SEGMENT INFORMATION (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Segment reporting information [Line Items]
Revenues		$ 9,035	$ 8,993	$ 17,630	$ 17,441
Margin		5,508	5,373	10,618	10,431
Total for operating segments [Member]
Segment reporting information [Line Items]
Revenues	[1]	9,070	8,996	17,683	17,447
Expenses		3,562	3,623	7,065	7,016
Margin	[2]	5,508	5,373	10,618	10,431
Total for operating segments [Member] | Total cloud and on-premise software business [Member]
Segment reporting information [Line Items]
Revenues	[1]	7,212	7,012	14,021	13,472
Expenses		2,315	2,250	4,569	4,287
Margin	[2]	4,897	4,762	9,452	9,185
Total for operating segments [Member] | Total cloud and on-premise software business [Member] | Cloud Software and On-Premise Software [Member]
Segment reporting information [Line Items]
Revenues	[1]	2,259	2,164	4,104	3,767
Cloud software as a service and platform as a service expenses		350	270	658	537
Sales and distribution expenses		1,617	1,602	3,197	2,995
Margin	[2]	292	292	249	235
Total for operating segments [Member] | Total cloud and on-premise software business [Member] | Cloud infrastructure as a service [Member]
Segment reporting information [Line Items]
Revenues		175	165	346	325
Cloud infrastructure as a service expenses		107	88	201	172
Sales and distribution expenses		16	15	32	37
Margin	[2]	52	62	113	116
Total for operating segments [Member] | Total cloud and on-premise software business [Member] | Software license updates and product support [Member]
Segment reporting information [Line Items]
Revenues	[1]	4,778	4,683	9,571	9,380
Software license updates and product support expenses		225	275	481	546
Margin	[2]	4,553	4,408	9,090	8,834
Total for operating segments [Member] | Total hardware business [Member]
Segment reporting information [Line Items]
Revenues	[1]	1,014	1,123	2,010	2,251
Expenses		580	708	1,163	1,388
Margin	[2]	434	415	847	863
Total for operating segments [Member] | Total hardware business [Member] | Hardware products [Member]
Segment reporting information [Line Items]
Revenues		497	573	959	1,142
Hardware products expenses		240	323	480	625
Sales and distribution expenses		202	218	404	424
Margin	[2]	55	32	75	93
Total for operating segments [Member] | Total hardware business [Member] | Hardware Support [Member]
Segment reporting information [Line Items]
Revenues	[1]	517	550	1,051	1,109
Hardware support expenses		138	167	279	339
Margin	[2]	379	383	772	770
Total for operating segments [Member] | Total services business [Member]
Segment reporting information [Line Items]
Revenues		844	861	1,652	1,724
Services expenses		667	665	1,333	1,341
Margin	[2]	$ 177	$ 196	$ 319	$ 383

[1] Cloud software and on-premise software, software license updates and product support and hardware support revenues for management reporting included revenues related to cloud SaaS and PaaS, software support and hardware support contracts, respectively, that would have otherwise been recorded by the acquired businesses as independent entities but were not recognized in our consolidated statements of operations for the periods presented. See Note 8 for an explanation of these adjustments and the table below for a reconciliation of our total operating segment revenues to our total revenues as reported in our condensed consolidated statements of operations.

[2] The margins reported reflect only the direct controllable costs of each line of business and do not include allocations of product development, corporate, general and administrative and IT expenses. Additionally, the margins reported do not reflect amortization of intangible assets, acquisition related and other expenses, restructuring expenses, stock-based compensation, interest expense or certain other non-operating income, net. Certain fiscal 2016 balances have been reclassified to conform to the current year presentation. Such reclassifications did not affect consolidated revenues or operating income.