Name:	tcp_CapitalUnitsPercentageOfSubsidiaryDistributionsSubjectToRightsOfHolderToReceivePartnersCapitalAccountDistributionsAtSpecifiedPercentageInExcessOfSpecifiedAmount
Namespace Prefix:	tcp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents, for rights of the holder of capital units to receive partners capital account distributions, the initial percentage (100%) to be applied during a specified period to 30 percent of subsidiary distributions in excess of a specified amount, as defined.

No definition available.

Name:	tcp_CapitalUnitsRightsOfHolderToReceivePartnersCapitalAccountDistributionsInitialEffectivePercentageAppliedToSubsidiaryDistributionsInExcessOfSpecifiedAmount
Namespace Prefix:	tcp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents, for rights of the holder of capital units to receive partners capital account distributions, the threshold of subsidiary distributions for payment to the holder.

No definition available.

Name:	tcp_CapitalUnitsRightsOfHolderToReceivePartnersCapitalAccountDistributionsThresholdOfSubsidiaryDistributionsForPayment
Namespace Prefix:	tcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Aggregate amount of net income allocated to limited partners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Name:	us-gaap_NetIncomeLossAllocatedToLimitedPartners
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

Name:	us-gaap_ScheduleOfCapitalizationEquityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_LimitedPartnersCapitalAccountByClassAxis=tcp_LimitedPartnerClassBUnitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=tcp_GasTransmissionNorthwestLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=tcp_TransCanadaCorporationAndSubsidiariesExcludingGeneralPartnerSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: