Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Receivables, allowance for doubtful accounts	$ 85	$ 52
Preferred stock, par	$ 1	$ 1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, issued	0	0
Common stock, par	$ 0.17	$ 0.17
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	193,230,310	190,244,741
Treasury stock, shares	29,225,996	21,795,051