Annual report pursuant to Section 13 and 15(d)

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

v3.21.2
Funds Held for Clients and Corporate Investments (Funds Held for Clients and Corporate Investments) (Details) - USD ($)
$ in Millions
May 31, 2021
May 31, 2020
Schedule of Available-for-sale Securities [Line Items]    
Funds held for clients' money market securities and other restricted cash equivalents, Amortized cost $ 739.6 $ 683.5
Funds held for clients' money market securities and other restricted cash equivalents, Gross unrealized gains
Funds held for clients' money market securities and other restricted cash equivalents, Gross unrealized losses
Funds held for clients' money market securities and other restricted cash equivalents, Fair value 739.6 683.5
AFS securities, Amortized cost 2,940.9 2,657.2
AFS securities, Gross unrealized gains 83.3 101.7
AFS securities, Gross unrealized losses (4.0) (1.7)
AFS securities, Fair value 3,020.2 2,757.2
Other, Amortized cost 26.4 25.4
Other, Gross unrealized gains 7.7 2.2
Other, Gross unrealized losses (0.1) (0.4)
Other, Fair value 34.0 27.2
Total funds held for clients and corporate investments, Amortized cost 3,706.9 3,366.1
Total funds held for clients and corporate investments, Gross unrealized gains 91.0 103.9
Total funds held for clients and corporate investments, Gross unrealized losses (4.1) (2.1)
Total funds held for clients and corporate investments, Fair value 3,793.8 3,467.9
Asset-Backed Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
AFS securities, Amortized cost 86.5 68.0
AFS securities, Gross unrealized gains 1.4 1.7
AFS securities, Gross unrealized losses  
AFS securities, Fair value 87.9 69.7
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
AFS securities, Amortized cost 635.8 649.6
AFS securities, Gross unrealized gains 28.8 34.1
AFS securities, Gross unrealized losses (0.2) (0.1)
AFS securities, Fair value 664.4 683.6
Municipal Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
AFS securities, Amortized cost 1,669.0 1,373.8
AFS securities, Gross unrealized gains 33.0 37.4
AFS securities, Gross unrealized losses (2.3) (1.6)
AFS securities, Fair value 1,699.7 1,409.6
U.S. Government Agency And Treasury Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
AFS securities, Amortized cost 549.6 565.8
AFS securities, Gross unrealized gains 20.1 28.5
AFS securities, Gross unrealized losses (1.5)  
AFS securities, Fair value $ 568.2 $ 594.3