Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Oct. 22, 2015
Numerator:
Net income (loss)		$ 44.5	$ (1,590.2)	$ 46.4	$ (2,653.7)
Denominator:
Weighted average shares outstanding for basic EPS		141,300,000	143,300,000	142,500,000	143,200,000
Dilutive effect of share-based awards	[1]	400,000	0	300,000	0
Weighted average shares outstanding for diluted EPS		141,700,000	143,300,000	142,800,000	143,200,000
Anti-dilutive share-based awards excluded from computation of diluted EPS		1,000,000	0	800,000	0
Share-based compensation arrangement by share-based payment award, options, exercises in period		99,800	185,000	146,100	283,000
Share price		$ 71.73		$ 71.72
Proceeds from (Repurchase of) Equity		$ 133.3		$ 191.5
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 1,300.0		$ 1,300.0
Perrigo Co PLC [Member]
Stock repurchase program, authorized amount						$ 2,000.0
Common Stock [Member]
Stock repurchase program, number of shares repurchased		1,858,705		2,670,889	0

[1] * In the period of a net loss, diluted shares equal basic shares.