Short-Term Borrowings - Narrative (Details) $ in Thousands		12 Months Ended
	Nov. 12, 2025 USD ($)	May 31, 2026 USD ($) facility	May 31, 2025 USD ($)
Short-term Debt [Line Items]
Maturity period			30 years
Short-term borrowings		$ 5,159,771	$ 5,091,416
Number of active facilities | facility		2
Revolving credit agreements
Short-term Debt [Line Items]
Short-term borrowings		$ 0
Line of credit facility, maximum borrowing capacity		3,500,000
Letters of credit outstanding		7,000
Letter of credit, maximum amount available		$ 300,000
Short-term borrowings
Short-term Debt [Line Items]
Maturity period		1 year
Short-term borrowings | Debt | Credit availability concentration risk
Short-term Debt [Line Items]
Concentration risk, percentage		14.00%	15.00%
Total commercial paper
Short-term Debt [Line Items]
Short-term borrowings		$ 3,221,103	$ 2,992,059
Total commercial paper | Minimum
Short-term Debt [Line Items]
Maturity period		1 day
Total commercial paper | Maximum
Short-term Debt [Line Items]
Maturity period		270 days
Select notes to members
Short-term Debt [Line Items]
Short-term borrowings		$ 1,361,207	$ 1,304,240
Select notes to members | Minimum
Short-term Debt [Line Items]
Maturity period		30 days
Select notes to members | Maximum
Short-term Debt [Line Items]
Maturity period		270 days
Three-year agreement | Revolving credit agreements
Short-term Debt [Line Items]
Maturity period	3 years	3 years
Line of credit facility, additional borrowing capacity	$ 150,000
Expiring at prior maturity date	$ 50,000
Line of credit facility, maximum borrowing capacity		$ 1,745,000
Letters of credit outstanding		$ 0
Four-year agreement | Revolving credit agreements
Short-term Debt [Line Items]
Maturity period	4 years	4 years
Line of credit facility, additional borrowing capacity	$ 50,000
Four-year agreement maturing on Nov 28, 2028 | Revolving credit agreements
Short-term Debt [Line Items]
Maturity period		4 years
Line of credit facility, maximum borrowing capacity		$ 1,755,000
Letters of credit outstanding		$ 7,000