CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities
Net income	$ 499.0	$ 661.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	29.9	31.8
Amortization	108.6	105.7
Gain on divestiture of business, excluding transaction costs (Note 4)	(18.0)	(155.8)
Other non-cash items, net	64.7	54.0
Increase/(decrease) in cash, excluding the effects of divestitures, resulting from changes in:
Other assets	(91.1)	(166.4)
Accounts payable and accrued liabilities	(47.5)	50.6
Income taxes payable	(60.0)	(29.6)
Other liabilities	33.0	(29.1)
Net cash provided by operating activities	518.6	522.4
Cash flows from investing activities
Payments for capitalized contract costs	(34.3)	(58.4)
Payments for internal use software	(66.7)	(68.0)
Purchases of property and equipment	(16.2)	(21.1)
Proceeds from divestiture, net of cash divested (Note 4)		896.4
Other investing activities	2.2	5.1
Net cash (used in)/provided by investing activities	(76.5)	366.7
Cash flows from financing activities
Cash dividends and dividend equivalents paid (Note 9)	(266.0)	(275.5)
Common stock repurchased (Note 9)	(97.1)	(193.1)
Net repayments of commercial paper	(10.0)	(100.0)
Principal payments on borrowings	(300.0)	(300.0)
Proceeds from exercise of options	0.3	9.5
Net change in settlement obligations	(162.2)	(31.0)
Other financing activities		(0.2)
Net cash used in financing activities	(835.0)	(890.3)
Net change in cash and cash equivalents, including settlement, and restricted cash	(392.9)	(1.2)
Cash and cash equivalents, including settlement, and restricted cash at beginning of period	2,040.7	2,110.9
Cash and cash equivalents, including settlement, and restricted cash at end of period	1,647.8	2,109.7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents on balance sheet	1,138.2	1,176.1
Settlement cash and cash equivalents (Note 8)	484.4	817.2
Restricted cash in Other assets	25.2	52.4
Cash and cash equivalents included in Assets held for sale (Note 4)		64.0
Cash and cash equivalents, including settlement, and restricted cash	1,647.8	2,109.7
Supplemental cash flow information:
Interest paid	73.1	64.8
Income taxes paid	176.6	180.8
Accrued and unpaid capitalized contract costs		36.0
Settlement Investments
Cash flows from investing activities
Purchases of investments	(382.0)	(663.3)
Proceeds from the sale of investments	207.6	544.1
Maturities of settlement investments	112.9	131.9
Non Settlement Investment
Cash flows from investing activities
Purchases of investments		$ (400.0)
Proceeds from the sale of investments	$ 100.0