Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Statement Of Cash Flows [Abstract]
Net loss	$ (47.2)	$ (45.0)
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred income tax expense (benefit)	6.4	(29.2)
Depreciation and amortization	42.5	38.3
Amortization of debt issuance costs and debt discount	2.0	6.2
Provision for doubtful accounts	1.7	0.9
Net periodic pension and postretirement cost	2.4	4.4
Share-based compensation	74.3	54.2
Change in fair value of contingent consideration	2.0
Other	(1.2)	(0.4)
Changes in operating assets and liabilities excluding effects of acquisitions and divestitures:
Trade and other receivables	(9.3)	(3.7)
Prepaid expenses and other current assets	(14.3)	(12.1)
Accounts payable and other accrued expenses	(3.3)	(1.5)
Deferred revenue	(5.2)	1.7
Employee compensation and benefits	(2.4)	(14.3)
Accrued interest		0.4
Accrued taxes	(7.9)	27.4
Other assets and liabilities	(1.8)	(4.2)
Net cash provided by operating activities	38.7	23.1
Cash Flows from Investing Activities
Purchase of customer funds marketable securities	(450.5)	(280.8)
Proceeds from sale and maturity of customer funds marketable securities	240.4	276.2
Expenditures for property, plant, and equipment	(6.6)	(5.9)
Expenditures for software and technology	(35.6)	(25.4)
Acquisition costs, net of cash and restricted cash acquired		(373.6)
Net cash used in investing activities	(252.3)	(409.5)
Cash Flows from Financing Activities
Increase (decrease) in customer funds obligations, net	1,983.4	(566.1)
Proceeds from issuance of common stock under share-based compensation plans	13.3	34.4
Repayment of long-term debt obligations	(4.2)	(2.7)
Proceeds from revolving credit facility		295.0
Repayment of revolving credit facility		(295.0)
Proceeds from issuance of convertible senior notes, net of issuance costs		561.8
Purchases of capped calls related to convertible senior notes		(45.0)
Net cash provided by (used in) financing activities	1,992.5	(17.6)
Effect of exchange rate changes on cash, restricted cash, and equivalents	(4.9)	6.7
Net increase (decrease) in cash, restricted cash, and equivalents	1,774.0	(397.3)
Cash, restricted cash, and equivalents at beginning of period	1,952.9	2,228.5
Cash, restricted cash, and equivalents at end of period	3,726.9	1,831.2
Reconciliation of cash, restricted cash, and equivalents to the condensed consolidated balance sheets
Cash and equivalents	371.2	335.2
Restricted cash	1.0	2.0
Restricted cash and equivalents included in customer funds	3,354.7	1,494.0
Cash, restricted cash, and equivalents at end of period	$ 3,726.9	$ 1,831.2