New Accounting Pronouncements - Narrative (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities	$ 5,852
Assets	788,482		$ 707,794
Liabilities	386,924		355,294
Equipment held for lease	$ 14,934		$ 14,298
Difference Between Lease Guidance in Effect Before and After Topic 842 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating leases, right of use assets		$ 6,200
Operating lease liabilities		5,900
ASC 842 [Member] | Difference Between Lease Guidance in Effect Before and After Topic 842 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets		(300)
Assets		5,900
Liabilities		$ 5,900
ASC 606 [Member] | Difference Between Lease Guidance in Effect Before and After Topic 842 [Member] | Aircraft Sold Under Fractional Aircraft Ownership Programs [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equipment held for lease				$ 3,500
Aircraft repurchase liabilities and unearned lease revenues				$ 3,500