CONSOLIDATED BALANCE SHEETS - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Deferred Revenue, Revenue Recognized	$ 319,400,000	$ 262,600,000
Current assets:
Cash and cash equivalents	1,472,700,000	1,320,800,000
Accounts receivable, net	2,261,500,000	2,479,800,000
Unbilled Contracts Receivable	716,800,000	536,800,000
Supplies inventory	401,400,000	423,200,000
Prepaid expenses and other	478,100,000	364,800,000
Total current assets	5,330,500,000	5,125,400,000
Property, plant and equipment, net	2,815,400,000	2,729,600,000
Goodwill, net	7,958,900,000	7,751,500,000
Intangible assets, net	3,735,500,000	3,961,100,000
Joint venture partnerships and equity method investments	60,900,000	73,500,000
Deferred Income Tax Assets, Net	21,600,000	20,600,000
Other assets, net	462,600,000	410,000,000.0
Total assets	20,385,400,000	20,071,700,000
Current liabilities:
Finance Lease, Liability, Current	10,500,000	6,700,000
Accounts payable	621,300,000	638,900,000
Accrued expenses and other	1,404,100,000	1,357,700,000
Deferred Revenue, Current	558,500,000	506,500,000
Operating Lease, Liability, Current	187,000,000.0	192,000,000.0
Short-term borrowings and current portion of long-term debt	1,500,000	376,700,000
Total current liabilities	2,782,900,000	3,078,500,000
Long-term debt, less current portion	5,416,500,000	5,419,000,000
Total maturities, due beyond one year	642,500,000	677,600,000
Total maturities, due beyond one year	84,600,000	84,400,000
Deferred income taxes and other tax liabilities	762,900,000	828,500,000
Other liabilities	402,000,000.0	526,400,000
Total liabilities	10,091,400,000	10,614,400,000
Commitments and contingent liabilities
Noncontrolling interest	20,600,000	20,700,000
Shareholders’ equity
Common stock, 93.1 and 97.5 shares outstanding at December 31, 2021 and 2020, respectively	8,500,000	9,000,000.0
Additional paid-in capital	0	110,300,000
Retained earnings	10,456,800,000	9,479,200,000
Accumulated other comprehensive loss	(191,900,000)	(161,900,000)
Total shareholders’ equity	10,273,400,000	9,436,600,000
Total liabilities and shareholders’ equity	$ 20,385,400,000	$ 20,071,700,000