Related Parties (Details) (Director [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Related Party Transaction Amount of Assets in Defined Contributions Plans	$ 22.8	$ 20.4	$ 19.3
Related Party Transaction Percent of Assets in Defined Contribution Plan Assets	6.00%	7.00%	7.00%
Trinity [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Assets Managed by Investment Advisory Firm under Director's Management	154.7	125.2	115.2
Related Party Transaction, Expenses from Transactions with Related Party	0.4	0.3	0.3
Pension Plans, Defined Benefit [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	0.3	0.3	0.3
Related Party Transaction Amount of Assets Under Management in Defined Benefit Plans	$ 148.6	$ 120.7	$ 107.1

Amounts Invested in Defined Contribution Plan Mutual Fund Managed by a Director's Investment Advisory Firm

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- Definition

Amounts Invested in Defined Contribution Plan Mutual Fund Managed by a Director's Investment Advisory Frim, Percentage of Total Defined Contribution Plan Investments

+ References

No definition available.

+ Details

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- Definition

Investment Assets Managed by a Directors Investment Advisory Firm

+ References

No definition available.

+ Details

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- Definition

Related Party Transaction Amount of Assets Under Management in Defined Benefit Plans

+ References

No definition available.

+ Details

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- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

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