Stock-Based Compensation (Details 4) (USD $) In Millions, except Per Share data	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Other restricted stock unit information
Weighted-average grant date fair value of restricted stock units granted during the year, per share	$ 21.05	$ 10.23	$ 30.13
Total fair value of restricted stock units vested during the year ($'s in millions)	$ 29	$ 28	$ 48

The weighted average fair value at grant for nonvested share-based awards issued during the period on other than stock option plans (for example, phantom stock plan, stock appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(2)(c)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph c(1)

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Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	duration