Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net income	$ 239.5	$ 370.2
Reconciliation of net income to net cash provided by operating activities:
Depreciation	73.3	65.6
Amortization	95.7	85.9
Lease expense	20.9	20.3
Stock-based compensation	21.0	19.2
Loss on extinguishment of debt	8.8	0.0
Deferred taxes	(2.4)	(3.3)
Other operating activities, net	17.9	5.6
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables	(34.0)	(127.0)
Inventories	(5.7)	(9.1)
Contract assets	4.7	(18.6)
Prepaid expenses and other assets	15.8	8.2
Accounts payable	(1.9)	71.0
Accrued and other current liabilities	(5.4)	12.6
Contract liabilities	15.9	13.1
Other long-term liabilities	(23.9)	(24.2)
Net cash provided by operating activities	440.2	489.5
Investing activities:
Capital expenditures	(72.7)	(56.6)
Acquisitions, net of cash acquired	(35.4)	(287.7)
Other investing activities, net	1.4	2.2
Net cash used in investing activities	(106.7)	(342.1)
Financing activities:
Proceeds from notes	740.7	0.0
Repayment of notes	(258.5)	0.0
Borrowings from revolving credit facility	500.0	0.0
Repayments of revolving credit facility	(500.0)	0.0
Financing costs	(24.2)	0.0
Repurchases of common stock	(341.7)	(232.1)
Dividends paid	(84.5)	(74.5)
Proceeds from exercise of stock options	12.9	27.3
Withholding tax paid related to stock-based compensation	(7.4)	(9.7)
Other financing activities, net	(0.6)	(2.7)
Net cash used in financing activities	36.7	(291.7)
Effect of foreign currency exchange rate changes on cash and cash equivalents	(2.4)	(1.2)
Change in cash and cash equivalents	367.8	(145.5)
Cash and cash equivalents at beginning of period	351.2	803.6
Cash and cash equivalents at end of period	$ 719.0	$ 658.1