EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		May 31, 2016		May 31, 2015	May 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan expense		$ 387		$ 362	$ 357
Deferred compensation plan assets		419		408
Deferred compensation plan liabilities		419		408
Total defined benefit plan pension expense		95		69	$ 64
Aggregate projected benefit obligation		949		1,000
Aggregate net liability (funded status)		$ 587		$ 599
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		$ 474
Unrecognized compensation expense related to non-vested restricted stock-based awards		$ 1,300
Weighted average recognition period of unrecognized compensation expense for shares expected to vest		2 years 7 days
Shares Under Option [Abstract]
Beginning balance		413		462	447
Granted		25	[1]	34	131
Assumed		1		3	5
Exercised		(53)		(70)	(95)
Canceled		(11)		(16)	(26)
Ending balance		375		413	462
Vested		253
Expected to vest	[2]	115
Total		368
Shares not expected to vest		7
Weighted Average Exercise Price [Abstract]
Beginning balance		$ 28.64		$ 27.37	$ 25.48
Granted		40.34	[1]	40.54	31.02
Assumed		4.97		21.98	9.02
Exercised		25.13		24.49	21.51
Canceled		35.19		33.76	30.60
Ending balance		29.66		$ 28.64	$ 27.37
Vested		27.52
Expected to vest	[2]	33.91
Total		$ 29.52
Weighted Average Remaining Contract Term (in years)
Vested		4 years 10 months 3 days
Expected to vest	[2]	7 years 2 months 13 days
Total		5 years 6 months 28 days
In-the-Money Options as of May 31, 2016 (in millions)
Vested		245
Expected to vest	[2]	76
Total		321
Aggregate Intrinsic Value (in millions)
Vested	[3]	$ 3,232
Expected to vest	[2],[3]	736
Total	[3]	$ 3,968
Closing stock price		$ 40.20
Shares Under Restricted Stock-based Awards [Abstract]
Beginning balance		28		1
Granted		34		28
Vested		(7)
Cancelled		(3)		(1)
Ending balance		52		28	1
Weighted Average Grant Date Fair Value [Abstract]
Beginning balance		$ 40.63		$ 35.29
Granted		38.50		40.73
Vested		40.39
Cancelled		39.73		39.52
Ending balance		$ 39.29		$ 40.63	$ 35.29
Total grant date fair value of restricted stock-based awards, vested		$ 261		$ 28
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		1,037		933	$ 805
Estimated income tax benefit included in provision for income taxes		(322)		(294)	(260)
Total stock-based compensation, net of estimated income tax benefit		715		639	545
Tax Benefits from Exercise of Stock Options and Vesting of Restricted Stock-Based Awards [Abstract]
Total cash received as a result of option exercises		1,300		1,700	2,000
Aggregate intrinsic value of vesting of restricted stock-based awards and options exercised		1,000		1,300	1,500
Tax benefits realized in connection with the vesting of restricted stock-based awards and exercises of stock options		311		396	480
Excess tax benefits on the exercise of stock options and vesting of restricted stock-based awards		$ 124		$ 244	$ 250
Weighted Average Input Assumptions Used and Resulting Fair Values [Abstract]
Expected life (in years)		4 years 9 months 22 days		5 years 1 month 7 days	4 years 10 months 29 days
Risk-free interest rate		1.60%		1.70%	1.30%
Volatility		24.00%		23.00%	27.00%
Dividend yield		1.50%		1.20%	1.50%
Weighted-average fair value per share		$ 8.49		$ 9.62	$ 7.47
Sales and marketing [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		$ 220		$ 180	$ 165
Cloud software as a service and platform as a service [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		17		10	8
Cloud infrastructure as a service [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		4		5	4
Software license updates and product support [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		23		21	22
Hardware products [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		7		6	5
Hardware support [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		5		6	6
Services
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		29		30	29
Research and development [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		609		522	385
General and administrative [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		120		148	171
Acquisition related and other [Member]
Stock-based Compensation Expense [Line Items]
Total stock-based compensation		$ 3		5	10
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		54
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		$ 153		$ 144	$ 134
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		2 years 10 months 21 days

[1] Approximately 7 million of the 25 million stock options granted during fiscal 2016 were to our Chief Executive Officers and Chief Technology Officer and had contractual lives of five years versus the 10-year contractual lives for the other stock options granted.

[2] 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, 2016 was approximately $474 million and is expected to be recognized over a weighted-average period of 2.02 years. Approximately 7 million shares outstanding as of May 31, 2016 were not expected to vest.

[3] The aggregate intrinsic value was calculated based on the gross difference between our closing stock price on the last trading day of fiscal 2016 of $40.20 and the exercise prices for all 'in-the-money' options outstanding, excluding tax effects.