Equity (Details)	Dec. 31, 2011	Dec. 31, 2010
Summary of Preferred Stock
Preferred stock, shares authorized	8,000,000	8,000,000
Preferred stock, shares issued	0	8,000
Preferred stock, shares outstanding	0	8,000
Summary of Common Stock
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	255,633,000	248,200,000
Common stock, shares outstanding	242,115,000	240,538,000
Undesignated [Member]
Summary of Preferred Stock
Preferred stock, shares authorized	5,250,000	5,250,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Series A [Member]
Summary of Preferred Stock
Preferred stock, shares authorized	1,750,000	1,750,000
Preferred stock, shares issued	0	8,221
Preferred stock, shares outstanding	0	8,221
Series X Junior Participating [Member]
Summary of Preferred Stock
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0