CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flow from (used in) operating activities:
Net income	$ 904.0	$ 740.6	$ 906.1
Adjustments to reconcile Net income to cash flow from (used in) operating activities:
Intangible amortization and impairments	160.3	29.0	48.3
Depreciation and other amortization	10.4	13.4	13.0
Deferred income tax expense	83.8	60.6	31.4
Equity method income (net)	(462.9)	(312.7)	(280.0)
Distributions received from equity method investments	467.8	403.9	490.8
Affiliate transaction gains	(371.3)	0.0	(133.1)
Share-based compensation and Affiliate equity expense	202.8	111.6	112.1
Net realized and unrealized gains on investment securities	(55.7)	(39.3)	(84.2)
Other non-cash items	8.1	(3.9)	(10.8)
Changes in assets and liabilities:
Purchases of securities by consolidated Affiliate sponsored investment products	(100.6)	(76.5)	(45.0)
Sales of securities by consolidated Affiliate sponsored investment products	72.7	62.2	54.3
Increase in receivables	(49.8)	(44.2)	(48.4)
Decrease (increase) in other assets	(28.1)	6.6	9.2
(Decrease) increase in payables, accrued liabilities, and other liabilities	131.7	(19.2)	(189.4)
Cash flow from operating activities	973.2	932.1	874.3
Cash flow from (used in) investing activities:
Investments in Affiliates	(776.0)	(5.9)	(294.7)
Proceeds from Affiliate transactions	403.8	0.0	294.0
Return of capital from equity method investments in Affiliates	9.8	0.7	0.2
Purchases of fixed assets	(6.1)	(3.4)	(12.4)
Purchases of investment securities	(103.8)	(510.4)	(731.1)
Maturities and sales of investment securities	266.2	898.1	1,008.5
Cash flow from (used in) investing activities	(206.1)	379.1	264.5
Cash flow from (used in) financing activities:
Borrowings of senior bank debt, senior notes, and junior subordinated notes	899.3	847.6	25.0
Repayments of senior bank debt, junior convertible securities, and senior notes	(826.1)	(750.0)	(25.0)
Repurchases of common stock, net	(706.3)	(709.8)	(341.9)
Dividends paid on common stock	(1.0)	(1.4)	(1.5)
Distributions to non-controlling interests	(252.3)	(258.0)	(271.3)
Affiliate equity purchases	(176.7)	(106.5)	(67.4)
Affiliate equity issuances	6.4	6.3	13.4
(Redemptions) subscriptions to consolidated Affiliate sponsored investment products, net	21.2	(6.4)	(12.6)
Settlement of deferred payments, net	0.0	(98.7)	(21.7)
Taxes paid on shares withheld on share-based awards	(108.0)	(87.1)	(31.4)
Other financing items	(5.2)	(11.9)	(23.9)
Cash flow used in financing activities	(1,148.7)	(1,175.9)	(758.3)
Effect of foreign currency exchange rate changes on cash and cash equivalents	11.6	(4.2)	6.9
Net increase (decrease) in cash and cash equivalents	(370.0)	131.1	387.4
Cash and cash equivalents at beginning of period	950.0	813.6	429.2
Effect of consolidation (deconsolidation) of Affiliates and Affiliate sponsored investment products	6.0	5.3	(3.0)
Cash and cash equivalents at end of period	586.0	950.0	813.6
Supplemental disclosure of cash flow information:
Income taxes paid, net	110.7	142.5	314.5
Interest paid	137.9	138.2	110.4
Operating lease liabilities paid	35.4	39.4	37.7
Supplemental disclosure of non-cash investing and financing activities:
Shares received from Affiliate transactions	154.0	0.0	0.0
Conversion premium obligations on junior convertible securities	164.7	0.0	0.0
Stock issued upon vesting of restricted stock units and exercise of stock options	137.5	114.4	55.0
Payables recorded for Affiliate equity purchases	131.4	35.0	43.0
Stock received for tax withholdings on share-based payments	108.0	87.1	31.4
Stock received for the exercise of stock options	103.1	113.9	0.6
Payables recorded for investments in Affiliates and contingent payment obligations	83.7	7.0	57.6
Right-of-use assets obtained in exchange for new operating leases	$ 13.0	$ 8.8	$ 17.5