Discontinued Operations Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Gulf Coast Fractionators	Mar. 07, 2014 Gulf Coast Fractionators
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue, External		$ 11.2	$ 6.8	$ 22.6
Disposal Group, Including Discontinued Operation, Revenue, Related Party		24.2	10.5	47.3
Operating revenues		35.4	17.3	69.9
Total operating expenses		29.4	15.7	53.8
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax		6.0	1.6	16.1
Income tax expense		2.2	0.6	5.8
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	3.8	1.0	10.3
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest	0	(0.5)	0	(1.1)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	3.3	1.0	9.2
Equity Method Investment, Ownership Percentage						38.75%	38.75%
Inventories					0.2
Other current assets					0.2
Total current assets					0.4
Property, plant & equipment					72.3
Total assets					72.7
Accounts Payable					3.2
Other current liabilities					1.1
Total current liabilities					4.3
Asset Retirement Obligation					7.1
Deferred income taxes					25.3
Other long-term liabilities					0.3
Total liabilities					$ 37.0