STATEMENTS OF CONSOLIDATED EQUITY (USD $) In Millions, unless otherwise specified	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Limited Partners [Member]
Balance at Dec. 31, 2010	$ 11,900.8	$ (32.5)	$ 526.6	$ 11,406.7
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	2,088.3	0	41.4	2,046.9
Cash distributions paid to limited partners	(1,974.3)	0	0	(1,974.3)
Cash distributions paid to noncontrolling interests	(60.7)	0	(60.7)	0
Cash contributions from noncontrolling interests	8.5	0	8.5	0
Net cash proceeds from the issuance of common units	542.9	0	0	542.9
Acquisition of noncontrolling interest in subsidiary	(15.0)	0	(9.6)	(5.4)
Amortization of fair value of equity-based awards	51.0	0	0.1	50.9
Issuance of common units pursuant to Duncan Merger (see Note 12)	0	(1.1)	(401.7)	402.8
Cash flow hedges	(316.5)	(316.5)	0	0
Other	(5.7)	(1.3)	1.3	(5.7)
Balance at Dec. 31, 2011	12,219.3	(351.4)	105.9	12,464.8
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	2,428.0	0	8.1	2,419.9
Cash distributions paid to limited partners	(2,178.6)	0	0	(2,178.6)
Cash distributions paid to noncontrolling interests	(13.3)	0	(13.3)	0
Cash contributions from noncontrolling interests	6.6	0	6.6	0
Net cash proceeds from the issuance of common units	816.8	0	0	816.8
Amortization of fair value of equity-based awards	58.9	0	0	58.9
Cash flow hedges	(22.5)	(22.5)	0	0
Other	(19.2)	3.5	1.0	(23.7)
Balance at Dec. 31, 2012	13,296.0	(370.4)	108.3	13,558.1
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	2,607.1	0	10.2	2,596.9
Cash distributions paid to limited partners	(2,400.3)	0	0	(2,400.3)
Cash distributions paid to noncontrolling interests	(8.9)	0	(8.9)	0
Cash contributions from noncontrolling interests	115.4	0	115.4	0
Net cash proceeds from the issuance of common units	1,792.0	0	0	1,792.0
Amortization of fair value of equity-based awards	72.4	0	0	72.4
Cash flow hedges	11.0	11.0	0	0
Other	(44.3)	0.4	0.6	(45.3)
Balance at Dec. 31, 2013	$ 15,440.4	$ (359.0)	$ 225.6	$ 15,573.8