Janus Henderson (JHG) 10-Q 3 May 23 2023 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 01, 2023
Document Information [Line Items]
Entity Central Index Key	0001274173
Entity Registrant Name	JANUS HENDERSON GROUP PLC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2023
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-38103
Entity Incorporation, State or Country Code	Y9
Entity Tax Identification Number	98-1376360
Entity Address, Address Line One	201 Bishopsgate
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	EC2M3AE
City Area Code	0
Local Phone Number	20 7818 1818
Title of 12(b) Security	Common Stock, $1.50 Per Share Par Value
Trading Symbol	JHG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		165,657,905

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 843.5	$ 1,162.3
Investment securities	388.2	261.6
Fees and other receivables	263.3	252.9
OEIC and unit trust receivables	195.7	65.7
Other current assets	115.9	120.3
Total current assets	2,293	2,214.8
Non-current assets:
Property, equipment and software, net	49.8	51.8
Intangible assets, net	2,422.2	2,414.7
Goodwill	1,269.7	1,253.1
Retirement benefit asset, net	101	97.9
Other non-current assets	220.4	205.5
Total assets	6,356.1	6,237.8
Current liabilities:
Accounts payable and accrued liabilities	218.5	232.6
Current portion of accrued compensation, benefits and staff costs	151.2	300.8
OEIC and unit trust payables	202.8	72.8
Total current liabilities	576.4	610.5
Non-current liabilities:
Accrued compensation, benefits and staff costs	22.8	46.9
Long-term debt	306.8	307.5
Deferred tax liabilities, net	576.4	574.6
Retirement benefit obligations, net	3.1	3
Other non-current liabilities	95.2	98.8
Total liabilities	1,580.7	1,641.3
Commitments and contingencies (See Note 15)
REDEEMABLE NONCONTROLLING INTERESTS	384.7	233.9
EQUITY
Common stock, $1.50 par value; 480,000,000 shares authorized, and 165,657,905 and 165,657,905 shares issued and outstanding as of March 31, 2023, and December 31, 2022, respectively	248.5	248.5
Additional paid-in capital	3,663.4	3,706.6
Treasury shares, 43,318 and 312,469 shares held at March 31, 2023, and December 31, 2022, respectively	(1.1)	(8.3)
Accumulated other comprehensive loss, net of tax	(606.3)	(647.7)
Retained earnings	1,083.4	1,060.7
Total shareholders’ equity	4,387.9	4,359.8
Nonredeemable noncontrolling interests	2.8	2.8
Total equity	4,390.7	4,362.6
Total liabilities, redeemable noncontrolling interests and equity	6,356.1	6,237.8
Variable Interest Entity, Primary Beneficiary [Member]
Current assets:
Cash and cash equivalents	18.8	14.1
Investment securities	462	334.3
Other current assets	5.6	3.6
Current liabilities:
Accounts payable and accrued liabilities	$ 3.9	$ 4.3

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Common stock, par value (in dollars per share)	$ 1.50	$ 1.50
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares issued (in shares)	165,657,905	165,657,905
Common stock, shares outstanding (in shares)	165,657,905	165,657,905
Treasury shares (in shares)	43,318	312,469

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue:
Total revenue	$ 495.8	$ 620
Operating expenses:
Employee compensation and benefits	140.3	164.6
Long-term incentive plans	55.5	51.4
Distribution expenses	112	141.8
Investment administration	11.6	14.8
Marketing	8.8	7.4
General, administrative and occupancy	61.1	73.1
Depreciation and amortization	6.1	9.5
Total operating expenses	395.4	462.6
Operating income:	100.4	157.4
Interest expense	(3.1)	(3.2)
Investment gains (losses), net	17.6	(32.2)
Other non-operating income (expenses), net	7.1	(7.8)
Income before taxes	122	114.2
Income tax benefit (provision)	(26)	(30.7)
Net income	96	83.5
Net loss (income) attributable to noncontrolling interests	(8.6)	20.1
Net income attributable to JHG	$ 87.4	$ 103.6
Earnings (loss) per share attributable to JHG common shareholders:
Basic (in dollars per share)	$ 0.53	$ 0.62
Diluted (in dollars per share)	$ 0.53	$ 0.61
Other comprehensive income (loss), net of tax:
Foreign currency translation gains (losses)	$ 44.5	$ (47)
Actuarial gains	0.1	0.1
Other comprehensive income (loss), net of tax	44.6	(46.9)
Other comprehensive income attributable to noncontrolling interests	(3.2)	(0.2)
Other comprehensive income (loss) attributable to JHG	41.4	(47.1)
Total comprehensive income	140.6	36.6
Total comprehensive loss (income) attributable to noncontrolling interests	(11.8)	19.9
Total comprehensive income attributable to JHG	128.8	56.5
Investment Advice [Member]
Revenue:
Total revenue	414.6	514
Investment Performance [Member]
Revenue:
Total revenue	(14.9)	(8.4)
Shareholder Service [Member]
Revenue:
Total revenue	51.5	62.4
Product and Service, Other [Member]
Revenue:
Total revenue	$ 44.6	$ 52

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Operating activities:
Net income	$ 96	$ 83.5
Adjustments to reconcile net income to net cash used for operating activities:
Depreciation and amortization	6.1	9.5
Deferred income taxes	1	8.1
Stock-based compensation plan expense	21.6	22.6
Loss on sale of Intech	0	9.1
Investment losses (gains), net	(17.6)	32.2
Contributions to pension plans in excess of costs recognized	(0.4)	(0.1)
Other, net	(1.4)	11.3
Changes in operating assets and liabilities:
OEIC and unit trust receivables and payables	0	(0.6)
Other assets	(22.1)	(1.1)
Other accruals and liabilities	(191.4)	(232)
Net operating activities	(108.2)	(57.5)
Investing activities:
Investment securities, net	(107.5)	(34.2)
Property, equipment and software	(2)	(2.9)
Investment securities by consolidated seeded investment products, net	(123.2)	13
Cash received (paid) on settled seed capital hedges, net	(3.1)	11.7
Dividends received from equity-method investments	0.7	0.5
Long-term note with Intech	0	(10)
Proceeds from sale of Intech	0	5
Net investing activities	(235.1)	(16.9)
Financing activities:
Proceeds from stock-based compensation plans	0	0.5
Purchase of common stock for stock-based compensation plans	(57.5)	(94.5)
Purchase of common stock for share buyback program	0	(43.3)
Dividends paid to shareholders	(64.7)	(64.3)
Distributions to noncontrolling interests	0	(1.3)
Third-party sales (purchases) in consolidated seeded investment products, net	136.2	(11.7)
Principal payments under capital lease obligations	(0.2)	(0.2)
Net financing activities	13.8	(214.8)
Cash and cash equivalents:
Effect of foreign exchange rate changes	15.4	(16)
Net change	(314.1)	(305.2)
At beginning of period	1,176.4	1,118.6
At end of period	862.3	813.4
Supplemental cash flow information:
Cash paid for interest	7.3	7.3
Cash paid for income taxes, net of refunds	14.1	18.4
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	862.3	813.4
Consolidated Entity, Excluding VIE [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	843.5	800.8
Variable Interest Entity, Primary Beneficiary [Member]
Reconciliation of cash and cash equivalents:
Total cash and cash equivalents	$ 18.8	$ 12.6

