Reinsurance - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2025	Jan. 02, 2025	Dec. 31, 2024
Insurance [Abstract]
Contract owner account balance uncer coinsurance		$ 3,800
Separate accounts liability under coinsurance		$ 20,600
Deposit asset	$ 900		$ 1,100
Funds withheld, funds held under reinsurance agreements, liability, direct	107		$ 103
Funds held under reinsurance agreements, liability, assumed	$ 900

Carrying amount of assets as of the balance sheet date pertaining to amounts paid by the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 340
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483081/340-30-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 340
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483054/340-30-50-1

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