Fair Value Measurements Derivative Instruments and hedging Activities Disclosure (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net Periodic Cash Settlements and Accrued Interest	$ 44.8	[1]	$ 43.4	[1]	$ 132.5	[1]	$ 128.3	[1]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 2.9		$ 9.3		$ 11.8		$ 27.7

[1] The derivative settlements under the terms of the interest rate swap agreements are recognized as interest expense and are paid monthly or quarterly.