Property, Plant and Equipment, Significant Sales (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Significant Acquisitions and Disposals [Line Items]
Proceeds from asset sales and insurance recoveries	$ 256.3	$ 1,167.4
Gains attributable to asset sales and insurance recoveries	68.4	102.9
Seminole Pipeline segment [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds from asset sales and insurance recoveries	86.9	0
Gains attributable to asset sales and insurance recoveries	$ 52.5	$ 0