Income Taxes - Schedule of Reconciliation of Total Income Tax Expense and Amount Computed by Statutory Federal Income Tax Rate to Income Before Taxes (Details) - USD ($) $ in Millions		3 Months Ended					12 Months Ended
		Feb. 28, 2019	Nov. 30, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	May 31, 2019	May 31, 2018		May 31, 2017
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Taxes computed at federal statutory rate							$ 138	$ 1,271		$ 1,603
Non-deductible expenses							79	81		76
Valuation allowance							(79)	31		44
TCJA	[1]						(71)	(1,354)
Foreign tax rate enactments							50	6
State and local income taxes, net of federal benefit							44	119		99
Benefits from share-based payments							(18)	(60)		(55)
Uncertain tax positions							8	86
Foreign tax credits from distributions				$ (133)	$ (12)	$ (80)	(8)	(225)
Foreign operations							(1)	25		(5)
Corporate structuring transactions				$ (255)				(255)	[2]	(68)	[2]
Goodwill impairment charge								109
Other, net							(27)	(53)		(112)
PROVISION FOR INCOME TAXES (BENEFIT)		$ 90	$ 60				$ 115	$ (219)		$ 1,582
Effective Tax Rate							17.60%	(5.00%)		34.60%

[1] Primary components in 2018 were a $1.15 billion benefit from the remeasurement of our net U.S. deferred tax liability and a $204 million one-time benefit from a contribution to our tax-qualified U.S. domestic pension plans (“U.S. Pension Plans”) in 2018.

[2] The 2018 and 2017 net benefits consist of foreign deferred tax benefits of $434 million and $94 million, respectively, which were partially offset by U.S. deferred tax expenses of $179 million and $26 million, respectively.