Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Amounts attributable to common stockholders:
Income from continuing operations	$ 69,568	$ 140,942
Income (loss) from discontinued operations	(2,062)	17,728
Net Income (Loss) Available to Common Stockholders, Basic	67,506	158,670
Preferred Stock Dividends, Income Statement Impact	(13)	(13)
Income attributable to common stockholders (numerator for basic EPS)	$ 67,493	$ 158,657
Denominator (in thousands):
Weighted average shares used in basic EPS	201,148	199,960
Effect of dilutive shares:
Incremental Common Shares Attributable to Conversion of Preferred Stock	2	2
Incremental Common Shares Attributable to Conversion of Preference Stock	396	398
Incremental Common Shares Attributable to Share-based Payment Arrangements	664	312
Weighted-average shares used in diluted EPS	202,210	200,672
Income from continuing operations	$ 0.35	$ 0.70
Income (loss) from discontinued operations	$ (0.01)	$ 0.09
Net income	$ 0.34	$ 0.79
Diluted earnings per share:
Income from continuing operations	$ 0.34	$ 0.70
Income (loss) from discontinued operations	$ (0.01)	$ 0.09
Net income	$ 0.33	$ 0.79
Anti-dilutive shares (in thousands):
Anti-dilutive shares not used in calculating diluted weighted-average shares	13,868	13,811