Selected Quarterly Financial Data (Unaudited), Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Data (Unaudited)
Excess tax benefit from option exercises	$ 16.8	$ 1.6	$ 12.9	$ 6.8	$ 5.7	$ 7.0	$ 3.0	$ 4.1	$ 38.1	$ 19.8	$ 66.6
Acquisition-related expenses			8.9	16.5	8.5				25.4	8.5	4.0
Acquisition-related expenses, net of tax			$ 7.8	$ 13.2	$ 7.2				21.0	7.2	3.7
Excess tax benefits related to stock-based compensation ( in dollars per share)		$ 0.01	$ 0.04	$ 0.02	$ 0.02
Gain (loss) on extinguishment of debt		$ (14.3)							(14.3)	0.0	$ 0.0
Gain (loss) on extinguishment of debt, after tax		$ (12.5)							$ (12.5)
Gain (loss) on extinguishment of debt, per diluted share		$ (0.04)							$ (0.04)
Net income (loss) per common share-Diluted, acquisition-related expenses (in dollars per share)			$ (0.03)	$ (0.04)	$ (0.02)
Income tax expense (benefit)					$ (14.5)					$ (14.5)
Impact on earnings per share related to Tax Cuts and Jobs Act (in dollars per share)					$ 0.04
Operating income (loss), aggregate effect			$ (8.9)	$ (16.5)	$ (8.5)
Net income, aggregate effect	16.8	$ (10.9)	5.1	(6.4)	13.0	7.0	3.0	4.1
Net income attributable to Amphenol Corporation shareholders, aggregate effect	$ 16.8	$ (10.9)	$ 5.1	$ (6.4)	$ 13.0	$ 7.0	$ 3.0	$ 4.1
Earnings per share - diluted, aggregate effect (in dollars per share)	$ 0.05	$ (0.03)	$ 0.01	$ (0.02)	$ 0.04	$ 0.02	$ 0.01	$ 0.01