Equity-based Awards, Other Awards (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Equity-based compensation expense [Abstract]
Total compensation expense	$ 60.0	$ 50.9	$ 70.4
Holdings Merger [Member]
Summary of awards activity, equity instruments other than options [Roll Forward]
Common unit exchange ratio in connection with merger			1.5
Unit Appreciation Rights [Member]
Equity-based compensation expense [Abstract]
Total compensation expense	0.9	(0.4)	3.1
Summary of awards activity, equity instruments other than options [Roll Forward]
Beginning of period (in units)	107,328	170,104	232,196
Vested (in units)	(107,328)	(17,776)
Settled, forfeited or cancelled (in units)		(45,000)	(197,092)	[1]
Awards assumed by Enterprise in connection with the Holdings Merger (in units)			135,000	[2]
End of period (in units)	0	107,328	170,104
Unit Appreciation Rights [Member] | Enterprise [Member]
Summary of awards activity, equity instruments other than options [Roll Forward]
Beginning of period (in units)	107,328	170,104	142,196
Vested (in units)	(107,328)	(17,776)
Settled, forfeited or cancelled (in units)		(45,000)	(107,092)	[1]
Awards assumed by Enterprise in connection with the Holdings Merger (in units)			135,000	[2]
End of period (in units)	0	107,328	170,104
Unit Appreciation Rights [Member] | Holdings [Member]
Summary of awards activity, equity instruments other than options [Roll Forward]
Beginning of period (in units)	0	0	90,000
Vested (in units)	0	0
Settled, forfeited or cancelled (in units)		0	(90,000)	[1]
Awards assumed by Enterprise in connection with the Holdings Merger (in units)			0	[2]
End of period (in units)	0	0	0
Cash paid to settle equity-based awards during period			2.5
Employee Partnerships [Member]
Equity-based compensation expense [Abstract]
Total compensation expense			31.3
Employee Partnerships [Abstract]
Costs recognized in connection with liquidation of Employee Partnerships			26.8
Changes in the aggregate grant date fair value of the Employee Partnerships [Roll Forward]
Liquidation of partnerships			$ 51.3

[1] Prior to the Holdings Merger, the non-employee directors of DEP GP, the general partner of Duncan Energy Partners, were granted 90,000 UARs denominated in Holdings units in connection with certain letter agreements. The compensation expense and associated liability for these UARs was recognized by Enterprise since it owned DEP GP. At the effective date of the Holdings Merger in November 2010, these UARs were settled and $2.5 million in cash was paid to award recipients.

[2] At the effective date of the Holdings Merger, Enterprise assumed 90,000 UARs that had been issued by Holdings GP to its non-employee directors. Since these UARs were denominated in Holdings units, they converted into 135,000 Enterprise UARs based on the 1.5:1 merger exchange ratio.