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.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 944
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479808/944-20-55-15

Name:	us-gaap_NetAmountAtRiskByProductAndGuaranteeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Short- Duration Insurance Contracts - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property & Casualty
Net Amount at Risk by Product and Guarantee [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years	$ 0	$ (2,000,000.0)	$ 0	$ (8,000,000.0)
Group Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years			$ 15,500,000	$ (11,700,000)