Derivative Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain on cash flow hedge due to forecasted transaction probably of not occurring	$ 10.8		$ 26.9
Loss on discontinuation of cash flow hedge due to forecasted transaction probable of not occurring		$ (2.3)		$ (2.1)
Cash flow hedges of forecasted transactions, net of tax, in accumulated OCI gain (loss)	$ 22.3		22.3		$ (126.9)
Cash flow hedge gain (loss) expected to be reclassified within 12 months			$ 25.7
Hedges maturity year			2020