Schedule VI. Supplementary Insurance Information Concerning Property-Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Line Items]
Current year	$ 4,024,116	$ 4,586,422	$ 4,125,557
Prior years	(450,607)	(247,582)	(249,470)
Consolidated Subsidiaries
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Line Items]
Deferred Policy Acquisition Costs	1,751,437	1,171,738	849,160
Reserves for Unpaid Claims and Claim Adjustment Expenses	20,486,869	15,892,573	13,294,630
Discount, if any, Deducted	0	0	0
Unearned Premiums	6,136,135	4,559,107	3,531,213
Earned Premiums	7,471,133	6,333,989	5,194,181
Net Investment Income	1,253,110	559,932	319,479
Current year	4,024,116	4,586,422	4,125,557
Prior years		(247,582)	(249,470)
Amortization of Deferred Policy Acquisition Costs	1,875,034	1,568,606	1,214,858
Paid Claims and Claim Adjustment Expenses	2,995,678	2,030,156	2,224,102
Net Premiums Written	$ 7,467,813	$ 7,196,160	$ 5,939,375