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes In Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock, Common [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2021	169
Balance at Dec. 31, 2021	$ 253.6	$ 3,771.8	$ (55.1)	$ (387)	$ 1,040.2	$ 15.4	$ 4,638.9
Net income	0	0	0	0	103.6	0	103.6
Other comprehensive income	0	0	0	(47.1)	0	0	(47.1)
Dividends paid to shareholders	0	0	0	0	(64.3)	0	(64.3)
Purchase of common stock for stock-based compensation plans	0	(94.1)	(0.4)	0	0	0	(94.5)
Vesting of stock-based compensation plans	0	(15.2)	15.2	0	0	0	0
Stock-based compensation plan expense	$ 0	21.9	0	0	0	0	21.9
Purchase of common stock from share buyback program (in shares)	(1.2)
Purchase of common stock from share buyback program	$ (1.9)	0	0	0	(41.4)	0	(43.3)
Distributions to noncontrolling interests	0	0	0	0	0	(1)	(1)
Sale of Intech	0	0	0	0	0	(11.6)	(11.6)
Fair value adjustments to redeemable noncontrolling interests	0	0	0	0	1.4	0	1.4
Proceeds from stock-based compensation plans	$ 0	0.5	0	0	0	0	0.5
Balance (in shares) at Mar. 31, 2022	167.8
Balance at Mar. 31, 2022	$ 251.7	3,684.9	(40.3)	(434.1)	1,039.5	2.8	4,504.5
Balance (in shares) at Dec. 31, 2022	165.7
Balance at Dec. 31, 2022	$ 248.5	3,706.6	(8.3)	(647.7)	1,060.7	2.8	4,362.6
Net income	0	0	0	0	87.4	0	87.4
Other comprehensive income	0	0	0	41.4	0	0	41.4
Dividends paid to shareholders	0		0	0	(64.7)	0	(64.7)
Dividends paid to shareholders		0
Purchase of common stock for stock-based compensation plans	0	(57.3)	(0.2)	0	0	0	(57.5)
Vesting of stock-based compensation plans	0	(7.5)	7.4	0	0	0	(0.1)
Stock-based compensation plan expense	$ 0	21.6	0	0	0	0	21.6
Balance (in shares) at Mar. 31, 2023	165.7
Balance at Mar. 31, 2023	$ 248.5	$ 3,663.4	$ (1.1)	$ (606.3)	$ 1,083.4	$ 2.8	$ 4,390.7

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes In Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Dividends paid (in dollars per share)	$ 0.39	$ 0.38

Note 1 - Basis of Presentation

Note 1 - Basis of Presentation	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Basis of Presentation and Significant Accounting Policies [Text Block]	Note 1 Basis of Presentation Basis of Presentation In the opinion of management of Janus Henderson Group plc (“JHG,” “the Company,” “we,” “us,” “our” and similar terms), the accompanying unaudited condensed consolidated financial statements contain all normal recurring adjustments necessary to fairly state our financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Such financial statements have been prepared in accordance with the instructions to Form 10 not 10 December 31, 2022 Revision of Previously Issued Financial Statements In conjunction with the preparation of our third 2022 2021 2020 2022 not 2022 2022 In the first 2020, first 2020, not first 2022 third 2022 The following table presents line items for the financial statements for the three March 31, 2022, March 31, 2022, not The impact of the error on the Condensed Consolidated Statements of Comprehensive Income for the three March 31, 2022, Three months ended March 31, 2022 As previously reported Impact of revisions As revised Operating expenses: Impairment of goodwill and intangible assets $ 32.8 $ (32.8 ) $ — Total operating expenses 495.4 (32.8 ) 462.6 Operating income (loss) 124.6 32.8 157.4 Income (loss) before taxes 81.4 32.8 114.2 Income tax benefit (provision) (22.8 ) (7.9 ) (30.7 ) Net income (loss) 58.6 24.9 83.5 Net income (loss) attributable to JHG $ 78.7 $ 24.9 $ 103.6 Earnings (loss) per share attributable to JHG common shareholders: Basic $ 0.47 $ 0.15 $ 0.62 Diluted $ 0.47 $ 0.14 $ 0.61 Other comprehensive income (loss), net of tax: Total comprehensive income (loss) $ 11.7 $ 24.9 $ 36.6 Total comprehensive income (loss) attributable to JHG $ 31.6 $ 24.9 $ 56.5 ​

Note 2 - Dispositions

Note 2 - Dispositions	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	Note 2 Dispositions On February 3, 2022, March 31, 2022, seventh ​ The terms of the transaction also included a $20.0 million seven first second March 31, 2023 first second

Note 3 - Consolidation

Note 3 - Consolidation	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Variable Interest Entities Voting Rights Entities Consolidation Disclosure [Text Block]	Note 3 Consolidation Variable Interest Entities Consolidated Variable Interest Entities Our consolidated variable interest entities (“VIEs”) as of March 31, 2023 December 31, 2022 not may not, third no ​ Unconsolidated Variable Interest Entities As of March 31, 2023 December 31, 2022 Voting Rights Entities Consolidated Voting Rights Entities The following table presents the balances related to consolidated voting rights entities (“VREs”) that were recorded on our Condensed Consolidated Balance Sheets, including our net interest in these products (in millions): March 31, December 31, 2023 2022 Investment securities $ 308.2 $ 206.0 Cash and cash equivalents 14.1 5.8 Other current assets 6.7 1.8 Accounts payable and accrued liabilities (2.9 ) (1.0 ) Total $ 326.1 $ 212.6 Redeemable noncontrolling interests in consolidated VREs (92.7 ) (35.1 ) JHG's net interest in consolidated VREs $ 233.4 $ 177.5 Third-party assets held in consolidated VREs are not may not, third no Our total exposure to consolidated VREs represents the value of our economic ownership interest in these seeded investment products. Unconsolidated Voting Rights Entities As of March 31, 2023 December 31, 2022

Note 4 - Investment Securities

Note 4 - Investment Securities	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Investment [Text Block]	Note 4 Investment Securities Our investment securities as of March 31, 2023 December 31, 2022 March 31, December 31, 2023 2022 Seeded investment products: Consolidated VIEs $ 462.0 $ 334.3 Consolidated VREs 308.2 206.0 Unconsolidated VIEs and VREs 5.7 4.9 Separate accounts 52.6 29.7 Total seeded investment products 828.5 574.9 Investments related to deferred compensation plans 11.2 10.7 Other investments 10.5 10.3 Total investment securities $ 850.2 $ 595.9 ​ Trading Securities Net unrealized gains (losses) on investment securities held as of March 31, 2023 2022 three March 31, 2023 2022 Three months ended March 31, 2023 2022 Unrealized gains (losses) on investment securities held at period end $ 17.6 $ (32.2 ) ​ Investment Gains (Losses), Net Investment gains (losses), net on our Condensed Consolidated Statements of Comprehensive Income included the following for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Seeded investment products and hedges, net $ 22.6 $ (11.5 ) Third-party ownership interests in seeded investment products (8.6 ) (20.1 ) Long Tail Alpha investment 3.0 1.5 Deferred equity plan — (1.5 ) Other 0.6 (0.6 ) Investment gains (losses), net $ 17.6 $ (32.2 ) ​ Gains and losses attributable to third not Cash Flows Cash flows related to our investment securities for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investment securities by consolidated seeded investment products $ (142.3 ) $ 19.1 $ (123.2 ) $ (3.9 ) $ 16.9 $ 13.0 Investment securities (113.2 ) 5.7 (107.5 ) (40.5 ) 6.3 (34.2 )

Note 5 - Derivative Instruments

Note 5 - Derivative Instruments	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Note 5 Derivative Instruments Derivative Instruments Used to Hedge Seeded Investment Products We maintain an economic hedge program that uses derivative instruments to mitigate against market exposure of certain seeded investments by using index and commodity futures (“futures”), total return swaps and credit default swaps. Certain foreign currency exposures associated with our seeded investment products are also hedged by using foreign currency forward contracts and swaps. We were party to the following derivative instruments as of March 31, 2023 December 31, 2022 Notional value March 31, 2023 December 31, 2022 Futures $ 361.4 $ 196.8 Credit default swaps 157.1 115.1 Total return swaps 40.7 37.2 Foreign currency forward contracts and swaps 180.6 131.7 The derivative instruments are not three March 31, 2023 2022 Three months ended March 31, 2023 2022 Futures $ (6.7 ) $ 15.4 Credit default swaps (1.9 ) 2.3 Total return swaps (6.0 ) 7.4 Foreign currency forward contracts and swaps 4.5 (7.0 ) Total gains (losses) from derivative instruments $ (10.1 ) $ 18.1 Derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities on our Condensed Consolidated Balance Sheets. The derivative assets and liabilities as of March 31, 2023 December 31, 2022 Fair value March 31, 2023 December 31, 2022 Derivative assets $ 9.5 $ 5.3 Derivative liabilities 13.4 4.0 In addition to using derivative instruments to mitigate against market exposure of certain seeded investments, we also engage in short sales of securities to hedge seed investments. As of March 31, 2023 December 31, 2022 not Derivative Instruments in Consolidated Seeded Investment Products Certain of our consolidated seeded investment products utilize derivative instruments to contribute to the achievement of defined investment objectives. These derivative instruments are classified within other current assets or in accounts payable and accrued liabilities on our Condensed Consolidated Balance Sheets. Gains and losses on these derivative instruments are classified within investment gains (losses), net on our Condensed Consolidated Statements of Comprehensive Income. Our consolidated seeded investment products were party to the following derivative instruments as of March 31, 2023 December 31, 2022 Notional value March 31, 2023 December 31, 2022 Futures $ 308.7 $ 141.3 Credit default swaps 2.9 2.2 Total return swaps 10.0 10.4 Options 1.2 0.1 Foreign currency forward contracts and swaps 61.1 18.3 ​ As of March 31, 2023 December 31, 2022 Derivative Instruments Foreign Currency Hedging Program We maintain a foreign currency hedging program to take reasonable measures to minimize the income statement effects of foreign currency remeasurement of monetary balance sheet accounts. The program utilizes foreign currency forward contracts and swaps to achieve its objectives, and it is considered an economic hedge for accounting purposes. The notional value of the foreign currency forward contracts and swaps as of March 31, 2023 December 31, 2022 Notional value March 31, 2023 December 31, 2022 Foreign currency forward contracts and swaps $ 76.4 $ 74.7 ​ The derivative assets and liabilities are generally recognized on a gross basis and included in other current assets or in accounts payable and accrued liabilities on our Condensed Consolidated Balance Sheets. As of March 31, 2023 December 31, 2022 Changes in fair value of the derivatives are recognized in other non-operating income (expenses), net on our Condensed Consolidated Statements of Comprehensive Income. Foreign currency remeasurement is also recognized in other non-operating income (expenses), net on our Condensed Consolidated Statements of Comprehensive Income. For the three March 31, 2023 2022 ​

