Shareholders' Equity (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Summary of preferred dividends declared on preferred stock issued
Total preferred stock dividends declared excluding series G	$ 35,000,000		$ 195,000,000
Total preferred stock dividends declared		160,000,000		320,000,000
Series A Preferred Stock [Member]
Summary of preferred dividends declared on preferred stock issued
Preferred stock dividends declared	231.77	231.77	471.35	471.35
Total preferred stock dividends declared	7,000,000	7,000,000	14,000,000	14,000,000
Series B Preferred Stock [Member]
Summary of preferred dividends declared on preferred stock issued
Preferred stock dividends declared	387.50	387.50	775.00	775.00
Total preferred stock dividends declared	13,000,000	13,000,000	25,000,000	24,000,000
Series C Preferred Stock [Member]
Summary of preferred dividends declared on preferred stock issued
Preferred stock dividends declared	247.22	247.22	502.78	502.78
Total preferred stock dividends declared	2,000,000	2,000,000	4,000,000	4,000,000
Series D Preferred Stock [Member]
Summary of preferred dividends declared on preferred stock issued
Preferred stock dividends declared	247.22	247.22	502.78	502.78
Total preferred stock dividends declared	13,000,000	13,000,000	27,000,000	27,000,000
Series G Preferred Stock [Member]
Summary of preferred dividends declared on preferred stock issued
Preferred stock dividends declared	0	2,500.00	2,500.00	5,000.00
Total preferred stock dividends declared	$ 0	$ 125,000,000	$ 125,000,000	$ 250,000,000