Description of Business and Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||||||||||||||||||
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Apr. 30, 2018
USD ($)
|
May 31, 2019
USD ($)
air-craft
$ / shares
shares
|
Feb. 28, 2019
USD ($)
$ / shares
|
Nov. 30, 2018
$ / shares
|
[1],[2] |
Aug. 31, 2018
$ / shares
|
[1],[2] |
May 31, 2018
USD ($)
$ / shares
|
Feb. 28, 2018
$ / shares
|
[2],[3] |
Nov. 30, 2017
$ / shares
|
[2],[3] |
Aug. 31, 2017
$ / shares
|
[2],[3] |
May 31, 2019
USD ($)
air-craft
Employee
$ / shares
shares
|
May 31, 2018
USD ($)
$ / shares
shares
|
May 31, 2017
USD ($)
$ / shares
shares
|
Jan. 26, 2016
shares
|
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| Organization Consolidation And Presentation Of Financial Statements [Line Items] | |||||||||||||||||||||||||||
| Gross contract assets related to in-transit packages | $ 533 | $ 542 | $ 533 | $ 542 | |||||||||||||||||||||||
| Contract assets net of deferred unearned revenue | 364 | 363 | 364 | 363 | |||||||||||||||||||||||
| Contract liabilities related to advance payments from customers | $ 11 | $ 13 | $ 11 | 13 | |||||||||||||||||||||||
| Payment terms of customer contracts | Under the typical payment terms of our customer contracts, the customer pays at periodic intervals (e.g., every 15 days, 30 days, 45 days, etc.) for shipments included on invoices received. It is not customary business practice to extend payment terms past 90 days, and as such, we do not have a practice of including a significant financing component within our revenue contracts with customers. | ||||||||||||||||||||||||||
| Advertising and promotion expenses | $ 468 | 442 | $ 458 | ||||||||||||||||||||||||
| Depreciable life range for majority of aircraft costs | 15 to 30 years | ||||||||||||||||||||||||||
| Depreciation expense, excluding gains and losses on sales of property and equipment | $ 3,353 | 3,095 | 2,995 | ||||||||||||||||||||||||
| Interest costs capitalized | $ 64 | 61 | $ 41 | ||||||||||||||||||||||||
| Number of Idle Aircraft | air-craft | 7 | 7 | |||||||||||||||||||||||||
| Number of months aircraft remained idle | an average of 23 months | ||||||||||||||||||||||||||
| Gain on sale of TNT express business | $ 8 | $ 85 | |||||||||||||||||||||||||
| Stock repurchase program number of shares authorized to be repurchased | shares | 25,000,000 | ||||||||||||||||||||||||||
| Number of shares repurchased | shares | 6,600,000 | 4,300,000 | 3,000,000 | ||||||||||||||||||||||||
| Treasury stock acquired, average cost per share | $ / shares | $ 222.94 | $ 237.45 | $ 172.13 | ||||||||||||||||||||||||
| Payments for repurchase of common stock | $ 1,480 | $ 1,017 | $ 509 | ||||||||||||||||||||||||
| Stock repurchase program, remaining number of shares authorized to be repurchased | shares | 5,100,000 | 5,100,000 | |||||||||||||||||||||||||
| Dividends payable, date declared | Jun. 10, 2019 | ||||||||||||||||||||||||||
| Dividends payable amount per share | $ / shares | $ 0.65 | $ 0.65 | |||||||||||||||||||||||||
| Dividends payable, date to be paid | Jul. 08, 2019 | ||||||||||||||||||||||||||
| Dividends payable, date of record | Jun. 24, 2019 | ||||||||||||||||||||||||||
| Number of employees left or voluntarily leaving | Employee | 1,500 | ||||||||||||||||||||||||||
| Business realignment costs | $ 316 | $ 4 | $ 320 | ||||||||||||||||||||||||
| Diluted | $ / shares | $ (7.56) | [1],[2] | $ 2.80 | [1],[2] | $ 3.51 | $ 3.10 | $ 4.15 | [2],[3] | $ 7.59 | $ 2.84 | $ 2.19 | $ 2.03 | $ 16.79 | $ 11.07 | |||||||||||||
| Business Realignment Activities [Member] | |||||||||||||||||||||||||||
| Organization Consolidation And Presentation Of Financial Statements [Line Items] | |||||||||||||||||||||||||||
| Business realignment costs | $ 320 | ||||||||||||||||||||||||||
| Business realignment costs, net of tax | $ 243 | ||||||||||||||||||||||||||
| Diluted | $ / shares | $ 0.91 | ||||||||||||||||||||||||||
| Business realignment costs paid at departure | $ 220 | ||||||||||||||||||||||||||
| Minimum [Member] | |||||||||||||||||||||||||||
| Organization Consolidation And Presentation Of Financial Statements [Line Items] | |||||||||||||||||||||||||||
| Intangible assets amortization periods | 3 years | ||||||||||||||||||||||||||
| Maximum [Member] | |||||||||||||||||||||||||||
| Organization Consolidation And Presentation Of Financial Statements [Line Items] | |||||||||||||||||||||||||||
| Intangible assets amortization periods | 15 years | ||||||||||||||||||||||||||
| FedEx Express Segment [Member] | |||||||||||||||||||||||||||
| Organization Consolidation And Presentation Of Financial Statements [Line Items] | |||||||||||||||||||||||||||
| Gain on sale of TNT express business | $ 85 | ||||||||||||||||||||||||||
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