Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=99404803&loc=d3e21412-158489

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=99397103&loc=d3e6824-158387

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (cc)
-URI https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437

Name:	us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Reinsurance and Indemnification - Reinsurance recoverables on paid and unpaid benefits (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	$ 9,606	$ 10,024
Property and casualty
Reinsurance Retention Policy [Line Items]
Paid and due from reinsurers and indemnitors	291	391
Unpaid losses estimated (including IBNR)	9,176	9,479	$ 7,033	$ 6,912
Reinsurance and indemnification recoverables, net	9,467	9,870
Accident and health insurance
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	$ 139	$ 154