Note 6 - Fair Value Measurement

Note 6 - Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Fair Value Disclosures [Text Block]	Note 6 Fair Value Measurements The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of March 31, 2023 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 514.5 $ — $ — $ 514.5 Investment securities: Consolidated VIEs 306.2 150.8 5.0 462.0 Other investment securities 299.1 88.9 0.2 388.2 Total investment securities 605.3 239.7 5.2 850.2 Seed hedge derivatives — 9.5 — 9.5 Derivatives used in consolidated seeded investment products — 1.4 — 1.4 Derivatives used in foreign currency hedging program — 0.7 — 0.7 Intech option agreement — — 0.4 0.4 Intech contingent consideration — — 12.0 12.0 Volantis contingent consideration — — 0.2 0.2 Total assets $ 1,119.8 $ 251.3 $ 17.8 $ 1,388.9 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 1.1 $ — $ 1.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Securities sold, not yet purchased 1.5 — — 1.5 Seed hedge derivatives — 13.4 — 13.4 Long-term debt (1) — 297.9 — 297.9 Deferred bonuses — — 60.0 60.0 Total liabilities $ 1.5 $ 312.8 $ 60.0 $ 374.3 ​ ( 1 Carried at amortized cost and disclosed at fair value. ​ The following table presents assets and liabilities reflected in the financial statements or disclosed in the notes to the financial statements at fair value on a recurring basis as of December 31, 2022 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 688.4 $ — $ — $ 688.4 Investment securities: Consolidated VIEs 275.4 54.0 4.9 334.3 Other investment securities 171.9 89.4 0.3 261.6 Total investment securities 447.3 143.4 5.2 595.9 Seed hedge derivatives — 5.3 — 5.3 Derivatives used in consolidated seeded investment products — 0.1 — 0.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Intech option agreement — — 0.8 0.8 Intech contingent consideration — — 12.1 12.1 Volantis contingent consideration — — 0.2 0.2 Total assets $ 1,135.7 $ 149.2 $ 18.3 $ 1,303.2 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 0.6 $ — $ 0.6 Derivatives used in foreign currency hedging program — 1.1 — 1.1 Securities sold, not yet purchased 0.5 — — 0.5 Seed hedge derivatives — 4.0 — 4.0 Long-term debt (1) — 295.4 — 295.4 Deferred bonuses — — 46.5 46.5 Total liabilities $ 0.5 $ 301.1 $ 46.5 $ 348.1 ( 1 Carried at amortized cost and disclosed at fair value. Level 1 Our Level 1 not Level 2 Our Level 2 2 Level 3 Investment Securities As of March 31, 2023 December 31, 2022 3 Intech Option Agreement and Contingent Consideration ​ As of March 31, 2023 December 31, 2022 Deferred Bonuses ​ Deferred bonuses represent liabilities to employees over the vesting period that will be settled by investments in our products or cash. The significant unobservable inputs used to value the liabilities are investment designations and vesting periods. Changes in Fair Value Changes in fair value of our Level 3 three March 31, 2023 2022 Three months ended March 31, 2023 2022 Beginning of period fair value $ 18.3 $ 8.8 Intech option agreement — 3.9 Contingent consideration from sale of Intech — 12.6 Fair value adjustments (0.5 ) (1.5 ) Purchases of securities — (0.2 ) Sales of securities — (0.3 ) Foreign currency translation — (0.1 ) End of period fair value $ 17.8 $ 23.2 Changes in fair value of our individual Level 3 three March 31, 2023 2022 Three months ended March 31, 2023 2022 Deferred Deferred bonuses bonuses Beginning of period fair value $ 46.5 $ 50.5 Fair value adjustments 1.5 (1.6 ) Vesting of deferred bonuses (33.2 ) (21.6 ) Amortization of deferred bonuses 8.4 8.4 Foreign currency translation 1.0 (1.4 ) Additions 35.8 — End of period fair value $ 60.0 $ 34.3 Nonrecurring Fair Value Measurements Nonrecurring Level 3 3.

Note 7 - Goodwill and Intangibl

Note 7 - Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Goodwill and Intangible Assets Disclosure [Text Block]	Note 7 Goodwill and Intangible Assets The following tables present movements in our intangible assets and goodwill during the three March 31, 2023 2022 Foreign December 31, currency March 31, 2022 Amortization Disposal translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ — $ 8.1 $ 2,054.6 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — — 0.7 69.6 Accumulated amortization (60.7 ) (0.5 ) — (0.8 ) (62.0 ) Net intangible assets $ 2,414.7 $ (0.5 ) $ — $ 8.0 $ 2,422.2 Goodwill $ 1,253.1 $ — $ — $ 16.6 $ 1,269.7 Foreign December 31, currency March 31, 2021 Amortization Disposal translation 2022 Indefinite-lived intangible assets: Investment management agreements $ 2,114.8 $ — $ — $ (7.8 ) $ 2,107.0 Trademarks 366.7 — (4.7 ) — 362.0 Definite-lived intangible assets: Client relationships 168.4 — (84.8 ) 0.1 83.7 Accumulated amortization (107.2 ) (1.9 ) 44.7 0.6 (63.8 ) Net intangible assets $ 2,542.7 $ (1.9 ) $ (44.8 ) $ (7.1 ) $ 2,488.9 Goodwill $ 1,341.5 $ — $ (7.0 ) $ (17.7 ) $ 1,316.8 Management Buyout of Intech As detailed in Note 2 March 31, 2022, Future Amortization Expected future amortization expense related to client relationships is summarized below (in millions): Future amortization Amount 2023 (remainder of year) $ 1.2 2024 0.4 2025 0.4 2026 0.4 2027 0.4 Thereafter 4.8 Total $ 7.6 ​

Note 8 - Debt

Note 8 - Debt	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 8 Debt Our debt as of March 31, 2023 December 31, 2022 ​ March 31, 2023 December 31, 2022 ​ Carrying Fair Carrying Fair ​ value value value value 4.875% Senior Notes due 2025 $ 306.8 $ 297.9 $ 307.5 $ 295.4 ​ 4.875% 2025 The 4.875% Senior Notes due 2025 “2025 February 1 August 1 August 1, 2025. 2025 March 31, 2023 2025 Credit Facility At March 31, 2023 may 3.00x March 31, 2023 February 16, 2024.

