Quarterly report pursuant to Section 13 or 15(d)

Funds Held for Clients and Corporate Investments (Funds Held for Clients and Corporate Investments) (Details)

v3.19.3
Funds Held for Clients and Corporate Investments (Funds Held for Clients and Corporate Investments) (Details) - USD ($)
$ in Millions
Aug. 31, 2019
May 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Funds held for clients' money market securities and other cash equivalents, Amortized cost $ 717.4 $ 204.5
Funds held for clients' money market securities and other cash equivalents, Fair value 717.4 204.5
Available-for-sale securities, Amortized cost 3,019.4 3,601.1
Available-for-sale securities, Gross unrealized gains 53.9 22.4
Available-for-sale securities, Gross unrealized losses (0.5) (2.7)
Available-for-sale securities, Fair value 3,072.8 3,620.8
Other, Amortized cost 27.7 26.3
Other, Gross unrealized gains 2.6 1.7
Other, Gross unrealized losses (0.2) (0.3)
Other, Fair value 30.1 27.7
Total funds held for clients and corporate investments, Amortized cost 3,764.5 3,831.9
Total funds held for clients and corporate investments, Gross unrealized gains 56.5 24.1
Total funds held for clients and corporate investments, Gross unrealized losses (0.7) (3.0)
Total funds held for clients and corporate investments, Fair value 3,820.3 3,853.0
Asset-backed Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 26.4 5.3
Available-for-sale securities, Gross unrealized gains 0.2  
Available-for-sale securities, Fair value 26.6 5.3
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 683.8 442.1
Available-for-sale securities, Gross unrealized gains 14.8 5.3
Available-for-sale securities, Gross unrealized losses (0.1) (0.9)
Available-for-sale securities, Fair value 698.5 446.5
General Obligation Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 775.0 840.6
Available-for-sale securities, Gross unrealized gains 14.1 7.5
Available-for-sale securities, Gross unrealized losses   (0.3)
Available-for-sale securities, Fair value 789.1 847.8
Pre-Refunded Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost [1] 23.3 25.6
Available-for-sale securities, Gross unrealized gains [1] 0.3 0.2
Available-for-sale securities, Fair value [1] 23.6 25.8
Revenue Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 512.1 545.4
Available-for-sale securities, Gross unrealized gains 9.2 4.7
Available-for-sale securities, Gross unrealized losses   (0.2)
Available-for-sale securities, Fair value 521.3 549.9
U.S. Government Agency And Treasury Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 963.8 612.5
Available-for-sale securities, Gross unrealized gains 15.3 4.7
Available-for-sale securities, Gross unrealized losses (0.4) (1.3)
Available-for-sale securities, Fair value 978.7 615.9
Variable Rate Demand Notes [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale securities, Amortized cost 35.0 1,129.6
Available-for-sale securities, Fair value $ 35.0 $ 1,129.6
[1] Pre-refunded municipal bonds are secured by an escrow fund of U.S. government obligations.