Derivative Instruments Derivative Instruments Affecting the Consolidated Statements of Operations and Consolidated Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in OCI on Derivative	$ (2.1)	$ 3.3	$ 55.1	$ 16.1
Amount of Gain/(Loss) Reclassified from AOCI into Income	(0.6)	(0.7)	(1.8)	(1.9)
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in OCI on Derivative	(2.1)	3.3	55.1	16.1
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreements [Member] \| Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Reclassified from AOCI into Income	(0.6)	(0.7)	(1.8)	(1.9)
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivative	4.9	6.7	0.8	(20.6)
Not Designated as Hedging Instrument [Member] \| Foreign Currency Forward Contracts [Member] \| Foreign Exchange Gain (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivative	$ 4.9	$ 6.7	$ 0.8	$ (20.6)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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