Consolidated Statement of Stockholders' Equity (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Aug. 31, 2010 Common Stock	Dec. 31, 2011 Series A Mandatory Convertible Preferred Stock
Price per share of stock sold (in dollars per share)	$ 14.00	$ 100.000

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

No definition available.

Name:	us-gaap_SaleOfStockPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant