Variable Interest Entities - Narrative (Details) - Variable Interest Entity, Primary Beneficiary - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Variable Interest Entity [Line Items]
Notes payable	$ 123		$ 123		$ 123
Allstate Protection
Variable Interest Entity [Line Items]
Insurance premiums and contract charges	59	$ 39	173	$ 122
Costs and expenses	$ 58	$ 61	$ 202	$ 174