Statutory Financial Information, Capital Requirements, and Restrictions on Dividends and Transfers of Funds (Tables)

12 Months Ended

Dec. 31, 2020

Insurance [Abstract]

Schedule of Insurance Subsidiaries Statutory Surplus Data

	State of Domicile	Unassigned Surplus			Statutory Surplus		Statutory Net Income
($ in millions)		2020		2019	2020	2019	2020	2019	2018
SICA	New Jersey	$	574.2	525.9	739.4	680.1	81.8	113.9	78.0
Selective Way Insurance Company ("SWIC")	New Jersey	374.0		339.2	430.0	388.2	54.0	59.2	47.5
SICSC	Indiana	148.6		132.6	182.8	163.8	20.8	23.9	16.5
SICSE	Indiana	115.9		103.1	143.5	128.7	16.8	18.5	12.9
SICNY	New York	111.7		99.4	139.4	127.1	15.3	17.0	12.0
Selective Insurance Company of New England ("SICNE")	New Jersey	30.0		25.3	61.2	55.4	6.8	7.8	5.6
Selective Auto Insurance Company of New Jersey ("SAICNJ")	New Jersey	70.0		62.5	114.9	105.4	12.9	14.9	9.9
MUSIC	New Jersey	34.4		27.1	103.9	95.6	11.4	13.2	9.4
Selective Casualty Insurance Company ("SCIC")	New Jersey	71.1		58.2	147.5	132.7	16.2	16.8	13.3
Selective Fire and Casualty Insurance Company ("SFCIC")	New Jersey	29.2		23.5	62.1	55.4	6.4	7.5	5.5
Total		$	1,559.1	1,396.8	2,124.7	1,932.4	242.4	292.7	210.6

Schedule of Insurance Subsidiaries Dividend Paid To Parent

Dividends		Twelve Months ended December 31, 2020		2021
($ in millions)	State of Domicile	Ordinary Dividends Paid		Maximum Ordinary Dividends
SICA	New Jersey	$	46.6	$	81.8
SWIC	New Jersey	22.5		54.1
SICSC	Indiana	7.5		20.8
SICSE	Indiana	5.3		16.8
SICNY	New York	3.0		13.9
SICNE	New Jersey	2.2		6.7
SAICNJ	New Jersey	5.9		12.9
MUSIC	New Jersey	6.0		11.4
SCIC	New Jersey	5.2		16.2
SFCIC	New Jersey	0.8		6.4
Total		$	105.0	$	241.0