Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net (loss) income	$ (31.1)	$ 20.4
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Share-based compensation expense	57.5	42.0
Depreciation, amortization, and accretion	60.4	54.0
Operating lease assets expense	11.7	10.5
Loss on extinguishment of debt	60.6	0.0
Other	(3.9)	10.3
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable, net	204.8	202.6
Prepaid expenses and other assets	(39.1)	(37.1)
Accounts payable	(29.4)	18.4
Accrued compensation	(61.5)	(59.8)
Income taxes payable	(23.1)	5.1
Other accrued liabilities	(72.6)	(27.0)
Deferred revenue	45.5	32.8
Net cash provided by operating activities	179.8	272.2
Cash flows from investing activities:
Purchases of property and equipment	(19.7)	(21.8)
Purchases of available-for-sale debt securities	(104.8)	(257.1)
Proceeds from sales of available-for-sale debt securities	283.7	94.0
Proceeds from maturities and redemptions of available-for-sale debt securities	118.1	354.0
Purchases of equity securities	(1.5)	(3.1)
Proceeds from sales of equity securities	2.9	3.1
Payments for business acquisitions, net of cash and cash equivalents acquired	(175.0)	(0.2)
Other	(1.3)	0.0
Net cash provided by investing activities	102.4	168.9
Cash flows from financing activities:
Repurchase and retirement of common stock	(131.9)	(203.2)
Proceeds from issuance of common stock	28.2	27.1
Payment of dividends	(65.2)	(65.5)
Payment of debt	(423.8)	0.0
Payment for debt extinguishment costs	(58.3)	0.0
Net cash used in financing activities	(651.0)	(241.6)
Effect of foreign currency exchange rates on cash, cash equivalents, and restricted cash	(2.0)	(16.2)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(370.8)	183.3
Cash, cash equivalents, and restricted cash at beginning of period	1,383.0	1,276.5
Cash, cash equivalents, and restricted cash at end of period	$ 1,012.2	$ 1,459.8