Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flow from operating activities:
Net income	$ 761.7	$ 608.6	$ 649.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	680.1	670.4	671.6
Equity in earnings of unconsolidated affiliates, net	(24.4)	(100.0)	(25.8)
Distributions received from unconsolidated affiliates	13.1	21.2	2.3
Stock-based compensation expense	203.3	159.5	124.8
Net gains on investments	(1.7)	(2.2)	(26.1)
Amortization and write-offs of loan origination costs and original issue discounts	8.4	13.5	13.9
Loss on extinguishment of debt, net	31.2	2.1	5.5
Loss on sale or disposition of property and equipment	1.6	11.7	0.6
Deferred income taxes	(115.4)	(82.9)	(77.0)
Provision for credit losses	15.4	11.4	10.6
Changes in operating assets and liabilities, excluding effects from acquisitions:
Accounts receivable	(119.1)	(23.1)	(38.1)
Prepaid expenses and other assets	(20.7)	(2.3)	17.7
Contract assets	(25.1)	22.5	(52.1)
Accounts payable	(10.7)	33.0	7.6
Accrued expenses and other liabilities	(16.5)	(106.0)	(135.5)
Income taxes prepaid and payable	(13.8)	(38.2)	27.0
Deferred revenue	21.2	15.9	(41.7)
Net cash provided by operating activities	1,388.6	1,215.1	1,134.3
Cash flow from investing activities:
Cash paid for asset acquisitions and business acquisitions, net of cash acquired	(647.1)	(34.1)	(1,636.2)
Additions to property and equipment	(61.4)	(56.6)	(63.4)
Proceeds from sale of property and equipment	4.8	0.1	11.4
Additions to capitalized software	(194.3)	(194.9)	(144.9)
Investments in securities	(0.1)	(0.6)	(10.0)
Proceeds from sales / maturities of investments	6.9	8.0	9.5
Distributions received from (contributions to) unconsolidated affiliates	25.3	(0.3)	66.2
Collection of other non-current receivables	10.2	10.0	9.8
Net cash used in investing activities	(855.7)	(268.4)	(1,757.6)
Cash flow from financing activities:
Cash received from debt borrowings, net of original issue discount	5,545.0	375.0	1,727.1
Repayments of debt	(5,255.1)	(749.7)	(599.8)
Payment of deferred financing fees	(39.4)	0.0	(14.7)
Net increase (decrease) in client funds obligations	235.8	1,669.7	(1,709.0)
Proceeds from exercise of stock options	355.1	115.4	91.8
Withholding taxes paid related to equity award net share settlement	(26.2)	(5.1)	(0.7)
Purchases of common stock for treasury	(737.5)	(471.6)	(476.1)
Dividends paid on common stock	(244.9)	(220.9)	(203.1)
Proceeds from noncontrolling interests	14.9	0.0	0.0
Net cash (used in) provided by financing activities	(152.3)	712.8	(1,184.5)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(8.7)	1.5	(26.0)
Net increase (decrease) in cash, cash equivalents and restricted cash	371.9	1,661.0	(1,833.8)
Cash, cash equivalents and restricted cash, beginning of period	2,998.6	1,337.6	3,171.4
Cash, cash equivalents and restricted cash and cash equivalents, end of period	3,370.5	2,998.6	1,337.6
Reconciliation of cash, cash equivalents and restricted cash and cash equivalents:
Cash and cash equivalents	567.1	432.2	440.1
Restricted cash and cash equivalents	3.7	2.4	3.3
Restricted cash and cash equivalents included in funds receivable and funds held on behalf of clients	2,799.7	2,564.0	894.2
Cash and cash equivalents and restricted cash	3,370.5	2,998.6	1,337.6
Supplemental disclosure of cash paid for:
Interest	452.4	461.8	298.0
Income taxes, net of refunds	$ 286.2	$ 348.5	$ 281.1