Financial Instruments and Risk Management (Effect Of Derivative Instruments on the Condensed Consolidated Statements of Operations Derivatives in Fair Value Hedging Relationships) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 35.6	$ 29.4
Fair Value Hedging Relationships | Interest expense (3) | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0.0	22.1
Fair Value Hedging Relationships | Interest expense (3) | 2023 Senior Notes (3.125% coupon)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	$ 0.0	$ (22.1)