Loss and Loss Adjustment Expense Reserves (Tables)

9 Months Ended

Sep. 30, 2019

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)	2019		2018
Balance, Beginning of period	$	15,400.8	$	13,086.9
Less reinsurance recoverables on unpaid losses	2,572.7		2,170.1
Net balance, Beginning of period	12,828.1		10,916.8
Incurred related to:
Current year	18,108.2		15,722.2
Prior years	215.2		47.0
Total incurred	18,323.4		15,769.2
Paid related to:
Current year	10,864.9		9,409.7
Prior years	6,061.7		5,031.9
Total paid	16,926.6		14,441.6
Net balance, End of period	14,224.9		12,244.4
Plus reinsurance recoverables on unpaid losses	3,145.1		2,376.4
Balance, End of period	$	17,370.0	$	14,620.8