Investments - Reverse Repurchase Agreements and Other Collateral Transactions (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Schedule of Investments [Abstract]
Securities for Reverse Repurchase Agreements	$ 278	$ 87

The carrying value of securities purchased to be resold in reverse repurchase transactions as of the balance sheet date.

No definition available.

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