DEBT AND CREDIT FACILITIES (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of debt and credit facilities

(millions of dollars)	2020		Weighted Average Interest Rate for the Year Ended December 31, 2020			2019	Weighted Average Interest Rate for the Year Ended December 31, 2019
TC PipeLines, LP
Senior Credit Facility due 2021	—		—			—	—
2013 Term Loan Facility due 2022	450		1.87	%		450	3.52	%
4.65% Unsecured Senior Notes due 2021	350	(c)	4.65	%	(a)	350	4.65	%	(a)
4.375% Unsecured Senior Notes due 2025	350		4.375	%	(a)	350	4.375	%	(a)
3.90% Unsecured Senior Notes due 2027	500		3.90	%	(a)	500	3.90	%	(a)
GTN
5.29% Unsecured Senior Notes due 2020	—		—			100	5.29	%	(a)
5.69% Unsecured Senior Notes due 2035	150		5.69	%	(a)	150	5.69	%	(a)
3.12% Series A Senior Notes due 2030	175		3.12	%	(a)	—	—
PNGTS
Revolving Credit Facility due 2023	25		1.88	%		39	3.47	%
2.84% Series A Senior Notes due 2030	125		2.84	%	(a)	—	—
Tuscarora
Unsecured Term Loan due 2021	23		2.13	%		23	3.39	%
North Baja
Unsecured Term Loan due 2021	50		1.70	%		50	3.34	%
	2,198					2,012
Less: unamortized debt issuance costs and debt discount	7					9
Less: current portion	423	(b)				123
	1,768					1,880

(a)Fixed interest rate.

(b)Includes the Partnership's 4.65% Unsecured Senior Notes due June 15, 2021, Tuscarora’s Unsecured Term Loan due August 20, 2021 and North Baja's Unsecured Term Loan due December 19, 2021.

(c)Refer to Note 21- Subsequent events for more details on the Partnership's announcement on its intention to exercise its option to redeem this Unsecured Senior Notes at March 15, 2021.

Schedule of principal repayments required on debt

The principal repayments required by the Partnership on its consolidated debt are as follows:

(millions of dollars)
2021	423
2022	450
2023	25
2024	—
2025	350
Thereafter	950
	2,198