Condensed Consolidated Statements of Changes in Common Stockholders' Investment - USD ($) $ in Millions		3 Months Ended
		Aug. 31, 2019	Aug. 31, 2018
Beginning Balance		$ 17,757
Net income		745	$ 835
Other comprehensive income, net of tax (expense)/benefit		(104)	(185)
Ending Balance		18,166	19,173
Common Stock
Beginning Balance		32	32
Ending Balance		32	32
Additional Paid-In Capital
Beginning Balance		3,231	3,117
Employee incentive plans and other		26	37
Ending Balance		3,257	3,154
Retained Earnings
Beginning Balance		24,648	24,823
Net income		745	835
Cash dividends declared		(339)	(344)
Employee incentive plans and other		(2)	1
Ending Balance		25,048	25,315
Retained Earnings | Accounting Standards Update 2016-02 and 2018-02
Adoption of new accounting standards on June 1, 2019	[1]	(4)
Accumulated Other Comprehensive Income
Beginning Balance		(865)	(578)
Other comprehensive income, net of tax (expense)/benefit		(104)	(185)
Ending Balance		(918)	(763)
Accumulated Other Comprehensive Income | Accounting Standards Update 2018-02
Reclassification to retained earnings due to the adoption of a new accounting standard on June 1, 2019	[2]	51
Treasury Stock
Beginning Balance		(9,289)	(7,978)
Purchase of treasury stock		(3)	(625)
Employee incentive plans and other		39	38
Ending Balance		$ (9,253)	$ (8,565)

[1] Relates to the adoption of Accounting Standards Update (“ASU”) 2016-02 and ASU 2018-02.

[2] Relates to the adoption of ASU 2018-02.