Note 9 - Income Taxes

Note 9 - Income Taxes	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 9 Income Taxes Our effective tax rates for the three March 31, 2023 2022 ​ Three months ended ​ March 31, ​ 2023 2022 Effective tax rate 21.3 % 26.8 % The effective tax rate for the three March 31, 2023 three March 31, 2022 As of March 31, 2023, 12

Note 10 - Noncontrolling Intres

Note 10 - Noncontrolling Intrests	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Noncontrolling Interest Disclosure [Text Block]	Note 10 Noncontrolling Interests Redeemable Noncontrolling Interests Redeemable noncontrolling interests as of March 31, 2023 December 31, 2022 March 31, December 31, 2023 2022 Redeemable noncontrolling interests in: Consolidated seeded investment products $ 384.7 $ 233.9 ​ Consolidated Seeded Investment Products Noncontrolling interests in consolidated seeded investment products are classified as redeemable noncontrolling interests when there is an obligation to repurchase units at the investor’s request. Redeemable noncontrolling interests in consolidated seeded investment products may third The following table presents the movement in redeemable noncontrolling interests in consolidated seeded investment products for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Opening balance $ 233.9 $ 148.5 Changes in market value 8.6 (20.1 ) Changes in ownership 140.2 22.2 Foreign currency translation 2.0 0.1 Closing balance $ 384.7 $ 150.7 Nonredeemable Noncontrolling Interests Nonredeemable noncontrolling interests as of March 31, 2023 December 31, 2022 March 31, December 31, 2023 2022 Nonredeemable noncontrolling interests in: Seed capital investments $ 2.8 $ 2.8

Note 11 - Long-Term Incentive a

Note 11 - Long-Term Incentive and Employee Compensation	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Share-Based Payment Arrangement [Text Block]	Note 11 Long-Term Incentive and Employee Compensation The following table presents restricted stock and mutual fund awards granted during the three March 31, 2023 Three months ended March 31, 2023 Restricted stock $ 60.1 Mutual fund awards 53.9 Total $ 114.0 ​ Restricted stock and mutual fund awards generally vest and will be recognized using a graded vesting method over a three

Note 12 - Retirement Benefit Pl

Note 12 - Retirement Benefit Plans	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Retirement Benefits [Text Block]	Note 12 Retirement Benefit Plans We operate defined contribution retirement benefit plans and defined benefit pension plans. Our primary defined benefit pension plan is the defined benefit section of the Janus Henderson Group UK Pension Scheme (“JHGPS”). Net Periodic Benefit Cost The components of net periodic benefit cost in respect of defined benefit plans for the three March 31, 2023 2022 ​ Three months ended March 31, 2023 2022 Interest cost $ (6.8 ) $ (4.5 ) Amortization of prior service cost (0.1 ) (0.1 ) Expected return on plan assets 6.6 4.5 Net periodic benefit cost $ (0.3 ) $ (0.1 )

Note 13 - Accumulated Other Com

Note 13 - Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Comprehensive Income (Loss) Note [Text Block]	Note 13 Accumulated Other Comprehensive Loss Changes in accumulated other comprehensive loss, net of tax for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (577.3 ) $ (70.4 ) $ (647.7 ) $ (354.2 ) $ (32.8 ) $ (387.0 ) Other comprehensive income (loss) 44.5 — 44.5 (47.8 ) — (47.8 ) Amounts reclassified from accumulated other comprehensive loss — 0.1 0.1 0.8 0.1 0.9 Total other comprehensive income (loss) 44.5 0.1 44.6 (47.0 ) 0.1 (46.9 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (3.2 ) — (3.2 ) (0.2 ) — (0.2 ) Ending balance $ (536.0 ) $ (70.3 ) $ (606.3 ) $ (401.4 ) $ (32.7 ) $ (434.1 ) ​ The components of other comprehensive loss, net of tax for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 41.5 $ 3.0 $ 44.5 $ (49.0 ) $ 1.2 $ (47.8 ) Reclassifications to net income 0.1 — 0.1 0.9 — 0.9 Total other comprehensive loss $ 41.6 $ 3.0 $ 44.6 $ (48.1 ) $ 1.2 $ (46.9 ) ​

Note 14 - Earnings and Dividend

Note 14 - Earnings and Dividends Per Share	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Earnings and Dividends Per Share [Text Block]	Note 14 Earnings and Dividends Per Share Earnings Per Share The following is a summary of the earnings per share calculation for the three March 31, 2023 2022 Three months ended March 31, 2023 2022 Net income attributable to JHG $ 87.4 $ 103.6 Allocation of earnings to participating stock-based awards (2.4 ) (2.6 ) Net income attributable to JHG common shareholders $ 85.0 $ 101.0 Weighted-average common shares outstanding — basic 160.2 164.0 Dilutive effect of nonparticipating stock-based awards 0.2 0.5 Weighted-average common shares outstanding — diluted 160.4 164.5 Earnings per share: Basic (two class) $ 0.53 $ 0.62 Diluted (two class) $ 0.53 $ 0.61 Dividends Per Share The payment of cash dividends is within the discretion of our Board of Directors and depends on many factors, including, but not The following is a summary of cash dividends declared and paid during the three March 31, 2023 Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 February 1, 2023 $ 64.7 February 28, 2023 On May 2, 2023 first 2023 May 31, 2023 May 15, 2023

Note 15 - Commitments and Conti

Note 15 - Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 15 Commitments and Contingencies Commitments and contingencies may ​ Litigation and Other Regulatory Matters We are periodically involved in various legal proceedings and other regulatory matters. ​ Sandra Schissler v Janus Henderson US (Holdings) Inc., Janus Henderson Advisory Committee, and John and Jane Does 1 30 On September 9, 2022, Schissler v. Janus Henderson US (Holdings) Inc., et al. 401 September 9, 2016. January 10, 2023, November 23, 2022, two September 9, 2016, September 9, 2022, February 9, 2023, March 13, 2023, March 28, 2023.

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation In the opinion of management of Janus Henderson Group plc (“JHG,” “the Company,” “we,” “us,” “our” and similar terms), the accompanying unaudited condensed consolidated financial statements contain all normal recurring adjustments necessary to fairly state our financial position, results of operations and cash flows in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Such financial statements have been prepared in accordance with the instructions to Form 10 not 10 December 31, 2022
Reclassification, Comparability Adjustment [Policy Text Block]	Revision of Previously Issued Financial Statements In conjunction with the preparation of our third 2022 2021 2020 2022 not 2022 2022 In the first 2020, first 2020, not first 2022 third 2022 The following table presents line items for the financial statements for the three March 31, 2022, March 31, 2022, not The impact of the error on the Condensed Consolidated Statements of Comprehensive Income for the three March 31, 2022, Three months ended March 31, 2022 As previously reported Impact of revisions As revised Operating expenses: Impairment of goodwill and intangible assets $ 32.8 $ (32.8 ) $ — Total operating expenses 495.4 (32.8 ) 462.6 Operating income (loss) 124.6 32.8 157.4 Income (loss) before taxes 81.4 32.8 114.2 Income tax benefit (provision) (22.8 ) (7.9 ) (30.7 ) Net income (loss) 58.6 24.9 83.5 Net income (loss) attributable to JHG $ 78.7 $ 24.9 $ 103.6 Earnings (loss) per share attributable to JHG common shareholders: Basic $ 0.47 $ 0.15 $ 0.62 Diluted $ 0.47 $ 0.14 $ 0.61 Other comprehensive income (loss), net of tax: Total comprehensive income (loss) $ 11.7 $ 24.9 $ 36.6 Total comprehensive income (loss) attributable to JHG $ 31.6 $ 24.9 $ 56.5 ​

Note 1 - Basis of Presentation

Note 1 - Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	Three months ended March 31, 2022 As previously reported Impact of revisions As revised Operating expenses: Impairment of goodwill and intangible assets $ 32.8 $ (32.8 ) $ — Total operating expenses 495.4 (32.8 ) 462.6 Operating income (loss) 124.6 32.8 157.4 Income (loss) before taxes 81.4 32.8 114.2 Income tax benefit (provision) (22.8 ) (7.9 ) (30.7 ) Net income (loss) 58.6 24.9 83.5 Net income (loss) attributable to JHG $ 78.7 $ 24.9 $ 103.6 Earnings (loss) per share attributable to JHG common shareholders: Basic $ 0.47 $ 0.15 $ 0.62 Diluted $ 0.47 $ 0.14 $ 0.61 Other comprehensive income (loss), net of tax: Total comprehensive income (loss) $ 11.7 $ 24.9 $ 36.6 Total comprehensive income (loss) attributable to JHG $ 31.6 $ 24.9 $ 56.5

Note 3 - Consolidation (Tables)

Note 3 - Consolidation (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Consolidated Voting Right Entities VRE [Table Text Block]	March 31, December 31, 2023 2022 Investment securities $ 308.2 $ 206.0 Cash and cash equivalents 14.1 5.8 Other current assets 6.7 1.8 Accounts payable and accrued liabilities (2.9 ) (1.0 ) Total $ 326.1 $ 212.6 Redeemable noncontrolling interests in consolidated VREs (92.7 ) (35.1 ) JHG's net interest in consolidated VREs $ 233.4 $ 177.5

