Financial Instruments and Risk Management (Effect Of Derivative Instruments on the Condensed Consolidated Statements of Operations Derivatives in Fair Value Hedging Relationships) (Details) - Fair Value Hedging Relationships - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Earnings on Derivatives	$ 3.9	$ 10.3	$ 1.5	$ 39.9
Amount of Gain (Loss) Recognized in Earnings on Hedged Items	(3.9)	(10.3)	(1.5)	(39.9)
Interest expense | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Earnings on Derivatives	3.9	10.3	1.5	39.9
Interest expense | 2023 Senior Notes (3.125% coupon)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Hedged Items	$ (3.9)	$ (10.3)	$ (1.5)	$ (39.9)