Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Data (Unaudited)
Net sales	$ 2,426.0	$ 2,323.4	$ 1,987.5	$ 1,862.0	$ 2,151.0	$ 2,100.6	$ 2,015.3	$ 1,958.5	$ 8,598.9	$ 8,225.4	$ 8,202.0
Gross Profit	765.6	734.9	603.8	559.8	678.7	661.9	647.6	627.8	2,664.1	2,616.0	2,654.9
Operating income	488.4	475.8	357.4	316.9	429.8	413.6	399.5	376.2	1,638.4	1,619.2	1,686.9
Net income (loss)	360.2	349.5	260.5	243.2	320.8	282.3	290.9	269.9	1,213.3	1,164.0	1,216.9
Net income (loss) attributable to Amphenol Corporation shareholders	$ 357.0	$ 346.6	$ 257.7	$ 242.1	$ 318.7	$ 280.3	$ 288.4	$ 267.5	$ 1,203.4	$ 1,155.0	$ 1,205.0
Net income (loss) per common share - Basic (in dollars per share)	$ 1.19	$ 1.16	$ 0.87	$ 0.81	$ 1.07	$ 0.95	$ 0.97	$ 0.90	$ 4.04	$ 3.88	$ 4.00
Net income (loss) per common share-Diluted (in dollars per share)	$ 1.15	$ 1.12	$ 0.85	$ 0.79	$ 1.03	$ 0.92	$ 0.93	$ 0.87	$ 3.91	$ 3.75	$ 3.85