UNAUDITED CONDENSED 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, 2013	$ 15,440.4	$ (359.0)	$ 225.6	$ 15,573.8
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	806.7	0	7.9	798.8
Cash distributions paid to limited partners	(639.2)	0	0	(639.2)
Cash distributions paid to noncontrolling interests	(8.0)	0	(8.0)	0
Net cash proceeds from the issuance of common units	83.0	0	0	83.0
Amortization of fair value of equity-based awards	17.4	0	0	17.4
Cash flow hedges	14.7	14.7	0	0
Other	(53.0)	0	(2.4)	(50.6)
Balance at Mar. 31, 2014	15,662.0	(344.3)	223.1	15,783.2
Balance at Dec. 31, 2014	19,692.2	(241.6)	1,629.0	18,304.8
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	650.6	0	14.5	636.1
Cash distributions paid to limited partners	(703.8)	0	0	(703.8)
Cash payments made in connection with distribution equivalent rights	(1.2)	0	0	(1.2)
Cash distributions paid to noncontrolling interests	(16.5)	0	(16.5)	0
Cash contributions from noncontrolling interests	4.0	0	4.0	0
Common units issued in connection with Step 2 of Oiltanking acquisition	0	0	(1,408.7)	1,408.7
Net cash proceeds from the issuance of common units	468.4	0	0	468.4
Amortization of fair value of equity-based awards	23.3	0	0	23.3
Cash flow hedges	(21.6)	(21.6)	0	0
Other	(37.3)	0	0.1	(37.4)
Balance at Mar. 31, 2015	$ 20,058.1	$ (263.2)	$ 222.4	$ 20,098.9