Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time.

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-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 99-7

-Paragraph 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3291-108585

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 20

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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

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Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: 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

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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The amount authorized by an entity's Board of Directors under a stock repurchase plan.

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The number of years over which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors.

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Stockholders' Equity and Accumulated Other Comprehensive Income (Loss) (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended		3 Months Ended	7 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Mar. 31, 2011 Accelerated Stock Buyback Program [Member]	Mar. 24, 2011 Accelerated Stock Buyback Program [Member]	Sep. 30, 2010 Accelerated Stock Buyback Program [Member]	Sep. 30, 2011 Share Repurchase Plan [Member]	Sep. 30, 2011 Share Repurchase Plan [Member]	Aug. 31, 2014 Share Repurchase Plan [Member]
Stock Repurchase Program, Authorized Amount							$ 300.0
Stock Repurchase Program, Period in Force								3
Stock Repurchased and Retired During Period, Shares			2.0		25.8	1.9
Stock Repurchased and Retired During Period, Value						24.4
Repurchase of shares of common stock, value	$ 24.4	$ 500.1			$ 500.0
Daily volume-weighted average share price				$ 17.95