Financial Instruments and Fair Value Measurements - Summary of Derivative Financial Instruments (Details) $ in Millions	Dec. 31, 2021 derivative	Dec. 31, 2021 USD ($)	Dec. 31, 2021 mortgage	Dec. 31, 2021	Dec. 31, 2021 Rate	Dec. 31, 2020 USD ($) derivative	Jun. 30, 2020 USD ($) derivative	Feb. 29, 2020 USD ($) derivative
Derivative [Line Items]
Notional Amount		$ 2,731.9				$ 1,541.4
Fair Value - asset (liability)		(41.1)				(81.5)
Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Notional Amount		1,092.4				916.4
Fair Value - asset (liability)		(26.4)				(73.3)
Interest rate swaps | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | derivative	1
Interest rate swaps | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | mortgage			1
Notional Amount		250.0				250.0
Weighted Average Strike Rate				3.04%
Fair Value - asset (liability)		(11.9)				(22.6)
Cross-currency swaps | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | mortgage			4
Notional Amount		166.3				166.4
Fair Value - asset (liability)		(13.8)				(21.4)
GBP cross-currency swaps | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | derivative	4
Notional Amount		166.3
GBP cross-currency swaps | Designated as hedging instrument | Cash flow hedge | Minimum
Derivative [Line Items]
Fixed strike rate				4.82%
GBP cross-currency swaps | Designated as hedging instrument | Cash flow hedge | Maximum
Derivative [Line Items]
Fixed strike rate				10.96%
GBP cross-currency swaps | Designated as hedging instrument | Cash flow hedge | Weighted Average
Derivative [Line Items]
Weighted Average Strike Rate				9.78%
Foreign currency forwards | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | mortgage			32
Notional Amount		176.1				0.0
Fair Value - asset (liability)		7.6				$ 0.0
Weighted average forward exchange rate | Rate					141.00%
Forward-starting swaps | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | derivative	6					6	6
Notional Amount							$ 500.0
Forward-starting swaps | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | derivative	6
Forward-starting swap, derivative | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments	4		4
Notional Amount		300.0				$ 300.0
Weighted Average Strike Rate				1.86%
Fair Value - asset (liability)		(3.2)				(16.5)
Forward-starting swaps, hybrid debt | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments	2		2
Notional Amount		200.0				200.0
Weighted Average Strike Rate				1.93%
Fair Value - asset (liability)		(5.1)				(12.8)
Currency exchange swap | Not designated as hedging instrument
Derivative [Line Items]
Number of derivative instruments | mortgage			4
Notional Amount		1,639.5				625.0
Fair Value - asset (liability)		(14.7)				(8.2)
GBP currency exchange swap | Not designated as hedging instrument
Derivative [Line Items]
Number of derivative instruments | derivative	2
Notional Amount		1,360.0
Weighted average forward exchange rate | Rate					134.00%
EUR currency exchange swap | Not designated as hedging instrument
Derivative [Line Items]
Number of derivative instruments | derivative	2
Notional Amount		$ 275.9
Weighted average forward exchange rate | Rate					116.00%
Treasury rate locks | Cash flow hedge
Derivative [Line Items]
Notional Amount						$ 500.0		$ 500.0
Treasury rate locks | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of derivative instruments | derivative								5