Note 4 - Investment Securities

Note 4 - Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Investment [Table Text Block]	March 31, December 31, 2023 2022 Seeded investment products: Consolidated VIEs $ 462.0 $ 334.3 Consolidated VREs 308.2 206.0 Unconsolidated VIEs and VREs 5.7 4.9 Separate accounts 52.6 29.7 Total seeded investment products 828.5 574.9 Investments related to deferred compensation plans 11.2 10.7 Other investments 10.5 10.3 Total investment securities $ 850.2 $ 595.9
Unrealized Gain (Loss) on Investments [Table Text Block]	Three months ended March 31, 2023 2022 Unrealized gains (losses) on investment securities held at period end $ 17.6 $ (32.2 )
Gain (Loss) on Securities [Table Text Block]	Three months ended March 31, 2023 2022 Seeded investment products and hedges, net $ 22.6 $ (11.5 ) Third-party ownership interests in seeded investment products (8.6 ) (20.1 ) Long Tail Alpha investment 3.0 1.5 Deferred equity plan — (1.5 ) Other 0.6 (0.6 ) Investment gains (losses), net $ 17.6 $ (32.2 )
Cash Flows Related to Investment Securities and Other Assets [Table Text Block]	Three months ended March 31, 2023 2022 Purchases Sales, Purchases Sales, and settlements and Net and settlements and Net settlements maturities cash flow settlements maturities cash flow Investment securities by consolidated seeded investment products $ (142.3 ) $ 19.1 $ (123.2 ) $ (3.9 ) $ 16.9 $ 13.0 Investment securities (113.2 ) 5.7 (107.5 ) (40.5 ) 6.3 (34.2 )

Note 5 - Derivative Instrumen_2

Note 5 - Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	Notional value March 31, 2023 December 31, 2022 Futures $ 361.4 $ 196.8 Credit default swaps 157.1 115.1 Total return swaps 40.7 37.2 Foreign currency forward contracts and swaps 180.6 131.7 Notional value March 31, 2023 December 31, 2022 Futures $ 308.7 $ 141.3 Credit default swaps 2.9 2.2 Total return swaps 10.0 10.4 Options 1.2 0.1 Foreign currency forward contracts and swaps 61.1 18.3 Notional value March 31, 2023 December 31, 2022 Foreign currency forward contracts and swaps $ 76.4 $ 74.7
Derivative Instruments, Gain (Loss) [Table Text Block]	Three months ended March 31, 2023 2022 Futures $ (6.7 ) $ 15.4 Credit default swaps (1.9 ) 2.3 Total return swaps (6.0 ) 7.4 Foreign currency forward contracts and swaps 4.5 (7.0 ) Total gains (losses) from derivative instruments $ (10.1 ) $ 18.1
Schedule of Derivative Instruments [Table Text Block]	Fair value March 31, 2023 December 31, 2022 Derivative assets $ 9.5 $ 5.3 Derivative liabilities 13.4 4.0

Note 6 - Fair Value Measureme_2

Note 6 - Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 514.5 $ — $ — $ 514.5 Investment securities: Consolidated VIEs 306.2 150.8 5.0 462.0 Other investment securities 299.1 88.9 0.2 388.2 Total investment securities 605.3 239.7 5.2 850.2 Seed hedge derivatives — 9.5 — 9.5 Derivatives used in consolidated seeded investment products — 1.4 — 1.4 Derivatives used in foreign currency hedging program — 0.7 — 0.7 Intech option agreement — — 0.4 0.4 Intech contingent consideration — — 12.0 12.0 Volantis contingent consideration — — 0.2 0.2 Total assets $ 1,119.8 $ 251.3 $ 17.8 $ 1,388.9 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 1.1 $ — $ 1.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Securities sold, not yet purchased 1.5 — — 1.5 Seed hedge derivatives — 13.4 — 13.4 Long-term debt (1) — 297.9 — 297.9 Deferred bonuses — — 60.0 60.0 Total liabilities $ 1.5 $ 312.8 $ 60.0 $ 374.3 Fair value measurements using: Quoted prices in Significant active markets for other Significant identical assets observable unobservable and liabilities inputs inputs (Level 1) (Level 2) (Level 3) Total Assets: Cash equivalents $ 688.4 $ — $ — $ 688.4 Investment securities: Consolidated VIEs 275.4 54.0 4.9 334.3 Other investment securities 171.9 89.4 0.3 261.6 Total investment securities 447.3 143.4 5.2 595.9 Seed hedge derivatives — 5.3 — 5.3 Derivatives used in consolidated seeded investment products — 0.1 — 0.1 Derivatives used in foreign currency hedging program — 0.4 — 0.4 Intech option agreement — — 0.8 0.8 Intech contingent consideration — — 12.1 12.1 Volantis contingent consideration — — 0.2 0.2 Total assets $ 1,135.7 $ 149.2 $ 18.3 $ 1,303.2 Liabilities: Derivatives used in consolidated seeded investment products $ — $ 0.6 $ — $ 0.6 Derivatives used in foreign currency hedging program — 1.1 — 1.1 Securities sold, not yet purchased 0.5 — — 0.5 Seed hedge derivatives — 4.0 — 4.0 Long-term debt (1) — 295.4 — 295.4 Deferred bonuses — — 46.5 46.5 Total liabilities $ 0.5 $ 301.1 $ 46.5 $ 348.1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended March 31, 2023 2022 Beginning of period fair value $ 18.3 $ 8.8 Intech option agreement — 3.9 Contingent consideration from sale of Intech — 12.6 Fair value adjustments (0.5 ) (1.5 ) Purchases of securities — (0.2 ) Sales of securities — (0.3 ) Foreign currency translation — (0.1 ) End of period fair value $ 17.8 $ 23.2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	Three months ended March 31, 2023 2022 Deferred Deferred bonuses bonuses Beginning of period fair value $ 46.5 $ 50.5 Fair value adjustments 1.5 (1.6 ) Vesting of deferred bonuses (33.2 ) (21.6 ) Amortization of deferred bonuses 8.4 8.4 Foreign currency translation 1.0 (1.4 ) Additions 35.8 — End of period fair value $ 60.0 $ 34.3

Note 7 - Goodwill and Intangi_2

Note 7 - Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Intangible Assets and Goodwill [Table Text Block]	Foreign December 31, currency March 31, 2022 Amortization Disposal translation 2023 Indefinite-lived intangible assets: Investment management agreements $ 2,046.5 $ — $ — $ 8.1 $ 2,054.6 Trademarks 360.0 — — — 360.0 Definite-lived intangible assets: Client relationships 68.9 — — 0.7 69.6 Accumulated amortization (60.7 ) (0.5 ) — (0.8 ) (62.0 ) Net intangible assets $ 2,414.7 $ (0.5 ) $ — $ 8.0 $ 2,422.2 Goodwill $ 1,253.1 $ — $ — $ 16.6 $ 1,269.7 Foreign December 31, currency March 31, 2021 Amortization Disposal translation 2022 Indefinite-lived intangible assets: Investment management agreements $ 2,114.8 $ — $ — $ (7.8 ) $ 2,107.0 Trademarks 366.7 — (4.7 ) — 362.0 Definite-lived intangible assets: Client relationships 168.4 — (84.8 ) 0.1 83.7 Accumulated amortization (107.2 ) (1.9 ) 44.7 0.6 (63.8 ) Net intangible assets $ 2,542.7 $ (1.9 ) $ (44.8 ) $ (7.1 ) $ 2,488.9 Goodwill $ 1,341.5 $ — $ (7.0 ) $ (17.7 ) $ 1,316.8
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Future amortization Amount 2023 (remainder of year) $ 1.2 2024 0.4 2025 0.4 2026 0.4 2027 0.4 Thereafter 4.8 Total $ 7.6

Note 8 - Debt (Tables)

Note 8 - Debt (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Long-Term Debt Instruments [Table Text Block]	​ March 31, 2023 December 31, 2022 ​ Carrying Fair Carrying Fair ​ value value value value 4.875% Senior Notes due 2025 $ 306.8 $ 297.9 $ 307.5 $ 295.4

Note 9 - Income Taxes (Tables)

Note 9 - Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	​ Three months ended ​ March 31, ​ 2023 2022 Effective tax rate 21.3 % 26.8 %

