Debt Financing - Narrative (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2023 USD ($) aircraft	Jun. 30, 2023 USD ($) aircraft	Aug. 03, 2023 USD ($)	Jul. 31, 2023 USD ($)	May 05, 2023 USD ($)	Dec. 31, 2022 USD ($) aircraft
Debt Instrument [Line Items]
Outstanding balance	$ 19,089,686,000	$ 19,089,686,000				$ 18,823,429,000
Senior unsecured securities
Debt Instrument [Line Items]
Outstanding balance	17,202,069,000	17,202,069,000				17,095,116,000
Medium Term Note Program Due 2028 | Total unsecured debt financing
Debt Instrument [Line Items]
Principal amount issued	$ 700,000,000	$ 700,000,000
Interest rate	5.30%	5.30%
Trust Certificates Due 2028
Debt Instrument [Line Items]
Principal amount issued	$ 600,000,000	$ 600,000,000
Interest rate	5.85%	5.85%
Revolving credit facility
Debt Instrument [Line Items]
Outstanding balance	$ 1,000,000,000	$ 1,000,000,000				1,020,000,000
Maximum borrowing capacity					$ 7,200,000,000
Facility fee		0.20%
Revolving credit facility | Mature May 5, 2027 | Subsequent Event
Debt Instrument [Line Items]
Line of credit, noncurrent			$ 6,800,000,000
Revolving credit facility | Mature May 5, 2026 | Subsequent Event
Debt Instrument [Line Items]
Line of credit, noncurrent			320,000,000
Revolving credit facility | Mature May 5, 2025 | Subsequent Event
Debt Instrument [Line Items]
Line of credit, noncurrent			32,500,000
Revolving credit facility | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Interest margin		1.05%
2023 Term Loan | Term financings
Debt Instrument [Line Items]
Principal amount issued	$ 650,000,000	$ 650,000,000
Credit spread adjustment	0.10%	0.10%
2023 Term Loan | Term financings | Subsequent Event
Debt Instrument [Line Items]
Outstanding balance			$ 0
Principal amount issued				$ 725,000,000
2023 Term Loan | Term financings | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Interest margin	1.40%
Secured Notes Due 2034 | Total secured debt financing
Debt Instrument [Line Items]
Principal amount issued	$ 112,200,000	$ 112,200,000
Number of aircraft pledged as collateral | aircraft	1	1
Secured Notes Due 2034 | Total secured debt financing | 3M SOFR
Debt Instrument [Line Items]
Interest margin	0.42%
Other Debt Financings
Debt Instrument [Line Items]
Outstanding balance	$ 887,600,000	$ 887,600,000				$ 708,300,000
Number of aircraft pledged as collateral | aircraft	3	3				3
Net book value of aircraft pledged as collateral	$ 318,200,000	$ 318,200,000				$ 212,100,000