General - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Oct. 13, 2017	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Stock-based compensation		$ 41	$ 36	$ 103	$ 93
Lease liability and related right-of-use asset		13,000		13,000
Operating income		$ 1,262	1,167	$ 2,379	2,431
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased		25,000,000		25,000,000
Number of Shares Repurchased		800,000		1,200,000
Treasury Stock Acquired, Average Cost Per Share		$ 220.67		$ 216.45
Payments for Repurchase of Common Stock		$ 184		$ 270	334
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased		14,800,000		14,800,000
Dividends Payable, Date Declared		Nov. 17, 2017
Dividends Payable Amount Per Share		$ 0.50		$ 0.50
Dividends Payable, Date To Be Paid		Jan. 02, 2018
Dividends Payable, Date Of Record		Dec. 11, 2017
ASU 201703 [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Operating income		$ 146	$ 112	$ 292	$ 224
Northwest Research, Inc. [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash paid for acquisition of business	$ 50