Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 28, 2020	Dec. 29, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in Persol Holdings	$ 127.2	$ 173.2
Measured on Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	121.5	4.9
Investment in Persol Holdings	127.2	173.2
Total assets at fair value	248.7	178.1
Measured on Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	121.5	4.9
Investment in Persol Holdings	127.2	173.2
Total assets at fair value	248.7	178.1
Measured on Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0.0	0.0
Investment in Persol Holdings	0.0	0.0
Total assets at fair value	0.0	0.0
Measured on Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0.0	0.0
Investment in Persol Holdings	0.0	0.0
Total assets at fair value	$ 0.0	$ 0.0