Quarterly report pursuant to Section 13 or 15(d)

Property and Equipment, Net of Accumulated Depreciation (Components of Property and Equipment, at Cost) (Details)

v3.7.0.1
Property and Equipment, Net of Accumulated Depreciation (Components of Property and Equipment, at Cost) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Feb. 28, 2017
Feb. 29, 2016
Feb. 28, 2017
Feb. 29, 2016
May 31, 2016
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross $ 1,032.2   $ 1,032.2   $ 1,012.2
Less: Accumulated depreciation 690.6   690.6   659.2
Property and equipment, net of accumulated depreciation 341.6   341.6   353.0
Depreciation expense 26.4 $ 25.1 77.2 $ 73.8  
Land and Improvements [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 8.3   8.3   8.3
Buildings and Improvements [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 103.3   103.3   103.0
Data Processing Equipment [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 196.7   196.7   196.1
Software [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 475.4   475.4   447.5
Furniture, Fixtures, and Equipment [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 113.6   113.6   125.0
Leasehold Improvements [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross 108.6   108.6   108.2
Construction in Progress [Member]          
Property, Plant and Equipment [Line Items]          
Total property and equipment, gross $ 26.3   $ 26.3   $ 24.1