Reserve for Property and Casualty Insurance Claims and Claims Expense - Average annual percentage payout of incurred claims by age, net of reinsurance (Details)	Dec. 31, 2022
Auto insurance – liability coverage
Claims Development [Line Items]
1 year	37.60%
2 years	28.70%
3 years	13.30%
4 years	8.50%
5 years	5.30%
Auto insurance - physical damage coverage
Claims Development [Line Items]
1 year	95.20%
2 years	4.40%
3 years	(0.30%)
4 years	(1.50%)
5 years	1.60%
Homeowners
Claims Development [Line Items]
1 year	72.00%
2 years	21.30%
3 years	2.90%
4 years	0.80%
5 years	0.80%