Financial Instruments (Effect of Risk-Management Instruments) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Cash flow hedges:
Total	$ 65.0	$ (80.3)	$ 181.2	$ (125.1)
Foreign currency-denominated notes
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), net investment hedges	119.0	(181.1)	268.8	(186.0)
Cross-currency interest rate swaps
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), net investment hedges	66.7	(110.4)	170.8	(55.4)
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), cash flow hedges	3.1	6.6	22.5	(58.3)
Forward-starting interest rate swaps
Cash flow hedges:
Effective portion of risk-management instruments that was recognized in other comprehensive income (loss), cash flow hedges	19.4	99.6	149.3	(231.9)
Designated as Hedging Instrument \| Foreign currency-denominated notes
Fair value hedges:
Effect from hedged fixed-rate debt	(10.1)	(14.0)	(60.5)	110.4
Designated as Hedging Instrument \| Interest rate contracts
Fair value hedges:
Effect from interest rate contracts	10.1	14.0	60.5	(110.4)
Cash flow hedges:
Effective portion of losses on interest rate contracts reclassified from accumulated other comprehensive loss	4.2	4.1	12.5	12.3
Designated as Hedging Instrument \| Cross-currency interest rate swaps
Cash flow hedges:
Effective portion of losses on interest rate contracts reclassified from accumulated other comprehensive loss	10.0	(30.2)	58.1	(54.6)
Not Designated as Hedging Instrument \| Foreign currency exchange contracts
Cash flow hedges:
Net (gains) losses on foreign currency exchange contracts not designated as hedging instruments	$ 50.8	$ (54.2)	$ 110.6	$ (82.8)

Cash Flow Hedge [Abstract]

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Derivative Instruments, Gain (Loss) Recognized

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Fair Value Hedge [Abstract]

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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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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Amount, before tax and reclassification, of gain (loss) from derivative designated and qualifying as net investment hedge.

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