EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		May 31, 2018		May 31, 2017		May 31, 2016
Shares Under Restricted Stock-based Awards [Abstract]
Beginning balance		83		52		28
Granted		44		42		34
Assumed				14
Vested and Issued		(27)		(18)		(7)
Canceled		(11)		(7)		(3)
Ending balance		89		83		52
Weighted Average Grant Date Fair Value [Abstract]
Total grant date fair value of restricted stock-based awards, vested and issued		$ 1,000		$ 715		$ 261
Beginning balance		$ 39.18		$ 39.29		$ 40.63
Granted		47.42		39.40		38.50
Assumed				37.83
Vested and Issued		39.10		40.39		40.39
Canceled		41.97		39.73		39.73
Ending balance		$ 42.93		$ 39.18		$ 39.29
Unrecognized compensation expense related to non-vested restricted stock-based awards				$ 2,500
Shares Under Stock Option [Abstract]
Beginning balance		312		375		413
Granted		77	[1]	18	[2]	25	[2]
Assumed				2		1
Exercised		(78)		(77)		(53)
Canceled		(7)		(6)		(11)
Ending balance		304		312		375
Vested		201
Expected to vest	[3]	60
Total		261
Weighted Average Exercise Price [Abstract]
Beginning balance		$ 29.02		$ 29.66		$ 28.64
Granted		50.95	[1]	40.90	[2]	40.34	[2]
Assumed				13.06		4.97
Exercised		28.78		26.65		25.13
Canceled		45.70		36.28		35.19
Ending balance		36.11		$ 29.02		$ 29.66
Vested		30.06
Expected to vest	[3]	45.91
Total		$ 33.74
Weighted Average Remaining Contract Term (in years) [Abstract]
Vested		3 years 10 months 20 days
Expected to vest	[3]	6 years 10 months 24 days
Total		4 years 7 months 2 days
Aggregate Intrinsic Value (in millions) [Abstract]
Vested	[4]	$ 3,344
Expected to vest	[3],[4]	202
Total	[4]	$ 3,546
Closing stock price		$ 46.72
Unrecognized compensation expense for shares expected to vest		$ 375
Shares not expected to vest		43
Weighted Average Input Assumptions Used and Resulting Fair Values [Abstract]
Expected life (in years)		4 years 8 months 12 days		4 years 9 months 18 days		4 years 9 months 18 days
Risk-free interest rate		2.00%		1.00%		1.60%
Volatility		22.00%		23.00%		24.00%
Dividend yield		1.50%		1.50%		1.50%
Weighted-average fair value per share		$ 9.34		$ 8.18		$ 8.49
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		$ 1,607		$ 1,350		$ 1,037
Estimated income tax benefit included in provision for income taxes		(451)		(423)		(322)
Total stock-based compensation, net of estimated income tax benefit		$ 1,156		$ 927		$ 715
Common stock issued under stock purchase plans		3		3		3
Other Postretirement Plans [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total defined benefit plan pension expense		$ 102		$ 85		$ 95
Aggregate projected benefit obligation				1,100		1,100
Aggregate net liability (funded status)				$ 711		$ 712
Employee Stock Purchase Plan [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Stock purchase price as a percentage of the fair market value on the purchase date		95.00%
Shares of common stock available for future awards		48
Common stock issued under stock purchase plans		3		3		3
Cloud services and license support [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		$ 82		$ 54		$ 44
Hardware [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		10		11		12
Services business [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		52		44		29
Sales and marketing [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		361		306		220
Research and development [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		921		770		609
General and administrative [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		180		130		120
Acquisition related and other [Member]
Stock-based compensation expense and valuations of stock awards [Abstract]
Total stock-based compensation		$ 1		$ 35		$ 3
Restricted Stock Units [Member]
Weighted Average Grant Date Fair Value [Abstract]
Weighted average recognition period of unrecognized compensation expense for shares expected to vest		2 years 8 months 12 days
Employee Stock Options [Member]
Weighted Average Grant Date Fair Value [Abstract]
Weighted average recognition period of unrecognized compensation expense for shares expected to vest		3 years 3 months 29 days
Performance-based stock options [Member]
Weighted Average Input Assumptions Used and Resulting Fair Values [Abstract]
Expected life (in years)		7 years
Risk-free interest rate		2.14%
Volatility		22.44%
Dividend yield		1.49%

[1] Awards granted in fiscal 2018 included 69 million PSOs granted in total to our Chief Executive Officers, Chief Technology Officer, and President, Product Development, the contractual terms of which are described in greater detail above.

[2] 7 million SOs were granted in total during each of fiscal 2017 and 2016 to our Chief Executive Officers and Chief Technology Officer and have contractual lives of five years versus the ten-year contractual lives for most of the other SOs granted.

[3] The unrecognized compensation expense calculated under the fair value method for shares expected to vest (unvested shares net of expected forfeitures) as of May 31, 2018 was approximately $375 million and is expected to be recognized over a weighted-average period of 3.33 years. Approximately 43 million shares outstanding as of May 31, 2018 were not expected to vest.

[4] The aggregate intrinsic value was calculated based on the gross difference between our closing stock price on the last trading day of fiscal 2018 of $46.72 and the exercise prices for all “in-the-money” options outstanding, excluding tax effects.