v3.25.2
Cover
Jun. 30, 2025
Document Information [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Jun. 30, 2025
Entity File Number 001-33067
Entity Registrant Name SELECTIVE INSURANCE GROUP, INC.
Entity Central Index Key 0000230557
Entity Tax Identification Number 22-2168890
Entity Incorporation, State or Country Code NJ
Entity Address, Address Line One 40 Wantage Avenue
Entity Address, City or Town Branchville
Entity Address, State or Province NJ
Entity Address, Postal Zip Code 07890
City Area Code 973
Local Phone Number 948-3000
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Common Stock [Member]  
Document Information [Line Items]  
Title of 12(b) Security Common Stock, par value $2 per share
Trading Symbol SIGI
Security Exchange Name NASDAQ
Depositary Shares [Member]  
Document Information [Line Items]  
Title of 12(b) Security Depositary Shares, each representing a 1/1,000th interest in a share of 4.60% Non-Cumulative Preferred Stock, Series B, without par value
Trading Symbol SIGIP
Security Exchange Name NASDAQ