($)	Dec. 31, 2020 CAD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2020 BBD ($)	Dec. 31, 2020 CAD ($)	Dec. 31, 2020 USD ($)	May 20, 2020 BSD ($)	May 20, 2020 USD ($)
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity						$ 2,463		$ 2,677
Proceeds from issuance of long-term debt					$ 428	1,066
Repayments of Long-term Debt					$ 513	1,103
Emera
Debt Instrument [Line Items]
Long-term Debt, Gross						2,496		2,291
NSPI
Debt Instrument [Line Items]
Debt instrument, available for issuance under this prospectus			$ 300
Debt Instrument, Maturity Date			Apr. 25, 2050
Stated interest rate			3.31%
Long-term Debt, Gross						$ 2,673		$ 2,956
NMGC \| Subsequent Event [Member]
Debt Instrument [Line Items]
Senior notes	$ 220
Repayments of Long-term Debt	$ 200
TECO Finance
Debt Instrument [Line Items]
Repayments of Long-term Debt				$ 300
Non-revolving term loan \| GBPC
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity											$ 22
Line of Credit Facility, Expiration Date		May 20, 2025
Variable rate		90-day LIBOR plus a margin
Debt Instrument, Term					5 years
Repayments of Long-term Debt		$ 22
Non-revolving term loan \| BPLC
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity							$ 110		$ 55
Stated interest rate							2.05%	2.05%	2.05%
Long-term Debt, Gross							$ 77		$ 38
Non-revolving term loan at 4% interest rate \| GBPC
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		May 20, 2025
Line of Credit Facility, Maximum Borrowing Capacity										$ 15	$ 15
Stated interest rate										4.00%	4.00%
Senior note maturity date of February 5, 2031 \| NMGC \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Feb. 05, 2031
Stated interest rate	2.26%
Senior notes	$ 70
Senior note maturity date of February 5, 2036 \| NMGC \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Feb. 05, 2036
Stated interest rate	2.51%
Senior notes	$ 65
Senior note maturity date of February 5, 2051 \| NMGC \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Feb. 05, 2051
Stated interest rate	3.34%
Senior notes	$ 85