Retirement Plans - Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2024	Nov. 30, 2023
Net Periodic Benefit Cost
Net periodic benefit cost	$ 70	$ 91	$ 140	$ 182
Pension Plans [Member] | U.S. Plans [Member]
Net Periodic Benefit Cost
Service cost	124	136	249	272
Interest cost	363	340	724	681
Expected return on plan assets	(430)	(399)	(860)	(799)
Amortization of prior service credit and other	(2)	(1)	(4)	(3)
Other retirement plans expense (income)	(69)	(60)	(140)	(121)
Net periodic benefit cost	55	76	109	151
Pension Plans [Member] | International Pension Plans [Member]
Net Periodic Benefit Cost
Service cost	11	10	20	20
Interest cost	10	12	22	22
Expected return on plan assets	(7)	(7)	(12)	(11)
Amortization of prior service credit and other	1	0	1	0
Other retirement plans expense (income)	4	5	11	11
Net periodic benefit cost	15	15	31	31
Postretirement Healthcare Plans [Member]
Net Periodic Benefit Cost
Service cost	6	7	13	14
Interest cost	16	14	32	30
Expected return on plan assets	0	0	0	0
Amortization of prior service credit and other	(1)	0	(2)	0
Other retirement plans expense (income)	15	14	30	30
Net periodic benefit cost	$ 21	$ 21	$ 43	$ 44