Note 10 - Noncontrolling Intr_2

Note 10 - Noncontrolling Intrests (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Redeemable Noncontrolling Interest [Table Text Block]	March 31, December 31, 2023 2022 Redeemable noncontrolling interests in: Consolidated seeded investment products $ 384.7 $ 233.9
Noncontrolling Interest Increase (Decrease) [Table Text Block]	Three months ended March 31, 2023 2022 Opening balance $ 233.9 $ 148.5 Changes in market value 8.6 (20.1 ) Changes in ownership 140.2 22.2 Foreign currency translation 2.0 0.1 Closing balance $ 384.7 $ 150.7
Nonredeemable Noncontrolling Interests [Table Text Block]	March 31, December 31, 2023 2022 Nonredeemable noncontrolling interests in: Seed capital investments $ 2.8 $ 2.8

Note 11 - Long-Term Incentive_2

Note 11 - Long-Term Incentive and Employee Compensation (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Share-Based Payment Arrangement, Activity [Table Text Block]	Three months ended March 31, 2023 Restricted stock $ 60.1 Mutual fund awards 53.9 Total $ 114.0

Note 12 - Retirement Benefit _2

Note 12 - Retirement Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Net Benefit Costs [Table Text Block]	Three months ended March 31, 2023 2022 Interest cost $ (6.8 ) $ (4.5 ) Amortization of prior service cost (0.1 ) (0.1 ) Expected return on plan assets 6.6 4.5 Net periodic benefit cost $ (0.3 ) $ (0.1 )

Note 13 - Accumulated Other C_2

Note 13 - Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Three months ended March 31, 2023 2022 Retirement Retirement Foreign benefit Foreign benefit currency asset, net Total currency asset, net Total Beginning balance $ (577.3 ) $ (70.4 ) $ (647.7 ) $ (354.2 ) $ (32.8 ) $ (387.0 ) Other comprehensive income (loss) 44.5 — 44.5 (47.8 ) — (47.8 ) Amounts reclassified from accumulated other comprehensive loss — 0.1 0.1 0.8 0.1 0.9 Total other comprehensive income (loss) 44.5 0.1 44.6 (47.0 ) 0.1 (46.9 ) Less: other comprehensive loss (income) attributable to noncontrolling interests (3.2 ) — (3.2 ) (0.2 ) — (0.2 ) Ending balance $ (536.0 ) $ (70.3 ) $ (606.3 ) $ (401.4 ) $ (32.7 ) $ (434.1 )
Comprehensive Income (Loss) [Table Text Block]	Three months ended March 31, 2023 2022 Pre-tax Tax Net Pre-tax Tax Net amount impact amount amount impact amount Foreign currency translation adjustments $ 41.5 $ 3.0 $ 44.5 $ (49.0 ) $ 1.2 $ (47.8 ) Reclassifications to net income 0.1 — 0.1 0.9 — 0.9 Total other comprehensive loss $ 41.6 $ 3.0 $ 44.6 $ (48.1 ) $ 1.2 $ (46.9 )

Note 14 - Earnings and Divide_2

Note 14 - Earnings and Dividends Per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Notes Tables
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	Three months ended March 31, 2023 2022 Net income attributable to JHG $ 87.4 $ 103.6 Allocation of earnings to participating stock-based awards (2.4 ) (2.6 ) Net income attributable to JHG common shareholders $ 85.0 $ 101.0 Weighted-average common shares outstanding — basic 160.2 164.0 Dilutive effect of nonparticipating stock-based awards 0.2 0.5 Weighted-average common shares outstanding — diluted 160.4 164.5 Earnings per share: Basic (two class) $ 0.53 $ 0.62 Diluted (two class) $ 0.53 $ 0.61
Dividends Declared [Table Text Block]	Dividend Date Dividends paid Date per share declared (in US$ millions) paid $ 0.39 February 1, 2023 $ 64.7 February 28, 2023

Note 1 - Basis of Presentatio_2

Note 1 - Basis of Presentation (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2020
Goodwill, Impairment Loss	$ 7	$ 123.5
Revision of Prior Period, Adjustment [Member]
Goodwill, Impairment Loss	$ 32.8

Note 1 - Basis of Presentatio_3

Note 1 - Basis of Presentation - Impact of Error Corrections on Financial Statements (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating expenses:
Impairment of goodwill and intangible assets		$ 0
Total operating expenses	$ 395.4	462.6
Operating income (loss)	100.4	157.4
Income (loss) before taxes	122	114.2
Income tax benefit (provision)	(26)	(30.7)
Net income (loss)	96	83.5
Net income (loss) attributable to JHG	$ 87.4	$ 103.6
Earnings (loss) per share attributable to JHG common shareholders:
Basic (in dollars per share)	$ 0.53	$ 0.62
Diluted (in dollars per share)	$ 0.53	$ 0.61
Other comprehensive income (loss), net of tax:
Total comprehensive income (loss)	$ 140.6	$ 36.6
Total comprehensive income (loss) attributable to JHG	$ 128.8	56.5
Previously Reported [Member]
Operating expenses:
Impairment of goodwill and intangible assets		32.8
Total operating expenses		495.4
Operating income (loss)		124.6
Income (loss) before taxes		81.4
Income tax benefit (provision)		(22.8)
Net income (loss)		58.6
Net income (loss) attributable to JHG		$ 78.7
Earnings (loss) per share attributable to JHG common shareholders:
Basic (in dollars per share)		$ 0.47
Diluted (in dollars per share)		$ 0.47
Other comprehensive income (loss), net of tax:
Total comprehensive income (loss)		$ 11.7
Total comprehensive income (loss) attributable to JHG		31.6
Revision of Prior Period, Adjustment [Member]
Operating expenses:
Impairment of goodwill and intangible assets		(32.8)
Total operating expenses		(32.8)
Operating income (loss)		32.8
Income (loss) before taxes		32.8
Income tax benefit (provision)		(7.9)
Net income (loss)		24.9
Net income (loss) attributable to JHG		$ 24.9
Earnings (loss) per share attributable to JHG common shareholders:
Basic (in dollars per share)		$ 0.15
Diluted (in dollars per share)		$ 0.14
Other comprehensive income (loss), net of tax:
Total comprehensive income (loss)		$ 24.9
Total comprehensive income (loss) attributable to JHG		$ 24.9

Note 2 - Dispositions (Details

Note 2 - Dispositions (Details Textual) $ in Millions		3 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Feb. 03, 2022
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ 0	$ (9.1)
Proceeds from Divestiture of Businesses		0	5
Intech Investment Management LLC [Member] | Term Note [Member]
Financing Receivable, before Allowance for Credit Loss	$ 20	14.6	20
Financing Receivable Term (Year)	7 years
Number Of Tranches	2
Interest Receivable		0.6
Intech Investment Management LLC [Member] | Term Note, Tranche One [Member]
Financing Receivable, before Allowance for Credit Loss	$ 10		$ 10
Investment Interest Rate	5.50%		5.50%
Intech Investment Management LLC [Member] | Term Note, Tranche Two [Member]
Financing Receivable, before Allowance for Credit Loss	$ 10		$ 10
Investment Interest Rate	6%		6%
Intech Investment Management LLC [Member]
Percentage Of Ownership Sold					97%
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	$ 9.1
Proceeds from Divestiture of Businesses	14.9
Disposal Group Including Discontinued Operation Contingent Consideration	$ 17.5	$ 12	$ 17.5	$ 12.1

Note 3 - Consolidation - VREs (

Note 3 - Consolidation - VREs (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Investment securities	$ 388.2	$ 261.6
Cash and cash equivalents	843.5	1,162.3
Other current assets	115.9	120.3
Accounts payable and accrued liabilities	(218.5)	(232.6)
Variable Rights Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Investment securities	308.2	206
Cash and cash equivalents	14.1	5.8
Other current assets	6.7	1.8
Accounts payable and accrued liabilities	(2.9)	(1)
Total	326.1	212.6
Redeemable noncontrolling interests in consolidated VREs	(92.7)	(35.1)
JHG's net interest in consolidated VREs	$ 233.4	$ 177.5

Note 4 - Investment Securitie_2

Note 4 - Investment Securities - General Disclosure (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Seeded investment products	$ 828.5	$ 574.9
Unconsolidated VIEs and VREs [Member]
Seeded investment products	5.7	4.9
Separately Managed Accounts [Member]
Seeded investment products	52.6	29.7
Investments Related to Deferred Compensation Plans [Member]
Estimated Fair Value	11.2	10.7
Other Security Investments [Member]
Estimated Fair Value	10.5	10.3
Securities Investment [Member]
Estimated Fair Value	850.2	595.9
Variable Interest Entity, Primary Beneficiary [Member]
Seeded investment products	462	334.3
Voting Rights Entity, Primary Beneficiary Aggregated Disclosure [Member]
Seeded investment products	$ 308.2	$ 206

