Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 10,288	$ 9,543
Accumulated depreciation	(6,438)	(5,777)
Property, plant and equipment, net	3,850	3,766
Depreciation	1,019	998	$ 867
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	283	255
Equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,378	6,684
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,373	2,308
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	171	162
Building construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	83	$ 134
Assets held for future use
Property, Plant and Equipment [Line Items]
Construction in progress on facilities held for future use	$ 44