STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME [Abstract]
Net income	$ 2,088.3	$ 1,383.7	$ 1,140.3
Commodity derivative instruments:
Changes in fair value of cash flow hedges	(221.9)	(76.3)	(179.6)
Reclassification of gains and losses to net income	232.3	44.0	294.2
Interest rate derivative instruments:
Changes in fair value of cash flow hedges	(333.2)	(0.1)	12.5
Reclassification of gains and losses to net income	6.3	25.6	26.4
Foreign currency derivative instruments:
Changes in fair value of cash flow hedges	0	(0.1)	(10.2)
Reclassification of gains and losses to net income	0	(0.3)	0
Total cash flow hedges	(316.5)	(7.2)	143.3
Foreign currency translation adjustment	0	0.9	2.1
Change in funded status of pension and postretirement plans, net of tax	(1.3)	0.4	0
Proportionate share of other comprehensive income of unconsolidated affiliate	0	10.2	2.5
Total other comprehensive income (loss)	(317.8)	4.3	147.9
Comprehensive income	1,770.5	1,388.0	1,288.2
Comprehensive income attributable to noncontrolling interests	(41.4)	(1,065.1)	(1,064.2)
Comprehensive income attributable to partners	$ 1,729.1	$ 322.9	$ 224.0