Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flow from operating activities:
Net income	$ 549.4	$ 428.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	500.2	544.1
Equity in earnings of unconsolidated affiliates, net	(1.9)	0.1
Cash distributions received from unconsolidated affiliates	10.0	8.0
Gain on bargain purchase	(3.2)
Stock-based compensation expense	82.7	65.9
Net gains on investments	(17.3)	(17.3)
Amortization and write-offs of loan origination costs and original issue discounts	10.0	10.4
Loss on extinguishment of debt, net	3.5	1.3
Loss on sale or disposition of property and equipment	0.6	4.0
Deferred income taxes	(82.5)	(115.9)
Provision for doubtful accounts	6.5	6.0
Changes in operating assets and liabilities, excluding effects from acquisitions:
Accounts receivable	(72.6)	20.0
Prepaid expenses and other assets	15.8	(86.2)
Contract assets	(1.1)	(4.0)
Accounts payable	(3.3)	(9.5)
Accrued expenses and other liabilities	(49.9)	(80.9)
Income taxes prepaid and payable	33.8	38.9
Deferred revenue	(35.8)	(57.9)
Net cash provided by operating activities	944.9	755.1
Cash flow from investing activities:
Cash paid for business acquisitions, net of cash acquired	7.3	(113.5)
Additions to property and equipment	(31.0)	(25.4)
Proceeds from sale of property and equipment	0.2
Additions to capitalized software	(65.2)	(54.6)
Investments in securities	(20.1)	(60.8)
Proceeds from sales / maturities of investments	42.3	50.8
Collection of other non-current receivables	8.3	7.6
Net cash used in investing activities	(58.2)	(195.9)
Cash flow from financing activities:
Cash received from debt borrowings	370.0	286.0
Repayments of debt	(687.8)	(616.3)
Net increase (decrease) in client funds obligations	1,226.3	(949.2)
Proceeds from exercise of stock options	124.2	129.6
Withholding taxes paid related to equity award net share settlement	(5.8)	(8.1)
Purchases of common stock for treasury	(487.9)	(219.8)
Dividends paid on common stock	(122.8)	(99.9)
Proceeds from Noncontrolling Interests	67.3
Net cash provided by (used in) financing activities	483.5	(1,477.7)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(4.2)	(2.0)
Net increase (decrease) in cash, cash equivalents and restricted cash	1,366.0	(920.5)
Cash, cash equivalents and restricted cash, beginning of period	1,337.9	1,789.4
Cash, cash equivalents and restricted cash and cash equivalents, end of period	2,703.9	868.9
Reconciliation of cash, cash equivalents and restricted cash and cash equivalents:
Cash and cash equivalents	351.1	184.5
Restricted cash and cash equivalents	3.7	6.0
Restricted cash and cash equivalents included in funds receivable and funds held on behalf of clients	2,349.1	678.4
Cash and cash equivalents and restricted cash	$ 2,703.9	$ 868.9