Debt Instrument, Administrative Fee, Percent

No definition available.

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- Definition

Debt Instrument, Interest Rate, Stated Percentage, Period of Time

+ References

No definition available.

+ Details

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- Definition

Represents the optional period for which payment of interest can be deferred on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

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

+ References

+ Details

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- 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

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

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- Definition

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments, excluding current portion.

+ References

+ Details

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- Details

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- Details

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- Details

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- Details

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JUNIOR SUBORDINATED NOTES (Details) CAD in Millions	1 Months Ended		12 Months Ended
JUNIOR SUBORDINATED NOTES (Details) CAD in Millions	Aug. 31, 2016 USD ($)	May 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 CAD	Dec. 31, 2015 USD ($)	Dec. 31, 2015 CAD
Debt Instrument [Line Items]
Outstanding at December 31 \| CAD				CAD 3,931		CAD 2,409
TRANSCANADA PIPELINES LIMITED
Debt Instrument [Line Items]
Outstanding at December 31 \| CAD				CAD 3,931		2,409
TRANSCANADA PIPELINES LIMITED \| Junior subordinated notes
Debt Instrument [Line Items]
Outstanding at December 31			$ 1,000,000,000
Stated interest rate			6.35%	6.35%
Redemption price as a percentage of principal amount plus accrued and unpaid interest			100.00%
Optional period for which payment of interest can be deferred (in years)			10 years
TRANSCANADA PIPELINES LIMITED \| Junior subordinated notes \| LIBOR
Debt Instrument [Line Items]
Basis points (percent)			2.21%
TRANSCANADA PIPELINES LIMITED \| Junior subordinated debt, due 2067
Debt Instrument [Line Items]
Outstanding at December 31			$ 1,000,000,000	CAD 1,342	$ 1,000,000,000	CAD 1,382
Effective Interest Rate			6.40%	6.40%	6.40%	6.40%
TRANSCANADA PIPELINES LIMITED \| Junior subordinated debt, due 2075
Debt Instrument [Line Items]
Outstanding at December 31			$ 742,000,000	CAD 996	$ 742,000,000	CAD 1,027
Effective Interest Rate			5.50%	5.50%	5.30%	5.30%
TRANSCANADA PIPELINES LIMITED \| Junior subordinated debt, due 2076
Debt Instrument [Line Items]
Outstanding at December 31			$ 1,186,000,000	CAD 1,593
Effective Interest Rate			6.20%	6.20%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in August 2076 \| Junior subordinated notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,200,000,000.0
Stated interest rate	6.125%
Administrative charge (percent)	0.25%
Redemption price as a percentage of principal amount plus accrued and unpaid interest	100.00%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in August 2076 \| August 2026 until August 2046 \| Junior subordinated notes \| LIBOR
Debt Instrument [Line Items]
Basis points (percent)	4.89%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in August 2076 \| August 2046 to August 2076 \| Junior subordinated notes \| LIBOR
Debt Instrument [Line Items]
Basis points (percent)	5.64%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in May 2075 \| Junior subordinated notes
Debt Instrument [Line Items]
Debt instrument, face amount		$ 750,000,000
Stated interest rate		5.875%
Administrative charge (percent)		0.25%
Redemption price as a percentage of principal amount plus accrued and unpaid interest		100.00%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in May 2075 \| May 2025 until May 2045 \| Junior subordinated notes \| LIBOR
Debt Instrument [Line Items]
Basis points (percent)		3.778%
TRANSCANADA PIPELINES LIMITED \| TransCanada Trust loan, due in May 2075 \| May 2045 to May 2075 \| Junior subordinated notes \| LIBOR
Debt Instrument [Line Items]
Basis points (percent)		4.528%
TransCanada Trust \| Trust Notes - Series 2016-A \| Notes payable
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,200,000,000.0
Stated interest rate, period of time (in years)		10 years
TransCanada Trust \| Trust Notes - Series 2016-A \| First Ten Years \| Notes payable
Debt Instrument [Line Items]
Stated interest rate	5.875%
TransCanada Trust \| Trust Notes - Series 2015-A \| Notes payable
Debt Instrument [Line Items]
Debt instrument, face amount		$ 750,000,000
Stated interest rate		5.625%
Stated interest rate, period of time (in years)			10 years