Share Repurchases (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Feb. 25, 2014
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Value	$ 16	$ 56
Number of shares repurchased under the authorization	1,071,690	2,023,938
Treasury Stock Acquired, Average Cost Per Share	$ 15.38	$ 27.72
Share Repurchase Program Twenty Fourteen [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount			350
Stock Repurchased During Period, Value	9	43
Number of shares repurchased under the authorization	604,032	1,570,346
Treasury Stock Acquired, Average Cost Per Share	$ 15.14	$ 27.70
Share Maintenance Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Value	$ 7	$ 13
Number of shares repurchased under the authorization	467,658	453,592
Treasury Stock Acquired, Average Cost Per Share	$ 15.69	$ 27.81

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

+ Details

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

+ Details

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