Share Repurchase Program (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013
Share Repurchase Program
Number of shares repurchased	8.3	19.9
Aggregate cost, including fees	$ 148.1	$ 280.8
Average price per share, including fees	$ 17.91	$ 14.12
Share repurchase program, remaining authorized repurchase amount	270.6
2013 Share Repurchase Program
Share Repurchase Program
Share repurchase program, authorized amount	300.0
Share repurchase program, increased authorized amount	500.0
2014 Share Repurchase Program
Share Repurchase Program
Share repurchase program, authorized amount	$ 300.0

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

+ References

No definition available.

+ Details

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

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- Definition

Amount remaining of a 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

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- Definition

Number of shares that have been repurchased during the period and are being held in treasury.

+ References

+ Details

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- Definition

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

+ 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 FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-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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