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.

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Schedule II - Condensed Financial Information of Registrant - Narrative (Details) - USD ($) $ in Millions			12 Months Ended
	Jun. 09, 2023	Jun. 17, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	May 14, 2024	Jun. 18, 2021
Condensed Financial Information of Registrant
Interest paid on debt			$ 395	$ 355	$ 323
Allstate Corporation
Condensed Financial Information of Registrant
Notes due to subsidiaries			350	0
Repayment of notes due to subsidiaries			0	1,000	1,000
Interest paid on debt			$ 395	$ 355	$ 323
Kennett Capital Inc \| Subsidiaries \| Allstate Corporation
Condensed Financial Information of Registrant
Notes due to subsidiaries		$ 1,000				$ 350	$ 1,000
Note stated interest rate (as a percent)		1.63%				5.57%	0.20%
Repayment of notes due to subsidiaries	$ 1,000	$ 1,000