Basis of Presentation (Tables)

9 Months Ended

Sep. 30, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Premium Receivable, Allowance for Credit Loss

The following table summarizes changes in our allowance for credit loss exposure on our premiums receivables:

	Three Months				Nine Months
Periods Ended September 30,	2021		2020		2021		2020
(millions)
Allowance for credit loss, beginning of period	$	245.2	$	437.9	$	356.2	$	283.2
Allowance acquired during period1	0		0		3.5		0
Increase (decrease) in allowance2	107.2		(3.6)		255.5		362.9
Write-offs3	(95.1)		(121.1)		(357.9)		(332.9)
Allowance for credit loss, end of period	$	257.3	$	313.2	$	257.3	$	313.2

1 Represents the amount of the allowance acquired in the Protective Insurance acquisition.

2 Represents the incremental increase (decrease) in other underwriting expenses.

3 Represents portion of allowance that is reversed when premiums receivables are written off.