XML 110 R106.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2

JUNIOR SUBORDINATED NOTES (Details)	1 Months Ended			3 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($)	May 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2018 USD ($)	May 31, 2017 CAD ($)
Debt Instrument [Line Items]
Outstanding					$ 37,019,000,000		$ 39,982,000,000
Unamortized debt discount and issue costs					(228,000,000)		(241,000,000)
Long-term Debt						$ 200,000,000		$ 750,000,000
TRANSCANADA PIPELINES LIMITED
Debt Instrument [Line Items]
Outstanding					29,433,000,000		31,856,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					8,694,000,000		7,572,000,000
Unamortized debt discount and issue costs					(80,000,000)		(64,000,000)
Long-term Debt					8,614,000,000		7,508,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2067 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 1,296,000,000		$ 1,364,000,000
Effective Interest Rate					5.10%	5.10%	5.60%	5.60%
Debt converted		$ 1,000,000,000
Stated interest rate					6.35%	6.35%			6.35%
Stated interest rate, period of time					10 years
Debt instrument, face amount						$ 1,000,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2067 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)		2.21%
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2075 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 972,000,000		$ 1,024,000,000
Effective Interest Rate					6.00%	6.00%	6.50%	6.50%
Stated interest rate					5.875%	5.875%
Stated interest rate, period of time					10 years
Debt instrument, face amount						$ 750,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2076 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 1,556,000,000		$ 1,637,000,000
Effective Interest Rate					6.70%	6.70%	7.20%	7.20%
Stated interest rate					6.125%	6.125%
Stated interest rate, period of time					10 years
Debt instrument, face amount						$ 1,200,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2077 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 1,944,000,000		$ 2,047,000,000
Effective Interest Rate					5.70%	5.70%	6.20%	6.20%
Stated interest rate					5.55%	5.55%
Stated interest rate, period of time					10 years
Debt instrument, face amount						$ 1,500,000,000
TRANSCANADA PIPELINES LIMITED | Canadian junior subordinated debt, due 2077 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 1,500,000,000		$ 1,500,000,000
Effective Interest Rate					5.40%	5.40%	5.50%	5.50%
Stated interest rate					4.90%	4.90%
Stated interest rate, period of time					10 years
Debt instrument, face amount					$ 1,500,000,000
TRANSCANADA PIPELINES LIMITED | Junior subordinated debt, due 2079 | Junior subordinated notes
Debt Instrument [Line Items]
Outstanding					$ 1,426,000,000		$ 0
Effective Interest Rate					6.30%	6.30%	0.00%	0.00%
Stated interest rate					5.75%	5.75%
Stated interest rate, period of time					10 years
Debt instrument, face amount						$ 1,100,000,000
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2019-A | Junior subordinated notes
Debt Instrument [Line Items]
Stated interest rate	5.75%
Debt instrument, face amount	$ 1,100,000,000
Administrative charge percentage	0.25%
Redemption price as a percentage of principal amount plus accrued and unpaid interest	100.00%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2019-A | September 2029 until September 2049 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)	4.404%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2019-A | September 2049 until September 2079 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)	5.154%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-B | Junior subordinated notes
Debt Instrument [Line Items]
Stated interest rate									4.90%
Debt instrument, face amount									$ 1,500,000,000
Administrative charge percentage									0.25%
Redemption price as a percentage of principal amount plus accrued and unpaid interest		100.00%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-B | May 2027 until May 2047 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)		3.33%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-B | May 2047 to May 2077 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)		4.08%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-A | Junior subordinated notes
Debt Instrument [Line Items]
Stated interest rate			5.55%	5.55%
Debt instrument, face amount			$ 1,500,000,000	$ 1,500,000,000
Administrative charge percentage			0.25%	0.25%
Redemption price as a percentage of principal amount plus accrued and unpaid interest			100.00%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-A | March 2027 until March 2047 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)			3.458%
TRANSCANADA PIPELINES LIMITED | Trust Notes - Series 2017-A | March 2047 until March 2077 | Junior subordinated notes | LIBOR
Debt Instrument [Line Items]
Basis points (percent)			4.208%
TransCanada Trust | Trust Notes - Series 2019-A | Notes payable
Debt Instrument [Line Items]
Stated interest rate, period of time	10 years
Debt instrument, face amount	$ 1,100,000,000
TransCanada Trust | Trust Notes - Series 2019-A | First Ten Years | Notes payable
Debt Instrument [Line Items]
Stated interest rate	5.50%
TransCanada Trust | Trust Notes - Series 2017-B | Notes payable
Debt Instrument [Line Items]
Stated interest rate, period of time		10 years
Debt instrument, face amount									$ 1,500,000,000
TransCanada Trust | Trust Notes - Series 2017-B | First Ten Years | Notes payable
Debt Instrument [Line Items]
Stated interest rate									4.65%
TransCanada Trust | Trust Notes - Series 2017-A | Notes payable
Debt Instrument [Line Items]
Stated interest rate, period of time				10 years
Debt instrument, face amount			$ 1,500,000,000	$ 1,500,000,000
TransCanada Trust | Trust Notes - Series 2017-A | First Ten Years | Notes payable
Debt Instrument [Line Items]
Stated interest rate			5.30%	5.30%

X

- Definition

Debt Instrument, Administrative Fee, Percent

+ References

No definition available.

+ Details

Name:	trp_DebtInstrumentAdministrativeFeePercent
Namespace Prefix:	trp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

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

+ References

No definition available.

+ Details

Name:	trp_DebtInstrumentInterestRateStatedPercentagePeriodofTime
Namespace Prefix:	trp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- 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/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

X

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

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

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_JuniorSubordinatedDebtDue2067Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_JuniorSubordinatedDebtDue2075Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_JuniorSubordinatedDebtDueTwoThousandSeventySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_JuniorSubordinatedDebtDueTwoThousandSeventySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_CanadianJuniorSubordinatedDebtDue2077Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_JuniorSubordinatedDebtDue2079Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_TrustNotesSeries2019AMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_TrustNotesSeries2017BMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=trp_TrustNotesSeries2017AMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodSixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodSevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_NotesPayableOtherPayablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	trp_DebtInstrumentInterestRatePeriodAxis=trp_PeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: