RELATED PARTY TRANSACTIONS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended					3 Months Ended					3 Months Ended					3 Months Ended			3 Months Ended				0 Months Ended
	Mar. 31, 2014 General Partner	Mar. 31, 2013 General Partner	Mar. 31, 2014 TransCanada's subsidiaries GTN	Mar. 31, 2013 TransCanada's subsidiaries GTN	Dec. 31, 2013 TransCanada's subsidiaries GTN	Mar. 31, 2014 TransCanada's subsidiaries Bison	Mar. 31, 2013 TransCanada's subsidiaries Bison	Mar. 31, 2014 TransCanada's subsidiaries North Baja	Mar. 31, 2013 TransCanada's subsidiaries North Baja	Dec. 31, 2013 TransCanada's subsidiaries North Baja	Mar. 31, 2014 TransCanada's subsidiaries Tuscarora	Mar. 31, 2013 TransCanada's subsidiaries Tuscarora	Mar. 31, 2014 TransCanada's subsidiaries Northern Border	Mar. 31, 2013 TransCanada's subsidiaries Northern Border	Dec. 31, 2013 TransCanada's subsidiaries Northern Border	Mar. 31, 2014 TransCanada's subsidiaries Great Lakes	Mar. 31, 2013 TransCanada's subsidiaries Great Lakes	Dec. 31, 2013 TransCanada's subsidiaries Great Lakes	Mar. 31, 2014 TransCanada's subsidiaries Great Lakes Transportation revenues	Mar. 31, 2013 TransCanada's subsidiaries Great Lakes Transportation revenues	Mar. 31, 2014 GTN Former parent, TransCanada subsidiaries Transaction between entities under common control Accounts payable to affiliates	Dec. 31, 2013 GTN Former parent, TransCanada subsidiaries Transaction between entities under common control Accounts payable to affiliates	Apr. 11, 2014 Subsequent event GTN Former parent, TransCanada subsidiaries Transaction between entities under common control
Capital and operating costs charged to the pipeline systems and amount payable
Capital and operating costs charged by TransCanada's subsidiaries	$ 1	$ 1	$ 6	$ 7		$ 1	$ 1	$ 1	$ 1		$ 1	$ 1	$ 7	$ 7		$ 7	$ 8
Impact on the Partnership's net income attributable to controlling interests			4	5		1	1	1	1		1	1	4	3		3	4
Amounts payable to TransCanada's subsidiaries			2		3	1		1		1			2		3	3		3
Percentage of capital and operating costs charged by TransCanada's subsidiaries			100.00%			100.00%							100.00%			100.00%
Revenues from TransCanada and its affiliates																			22	21
Percentage of revenues from TransCanada and its affiliates to total revenues																			47.00%	59.00%
Revenue from TransCanada and its affiliates included in the Partnership's equity earnings																11	10
Amount included in receivables in regards to the transportation contracts with TransCanada and its affiliates																11		11
Accrued additional consideration																					25	25
Payment with respect to the Carty Lateral consideration																							$ 25