Buildings and Equipment (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Original Cost	$ 1,236.4
Accumulated Depreciation	769.8
Net Book Value	466.6	$ 446.9
Land Improvements
Property, Plant and Equipment [Line Items]
Original Cost	26.5
Accumulated Depreciation	0.8
Net Book Value	25.7
Buildings
Property, Plant and Equipment [Line Items]
Original Cost	247.2
Accumulated Depreciation	134.7
Net Book Value	112.5
Equipment
Property, Plant and Equipment [Line Items]
Original Cost	524.8
Accumulated Depreciation	344.4
Net Book Value	180.4
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Original Cost	357.9
Accumulated Depreciation	236.1
Net Book Value	121.8
Buildings Leased under Capital Leases
Property, Plant and Equipment [Line Items]
Original Cost	80.0
Accumulated Depreciation	53.8
Net Book Value	$ 26.2