Fair Value Measurements - Fair Value, Assets Measured on Nonrecurring Basis, Valuation Techniques (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Aircraft value publications
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	$ 23
Aircraft value publications | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	21
Aircraft value publications | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	27
Aircraft condition adjustments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	(8)
Aircraft condition adjustments | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	(8)
Aircraft condition adjustments | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Range Median or Average	0
Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	33
Fair Value, Nonrecurring | Operating lease equipment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	15
Level 3 | Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	15
Valuation, Market Approach | Level 3 | Fair Value, Nonrecurring | Operating lease equipment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 15