XML 44 R28.htm IDEA: XBRL DOCUMENT
v3.25.2

Note 4 - Investments (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2025
Notes Tables |
Investment [Table Text Block] |
|  | June 30, |  |  | December 31, |
|  | 2025 |  |  | 2024 |
Current investments: |  |  |  |  |  |  |  |
Seeded investment products: |  |  |  |  |  |  |  |
Consolidated VIEs |  | $ | 1,059.4 |  |  | $ | 502.1 |
Consolidated VREs |  |  | 148.1 |  |  |  | 132.5 |
Unconsolidated VIEs and VREs |  |  | 91.5 |  |  |  | 127.1 |
Separately managed accounts |  |  | 41.6 |  |  |  | 41.9 |
Total seeded investment products |  |  | 1,340.6 |  |  |  | 803.6 |
Investments related to deferred compensation plans |  |  | 39.2 |  |  |  | 29.8 |
Other investments |  |  | 60.3 |  |  |  | 5.8 |
Total current investments |  | $ | 1,440.1 |  |  | $ | 839.2 |
Non-current investments: |  |  |  |  |  |  |  |
Equity method investments |  |  | 18.9 |  |  |  | 23.1 |
Other non-current investments |  |  | 8.9 |  |  |  | — |
Total investments |  | $ | 1,467.9 |  |  | $ | 862.3 |
Gain (Loss) on Securities [Table Text Block] |
|  | Three months ended |  |  | Six months ended |
|  | June 30, |  |  | June 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Seeded investment products and seed hedges, net |  | $ | 13.8 |  |  | $ | 4.6 |  |  | $ | 19.6 |  |  | $ | 16.5 |
Third-party ownership interests in seeded investment products |  |  | 36.7 |  |  |  | 3.8 |  |  |  | 33.4 |  |  |  | 14.3 |
Equity method investments |  |  | (1.6 | ) |  |  | (2.1 | ) |  |  | (3.3 | ) |  |  | (3.5 | )
Other |  |  | 3.7 |  |  |  | 0.1 |  |  |  | (2.6 | ) |  |  | 1.6 |
Investment gains, net |  | $ | 52.6 |  |  | $ | 6.4 |  |  | $ | 47.1 |  |  | $ | 28.9 |
Cash Flows Related to Investment Securities and Other Assets [Table Text Block] |
|  | Six months ended June 30, |
|  | 2025 |  |  | 2024 |
|  | Purchases |  |  | Sales, |  |  |  |  |  |  | Purchases |  |  | Sales, |  |  |  |  |
|  | and |  |  | settlements and |  |  | Net |  |  | and |  |  | settlements and |  |  | Net |
|  | settlements |  |  | maturities |  |  | cash flow |  |  | settlements |  |  | maturities |  |  | cash flow |
Investments by consolidated seeded investment products |  | $ | (348.1 | ) |  | $ | 40.4 |  |  | $ | (307.7 | ) |  | $ | (103.5 | ) |  | $ | 39.4 |  |  |  | (64.1 | )
Investments |  |  | (267.8 | ) |  |  | 101.4 |  |  |  | (166.4 | ) |  |  | (114.8 | ) |  |  | 72.6 |  |  |  | (42.2 | )

X
- Definition Tabular disclosure of cash flows related to investment securities and other assets. + References No definition available. + Details
Name: | jhg_CashFlowsRelatedToInvestmentSecuritiesAndOtherAssetsTableTextBlock
Namespace Prefix: | jhg_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of realized and unrealized gain (loss) on investment in security. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(9)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_GainLossOnInvestmentsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of investment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/320/tableOfContent Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Topic 321 -Publisher FASB -URI https://asc.fasb.org/321/tableOfContent Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Topic 325 -Publisher FASB -URI https://asc.fasb.org/325/tableOfContent + Details
Name: | us-gaap_InvestmentTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration