Document and Entity Information - USD ($)	12 Months Ended
	Jan. 01, 2017	Feb. 05, 2017	Jul. 03, 2016
Document Information [Line Items]
Entity Registrant Name	Kelly Services Inc
Document Type	10-K
Current Fiscal Year End Date	--01-01
Entity Public Float			$ 560,567,627
Amendment Flag	false
Entity Central Index Key	0000055135
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Jan. 01, 2017
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		34,806,309
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,437,643