Mandatory Convertible Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Mar. 31, 2011
Mandatory Convertible Preferred Stock (Textuals) [Abstract]
Mandatory convertible preferred stock, outstanding						10,000,000
Issue price preferred stock						$ 50.00
Mandatory convertible preferred stock, dividends on each share			5.875%
Mandatory convertible preferred stock, liquidation preference	$ 50		$ 50		$ 50	$ 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.
Payments of Dividends, Preferred Stock and Preference Stock	$ 7	$ 7	$ 15	$ 0
Dividends payable, date declared, day, month and year			Jun. 04, 2012
Dividends payable, amount per share	$ 0.7344		$ 0.7344
Dividends payable, amount	$ 7		$ 7
Dividends payable, date to be paid, day, month and year			Jul. 02, 2012
Dividends payable, date of record, day, month and year			Jun. 15, 2012
Mandatory Convertible Preferred Stock Minimum Conversion Rate [Member]
Mandatory Convertible Preferred Stock additional (Textuals) [Abstract]
Convertible preferred stock, shares issued upon conversion	2.7454		2.7454
Mandatory Convertible Preferred Stock Maximum Conversion Rate [Member]
Mandatory Convertible Preferred Stock additional (Textuals) [Abstract]
Convertible preferred stock, shares issued upon conversion	3.4317		3.4317