Leases - Property and Equipment under Capital Leases (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 28,934	$ 26,869
Accumulated depreciation and amortization	$ (16,890)	(15,520)
Property and equipment, net		11,349
Assets Held under Capital Leases
Property, Plant and Equipment [Line Items]
Total property and equipment		582
Accumulated depreciation and amortization		(163)
Property and equipment, net		$ 419

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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business 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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