Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200	200
Common stock, shares issued	106.4	104.3
Common stock, shares outstanding	106.4	104.3