Property, Plant, and Capitalized Software Property Plant and Equipment Table (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Land and improvements	$ 237	$ 310
Buildings and improvements	2,420	2,295
Computer equipment	1,945	1,693
Furniture and fixtures	790	675
Less accumulated depreciation	(2,163)	(1,982)
Property and equipment, net	3,229	2,991
Capitalized software	2,642	2,399
Less accumulated amortization	(1,010)	(972)
Capitalized software, net	1,632	1,427
Total property, equipment and capitalized software, net	$ 4,861	$ 4,418