Note 4 - Investment Securitie_3

Note 4 - Investment Securities - Net Unrealized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Securities Investment [Member]
Unrealized gains (losses) on investment securities held at period end	$ 17.6	$ (32.2)

Note 4 - Investment Securitie_4

Note 4 - Investment Securities - Investment Gains (Losses), Net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Investment gains (losses), net	$ 17.6	$ (32.2)
Seeded Investment Products and Hedges, Net [Member]
Investment gains (losses), net	22.6	(11.5)
Third-party Ownership Interests in Seeded Investment Products [Member]
Investment gains (losses), net	(8.6)	(20.1)
Long Tail Alpha Investment [Member]
Investment gains (losses), net	3	1.5
Deferred Equity Plan [Member]
Investment gains (losses), net	0	(1.5)
Other Security Investments [Member]
Investment gains (losses), net	$ 0.6	$ (0.6)

Note 4 - Investment Securitie_5

Note 4 - Investment Securities - Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net cash flow	$ 107.5	$ 34.2
Seeded Investment Products [Member]
Purchases and settlements	(142.3)	(3.9)
Sales, settlements and maturities	19.1	16.9
Net cash flow	(123.2)	13
Securities Investment [Member]
Purchases and settlements	(113.2)	(40.5)
Sales, settlements and maturities	5.7	6.3
Net cash flow	$ (107.5)	$ (34.2)

Note 5 - Derivative Instrumen_3

Note 5 - Derivative Instruments (Details Textual) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022
Financial Instruments Sold, Not yet Purchased, Derivatives and Other Contracts	$ 1.5	$ 0.5

Note 5 - Derivative Instrumen_4

Note 5 - Derivative Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Futures [Member]
Notional value of derivative	$ 361.4	$ 196.8
Futures [Member] | Seeded Investment Products [Member]
Notional value of derivative	308.7	141.3
Foreign Currency, Forward Contracts and Swaps [Member]
Notional value of derivative	180.6	131.7
Foreign Currency, Forward Contracts and Swaps [Member] | Not Designated as Hedging Instrument, Economic Hedge [Member]
Notional value of derivative	76.4	74.7
Foreign Currency, Forward Contracts and Swaps [Member] | Seeded Investment Products [Member]
Notional value of derivative	61.1	18.3
Credit Default Swaps [Member]
Notional value of derivative	157.1	115.1
Credit Default Swaps [Member] | Seeded Investment Products [Member]
Notional value of derivative	2.9	2.2
Total Return Swaps [Member]
Notional value of derivative	40.7	37.2
Total Return Swaps [Member] | Seeded Investment Products [Member]
Notional value of derivative	10	10.4
Options [Member] | Seeded Investment Products [Member]
Notional value of derivative	$ 1.2	$ 0.1

Note 5 - Derivative Instrumen_5

Note 5 - Derivative Instruments - Change in Fair Value of Derivatives (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Gain (losses) from derivative instruments	$ (10.1)	$ 18.1
Futures [Member]
Gain (losses) from derivative instruments	(6.7)	15.4
Credit Default Swaps [Member]
Gain (losses) from derivative instruments	(1.9)	2.3
Total Return Swaps [Member]
Gain (losses) from derivative instruments	(6)	7.4
Foreign Currency, Forward Contracts and Swaps [Member]
Gain (losses) from derivative instruments	$ 4.5	$ (7)

Note 5 - Derivative Instrumen_6

Note 5 - Derivative Instruments - Derivative Assets and Liabilities (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Derivative assets	$ 9.5	$ 5.3
Derivative liabilities	$ 13.4	$ 4

Note 6 - Fair Value Measureme_3

Note 6 - Fair Value Measurements (Details Textual) - Intech Investment Management LLC [Member] - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Disposal Group, Including Discontinued Operation, Contingent Consideration, Options Agreement, Fair Value	$ 0.4	$ 0.8
Disposal Group Including Discontinued Operation Contingent Consideration	$ 12	$ 12.1	$ 17.5

Note 6 - Fair Value Measureme_4

Note 6 - Fair Value Measurements - Level of Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2023		Dec. 31, 2022		Mar. 31, 2022
Total investment securities	$ 388.2		$ 261.6
Securities sold, not yet purchased	1.5				$ 0.5
Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	462		334.3
Fair Value, Recurring [Member]
Cash equivalents	514.5		688.4
Total investment securities	850.2		595.9
Total assets	1,388.9		1,303.2
Securities sold, not yet purchased	1.5		0.5
Long-term debt	297.9		295.4
Total liabilities	374.3		348.1
Fair Value, Recurring [Member] | Intech Investment Management LLC [Member]
Contingent consideration	12		12.1
Fair Value, Recurring [Member] | Volantis [Member]
Contingent consideration	0.2		0.2
Fair Value, Recurring [Member] | Seed Hedge Derivatives [Member]
Derivative assets	9.5		5.3
Derivative liabilities	13.4		4
Fair Value, Recurring [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	1.4		0.1
Derivative liabilities	1.1		0.6
Fair Value, Recurring [Member] | Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0.7		0.4
Derivative liabilities	0.4		1.1
Fair Value, Recurring [Member] | Options [Member] | Intech Investment Management LLC [Member]
Derivative assets	0.4		0.8
Fair Value, Recurring [Member] | Deferred Bonuses Hedge [Member]
Derivative liabilities	60		46.5
Fair Value, Recurring [Member] | Other Investment Securities [Member]
Total investment securities	388.2		261.6
Fair Value, Recurring [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	462		334.3
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents	514.5		688.4
Total investment securities	605.3		447.3
Total assets	1,119.8		1,135.7
Securities sold, not yet purchased	1.5		0.5
Long-term debt	0		0	[1]
Total liabilities	1.5		0.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Intech Investment Management LLC [Member]
Contingent consideration	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Volantis [Member]
Contingent consideration	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Seed Hedge Derivatives [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Options [Member] | Intech Investment Management LLC [Member]
Derivative assets	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Deferred Bonuses Hedge [Member]
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Investment Securities [Member]
Total investment securities	299.1		171.9
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	306.2		275.4
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents	0		0
Total investment securities	239.7		143.4
Total assets	251.3		149.2
Securities sold, not yet purchased	0		0
Long-term debt	297.9	[1]	295.4
Total liabilities	312.8		301.1
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Intech Investment Management LLC [Member]
Contingent consideration	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Volantis [Member]
Contingent consideration	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Seed Hedge Derivatives [Member]
Derivative assets	9.5		5.3
Derivative liabilities	13.4		4
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	1.4		0.1
Derivative liabilities	1.1		0.6
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0.7		0.4
Derivative liabilities	0.4		1.1
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Options [Member] | Intech Investment Management LLC [Member]
Derivative assets	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Deferred Bonuses Hedge [Member]
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Investment Securities [Member]
Total investment securities	88.9		89.4
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	150.8		54
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents	0		0
Total investment securities	5.2		5.2
Total assets	17.8		18.3
Securities sold, not yet purchased	0		0
Long-term debt	0		0
Total liabilities	60		46.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Intech Investment Management LLC [Member]
Contingent consideration	12		12.1
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Volantis [Member]
Contingent consideration	0.2		0.2
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Seed Hedge Derivatives [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Currency, Forward Contracts and Swaps [Member]
Derivative assets	0		0
Derivative liabilities	0		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Options [Member] | Intech Investment Management LLC [Member]
Derivative assets	0.4		0.8
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Deferred Bonuses Hedge [Member]
Derivative liabilities	60		46.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Investment Securities [Member]
Total investment securities	0.2		0.3
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Total investment securities	$ 5		$ 4.9
[1]Carried at amortized cost and disclosed at fair value.

