Loss and Loss Adjustment Expense Reserves (Tables)

9 Months Ended

Sep. 30, 2024

Loss and Loss Adjustment Expenses Reserves [Abstract]

Schedule of Liability for Unpaid Claims and Claims Adjustment Expense

Activity in the loss and loss adjustment expense reserves is summarized as follows:

	September 30,
(millions)	2024		2023
Balance at January 1	$	34,389.2	$	30,359.3
Less reinsurance recoverables on unpaid losses	4,789.0		5,559.2
Net balance at January 1	29,600.2		24,800.1
Incurred related to:
Current year	36,276.6		33,035.0
Prior years	(199.4)		1,147.0
Total incurred	36,077.2		34,182.0
Paid related to:
Current year	19,669.0		18,581.3
Prior years	12,492.9		11,764.7
Total paid	32,161.9		30,346.0
Net balance at September 30	33,515.5		28,636.1
Plus reinsurance recoverables on unpaid losses	4,546.0		4,941.2
Balance at September 30	$	38,061.5	$	33,577.3