Property, Plant And Equipment (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 21,793	$ 19,409
Property, plant and equipment, accumulated depreciation	7,872	6,766
Assets Held Under Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	510	417
Property, plant and equipment, accumulated depreciation	111	79
Construction In Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 747	$ 520