Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Feb. 28, 2019	May 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash	$ 540	$ 415
Assets at Fair Value	4,046	5,245
Cash and Equivalents	3,695	4,249
Short-term Investments	351	996
Fair Value Measurements Using Level 1 | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	417	1,178
Cash and Equivalents	100	500
Short-term Investments	317	678
Fair Value Measurements Using Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	3,089	3,652
Cash and Equivalents	3,055	3,334
Short-term Investments	34	318
Fair Value Measurements Using Level 2 | Commercial paper and bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	31	451
Cash and Equivalents	1	153
Short-term Investments	30	298
Fair Value Measurements Using Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	1,379	2,174
Cash and Equivalents	1,379	2,174
Short-term Investments	0	0
Fair Value Measurements Using Level 2 | Time deposits
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	1,678	925
Cash and Equivalents	1,675	907
Short-term Investments	3	18
Fair Value Measurements Using Level 2 | U.S. Agency securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets at Fair Value	1	102
Cash and Equivalents	0	100
Short-term Investments	$ 1	$ 2