Equity (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended			0 Months Ended
	Jul. 24, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	May 15, 2013 Tangible Equity Units, Equity Component [Member]	Jul. 26, 2013 Series A Preferred Stock [Member]	Dec. 31, 2012 Series A Preferred Stock [Member]	Jul. 25, 2013 Series C Preferred Stock [Member]	Jul. 25, 2013 Series C Preferred Stock [Member] Three-month LIBOR [Member]
Class of Stock [Line Items]
Preferred stock, shares issued						967,870	967,870
Liquidation value						$ 967,900,000.0
Proceeds from issuance in public offering		125,862,000	0	0				130,000,000
Proceeds from issuance in public offering, net of offering costs								125,900,000
Preferred stock, dividend rate, percentage								7.875%	6.39%
Common stock, shares issued	59,870,550	978,044,909	792,272,692		122,848,209
Common stock public offering, price per share	$ 3.09
Proceeds from issuance of common stock	$ 175,200,000	$ 175,174,000	$ 0	$ 0
Units issued					13,800,000
Reclassification from additional paid-in capital to common stock, value per common share issued					$ 1.00