Condensed Consolidated Statements of Cash Flows $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Cash flows from operating activities:
Net income	$ 380.9	$ 284.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	118.0	133.8
Amortization of debt issuance cost and debt discount	1.5	1.7
Change in fair value of contingent consideration		2.4
Realized gain on available-for-sale securities	(0.4)	(1.2)
Provision for accounts receivable credit losses	0.1	0.8
Provision for deferred income taxes	(8.8)	(18.4)
Provision for notes receivable credit losses	6.7
Stock-based compensation expense	17.3	17.0
Impairment of property held for sale	8.1	6.1
Loss related to deconsolidation of former subsidiary		2.0
Impairment of goodwill		10.5
Equity in investments	(0.9)	(1.7)
Impairment of investment	4.1
Bargain purchase gain	(32.6)
Changes in assets and liabilities:
Accounts receivable	(43.3)	49.8
Restricted cash and cash equivalents (margin deposit and clearing fund)	771.9
Income taxes receivable	0.2	5.4
Other current assets	(5.9)	(14.8)
Other assets	(17.2)
Accounts payable and accrued liabilities	21.4	(39.4)
Section 31 fees payable	(59.4)	(55.7)
Deferred revenue	7.9	(0.3)
Income taxes payable	(1.5)	(3.1)
Unrecognized tax benefits	21.4	20.0
Other liabilities	(0.1)	(4.3)
Net cash provided by operating activities	1,189.4	395.1
Cash flows from investing activities:
Acquisitions, net of cash acquired	(103.3)
Purchases of available-for-sale financial investments	(154.9)	(61.8)
Proceeds from maturities of available-for-sale financial investments	202.5	98.0
Return of capital from investments		22.0
Contributions to investments	(11.7)
Purchases of property and equipment	(37.2)	(26.9)
Net cash (used in) provided by investing activities	(104.6)	31.3
Cash flows from financing activities:
Principal payments of long term debt		(350.0)
Proceeds from credit facility	70.0
Cash dividends on common stock	(125.3)	(110.0)
Repurchases of common stock from employee stock plans	(14.2)	(10.7)
Exercise of common stock options	0.2	9.1
Payment of contingent consideration from acquisition	(2.2)
Purchase of common stock	(261.1)	(87.4)
Net cash used in financing activities	(332.6)	(549.0)
Effect of foreign currency exchange rates on cash, cash equivalents, and restricted cash and cash equivalents	3.1	(2.5)
Increase (decrease) in cash, cash equivalents, and restricted cash and cash equivalents	755.3	(125.1)
Cash, cash equivalents, and restricted cash and cash equivalents: Beginning of period	229.3	275.1
Cash, cash equivalents, and restricted cash and cash equivalents: End of period	984.6	150.0
Supplemental disclosure of cash transactions:
Cash paid for income taxes	145.4	98.9
Cash paid for interest	27.3	31.0
Supplemental disclosure of noncash investing activities:
Note receivable issued in connection with deconsolidation of former subsidiary		3.7
Investment recognized in connection with deconsolidation of former subsidiary		2.9
Net assets of former subsidiary deconsolidated		$ 14.5
Accounts receivable acquired	6.4
Income taxes receivable acquired	1.6
Other current assets acquired	4.8
Goodwill acquired	105.9
Intangible assets acquired	91.3
Property and equipment, net acquired	3.5
Accounts payable and accrued expenses assumed	(14.7)
Income taxes payable assumed	(0.9)
Deferred revenue acquired	(1.3)
Contingent consideration related to acquisitions	(37.9)
Deferred income taxes acquired	$ 7.3