Equity-Based Awards, Phantom Unit Awards (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Summary of awards activity, equity instruments other than options, additional disclosures [Abstract]
Cash payments made in connection with DERs				$ 8.5	$ 5.6
Phantom Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rate of phantom unit awards		25.00%		25.00%
Summary of awards activity, equity instruments other than options [Roll Forward]
Beginning of period (in units)				5,426,949
Granted (in units)	[1]			4,486,910
Vested (in units)				(1,728,388)
Forfeited (in units)				(364,506)
End of period (in units)		7,820,965		7,820,965
Phantom units outstanding, weighted-average grant date fair value [Roll Forward]
Weighted-average grant date fair value per unit, at beginning of period (in dollars per unit)	[2]			$ 33.63
Granted weighted-average grant date fair value per unit (in dollars per unit)	[1],[2]			21.88
Vested weighted-average grant date fair value per unit (in dollars per unit)	[2]			33.13
Forfeited weighted-average grant date fair value per unit (in dollars per unit)	[2]			28.71
Weighted-average grant date fair value per unit, at end of period (in dollars per unit)	[2]	$ 27.23		$ 27.23
Summary of awards activity, equity instruments other than options, additional disclosures [Abstract]
Aggregate grant date fair value				$ 98.2
Estimated forfeiture rate				3.90%
Cash payments made in connection with DERs		$ 3.2	$ 2.2	$ 8.5	5.6
Total intrinsic value of phantom unit awards that vested during period		3.0	$ 2.3	40.1	$ 31.0
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost		99.7		$ 99.7
Recognition period for total unrecognized compensation cost				2 years
Phantom Unit Awards [Member] | Minimum [Member]
Summary of awards activity, equity instruments other than options, additional disclosures [Abstract]
Grant date market price of common units (in dollars per unit)				$ 21.86
Phantom Unit Awards [Member] | Maximum [Member]
Summary of awards activity, equity instruments other than options, additional disclosures [Abstract]
Grant date market price of common units (in dollars per unit)				$ 27.39
Phantom Unit Awards [Member] | Enterprise [Member]
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost		$ 89.9		$ 89.9

[1] The aggregate grant date fair value of phantom unit awards issued during 2016 was $98.2 million based on grant date market prices of our common units ranging from $21.86 per unit to $27.39 per unit. An estimated annual forfeiture rate of 3.9% was applied to these awards.

[2] Determined by dividing the aggregate grant date fair value of awards (before an allowance for forfeitures) by the number of awards issued.