Leases - Carrying Value of Assets Subject to Operating Leases (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Carrying value of assets subject to operating leases, net of accumulated depreciation	$ 27,109	$ 25,813
Assets subject to operating leases
Lessee, Lease, Description [Line Items]
Carrying value of assets subject to operating leases, net of accumulated depreciation	21,155	23,587
Accumulated depreciation	$ 6,388	$ 6,121

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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