Basis of Presentation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Partnership Ownership Disclosure [Abstract]
General partner ownership interest (in hundredths)	2.00%
Parent's percentage ownership in the general partner of the Partnership	100.00%
Number of Partnership common units owned (in units)	12,945,659
Reclassification [Line Items]
Prior Period Reclassification Adjustment	$ 18.9
Cash flows from operating activities
Accounts payable and other liabilities	7.8	(41.0)
Net cash provided by operating activities	318.7	192.9
Cash flows from investing activities
Outlays for property, plant and equipment	(197.7)	(221.8)
Net cash used in investing activities	(193.7)	(226.4)
As reported [Member]
Cash flows from operating activities
Accounts payable and other liabilities		(59.9)
Net cash provided by operating activities		174.0
Cash flows from investing activities
Outlays for property, plant and equipment		(202.9)
Net cash used in investing activities		(207.5)
Reclassification [Member]
Cash flows from operating activities
Accounts payable and other liabilities		18.9
Net cash provided by operating activities		18.9
Cash flows from investing activities
Outlays for property, plant and equipment		(18.9)
Net cash used in investing activities		$ 18.9
Limited Partner [Member]
Partnership Ownership Disclosure [Abstract]
General partner ownership interest (in hundredths)	11.40%