Equity-based Awards, Unit Option Awards (Details) (Unit Option Awards [Member], USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Unit Option Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Summary of awards activity, options [Roll Forward]
Beginning of period (in units)	1,270,000	[1]
Exercised (in units)	(940,000)
End of period (in units)	330,000	[1]
Options outstanding, weighted-average strike price [Roll Forward]
Weighted average strike price, beginning of period (in dollars per unit)	$ 16.14
Weighted average strike price, exercised (in dollars per unit)	$ 16.14
Weighted average strike price, end of period (in dollars per unit)	$ 16.14
Weighted average remaining contractual term	0 years 9 months 18 days
Aggregate intrinsic value	$ 5.5	[2]
Total intrinsic value of unit option awards exercised during period	17.4		54.7
Cash received from EPCO in connection with the exercise of unit option awards	10.1		31.8
Unit option award-related cash reimbursements to EPCO	$ 17.4		$ 54.7

[1] All of the unit option awards outstanding at March 31, 2015 were exercisable. None of the unit option awards outstanding at December 31, 2014 were exercisable.

[2] Aggregate intrinsic value reflects fully vested unit option awards at the dates indicated.