Business Acquisitions, Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic earnings per unit [Abstract]
As reported basic earnings per unit (in dollars per unit)	$ 0.33	$ 0.38	$ 0.94	$ 1.16
Diluted earnings per unit [Abstract]
As reported diluted earnings per unit (in dollars per unit)	$ 0.32	$ 0.37	$ 0.92	$ 1.13
Eagle Ford Midstream Assets [Member]
Pro forma earnings data [Abstract]
Revenues		$ 12,388.7	$ 20,993.5	$ 37,927.5
Costs and expenses		11,502.6	18,645.5	35,195.2
Operating income		958.4	2,650.5	2,911.4
Net income		715.3	1,900.9	2,195.5
Net income attributable to noncontrolling interests		8.1	28.5	24.8
Net income attributable to limited partners		$ 707.2	$ 1,872.4	$ 2,170.7
Basic earnings per unit [Abstract]
As reported basic earnings per unit (in dollars per unit)		$ 0.38	$ 0.94	$ 1.16
Pro forma basic earnings per unit (in dollars per unit)		0.38	0.96	1.18
Diluted earnings per unit [Abstract]
As reported diluted earnings per unit (in dollars per unit)		0.37	0.92	1.13
Pro forma diluted earnings per unit (in dollars per unit)		$ 0.38	$ 0.94	$ 1.15