XML 177 R160.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments and Contingencies (Guarantees and Letters of Credit) (Details) - Dec. 31, 2017 | CAD ($) | USD ($)
--- | --- | ---
TECO Energy Inc [Member] | Jointly Owned Electricity Generation Plant [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount |  | $ 5,000,000
Financial Standby Letter of Credit [Member] | Nova Scotia Power Inc. [Member] |  |
Guarantor Obligations [Line Items] |  |
Guaranty Liabilities | $ 51,000,000 |
Financial Standby Letter of Credit [Member] | NSP Maritime Link Inc. [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount |  | 21,000,000
Financial Standby Letter of Credit [Member] | Bear Swamp Power Company LLC [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount |  | 28,000,000
Pension plan [Member] | Nova Scotia Power Inc. [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount | 51,000,000 |
Reinsurance agreements [Member] | Emera Reinsurance Limited [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount |  | 6,000,000
Indemnified bonds [Member] | TECO Energy Inc [Member] |  |
Guarantor Obligations [Line Items] |  |
Letters of Credit Outstanding, Amount | $ 6,000,000 | $ 5,000,000

X
- 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
Name: | us-gaap_GuaranteeObligationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents a non-contingent liability for the fair value of an obligation to stand ready to perform over the term of a guaranty issued in the event that specified triggering events or conditions occur. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 25 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=82913062&loc=d3e11049-110243 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=82913062&loc=d3e11019-110243 + Details
Name: | us-gaap_GuarantyLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=ema_TecoEnergyIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=us-gaap_JointlyOwnedElectricityGenerationPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_FinancialStandbyLetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ema_NovaScotiaPowerIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ema_NspMaritimeLinkIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ema_BearSwampPowerCompanyLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ema_PensionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ema_ReinsuranceAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ema_EmeraReinsuranceLimitedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ema_IndemnifiedBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |