Equity-based Awards, Unit Option Awards (Details) (Unit Option Awards [Member], USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended			12 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Unit Option Awards [Member]
Summary of awards activity, options [Roll Forward]
Beginning of period (in units)	2,761,140
Exercised (in units)	(736,140)
End of period (in units)	2,025,000			2,761,140
Options outstanding, weighted-average strike price [Roll Forward]
Weighted average strike price, beginning of period (in dollars per unit)	$ 27.41
Weighted average strike price, exercised (in dollars per unit)	$ 29.95
Weighted average strike price, end of period (in dollars per unit)	$ 26.49			$ 27.41
Weighted average remaining contractual term	1 year 7 months			2 years
Aggregate intrinsic value	$ 50.0	[1]		$ 13.0	[1]
Exercisable (in units)	0
Exercisable - Weighted average strike price (in dollars per unit)	$ 0
Exercisable - Weighted average remaining contractual term (in years)	0 years
Exercisable - Aggregate intrinsic value	0	[1]
Total intrinsic value of unit option awards exercised during period	19.8		14.0
Cash received from EPCO in connection with the exercise of unit option awards	11.5		10.2
Unit option award-related cash reimbursements to EPCO	19.8		14.0
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost	$ 0.2
Recognition period for total unrecognized compensation cost	0 years 5 months

[1] Aggregate intrinsic value reflects fully vested unit option awards at the date indicated.