CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net earnings	$ 465,700,000	$ 556,700,000	$ 545,400,000
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	77,200,000	85,800,000	84,400,000
Non-cash gain on disposition of previously held equity interest	(80,400,000)
Non-cash gain on disposition of previously held controlling interest	(30,400,000)
Goodwill impairment charge	64,000,000.0
Deferred income taxes	(43,000,000.0)	(11,900,000)	(196,800,000)
Provision for doubtful accounts	21,800,000	23,000,000.0	18,100,000
Share-based compensation	26,300,000	27,800,000	28,700,000
Change in operating assets and liabilities, excluding the impact of acquisitions:
Accounts receivable	(80,200,000)	(146,400,000)	(544,900,000)
Other assets	122,300,000	58,700,000	(68,600,000)
Other liabilities	271,100,000	(110,600,000)	534,600,000
Cash provided by operating activities	814,400,000	483,100,000	400,900,000
Cash Flows from Investing Activities
Capital expenditures	(52,900,000)	(64,700,000)	(54,700,000)
Acquisitions of businesses, net of cash acquired	77,800,000	(9,100,000)	(32,700,000)
Impact to cash resulting from deconsolidation of subsidiaries	(57,900,000)
Proceeds from the sale of subsidiaries, investments, property and equipment	16,800,000	18,900,000	12,900,000
Cash used in investing activities	(16,200,000)	(54,900,000)	(74,500,000)
Cash Flows from Financing Activities
Net change in short-term borrowings	11,200,000	3,500,000	5,500,000
Proceeds from long-term debt	9,600,000	583,300,000	100,000
Repayments of long-term debt	(1,300,000)	(408,600,000)	(400,000)
Payments for debt issuance costs		(2,500,000)
Payments of contingent consideration for acquisitions	(22,800,000)	(18,600,000)	(13,000,000.0)
Proceeds from share-based awards	7,000,000.0	5,200,000	44,200,000
Payments to noncontrolling interests	(2,100,000)	(1,900,000)	(10,000,000.0)
Other share-based award transactions	(7,200,000)	(17,300,000)	(18,100,000)
Repurchases of common stock	(203,000,000.0)	(500,700,000)	(203,900,000)
Dividends paid	(129,300,000)	(127,300,000)	(123,700,000)
Miscellaneous, net	500,000
Cash used in financing activities	(337,400,000)	(484,900,000)	(319,300,000)
Effect of exchange rate changes on cash	(26,900,000)	(40,400,000)	83,400,000
Change in cash and cash equivalents	433,900,000	(97,100,000)	90,500,000
Cash and cash equivalents, beginning of year	591,900,000	689,000,000.0	598,500,000
Cash and cash equivalents, end of year	1,025,800,000	591,900,000	689,000,000.0
Cash paid during the period for:
Interest	42,400,000	49,900,000	37,000,000.0
Income taxes, net	179,200,000	$ 184,600,000	$ 127,100,000
Operating lease liabilities	150,100,000
Non-cash operating activity:
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 129,300,000