Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
		Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016	Oct. 22, 2015
Stock Repurchase Program, Number of Shares Authorized to be Repurchased			0		0
Numerator:
Net income (loss)		$ (69.6)	$ (534.3)	$ 2.0	$ (1,063.5)
Denominator:
Weighted average shares outstanding for basic EPS		143,300,000	143,200,000	143,300,000	143,200,000
Dilutive effect of share-based awards	[1]	0	0	300,000	0
Weighted average shares outstanding for diluted EPS		143,300,000	143,200,000	143,600,000	143,200,000
Anti-dilutive share-based awards excluded from computation of diluted EPS		0	0	800,000	0
Share-based compensation arrangement by share-based payment award, options, exercises in period		31,900	19,000	46,400	98,000
Stock repurchase program, authorized amount		$ 0.8		$ 0.8
Stock repurchase program, remaining authorized repurchase amount		$ 1,400.0		$ 1,400.0
Share price				$ 71.67
Proceeds from (Repurchase of) Equity				$ 58.2
Perrigo Co PLC [Member]
Denominator:
Stock repurchase program, authorized amount						$ 2,000.0

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