Retirement Plans - Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Other retirement plans expense (income):
MTM net loss		$ 260		$ 260
Pension Plans [Member] | U.S. Plans [Member]
Net Periodic Benefit Cost
Service cost	$ 163	208	$ 326	416
Other retirement plans expense (income):
Interest cost	305	255	609	511
Expected return on plan assets	(422)	(477)	(844)	(955)
Amortization of prior service credit and other	(2)	(2)	(4)	(4)
MTM net loss		36		36
Other retirement plans (income) expense	(119)	(188)	(239)	(412)
Net periodic benefit cost	44	20	87	4
Pension Plans [Member] | International Pension Plans [Member]
Net Periodic Benefit Cost
Service cost	10	14	21	29
Other retirement plans expense (income):
Interest cost	8	7	17	19
Expected return on plan assets	(4)	(6)	(8)	(20)
Amortization of prior service credit and other		(1)		(1)
MTM net loss		224		224
Other retirement plans (income) expense	4	224	9	222
Net periodic benefit cost	14	238	30	251
Postretirement Healthcare Plans [Member]
Net Periodic Benefit Cost
Service cost	9	12	18	24
Other retirement plans expense (income):
Interest cost	14	11	28	21
Other retirement plans (income) expense	14	11	28	21
Net periodic benefit cost	$ 23	$ 23	$ 46	$ 45