Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Allowances, accounts receivable	$ 2	$ 3
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10	10
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	600	600
Common stock, shares issued	175	174
Common stock, shares outstanding	132	147
Treasury stock at cost, shares	43	27