Business Acquisitions and Dispositions (Details) $ in Millions							9 Months Ended	12 Months Ended
	Jan. 03, 2022 USD ($)	Oct. 15, 2021 USD ($)	Mar. 17, 2021 USD ($)	Sep. 03, 2020 USD ($)	Oct. 29, 2019 USD ($)	Feb. 05, 2019 USD ($)	Sep. 30, 2021 acquisition	Dec. 31, 2021 USD ($) acquisition	Dec. 31, 2020 USD ($) acquisition	Dec. 31, 2019 USD ($) acquisition	Dec. 30, 2021	Aug. 22, 2019	Apr. 18, 2019
Business Acquisition [Line Items]
Number of businesses acquired | acquisition							4	7	6	4
Aggregate purchase price										$ 2,387.6
Goodwill acquired during period								$ 138.8	$ 3,533.0
Other identifiable intangibles								104.9
Disposal group, disposed of by sale, not discontinued operations | Sedaru, Inc | Gatan
Business Acquisition [Line Items]
Consideration receivable or received on disposal			$ 27.1
Pretax gain			27.1
Income tax expense in connection with sale			$ 5.5
Disposal group, disposed of by sale, not discontinued operations | AMETEK | Gatan
Business Acquisition [Line Items]
Consideration receivable or received on disposal					$ 925.0
Pretax gain					801.1
Income tax expense in connection with sale					$ 201.2
Disposal group, disposed of by sale, not discontinued operations | Teledyne | Imaging Businesses
Business Acquisition [Line Items]
Consideration receivable or received on disposal						$ 225.0
Pretax gain						119.6
Income tax expense in connection with sale						$ 32.2
Customer related intangibles
Business Acquisition [Line Items]
Other identifiable intangibles								$ 94.6
Weighted average useful life of finite-lived intangible assets (in years)								12 years 10 months 24 days
Technology
Business Acquisition [Line Items]
Other identifiable intangibles								$ 10.3
Weighted average useful life of finite-lived intangible assets (in years)								5 years 3 months 18 days
American LegalNet Inc
Business Acquisition [Line Items]
Percentage of voting interests acquired (as a percent)											100.00%
Horizon Lab Systems | Subsequent event
Business Acquisition [Line Items]
Percentage of voting interests acquired (as a percent)	100.00%
Cash transaction	$ 49.7
Vertafore
Business Acquisition [Line Items]
Aggregate purchase price				$ 5,398.6
Percentage of voting interests acquired (as a percent)				100.00%
Goodwill acquired during period				$ 3,229.1
Other identifiable intangibles				2,660.0
Business acquisition, enterprise value				5,335.0
Purchase price				120.0
Amortizable intangible assets				2,540.0
Deferred tax assets (liabilities), net				489.0
Deferred tax liabilities				638.0
Vertafore | Trade names
Business Acquisition [Line Items]
Indefinite-lived intangible assets				120.0
Vertafore | Customer related intangibles
Business Acquisition [Line Items]
Other identifiable intangibles				$ 2,230.0
Weighted average useful life of finite-lived intangible assets (in years)				17 years
Vertafore | Technology
Business Acquisition [Line Items]
Other identifiable intangibles				$ 310.0
Weighted average useful life of finite-lived intangible assets (in years)				8 years
Other acquisitions
Business Acquisition [Line Items]
Number of businesses acquired | acquisition									5
Aggregate purchase price								$ 225.9	$ 612.8
Goodwill acquired during period		$ 303.9								1,447.0
Other identifiable intangibles		313.0								$ 1,181.9
Other acquisitions | Customer related intangibles
Business Acquisition [Line Items]
Other identifiable intangibles		$ 283.7
Weighted average useful life of finite-lived intangible assets (in years)		16 years								15 years 9 months 18 days
Amortizable intangible assets										$ 1,020.0
Other acquisitions | Technology
Business Acquisition [Line Items]
Other identifiable intangibles		$ 29.3
Weighted average useful life of finite-lived intangible assets (in years)		5 years
Other acquisitions | Unpatented technology
Business Acquisition [Line Items]
Weighted average useful life of finite-lived intangible assets (in years)										6 years 9 months 18 days
Amortizable intangible assets										$ 109.3
Foundry
Business Acquisition [Line Items]
Percentage of voting interests acquired (as a percent)													100.00%
iPipeline
Business Acquisition [Line Items]
Percentage of voting interests acquired (as a percent)												100.00%