Other Income (Expense), Net - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
Oct. 01, 2023	Oct. 02, 2022
Other Income (Expense) [Line Items]
Proceeds from equity securities	$ 2.0	$ 0.0
Brazil
Other Income (Expense) [Line Items]
Increase to indemnification liability		0.8
Business Talent Group, LLC
Other Income (Expense) [Line Items]
Proceeds from equity securities	$ 2.0
Kelly Services Japan, Inc.
Other Income (Expense) [Line Items]
Unrealized gain (loss), foreign currency transaction, after tax		$ 5.5

Amount, after tax, of unrealized gain (loss) from foreign currency transaction.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 205
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480767/946-205-45-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 6
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 45
-Paragraph 38
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480228/946-830-45-38

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