RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Unrealized and Realized (Losses)/Gains (Details) - CAD CAD in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Fair Value Hedges \| Interest expense
Derivative [Line Items]
Amount of realized (losses)/gains in the year	CAD 11	CAD 7
Commodity contract
Derivative [Line Items]
Unrealized losses on derivative instruments held for trading	(37)	(40)
Realized losses on derivative instruments held for trading	(151)	(28)
Commodity contract \| Derivative Financial Instruments in Hedging Relationships
Derivative [Line Items]
Amount of realized (losses)/gains in the year	(179)	130
Foreign exchange
Derivative [Line Items]
Unrealized losses on derivative instruments held for trading	(21)	(20)
Realized losses on derivative instruments held for trading	(112)	(28)
Interest rate \| Derivative Financial Instruments in Hedging Relationships
Derivative [Line Items]
Amount of realized (losses)/gains in the year	CAD 8	CAD 4

Realized Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net

No definition available.

Name:	trp_RealizedGainLossonDerivativeInstrumentsHeldforTradingPurposesNet
Namespace Prefix:	trp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Unrealized Gain (Loss) on Derivative Instruments Held for Trading Purposes, Net

+ References

No definition available.

+ Details

Name:	trp_UnrealizedGainLossonDerivativeInstrumentsHeldforTradingPurposesNet
Namespace Prefix:	trp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

+ Details

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

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

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_InterestExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: