Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

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- Definition

Average fixed interest rate that will be received or paid upon exercise of a group of interest rate swaption contracts.

+ References

No definition available.

+ Details

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- Definition

Contractual rate at which a foreign currency can be purchased or sold.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

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- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
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-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

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Financial Instruments and Fair Value Measurements - Derivative Financial Instruments (Details) £ in Millions, $ in Millions	Jun. 30, 2021 GBP (£) derivative Rate	Jun. 30, 2021 USD ($) derivative Rate	Dec. 31, 2020 USD ($)	Feb. 29, 2020 derivative
Derivative [Line Items]
Notional Amount		$ 2,059.7	$ 1,541.4
Fair Value - asset (liability)		$ (21.1)	(81.5)
Interest rate swap \| Designated as hedging instrument \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	1	1
Notional Amount		$ 250.0	250.0
Strike (percent)	3.04%	3.04%
Fair Value - asset (liability)		$ (17.8)	(22.6)
Cross-currency swaps \| Designated as hedging instrument \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	4	4
Notional Amount		$ 166.4	166.4
Fair Value - asset (liability)		$ (20.5)	(21.4)
Cross-currency swaps \| Designated as hedging instrument \| Cash flow hedge \| GBP \| Minimum
Derivative [Line Items]
Strike (percent)	4.82%	4.82%
Cross-currency swaps \| Designated as hedging instrument \| Cash flow hedge \| GBP \| Maximum
Derivative [Line Items]
Strike (percent)	10.96%	10.96%
Cross-currency swaps \| Designated as hedging instrument \| Cash flow hedge \| USD \| Weighted Average
Derivative [Line Items]
Strike (percent)	9.78%	9.78%
Currency exchange swaps \| Not designated as hedging instrument
Derivative [Line Items]
Number of Instruments \| derivative	1	1
Notional Amount	£ 672.5	$ 950.0	625.0
Fair Value - asset (liability)		$ 21.1	(8.2)
Forward exchange rate \| Rate	138.00%	138.00%
Forward-starting swap, derivative \| Designated as hedging instrument \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	4	4
Notional Amount		$ 300.0	300.0
Strike (percent)	1.86%	1.86%
Fair Value - asset (liability)		$ (2.8)	(16.5)
Forward-starting swaps, hybrid debt \| Designated as hedging instrument \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	2	2
Notional Amount		$ 200.0	200.0
Strike (percent)	1.93%	1.93%
Fair Value - asset (liability)		$ (5.0)	(12.8)
Foreign currency forwards \| Designated as hedging instrument \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	36	36
Notional Amount	£ 136.9	$ 193.3	0.0
Fair Value - asset (liability)		$ 3.9	$ 0.0
Foreign currency forwards \| Not designated as hedging instrument
Derivative [Line Items]
Forward exchange rate \| Rate	141.00%	141.00%
Treasury rate locks \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative				5
Forward-starting swaps \| Cash flow hedge
Derivative [Line Items]
Number of Instruments \| derivative	6	6