Earnings Per Share - Antidilutive Securities Excluded from Computation of EPS Table (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Earnings Per Share, Basic	$ 0.57	$ 0.02
Diluted	$ 0.54	$ 0.02
Weighted Average Number of Shares Outstanding, Basic	658	651
Weighted Average Number of Shares Outstanding, Diluted	765	651
Convertible Debt Securities [Member] | 5.75% Cumulative Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income Adjustments		$ 21
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		56
Convertible Debt Securities [Member] | 5.75% Cumulative Convertible Preferred Stock Series A
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income Adjustments		16
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		39
Convertible Debt Securities [Member] | 5.0% Cumulative Convertible Preferred Stock Series Two Thousand And Five B [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income Adjustments		3
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		5
Convertible Debt Securities [Member] | 4.50% Cumulative Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income Adjustments		3
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		6
Restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income Adjustments		$ 0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		0