Quarterly report [Sections 13 or 15(d)]

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

v3.26.1
Fair Value Measurements (Schedule of Amortized Cost and Fair Value of Borrowings) (Details) - USD ($)
$ in Millions
Feb. 28, 2026
May 31, 2025
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost $ 4,954.1 $ 4,948.2
Long-term borrowings, Fair value 5,057.4 5,005.7
Senior Notes, Series A [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 400.0 399.8
Long-term borrowings, Fair value 400.0 398.3
Senior Notes, Series B [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 399.4 399.3
Long-term borrowings, Fair value 403.1 395.5
5-Year Fixed Rate Corporate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,487.1 1,484.8
Long-term borrowings, Fair value 1,519.0 1,505.1
7-Year Fixed Rate Corporate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,484.6 1,482.7
Long-term borrowings, Fair value 1,522.6 1,504.9
10-Year Fixed Rate Corporate Bonds [Member]    
Debt Instrument [Line Items]    
Long-term borrowings, Amortized cost 1,183.0 1,181.6
Long-term borrowings, Fair value $ 1,212.7 $ 1,201.9