Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Doubtful accounts and allowances	$ 60	$ 48
Inventory reserves	157	146
Accumulated depreciation	$ 9,974	$ 9,188
Convertible preferred stock, par value (in dollars per share)	$ 100	$ 100
Convertible preferred stock, shares authorized (in shares)	3,100	3,100
Convertible preferred stock, shares issued (in shares)	2,300	2,300