Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Doubtful accounts and allowances	$ 26	$ 19
Accumulated depreciation	$ 7,652	$ 7,204
Common stock, par value	$ 0.5	$ 0.5
Common stock, shares authorized	3,800,000,000	3,800,000,000
Common stock, shares issued	1,649,000,000	1,636,000,000
Treasury stock, at cost, shares held	179,000,000	121,000,000