Summary of Property and Equipment (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property Plant And Equipment [Abstract]
Land and land improvements	$ 1,990us-gaap_LandAndLandImprovements	$ 1,973us-gaap_LandAndLandImprovements
Buildings and leasehold improvements	13,336us-gaap_BuildingsAndImprovementsGross	13,435us-gaap_BuildingsAndImprovementsGross
Furniture and equipment	2,217us-gaap_FixturesAndEquipmentGross	2,223us-gaap_FixturesAndEquipmentGross
Construction in progress	209us-gaap_ConstructionInProgressGross	176us-gaap_ConstructionInProgressGross
Property, Plant and Equipment, Gross, Total	17,752us-gaap_PropertyPlantAndEquipmentGross	17,807us-gaap_PropertyPlantAndEquipmentGross
Less accumulated depreciation and amortization	(7,177)	(6,812)
Property and equipment, net	$ 10,575us-gaap_PropertyPlantAndEquipmentNet	$ 10,995us-gaap_PropertyPlantAndEquipmentNet	$ 11,588us-gaap_PropertyPlantAndEquipmentNet

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

+ References

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depreciation of fixtures and equipment. Includes, but is not limited to, machinery, equipment, and engines.

+ References

No definition available.

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- Definition

Amount before accumulated deprecation and depletion of real estate held for productive use and additions or improvements to real estate held for productive use, examples include, but are not limited to, walkways, driveways, fences, and parking lots. Excludes land held for sale.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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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.

+ References

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