Annual report [Section 13 and 15(d), not S-K Item 405]

Fair Value Measurements (Schedule of Amortized Cost and Fair Value of Borrowings) (Details)

v3.25.2
Fair Value Measurements (Schedule of Amortized Cost and Fair Value of Borrowings) (Details) - USD ($)
$ in Millions
May 31, 2025
May 31, 2024
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost $ 4,948.2 $ 798.6
Long-term borrowings, Fair value 5,005.7 777.8
Senior Notes, Series A [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 399.8 399.5
Long-term borrowings, Fair value 398.3 391.8
Senior Notes, Series B [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 399.3 399.1
Long-term borrowings, Fair value 395.5 $ 386.0
5-Year Fixed Rate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,484.8  
Long-term borrowings, Fair value 1,505.1  
7-Year Fixed Rate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,482.7  
Long-term borrowings, Fair value 1,504.9  
10-Year Fixed Rate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,181.6  
Long-term borrowings, Fair value $ 1,201.9