EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		May. 31, 2015	May. 31, 2014	May. 31, 2013
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan expense		$ 362	$ 357	$ 353
Deferred compensation plan assets		408	367
Deferred compensation plan liabilities		408	367
Total defined benefit plan pension expense		69	64	$ 81
Aggregate projected benefit obligation		1,000	853
Aggregate net liability (funded status)		$ 599	$ 436
Employee Stock Purchase Plan [Line Items]
Common stock issued under stock purchase plans		3	3	3
Nonvested Awards Compensation Cost Not Yet Recognized [Line Items]
Unrecognized compensation expense for shares expected to vest		$ 804
Unrecognized compensation expense related to non-vested restricted stock-based awards		$ 774
Weighted average recognition period of unrecognized compensation expense for shares expected to vest		2 years 1 month 28 days
Shares Under Option [Abstract]
Beginning balance		462	447	422
Granted		34	131	119
Assumed		3	5	9
Exercised		(70)	(95)	(83)
Canceled		(16)	(26)	(20)
Ending balance		413	462	447
Vested		223
Expected to vest	[1]	175
Total		398
Shares not expected to vest		15
Weighted Average Exercise Price [Abstract]
Beginning balance		$ 27.37	$ 25.48	$ 22.66
Granted		40.54	31.02	29.90
Assumed		21.98	9.02	32.52
Exercised		24.49	21.51	17.38
Canceled		33.76	30.60	28.94
Ending balance		28.64	$ 27.37	$ 25.48
Vested		25.53
Expected to vest	[1]	32.17
Total		$ 28.45
Weighted Average Remaining Contract Term (in years)
Vested		5 years 26 days
Expected to vest	[1]	7 years 9 months 11 days
Total		6 years 3 months 5 days
In-the-Money Options as of May 31, 2015 (in millions)
Vested		222
Expected to vest	[1]	175
Total		397
Aggregate Intrinsic Value (in millions)
Vested	[2]	$ 4,034
Expected to vest	[1],[2]	1,986
Total	[2]	$ 6,020
Closing stock price		$ 43.49
Shares Under Restricted Stock-based Awards [Abstract]
Beginning balance		1
Granted		28
Cancelled		(1)
Ending balance		28	1
Weighted Average Grant Date Fair Value [Abstract]
Beginning balance		$ 35.29
Granted		40.73
Cancelled		39.52
Ending balance		$ 40.63	$ 35.29
Total grant date fair value of restricted stock-based awards, vested		$ 28
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		933	$ 805	$ 755
Estimated income tax benefit included in provision for income taxes		(294)	(260)	(243)
Total stock-based compensation, net of estimated income tax benefit		639	545	512
Tax Benefits from Exercise of Stock Options and Vesting of Restricted Stock-Based Awards [Abstract]
Total cash received as a result of option exercises		1,700	2,000	1,400
Aggregate intrinsic value of options exercised and vesting of restricted stock-based awards		1,300	1,500	1,300
Tax benefits realized in connection with the exercises of stock options and vesting of restricted stock-based awards		396	480	410
Excess tax benefits on the exercise of stock options and vesting of restricted stock-based awards		$ 244	$ 250	$ 241
Weighted Average Input Assumptions Used and Resulting Fair Values [Abstract]
Expected life (in years)		5 years 1 month 7 days	4 years 10 months 29 days	5 years
Risk-free interest rate		1.70%	1.30%	0.70%
Volatility		23.00%	27.00%	31.00%
Dividend yield		1.20%	1.50%	0.80%
Weighted-average fair value per share		$ 9.62	$ 7.47	$ 7.99
Sales and marketing [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		$ 180	$ 165	$ 137
Cloud software as a service and platform as a service [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		10	8	10
Cloud infrastructure as a service [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		5	4	8
Software license updates and product support [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		21	22	20
Hardware systems products [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		6	5	3
Hardware systems support [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		6	6	5
Services [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		30	29	23
Research and development [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		522	385	352
General and administrative [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		148	171	164
Acquisition related and other [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		$ 5	10	33
Employee Stock Purchase Plan [Member]
Employee Stock Purchase Plan [Line Items]
Stock purchase price as a percentage of the fair market value on the purchase date		95.00%
Shares reserved for future issuances under the Purchase Plan		57
United States [Member]
Defined Contribution Plan Disclosure [Line Items]
Oracle 401(K) Plan employee contribution maximum rate		40.00%
Oracle 401 (K) employer contribution match rate		50.00%
Oracle 401(K) employer maximum match on employee contribution each pay period		6.00%
Defined contribution plan expense		$ 144	$ 134	$ 129
Restricted Stock Units [Member]
Nonvested Awards Compensation Cost Not Yet Recognized [Line Items]
Weighted average recognition period of unrecognized compensation expense for shares expected to vest		3 years 2 months 20 days

[1] 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, 2015 was approximately $804 million and is expected to be recognized over a weighted average period of 2.16 years. Approximately 15 million shares outstanding as of May 31, 2015 were not expected to vest.

[2] The aggregate intrinsic value was calculated based on the gross difference between our closing stock price on the last trading day of fiscal 2015 of $43.49 and the exercise prices for all "in-the-money" options outstanding, excluding tax effects.