Segment Disclosures - Segment Earnings (loss) From Operations (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Earnings (loss) from Operations
Gross profit	$ 231.0	$ 189.2	$ 444.3	$ 412.5
SG&A expenses	(217.3)	(178.1)	(420.0)	(397.6)
Earnings (loss) from operations	13.7	11.1	24.3	(100.7)
Gain (loss) on investment in Persol Holdings	6.3	29.6	36.3	(48.2)
Other income (expense), net	(0.3)	2.6	(3.7)	4.3
Earnings (loss) before taxes and equity in net earnings (loss) of affiliate	19.7	43.3	56.9	(144.6)
Corporate
Earnings (loss) from Operations
Earnings (loss) from operations	(21.4)	(19.3)	(43.3)	(159.0)
Professional & Industrial \| Reporting Segments
Earnings (loss) from Operations
Gross profit	75.2	78.9	151.1	164.0
SG&A expenses	(69.0)	(64.6)	(138.4)	(145.1)
Earnings (loss) from operations	6.2	14.3	12.7	18.9
Science, Engineering & Technology \| Reporting Segments
Earnings (loss) from Operations
Gross profit	66.5	50.6	119.7	105.3
SG&A expenses	(46.9)	(31.3)	(82.6)	(67.8)
Earnings (loss) from operations	19.6	19.3	37.1	37.5
Education \| Reporting Segments
Earnings (loss) from Operations
Gross profit	16.8	4.3	34.0	24.7
SG&A expenses	(15.3)	(9.5)	(29.5)	(26.1)
Earnings (loss) from operations	1.5	(5.2)	4.5	(1.4)
Outsourcing & Consulting \| Reporting Segments
Earnings (loss) from Operations
Gross profit	34.8	29.2	66.1	58.0
SG&A expenses	(30.1)	(25.1)	(58.5)	(53.7)
Earnings (loss) from operations	4.7	4.1	7.6	4.3
International \| Reporting Segments
Earnings (loss) from Operations
Gross profit	37.7	26.2	73.4	60.5
SG&A expenses	(34.6)	(28.3)	(67.7)	(61.5)
Earnings (loss) from operations	$ 3.1	$ (2.1)	$ 5.7	$ (1.0)

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting.

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