General - Additional Information (Details) $ / shares in Units, € in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2017 USD ($) $ / shares shares	Feb. 29, 2016 USD ($)	Feb. 28, 2017 USD ($) $ / shares shares	Feb. 29, 2016 USD ($)	May 31, 2016 USD ($)	May 25, 2016 USD ($)	May 25, 2016 EUR (€)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Goodwill	$ 7,000		$ 7,000		$ 6,747
Stock-based compensation	$ 31	$ 29	$ 123	$ 115
Stock Repurchase Program Number Of Shares Authorized To Be Repurchased | shares	25,000,000		25,000,000
Number of Shares Repurchased | shares	130,000		2,200,000
Treasury Stock Acquired, Average Cost Per Share | $ / shares	$ 187.34		$ 165.44
Payments for Repurchase of Common Stock	$ 24		$ 358	$ 2,133
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased | shares	16,800,000		16,800,000
Dividends Payable, Date Declared	Feb. 17, 2017
Dividends Payable Amount Per Share | $ / shares	$ 0.40		$ 0.40
Dividends Payable, Date To Be Paid	Apr. 03, 2017
Dividends Payable, Date Of Record	Mar. 13, 2017
ASU 201609 [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Share-based payment tax benefit	$ 21		$ 42
Share-based payment change effect on diluted EPS | $ / shares	$ 0.07		$ 0.14
TNT acquisition [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Total purchase price	$ 4,894		$ 4,894			$ 4,900	€ 4,400
Cash and cash equivalents						$ 280	€ 250
Purchase price adjustment to Goodwill after acquisition			417
Goodwill	$ 3,381		$ 3,381