v3.26.1
Corporate Investments and Funds Held for Clients - Schedule of Available-For-Sale Securities that Have Been in an Unrealized Loss Position (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Jun. 30, 2025
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses $ (92.2) $ (10.2)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 10,688.7 1,963.9
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (445.0) (672.1)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 10,595.8 16,184.9
Total, Gross Unrealized Losses (537.2) (682.3)
Total, Fair Market Value 21,284.5 18,148.8
Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (52.1) (5.4)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 5,174.2 690.4
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (278.4) (414.8)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 7,268.0 10,218.8
Total, Gross Unrealized Losses (330.5) (420.2)
Total, Fair Market Value 12,442.2 10,909.2
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (17.5) (0.8)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 3,162.6 732.2
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (9.5) (42.9)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 758.3 1,801.7
Total, Gross Unrealized Losses (27.0) (43.7)
Total, Fair Market Value 3,920.9 2,533.9
Asset-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (5.1) (0.2)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 641.0 101.4
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (7.5) (15.3)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 331.2 481.4
Total, Gross Unrealized Losses (12.6) (15.5)
Total, Fair Market Value 972.2 582.8
Canadian government obligations and Canadian government agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (3.5) (1.4)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 625.9 219.2
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (21.3) (31.0)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 487.1 870.2
Total, Gross Unrealized Losses (24.8) (32.4)
Total, Fair Market Value 1,113.0 1,089.4
Canadian provincial bonds    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (1.3) (0.8)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 166.1 44.3
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (19.6) (26.9)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 444.0 588.8
Total, Gross Unrealized Losses (20.9) (27.7)
Total, Fair Market Value 610.1 633.1
U.S. government agency securities    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (0.7) (0.1)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 52.3 8.0
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (66.6) (79.9)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 663.6 1,093.8
Total, Gross Unrealized Losses (67.3) (80.0)
Total, Fair Market Value 715.9 1,101.8
Other securities    
Debt Securities, Available-for-sale [Line Items]    
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses (12.0) (1.5)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value 866.6 168.4
Securities in Unrealized Loss Position Greater Than 12 Months, Gross Unrealized Losses (42.1) (61.3)
Securities in Unrealized Loss Position Greater Than 12 Months, Fair Market Value 643.6 1,130.2
Total, Gross Unrealized Losses (54.1) (62.8)
Total, Fair Market Value $ 1,510.2 $ 1,298.6