Leases - Carrying Value of Assets Subject to Operating Leases (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Carrying value of assets subject to operating leases, net of accumulated depreciation	$ 24,160	$ 14,934
Carrying value of assets subject to operating leases, net of accumulated depreciation		21,428
Accumulated depreciation		$ 5,303
Assets subject to operating leases
Lessee, Lease, Description [Line Items]
Carrying value of assets subject to operating leases, net of accumulated depreciation	22,052
Accumulated depreciation	$ 5,555

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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The amount of accumulated depreciation, by major property class, recorded on property subject to or available for lease as of the balance sheet date.

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The amount of property, by major property class, net of accumulated depreciation, subject to or available for lease as of the balance sheet date.

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