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Derivative Financial Instruments - Effect on Statement of Comprehensive Income and Statement of Income (Details) - Designated as Hedging Instrument - Derivatives in Net Investment Hedging Relationship - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		$ 6.9	$ (4.0)	$ 7.3	$ (3.7)
Gain Reclassified from Accumulated Other Comprehensive Loss into Earnings		0.0	0.0	0.1	(0.3)
Gain Recognized in Earnings from Excluded Components	[1]	3.5	0.5	10.4	0.5
Forward contracts
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		22.8	(5.9)	32.6	(5.6)
Gain Reclassified from Accumulated Other Comprehensive Loss into Earnings		0.0	0.0	0.1	(0.3)
Gain Recognized in Earnings from Excluded Components	[1]	3.5	0.5	10.4	0.5
Put options
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		(8.4)	1.6	(2.8)	1.6
Gain Reclassified from Accumulated Other Comprehensive Loss into Earnings		0.0	0.0	0.0	0.0
Gain Recognized in Earnings from Excluded Components	[1]	0.0	0.0	0.0	0.0
Call options
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		(7.5)	0.3	(22.5)	0.3
Gain Reclassified from Accumulated Other Comprehensive Loss into Earnings		0.0	0.0	0.0	0.0
Gain Recognized in Earnings from Excluded Components	[1]	$ 0.0	$ 0.0	$ 0.0	$ 0.0
[1] The excluded components of the forward contracts are recognized in earnings on a straight-line basis over the respective period of the contracts as a reduction to Interest expense on the Consolidated Statements of Income.

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- Definition

Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Net of Tax

+ References

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Amount, before tax and adjustments, of gain (loss) from increase (decrease) in value of excluded component of derivative designated and qualifying as hedge. Adjustments include, but are not limited to, reclassifications for sale and settlement, and amounts recognized under systematic and rational method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Section 45
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
-Paragraph 4CCC
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-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998896-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109974929&loc=SL110061190-113977

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Amount, after tax, of reclassification from accumulated other comprehensive income (AOCI) of gain (loss) from increase (decrease) in fair value of net investment hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CCC
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998896-113959

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