v3.25.1
Cover
May 16, 2025
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date May 16, 2025
Entity File Number 001-38103
Entity Registrant Name JANUS HENDERSON GROUP PLC
Entity Central Index Key 0001274173
Entity Tax Identification Number 98-1376360
Entity Incorporation, State or Country Code Y9
Entity Address, Address Line One 201 Bishopsgate
Entity Address, City or Town London
Entity Address, Country GB
Entity Address, Postal Zip Code EC2M3AE
Country Region +44
City Area Code (0) 20
Local Phone Number 7818 1818
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, $1.50 Per Share Par Value
Trading Symbol JHG
Security Exchange Name NYSE
Entity Emerging Growth Company false