Fair Value, Assets Measured On Nonrecurring Basis, Valuation Techniques (Details) - USD ($) $ in Millions	Mar. 31, 2016	Mar. 31, 2015
Aircraft Value Publications [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value of assets and liabilities measured on nonrecurring basis valuation techniques, median	$ 100
Aircraft Value Publications [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Range of fair value of assets measured on nonrecurring basis valuation techniques	65
Aircraft Value Publications [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Range of fair value of assets measured on nonrecurring basis valuation techniques	115
Aircraft Condition Adjustments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Net fair value of assets measured on nonrecurring basis valuation techniques	(60)
Aircraft Condition Adjustments [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Range of fair value of assets measured on nonrecurring basis valuation techniques	(61)
Aircraft Condition Adjustments [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Range of fair value of assets measured on nonrecurring basis valuation techniques	1
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Market Approach Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Operating Lease Equipment	$ 40	$ 63