Mandatory Convertible Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Mandatory Convertible Preferred Stock (Textuals) [Abstract]
Mandatory convertible preferred stock, outstanding	10,000,000	10,000,000
Mandatory convertible preferred stock, dividends on each share		5.875%
Mandatory convertible preferred stock, liquidation preference	$ 50.00	$ 50.00		$ 50.00
Preferred stock, dividend payment terms		Dividends will accrue and accumulate from the date of issuance and, to the extent that we are legally permitted to pay a dividend and the Board of Directors declares a dividend payable, we will pay dividends in cash on January 1, April 1, July 1 and October 1 of each year, commencing on July 1, 2011 and ending on April 1, 2014.
Convertible preferred stock, terms of conversion		Unless converted earlier, each share of the mandatory convertible preferred stock will automatically convert on April 1, 2014 into between 2.7454 and 3.4317 shares of common stock, depending on the market value of our common stock for the 20 consecutive trading day period ending on the third trading day prior to April 1, 2014, subject to customary anti-dilution adjustments. At any time prior to April 1, 2014, holders may elect to convert shares of the mandatory convertible preferred stock at the minimum conversion rate of 2.7454 shares of common stock, subject to customary anti-dilution adjustments.
Preferred stock dividends paid		$ 15	$ 15
Dividends payable, date declared, day, month and year	Jun. 03, 2013
Dividends Payable, Date of Record	Jun. 14, 2013
Dividends payable, date to be paid, day, month and year	Jul. 01, 2013
Dividends payable, amount per share	$ 0.7344	$ 0.7344
Dividends Payable	$ 7	$ 7
Mandatory Convertible Preferred Stock Minimum Conversion Rate [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion	2.7454	2.7454
Mandatory Convertible Preferred Stock Maximum Conversion Rate [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion	3.4317	3.4317