Amount of cash outflow in the form amortization of derivatives loss.

No definition available.

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- Definition

Rate to unwind an interest rate swap that is used to hedged a credit facility.

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- Definition

The cash outflow for settlement of derivative instruments during the period, which are designated as hedging instruments.

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No definition available.

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Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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

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- Definition

Average fixed interest rate related to the group of interest rate derivatives.

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No definition available.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

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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.

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No definition available.

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- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

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- Definition

Amount, after tax and before reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

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FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Millions		12 Months Ended
FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Millions	Jun. 26, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest rate derivatives
Change in fair value of cash flow hedges (Notes 11 and 19)		$ (16.0)	$ (13.0)	$ (2.0)
Amortization of Derivatives Loss		0.0	0.0	$ 1.0
Accounts receivable
Interest rate derivatives
Maximum counterparty credit exposure		$ 0.0
2013 Term Loan Facility
Interest rate derivatives
Repayments of secured debt	$ 50.0
Unwind rate of interest rate swap (as a percent)	2.81%
Secured debt \| PNGTS 5.90% Senior Secured Notes due 2018
Interest rate derivatives
Stated interest rate				5.90%
Interest rate swaps \| Term loan \| TC PipeLines, LP 2013 Term Loan Facility due 2022
Interest rate derivatives
Weighted average fixed interest rate (as a percent)		3.26%
Hedges of cash flows \| Interest rate swaps \| Financial charges and other
Interest rate derivatives
Net realized gain related to the interest rate swaps included in financial charges and other		$ (7.0)	1.0	$ 2.0
Hedges of cash flows \| Recurring fair value measurement \| Level 2 \| Interest rate swaps
Interest rate derivatives
Fair value of derivative liability, gross		15.0	6.0
Fair value of derivative liability, net		15.0	6.0
PNGTS
Interest rate derivatives
Amortization of Derivatives Loss				$ 1.0
PNGTS
Interest rate derivatives
Ownership interest (as a percent)				61.71%
PNGTS
Interest rate derivatives
Payments for derivative instruments				$ 20.9
Change in fair value of cash flow hedges (Notes 11 and 19)				$ 20.9
Fair Value \| Level 2
Interest rate derivatives
Fair value of debt		$ 2,388.0	$ 2,111.0