Debt (Details 1) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Additional information related to Convertible Contingent Debt Securities
Carrying amount of the equity component (conversion feature)	$ 64	$ 64
Unamortized discount of liability component amortized through February 1, 2011	0	2
Net carrying amount of liability component	$ 689	$ 698

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph a

Name:	us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant