Earnings Per Share and Shareholders Equity (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		15 Months Ended
		Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Oct. 22, 2015
Numerator:
Net income (loss)		$ (1,590.2)	$ 260.9	$ (2,653.7)	$ 216.4
Denominator:
Weighted average shares outstanding for basic EPS (in shares)		143,300,000	146,300,000	143,200,000	144,400,000
Dilutive effect of share-based awards (in shares)	[1]	0	600,000	0	600,000
Weighted average shares outstanding for diluted EPS (in shares)		143,300,000	146,900,000	143,200,000	145,000,000
Anti-dilutive share-based awards excluded from computation of diluted EPS (in shares)	[1]	0	100,000	0	0
Exercises in period (in shares)		185,000	154,000	283,000	246,000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, remaining authorized repurchase amount		$ 1,500.0		$ 1,500.0		$ 1,500.0
Shares repurchased in period (in shares)						0
Perrigo Co PLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount							$ 2,000.0

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