Retirement Plans - Schedule of Retirement Plan Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2024	Nov. 30, 2023
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Defined benefit pension plans	$ 70	$ 91	$ 140	$ 182
Defined contribution plans	288	242	575	482
Postretirement healthcare plans	21	21	43	44
Retirement plans costs	$ 379	$ 354	$ 758	$ 708