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Nominal or face amount used to calculate payment on derivative.

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Amount of gain (loss) from the increase (decrease) in fair value of foreign currency derivatives and nonderivative instruments designated as fair value hedging instruments which were recognized in earnings, net of offsets by the gain (loss) on the hedged item to the extent that the fair value hedge was determined to be effective.

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Derivative Contracts - Additional Information (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
	Oct. 01, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Reinsurance Contracts [Axis]: Funds withheld credited with interest for periods after October 1, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Reinsurance Retention Policy, Retrocession Premium, Interest Rate	1.75%
Level 3 \| Liability \| Fair Value, Recurring [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Liability, increase (decrease) in fv included in net income		$ 8.3		$ (14.5)
Foreign exchange contracts \| Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Purchase of US and foreign exchange		1,884.0		1,675.3	$ 1,545.7
Foreign exchange contracts \| Not Designated as Hedging Instrument \| Derivative At Fair Value
Derivative Instruments, Gain (Loss) [Line Items]
Purchase of US and foreign exchange		670.6		945.8	759.8
Foreign exchange contracts \| Not Designated as Hedging Instrument \| Liabilities Under Derivative Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Purchase of US and foreign exchange		1,213.4		729.5	785.9
Foreign exchange contracts \| Designated as Hedging Instrument \| Derivative At Fair Value
Derivative Instruments, Gain (Loss) [Line Items]
Purchase of US and foreign exchange		54.7		109.7	0.0
Foreign exchange contracts \| Designated as Hedging Instrument \| Liabilities Under Derivative Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Purchase of US and foreign exchange				0.0	143.1
Foreign exchange contracts \| Net change from current period hedged transactions \| Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency fair value hedge derivatives		(4.3)	$ (6.4)	15.4	(6.2)
Foreign exchange contracts \| General, administrative and corporate expenses \| Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on foreign currency fair value hedge derivatives		(3.7)	2.8	5.9	(5.7)
Foreign exchange contracts \| Gain (loss) on derivative instruments \| Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to net income from derivative instruments		19.6	(84.9)	(80.5)	$ (35.9)
Loss Portfolio Transfer \| Level 3 \| Liability \| Fair Value, Recurring [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Liability, increase (decrease) in fv included in net income				$ (14.5)
Loss Portfolio Transfer \| Fair value of derivatives \| Level 3 \| Fair Value, Recurring [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Liability, increase (decrease) in fv included in net income		$ 8.3	$ 0.0