Financing Arrangements - Additional Information (Details)		9 Months Ended
	Mar. 15, 2022 USD ($)	Feb. 28, 2022 USD ($) AirCraft	May 31, 2021 USD ($)
Line Of Credit Facility [Line Items]
Number of Boeing aircraft | AirCraft		19
Net book value of Boeing aircraft		$ 1,800,000,000
Financial covenant terms ratio		350.00%
Financial covenant compliance ratio		187.00%
Long term debt, including current maturities and exclusive of finance leases carrying value		$ 20,000,000,000.0	$ 20,400,000,000
Long term debt, including current maturities and exclusive of finance leases fair value		$ 21,200,000,000	$ 23,100,000,000
Long-term debt weighted-average interest rate		3.50%
Five-Year Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Letter of credit outstanding sublimit unused amount		$ 250,000,000
Five-Year Credit Agreement [Member] | Subsequent Event [Member]
Line Of Credit Facility [Line Items]
Line of credit facility, term	5 years
Line of credit facility maximum borrowing capacity	$ 2,000,000,000.0
Line of credit facility, expiration date	2026-03
Letter of credit maximum sublimit amount	$ 250,000,000
364-Day Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Line of credit facility, term		364 days
Line of credit facility maximum borrowing capacity		$ 1,500,000,000
Three Year Credit Agreement [Member] | Subsequent Event [Member]
Line Of Credit Facility [Line Items]
Line of credit facility, term	3 years
Line of credit facility maximum borrowing capacity	$ 1,500,000,000
Line of credit facility, expiration date	2025-03
Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Commercial paper outstanding		0
1.875% due in February 2034 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount		$ 970,000,000
Fixed interest rate		1.875%
Debt instrument, maturity date		2034-02