Segment and Geographic Area Information (Schedule of Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net revenues	$ 1,512.3	$ 1,462.8	$ 1,426.6	$ 1,376.1	$ 1,335.6	$ 1,198.2	$ 1,137.8	$ 1,182.6	$ 5,777.8	$ 4,854.2	$ 4,727.7
Operating profit 1									1,579.7	1,273.5	1,328.3
Assets:
Operating assets	1,356.1				1,225.3				1,356.1	1,225.3	1,106.8
Intangible assets, net	20,683.0				21,134.2				20,683.0	21,134.2	15,015.2
Other	886.2				819.5				886.2	819.5	1,174.4
Total assets	22,925.3				23,179.0				22,925.3	23,179.0	17,296.4
Capital expenditures									32.9	28.3	43.0
Capitalized software expenditures									29.7	17.7	10.2
Depreciation and other amortization									634.1	512.9	408.8
Impairment of intangible assets									99.5	0.0	0.0
Disposal group, held-for-sale, not discontinued operations | TransCore and Zetec and CIVCO Radiotherapy
Assets:
Operating assets classified as held for sale	788.6				845.8				788.6	845.8	812.5
Operating Segments | Application Software
Segment Reporting Information [Line Items]
Net revenues									2,380.6	1,799.9	1,588.0
Operating profit 1									635.9	468.7	405.4
Assets:
Operating assets	577.6				526.6				577.6	526.6	382.2
Intangible assets, net	13,498.4				13,844.6				13,498.4	13,844.6	7,833.6
Other	205.7				173.1				205.7	173.1	168.5
Capital expenditures									18.0	12.9	17.4
Capitalized software expenditures									26.3	16.3	9.7
Depreciation and other amortization									421.0	296.9	230.2
Operating Segments | Network Software & Systems
Segment Reporting Information [Line Items]
Net revenues									1,338.4	1,173.7	1,004.2
Operating profit 1									511.6	413.9	389.1
Assets:
Operating assets	243.9				217.3				243.9	217.3	206.0
Intangible assets, net	5,551.2				5,621.6				5,551.2	5,621.6	5,505.5
Other	50.4				48.4				50.4	48.4	48.7
Capital expenditures									6.0	6.2	6.1
Capitalized software expenditures									3.4	1.4	0.5
Depreciation and other amortization									171.8	171.9	127.1
Operating Segments | Measurement &Analytical Solutions
Segment Reporting Information [Line Items]
Net revenues									1,559.6	1,425.6	1,544.3
Operating profit 1									482.6	463.3	491.4
Assets:
Operating assets	346.9				328.6				346.9	328.6	332.9
Intangible assets, net	1,356.7				1,383.9				1,356.7	1,383.9	1,390.5
Other	100.9				107.6				100.9	107.6	117.9
Capital expenditures									6.4	7.9	17.1
Capitalized software expenditures									0.0	0.0	0.0
Depreciation and other amortization									33.3	34.1	39.7
Operating Segments | Process Technologies
Segment Reporting Information [Line Items]
Net revenues									499.2	455.0	591.2
Operating profit 1									152.9	115.3	211.4
Assets:
Operating assets	172.3				148.9				172.3	148.9	181.4
Intangible assets, net	276.7				284.1				276.7	284.1	285.6
Other	81.9				67.3				81.9	67.3	65.5
Capital expenditures									1.4	1.1	2.2
Capitalized software expenditures									0.0	0.0	0.0
Depreciation and other amortization									7.7	9.6	11.2
Corporate
Segment Reporting Information [Line Items]
Net revenues									0.0	0.0	0.0
Operating profit 1									(203.3)	(187.7)	(169.0)
Assets:
Operating assets	15.4				3.9				15.4	3.9	4.3
Intangible assets, net	0.0				0.0				0.0	0.0	0.0
Other	$ 447.3				$ 423.1				447.3	423.1	773.8
Capital expenditures									1.1	0.2	0.2
Capitalized software expenditures									0.0	0.0	0.0
Depreciation and other amortization									$ 0.3	$ 0.4	$ 0.6