Note 6 - Fair Value Measureme_5

Note 6 - Fair Value Measurements - Changes in Level 3 Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Beginning of period fair value	$ 18.3	$ 8.8
Intech option agreement	0	3.9
Contingent consideration from sale of Intech	0	12.6
Fair value adjustments	(0.5)	(1.5)
Purchases of securities	0	(0.2)
Sales of securities	0	(0.3)
Foreign currency translation	0	(0.1)
End of period fair value	$ 17.8	$ 23.2

Note 6 - Fair Value Measureme_6

Note 6 - Fair Value Measurements - Changes in Level 3 Liabilities (Details) - Deferred Bonuses [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Beginning of period fair value	$ 46.5	$ 50.5
Fair value adjustments	1.5	(1.6)
Vesting of deferred bonuses	(33.2)	(21.6)
Amortization of deferred bonuses	8.4	8.4
Foreign currency translation	1	(1.4)
Additions	35.8	0
End of period fair value	$ 60	$ 34.3

Note 7 - Goodwill and Intangi_3

Note 7 - Goodwill and Intangible Assets (Details Textual) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022
Disposal Group, Including Discontinued Operation, Goodwill	$ 0
Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Goodwill		$ 7
Trademarks [Member] | Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets		4.7
Client Relationships [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets	$ 0	84.8
Client Relationships [Member] | Intech Investment Management LLC [Member]
Disposal Group, Including Discontinued Operation, Intangible Assets		$ 40.1

Note 7 - Goodwill and Intangi_4

Note 7 - Goodwill and Intangible Assets - Intangible Assets and Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2020
Intangible assets, amortization	$ (0.5)	$ (1.9)
Accumulated amortization, balance	(60.7)	(107.2)
Accumulated amortization, disposals	0
Foreign currency translation	(0.8)	0.6
Net intangible assets, balance	2,414.7	2,542.7
Net intangible assets, disposals	0
Net intangible assets	8	(7.1)
Goodwill, balance	1,253.1	1,341.5
Goodwill, disposals	0
Goodwill, foreign currency translation	16.6	(17.7)
Intangible assets, impairment		(44.8)
Accumulated amortization, balance	(62)	(63.8)
Net intangible assets, balance	2,422.2	2,488.9
Goodwill impairment		(7)	$ (123.5)
Goodwill, balance	1,269.7	1,316.8
Client Relationships [Member]
Intangible assets, disposals	0	(84.8)
Foreign currency translation	0.7	0.1
Balance	68.9	168.4
Intangible assets, amortization	0	0
Client relationships	0.7	0.1
Balance	69.6	83.7
Investment Management Agreements [Member]
Balance	2,046.5	2,114.8
Intangible assets, disposals	0
Foreign currency translation	8.1	(7.8)
Client relationships	8.1	(7.8)
Intangible assets, impairment		0
Balance	2,054.6	2,107
Trademarks [Member]
Balance	360	366.7
Intangible assets, disposals	0
Foreign currency translation	0	0
Client relationships	0	0
Intangible assets, impairment		(4.7)
Balance	$ 360	$ 362

Note 7 - Goodwill and Intangi_5

Note 7 - Goodwill and Intangible Assets - Schedule of Future Amortization (Details) $ in Millions	Mar. 31, 2023 USD ($)
2023 (remainder of year)	$ 1.2
2024	0.4
2025	0.4
2026	0.4
2027	0.4
Thereafter	4.8
Total	$ 7.6

Note 8 - Debt (Details Textual)

Note 8 - Debt (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 200,000
Line of Credit Facility, Covenant Terms Financing Leverage Ratio, Upper Range Limit	3
Long-Term Line of Credit, Total	$ 0
Senior Notes, 4.876 Percent, Due 2025 [Member]
Debt Instrument, Interest Rate, Stated Percentage	4.875%
Debt Instrument, Face Amount	$ 300,000
Debt Instrument, Unamortized Premium	$ 6,800

Note 8 - Debt - Schedule of Deb

Note 8 - Debt - Schedule of Debt (Details) - Senior Notes, 4.876 Percent, Due 2025 [Member] - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Long-term debt	$ 306.8	$ 307.5
Long-term debt, fair value	$ 297.9	$ 295.4

Note 9 - Income Taxes (Details

Note 9 - Income Taxes (Details Textual) $ in Millions	Mar. 31, 2023 USD ($)
Unrecognized Tax Benefits	$ 26.5
Maximum [Member]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 8.5

Note 9 - Income Taxes - Schedul

Note 9 - Income Taxes - Schedule of Effective Income Tax Rate (Details)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Effective tax rate	21.30%	26.80%

Note 10 - Noncontrolling Intere

Note 10 - Noncontrolling Interests - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Total redeemable noncontrolling interests	$ 384.7	$ 233.9	$ 150.7	$ 148.5
Consolidated Entity, Excluding VIE [Member]
Total redeemable noncontrolling interests	$ 384.7	$ 233.9

Note 10 - Noncontrolling Inte_2

Note 10 - Noncontrolling Interests -Schedule of Changes in Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Opening balance	$ 233.9	$ 148.5
Changes in market value	8.6	(20.1)
Changes in ownership	140.2	22.2
Foreign currency translation	2	0.1
Closing balance	$ 384.7	$ 150.7

Note 10 - Noncontrolling Inte_3

Note 10 - Noncontrolling Interests - Nonredeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Noncontrolling interests	$ 2.8	$ 2.8

Note 11 - Long-Term Incentive_3

Note 11 - Long-Term Incentive and Employee Compensation - Award Activity (Details) shares in Millions	3 Months Ended
	Mar. 31, 2023 shares
Awards granted (in shares)	114
Restricted Stock [Member]
Awards granted (in shares)	60.1
Mutual Fund Awards [Member]
Awards granted (in shares)	53.9

Note 12 - Retirement Benefit _3

Note 12 - Retirement Benefit Plans - Actuarial Gains (Losses), Benefit Cost, Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Interest cost	$ (6.8)	$ (4.5)
Amortization of prior service cost	(0.1)	(0.1)
Expected return on plan assets	6.6	4.5
Net periodic benefit cost	$ (0.3)	$ (0.1)

Note 13 - Accumulated Other C_3

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Beginning balance	$ 4,359.8
Total other comprehensive income (loss)	44.6	$ (46.9)
Less: other comprehensive loss (income) attributable to noncontrolling interests	3.2	0.2
Ending balance	4,387.9
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Beginning balance	(577.3)	(354.2)
Other comprehensive income (loss)	44.5	(47.8)
Amounts reclassified from accumulated other comprehensive loss	0	0.8
Total other comprehensive income (loss)	44.5	(47)
Less: other comprehensive loss (income) attributable to noncontrolling interests	(3.2)	(0.2)
Ending balance	(536)	(401.4)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Beginning balance	(70.4)	(32.8)
Other comprehensive income (loss)	0	0
Amounts reclassified from accumulated other comprehensive loss	0.1	0.1
Total other comprehensive income (loss)	0.1	0.1
Less: other comprehensive loss (income) attributable to noncontrolling interests	0	0
Ending balance	(70.3)	(32.7)
AOCI Attributable to Parent [Member]
Beginning balance	(647.7)	(387)
Other comprehensive income (loss)	44.5	(47.8)
Amounts reclassified from accumulated other comprehensive loss	0.1	0.9
Total other comprehensive income (loss)	44.6	(46.9)
Less: other comprehensive loss (income) attributable to noncontrolling interests	(3.2)	(0.2)
Ending balance	$ (606.3)	$ (434.1)

Note 13 - Accumulated Other C_4

Note 13 - Accumulated Other Comprehensive Loss - Schedule of Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Total other comprehensive loss, pre tax	$ 41.6	$ (48.1)
Total other comprehensive loss, tax	3	1.2
Total other comprehensive loss, net	44.6	(46.9)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Total other comprehensive loss, pre tax	41.5	(49)
Total other comprehensive loss, tax	3	1.2
Total other comprehensive loss, net	44.5	(47.8)
Reclassification to Net Income [Member]
Total other comprehensive loss, pre tax	0.1	0.9
Total other comprehensive loss, tax	0	0
Total other comprehensive loss, net	$ 0.1	$ 0.9

Note 14 - Earnings and Divide_3

Note 14 - Earnings and Dividends Per Share (Details Textual) - $ / shares		3 Months Ended
	May 02, 2023	Mar. 31, 2023
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.39
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.39

Note 14 - Earnings and Divide_4

Note 14 - Earnings and Dividends Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net income (loss) attributable to JHG	$ 87.4	$ 103.6
Allocation of earnings to participating stock-based awards	(2.4)	(2.6)
Net income attributable to JHG common shareholders	$ 85	$ 101
Weighted-average common shares outstanding — basic (in shares)	160.2	164
Dilutive effect of nonparticipating stock-based awards (in shares)	0.2	0.5
Weighted-average common shares outstanding — diluted (in shares)	160.4	164.5
Basic (in dollars per share)	$ 0.53	$ 0.62
Diluted (in dollars per share)	$ 0.53	$ 0.61

Note 14 - Earnings and Divide_5

Note 14 - Earnings and Dividends Per Share - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Dividend per share (in dollars per share)	$ 0.39
Dividends paid	$ 64.7	$ 64.3