Selected Quarterly Financial Data (Unaudited), Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Selected Quarterly Financial Data (Unaudited)
Excess tax benefit from option exercises	$ 5.7	$ 7.0	$ 3.0	$ 4.1	$ 20.8	$ 16.6	$ 21.2	$ 8.0		$ 19.8	$ 66.6	$ 0.0
Net income relating to excess tax benefits of stock-based compensation		7.0	3.0	4.1		16.6		8.0
Net income attributable to Amphenol Corporation shareholders relating to excess tax benefits of stock-based compensation		$ 7.0	$ 3.0	$ 4.1		$ 16.6		$ 8.0
Net income (loss) per common share—Diluted, excess tax benefit from stock-based compensation (in dollars per share)	$ 0.02	$ 0.02	$ 0.01	$ 0.01	$ 0.07	$ 0.05	$ 0.07	$ 0.02
Acquisition-related expenses	$ 8.5						$ 4.0		$ 6.3	8.5	$ 4.0	$ 36.6
Acquisition-related expenses, net of tax	$ 7.2						$ 3.7		$ 5.8
Net income (loss) per common share—Diluted, acquisition-related expenses (in dollars per share)	$ (0.02)						$ (0.01)
Income tax benefit	$ 14.5									$ 14.5
Impact on earnings per share related to Tax Cuts and Jobs Act (in dollars per share)	$ 0.04				$ (1.26)
Operating income (loss), aggregate effect	$ (8.5)						$ (4.0)
Net income, aggregate effect	13.0				$ (377.7)		17.5
Net income attributable to Amphenol Corporation shareholders, aggregate effect	$ 13.0				$ (377.7)		$ 17.5
Earnings per share - diluted, aggregate effect (in dollars per share)	$ 0.04				$ (1.20)		$ 0.06
Provisional Tax Act Charge					$ 398.5
Anti-dilutive stock options, excluded from the computations of earning per share (in shares)					12.4					3.3	1.6	8.5
Earnings per share - diluted change (in dollars per share)					$ 0.01