Variable Interest Entities - Narrative (Details) - Variable Interest Entity, Primary Beneficiary - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Variable Interest Entity [Line Items]
Notes payable	$ 123		$ 123		$ 123
Allstate Protection
Variable Interest Entity [Line Items]
Property and casualty insurance premiums	41	$ 45	83	$ 90
Incurred expense (adjustment)	$ 26	$ 29	$ 60	$ 67