Segment Disclosures - Segment Earnings (loss) From Operations (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Earnings (loss) from Operations
Gross profit	$ 189.2	$ 244.0	$ 412.5	$ 495.6
SG&A expenses	(178.1)	(221.5)	(397.6)	(456.3)
Earnings (loss) from operations	11.1	34.8	(100.7)	51.6
Gain (loss) on investment in Persol Holdings	29.6	61.2	(48.2)	74.4
Other income (expense), net	2.6	0.2	4.3	(0.9)
Earnings (loss) before taxes and equity in net earnings (loss) of affiliate	43.3	96.2	(144.6)	125.1
Less: Intersegment
Earnings (loss) from Operations
Gross profit	(0.4)	(0.6)	(0.8)	(1.2)
SG&A expenses	0.4	0.6	0.8	1.2
Earnings (loss) from operations	0.0	0.0	0.0	0.0
Corporate
Earnings (loss) from Operations
Earnings (loss) from operations	(19.5)	(9.7)	(158.5)	(37.9)
Americas Staffing \| Reporting Segments
Earnings (loss) from Operations
Gross profit	63.4	108.8	157.0	226.0
SG&A expenses	(69.7)	(93.2)	(163.2)	(194.4)
Earnings (loss) from operations	(6.3)	15.6	(6.2)	31.6
Global Talent Solutions \| Reporting Segments
Earnings (loss) from Operations
Gross profit	103.0	99.7	203.2	200.1
SG&A expenses	(64.2)	(74.3)	(137.9)	(149.0)
Earnings (loss) from operations	38.8	25.4	65.3	51.1
International Staffing \| Reporting Segments
Earnings (loss) from Operations
Gross profit	23.2	36.1	53.1	70.7
SG&A expenses	(25.1)	(32.6)	(54.4)	(63.9)
Earnings (loss) from operations	$ (1.9)	$ 3.5	$ (1.3)	$ 6.8

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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