Acquisitions (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified										1 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Jan. 08, 2013	Mar. 21, 2014 Red Rock Transportation, Inc. [Member]	Oct. 08, 2013 Red Rock Transportation, Inc. [Member] tractor trailer_tanks double_bottom_body_tanks bbl	Mar. 31, 2014 Inergy Midstream	Jun. 30, 2013 Inergy Midstream		Oct. 31, 2013 Arrow Midstream Holdings, LLC	Mar. 31, 2014 Arrow Midstream Holdings, LLC	Nov. 08, 2013 Arrow Midstream Holdings, LLC	Oct. 08, 2013 Arrow Midstream Holdings, LLC	Jun. 19, 2013 Storage and Transportation	Mar. 31, 2013 Storage and Transportation	Mar. 31, 2014 NGL and Crude Services	Jun. 19, 2013 NGL and Crude Services	Mar. 31, 2013 NGL and Crude Services
Business Acquisition [Line Items]
Goodwill	$ 2,548.6	$ 2,552.2	$ 352.2			$ 3.2	$ 2,139.8	$ 2,149.9	[1]			$ 48.8		$ 728.6	$ 0	$ 1,463.2	$ 1,411.2	$ 0
Business Combination, Consideration Transferred				258.0	14.1								750.0
Business Combination, Consideration Transferred, Other													12.8
Payments to Acquire Businesses, Gross										550
Partners' Capital Account, Units, Acquisitions										8,826,125
Business Combination, Acquisition Related Costs											4.6
Business Acquisition, Cost of Acquired Entity, Cash Paid						12.1
Business Acquisition, Cost of Acquired Entity, Liabilities Incurred						2.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Trailer Tanks, Number						56
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Double Bottom Tanks						22
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tractors						44
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Crude Hauling Capacity						25,000
Property, plant and equipment						$ 10.9	$ 2,088.1	$ 2,088.2	[1]			$ 400.2

[1] Preliminary amount recorded as of December 31, 2013.