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The cash outflow to reacquire common stock during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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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

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Amount of stock repurchase plan authorized.

+ References

No definition available.

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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

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Shareholders' Equity - Shares Repurchased (Details) (USD $)	12 Months Ended			2 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 26, 2015
Equity, Class of Treasury Stock [Line Items]
Repurchases of common stock	$ (590,000,000)	$ (264,000,000)	$ (24,000,000)
Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount	210,000,000
Shares repurchased	24,413,781	12,512,759	2,066,759
Repurchases of common stock	(590,000,000)	(264,000,000)	(24,000,000)
Average price paid (in dollars per share)	$ 24.17	$ 21.12	$ 11.76
Affiliated Entity [Member] \| Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount		5,000,000
Repurchases of common stock		(109,700,000)
Subsequent Event [Member] \| Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased				3,581,767
Repurchases of common stock				$ (92,000,000)
Average price paid (in dollars per share)				$ 25.63