Summary of Quarterly Operating Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	May. 31, 2015		Feb. 28, 2015		Nov. 30, 2014		Aug. 31, 2014		May. 31, 2014		Feb. 28, 2014		Nov. 30, 2013		Aug. 31, 2013		May. 31, 2015	May. 31, 2014	May. 31, 2013
Selected Quarterly Financial Information Special Items [Abstract]
Asset Impairment Charges	$ 276
Ground legal reserve	197
Mark to Market pension accounting	2,200
Selected Quarterly Financial Information [Abstract]
Revenues	12,114		$ 11,716		$ 11,939		$ 11,684		$ 11,839		$ 11,301		$ 11,403		$ 11,024		$ 47,453	$ 45,567	$ 44,287
Operating income	(1,321)	[1]	1,038	[1]	1,088	[1]	1,062	[1]	1,264	[1]	737	[1]	923	[1]	891	[1]	1,867	3,815	4,434
Net income	$ (895)	[1]	$ 628	[1]	$ 663	[1]	$ 653	[1]	$ 780	[1]	$ 437	[1]	$ 559	[1]	$ 548	[1]	$ 1,050	$ 2,324	$ 2,716
Basic earnings per common share	$ (3.16)	[2]	$ 2.21	[2]	$ 2.34	[2]	$ 2.29	[2]	$ 2.66	[2]	$ 1.44	[2]	$ 1.77	[2]	$ 1.73	[2]	$ 3.70	$ 7.56	$ 8.61
Diluted earnings per common share	$ (3.16)	[2]	$ 2.18	[2]	$ 2.31	[2]	$ 2.26	[2]	$ 2.62	[2]	$ 1.42	[2]	$ 1.75	[2]	$ 1.72	[2]	$ 3.65	$ 7.48	$ 8.55

[1] The fourth quarter of 2015 includes a $2.2 billion retirement plans mark-to-market loss, $276 million of impairment and related charges resulting from the decision to permanently retire and adjust the retirement schedule of certain aircraft and related engines at FedEx Express and a $197 million reserve increase due to the settlement of a legal matter at FedEx Ground. In addition, the first, second and third quarters of 2015 and all quarters of 2014 have been recast to conform to the current year presentation reflecting the retirement plans accounting changes discussed further in Note 1 and Note 13 and that were included in our June 12, 2015, Form 8-K filing with the Securities and Exchange Commission.

[2] The sum of the quarterly earnings per share may not equal annual amounts due to differences in the weighted-average number of shares outstanding during the respective periods.