Acquisitions (Details) $ in Millions					3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 18, 2025 USD ($)	Aug. 04, 2025 USD ($)	Jan. 31, 2025 USD ($)	Jul. 18, 2024	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) agreement	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) agreement	Aug. 22, 2025 USD ($)
Acquisitions
Number of acquisitions | agreement									2
Purchase price, net of cash acquired							$ 2,772.2	$ 2,099.8	$ 2,156.4
Goodwill					$ 9,868.6		9,868.6		8,236.2
Acquisition-related expenses					0.0	$ 45.4	$ 56.0	115.4
Delayed Draw Term Loan With 3 Years Term
Acquisitions
Debt instrument, principal amount										$ 2,000.0
Delayed Draw Term Loan With 364 Days Term
Acquisitions
Debt instrument, principal amount										2,000.0
Senior Unsecured Bridge Facility [Member]
Acquisitions
Maximum borrowing capacity		$ 10,500.0
2025 Acquisitions
Acquisitions
Number of acquisitions | agreement							4
Purchase price, net of cash acquired							$ 2,772.2
Goodwill					875.0		875.0
Definite-lived intangible assets							800.0
Goodwill deductible for tax purposes					813.0		813.0
Acquisition-related expenses							133.8
Acquisition-related expenses, net of tax							106.3
2024 Acquisitions
Acquisitions
Goodwill					1,198.2		1,198.2
Definite-lived intangible assets							576.0
Goodwill deductible for tax purposes					61.2		$ 61.2
Total acquisition-related expenses						63.6		133.6
Total acquisition-related expenses, net of tax						49.8		109.7
Acquisition-related expenses						45.4		115.4
Andrew Business Acquisition
Acquisitions
Business acquisition, effective date			Jan. 31, 2025
Business acquisition, date of agreement				Jul. 18, 2024
Purchase price, net of cash acquired			$ 2,022.7
Connectivity and Cable Solutions Business
Acquisitions
Business acquisition, date of agreement		Aug. 04, 2025
Expected price of acquisition		$ 10,500.0
Connectivity and Cable Solutions Business | Scenario, Plan [Member] | Delayed Draw Term Loans [Member]
Acquisitions
Debt instrument, principal amount										$ 4,000.0
Connectivity and Cable Solutions Business | Scenario, Plan [Member] | New Senior Unsecured Notes [Member]
Acquisitions
Debt instrument, principal amount		$ 6,500.0
Trexon Acquisition
Acquisitions
Business acquisition, date of agreement	Aug. 18, 2025
Expected price of acquisition	$ 1,000.0
Customer relationships | 2025 Acquisitions | Minimum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							12 years
Customer relationships | 2025 Acquisitions | Maximum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							15 years
Customer relationships | 2024 Acquisitions | Minimum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							8 years
Customer relationships | 2024 Acquisitions | Maximum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							15 years
Proprietary technology | 2025 Acquisitions | Minimum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							12 years
Proprietary technology | 2025 Acquisitions | Maximum
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							15 years
Backlog | 2025 Acquisitions
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							3 months
Backlog | 2024 Acquisitions
Acquisitions
Finite-lived acquired intangible assets weighted-average useful life							4 months 24 days
Amortization of Inventory step-up costs recorded to Cost of Sales | Carlisle Interconnect Technologies Acquisition
Acquisitions
Amortization of acquisition-related inventory step-up costs recorded in Cost of sales						$ 18.2		$ 18.2
Amortization of Inventory step-up costs recorded to Cost of Sales | Andrew Business Acquisition
Acquisitions
Amortization of acquisition-related inventory step-up costs recorded in Cost of sales							$ 77.8
Communications Solutions
Acquisitions
Goodwill					3,856.4		$ 3,856.4		$ 2,951.5
Communications Solutions | Andrew Business Acquisition
Acquisitions
Number of acquisitions | agreement							1
Harsh Environment Solutions
Acquisitions
Number of acquisitions | agreement							2		2
Goodwill					3,568.3		$ 3,568.3		$ 3,180.0
Interconnect and Sensor Systems
Acquisitions
Number of acquisitions | agreement							1
Goodwill					$ 2,443.9		$ 2,443.9		$ 2,104.7