ORGANIZATION (Details 2)				1 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 29, 2012 General Partner	May 31, 2011 General Partner	Nov. 30, 2009 General Partner	Dec. 31, 2011 General Partner	Dec. 31, 2010 General Partner	Jan. 31, 2012 General Partner	Dec. 31, 2011 TransCanada Corporation	Jan. 31, 2012 TransCanada Corporation
Common units and interest in the partnership
General partner ownership interest in the partnership (as a percent)				2.00%	2.00%	2.00%	2.00%
Number of common units owned	53,500,000	46,200,000	46,200,000				5,797,106		5,797,106	11,287,725	11,287,725
Limited partner interest (as a percent)										20.70%
Aggregate ownership interest in the Partnership (as a percent)							12.60%	14.30%		33.30%