Fair Value Disclosure (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Derivative [Line Items]
Property, Plant and Equipment, Net	$ 5,599.8		$ 5,070.3
Asset Impairment Charges	(0.3)	(0.9)
Fair Value Disclosure (Textual) [Abstract]
Derivative Asset, Notional Amount	500.0		200.0
Derivative, Notional Amount	163.5		163.6
Cash Flow Hedge Pre Tax Gain Loss to be Reclassified within Twelve Months	(9.5)
Expected After tax reclassification of net losses from accumulated other comprehensive income to earnings in Next Twelve Months	6.0
Aggregate fair value of all derivative instruments with Net liability position	$ 4.2
Document Period End Date	Mar. 31, 2014
Fair Value Hedging [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	6		3
Maturity Date Range of Derivative Instruments	2015 to 2019
Cash Flow Hedges [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	6		6
Maturity Date Range of Derivative Instruments	2014 to 2020