Description of Business Segments and Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, € in Millions		1 Months Ended	12 Months Ended
	Mar. 16, 2021 USD ($)	Jan. 31, 2021 Employee	May 31, 2023 USD ($)	May 31, 2021 USD ($) air-craft $ / shares shares	May 31, 2020 USD ($) air-craft $ / shares shares	May 31, 2019 USD ($) Employee $ / shares shares	May 31, 2021 EUR (€) air-craft shares	Jan. 26, 2016 shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Gross contract assets related to in-transit shipments				$ 715,000,000	$ 563,000,000
Contract assets net of deferred unearned revenue				572,000,000	456,000,000
Contract liabilities related to advance payments from customers				$ 9,000,000	10,000,000
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				$ 428,000,000	427,000,000	$ 468,000,000
Depreciable life range for majority of aircraft costs				15 to 30 years
Depreciation expense, excluding gains and losses on sales of property and equipment				$ 3,793,000,000	3,615,000,000	3,353,000,000
Interest costs capitalized				$ 68,000,000	$ 54,000,000	$ 64,000,000
Number of aircraft to be permanently retired from service | air-craft					10
Number of aircraft engines to be permanently retired from service | air-craft					12
Noncash impairment charges					$ 66,000,000
Noncash impairment charges net of tax					$ 50,000,000
Noncash impairment charges net of tax per diluted share | $ / shares					$ 0.19
Number of Idle Aircraft | air-craft				9			9
Number of months aircraft remained idle				an average of 17 months
Denominated debt as a net investment hedge | €							€ 210
Stock repurchase program number of shares authorized to be repurchased | shares								25,000,000
Stock repurchase program, remaining number of shares authorized to be repurchased | shares				5,100,000			5,100,000
Number of shares repurchased | shares					20,000.00	6,600,000
Treasury stock acquired, average cost per share | $ / shares					$ 156.90	$ 222.94
Payments for repurchase of common stock					$ 3,000,000	$ 1,480,000,000
Dividends payable, date declared				Jun. 14, 2021
Dividends payable amount per share | $ / shares				$ 0.75
Dividends payable, date to be paid				Jul. 12, 2021
Dividends payable, date of record				Jun. 28, 2021
Number of employees left or voluntarily leaving | Employee						1,500
Business realignment costs				$ 116,000,000		$ 320,000,000
Diluted | $ / shares				$ 19.45	$ 4.90	$ 2.03
Restructuring plan execution period		18 months
Business realignment costs, net of tax				$ 90,000,000
Business realignment costs per diluted share | $ / shares				$ 0.33
Business employee severance costs paid				$ 15,000,000
Business Realignment Activities [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Business realignment costs						$ 320,000,000
Costs associated with funding to healthcare reimbursement accounts						50,000,000
Business Realignment Activities [Member] | Severance Payments [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Payment of severance cost at departure					$ 50,000,000	$ 220,000,000
Amended and Restated Five-Year Credit Agreement [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Line Of Credit Facility Maximum Borrowing Capacity	$ 2,000,000,000.0
Amended and Restated 364-Day Credit Agreement [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Line Of Credit Facility Maximum Borrowing Capacity	$ 1,500,000,000
Line of Credit Facility, Term	364 days
Amendments to Credit Agreements [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Dividends payable amount per share | $ / shares					$ 0.65
Minimum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Intangible assets amortization periods				1 year
Number of employees left or voluntarily leaving | Employee		5,500
Minimum [Member] | Forecast [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Business realignment costs			$ 300,000,000
Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Intangible assets amortization periods				15 years
Number of employees left or voluntarily leaving | Employee		6,300
Maximum [Member] | Forecast [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Business realignment costs			$ 575,000,000