ORGANIZATION (Details 2)				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 General Partner	Dec. 31, 2011 General Partner	Dec. 31, 2012 TransCanada Corporation
Common units and interest in the partnership
General partner ownership interest in the partnership (as a percent)				2.00%
Number of common units owned	53,500,000	53,500,000	46,200,000	5,797,106		11,287,725
Limited partner interest (as a percent)						20.70%
Aggregate ownership interest in the Partnership (as a percent)				12.60%	12.60%	33.30%