Income Taxes - Deferred Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jan. 01, 2017
Components of Deferred Tax Assets and Liabilities
Depreciation and amortization	$ (13.4)	$ (14.6)
Employee compensation and benefit plans	57.3	75.5
Workers’ compensation	14.5	22.4
Unrealized gain on securities	(60.1)	(33.6)
Investment in equity affiliate	(15.5)	(22.7)
Loss carryforwards	38.8	36.4
Credit carryforwards	132.7	121.2
Other, net	3.1	3.5
Valuation allowance	(34.6)	(42.1)
Deferred Tax Assets, Net	$ 122.8	$ 146.0