Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended																12 Months Ended
		May 31, 2016	[2],[3]	Feb. 29, 2016	[2],[3]	Nov. 30, 2015	[2],[3]	Aug. 31, 2015	[3]	May 31, 2015	[3],[4]	Feb. 28, 2015	[3]	Nov. 30, 2014	[3]	Aug. 31, 2014	[3]	May 31, 2016	May 31, 2015	May 31, 2014
Basic earnings per common share:
Net earnings allocable to common shares	[1]																	$ 1,818	$ 1,048	$ 2,320
Weighted-average common shares																		276.0	283.0	307.0
Basic earnings per common share		$ (0.26)		$ 1.86		$ 2.47		$ 2.45		$ (3.16)		$ 2.21		$ 2.34		$ 2.29		$ 6.59	$ 3.70	$ 7.56
Diluted earnings per common share:
Net earnings allocable to common shares	[1]																	$ 1,818	$ 1,048	$ 2,320
Weighted-average common shares																		276.0	283.0	307.0
Dilutive effect of share-based awards																		3.0	4.0	3.0
Weighted-average diluted shares																		279.0	287.0	310.0
Diluted earnings per common share		$ (0.26)		$ 1.84		$ 2.44		$ 2.42		$ (3.16)		$ 2.18		$ 2.31		$ 2.26		$ 6.51	$ 3.65	$ 7.48
Anti-dilutive options excluded from diluted earnings per common share																		3.9	2.1	3.3

[1] Net earnings available to participating securities were immaterial in all periods presented.

[2] The fourth quarter of 2016 includes a $1.5 billion retirement plans mark-to-market loss and TNT Express transaction, financing and integration planning expenses and immaterial financial results from the time of acquisition totaling $79 million. In addition, the fourth quarter of 2016 includes a $76 million favorable tax impact from an internal corporate restructuring to facilitate the integration of FedEx Express and TNT Express and $11 million of expenses related to independent contractor litigation matters at FedEx Ground. The third quarter of 2016 includes provisions related to independent contractor litigation matters at FedEx Ground for $204 million and expenses related to the settlement of a U.S. Customs and Border Protection notice of action in the amount of $69 million, as well as TNT Express transaction, financing and integration planning expenses of $25 million. The second quarter of 2016 includes provisions related to independent contractor litigation matters at FedEx Ground for $41 million and $19 million of TNT Express transaction, financing and integration planning expenses.

[3] 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.

[4] 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.