Consolidated Statements of Equity (Unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Consolidated Statements of Stockholders Equity [Abstract]
Amount of net income (loss) attributable to noncontrolling interests excluded from noncontrolling interests equity	$ 5	$ (7)

Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

No definition available.

Name:	us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration