Reinsurance (Tables)

12 Months Ended

Dec. 31, 2022

Reinsurance Disclosures [Abstract]

Effect of Reinsurance on Premiums Written and Earned

The effect of reinsurance on premiums written and earned for the years ended December 31, was as follows:

	2022				2021				2020
(millions)	Written		Earned		Written		Earned		Written		Earned
Direct premiums	$	52,335.6	$	50,650.2	$	48,129.6	$	46,018.6	$	41,736.4	$	40,687.7
Ceded premiums:
Regulated	(621.5)		(674.8)		(674.5)		(650.2)		(648.2)		(686.5)
Non-Regulated	(633.0)		(734.2)		(1,049.9)		(999.7)		(519.5)		(739.6)
Total ceded premiums	(1,254.5)		(1,409.0)		(1,724.4)		(1,649.9)		(1,167.7)		(1,426.1)
Net premiums	$	51,081.1	$	49,241.2	$	46,405.2	$	44,368.7	$	40,568.7	$	39,261.6

Prepaid Reinsurance Premiums and Reinsurance Recoverables

Our reinsurance recoverables and prepaid reinsurance premiums were comprised of the following at December 31:

	Reinsurance Recoverables								Prepaid Reinsurance Premiums
($ in millions)	2022				2021				2022				2021
Regulated:
MCCA	$	2,332.3	40	%	$	2,364.0	47	%	$	26.4	9	%	$	26.7	6	%
CAIP	626.8		11		529.0		11		50.4		17		111.2		24
FHCF	437.3		7		81.3		2		0		0		0		0
NFIP	215.4		4		13.9		0		60.1		20		62.4		14
NCRF	143.2		2		118.7		2		54.5		18		44.4		10
Other	2.9		0		2.2		0		1.5		1		1.4		0
Total Regulated	3,757.9		64		3,109.1		62		192.9		65		246.1		54
Non-Regulated:
Commercial Lines	1,544.3		27		1,518.4		31		91.0		31		198.2		43
Property	524.4		9		345.8		7		11.6		4		13.3		3
Other	5.5		0		7.2		0		0		0		0		0
Total Non-Regulated	2,074.2		36		1,871.4		38		102.6		35		211.5		46
Total	$	5,832.1	100	%	$	4,980.5	100	%	$	295.5	100	%	$	457.6	100	%