Document and Entity Information - shares	9 Months Ended
	Oct. 31, 2020	Nov. 27, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Oct. 31, 2020
Document Transition Report	false
Entity File Number	1-32349
Entity Registrant Name	SIGNET JEWELERS LIMITED
Entity Incorporation, State or Country Code	D0
Entity Address, Address Line One	Clarendon House
Entity Address, Address Line Two	2 Church Street
Entity Address, City or Town	Hamilton
Entity Address, Postal Zip Code	HM11
Entity Address, Country	BM
City Area Code	441
Local Phone Number	296 5872
Title of 12(b) Security	Common Shares of $0.18 each
Trading Symbol	SIG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		52,338,811
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000832988
Current Fiscal Year End Date	--01-30