Boeing 737 MAX Aircraft Grounding (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) aircraft	Mar. 31, 2019 USD ($)
Number of Aircraft Grounded Under Emergency Order	34
After-Tax Potential Concessions and Other Considerations Announced July 2019 | $	$ 4,900
Pre-Tax Potential Concessions and Other Considerations Announced January 2020 | $	$ 2,600
Number of Aircraft Not Delivered Due to Grounding Under Emergency Order	41
Supplier Proceeds | $	$ (300)	$ 0
Contract to Own Aircraft
Number of Aircraft Not Delivered Due to Grounding Under Emergency Order	28
Contract to Lease Aircraft
Number of Aircraft Not Delivered Due to Grounding Under Emergency Order	13
B-737-Max
Owned Assets, Number of Units	31