Derivative Financial Instruments - Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location (Details) - Interest Rate Contract [Member] - Cash Flow Hedging [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of (Gain) Loss Recognized in OCI on Derivatives (Effective Portion)	$ (0.5)	$ (0.3)	$ 1.7	$ 4.5
Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of (Gain) Loss Reclassified from Accumulated OCI to Income (Effective Portion)	1.6	1.6	3.2	3.2
Amount of (Gain) Loss Recognized in Income on Derivatives (Ineffective Portion)	$ 0.9	$ 0.2	$ 3.3	$ 1.4