Employee Benefit Plans (Details 3) (Defined benefit pension plan, USD $) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Significant unobservable inputs (Level 3) Recurring Basis	Dec. 31, 2011 Significant unobservable inputs (Level 3) Recurring Basis	Dec. 31, 2012 Private investment funds-non-redeemable Significant unobservable inputs (Level 3) Recurring Basis	Dec. 31, 2011 Private investment funds-non-redeemable Significant unobservable inputs (Level 3) Recurring Basis	Dec. 31, 2012 Insurance annuity contracts Significant unobservable inputs (Level 3) Recurring Basis	Dec. 31, 2010 Insurance annuity contracts Significant unobservable inputs (Level 3) Recurring Basis
Fair Value Measurement Using Significant Unobservable Inputs (Level 3)
Fair value of plan assets at the beginning of period	$ 721.1	$ 656.3	$ 3.4	$ 5.4	$ 1.0	$ 0.3	$ 4.4	$ 4.4
Transfer in from level 2						1.4
Actual return on plan assets	61.0	53.9			0.1
Settlements					(1.0)	(0.7)	(1.1)
Fair value of plan assets at end of period	$ 805.8	$ 721.1	$ 3.4	$ 5.4	$ 0.1	$ 1.0	$ 3.3	$ 4.4

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

-URI http://asc.fasb.org/extlink&oid=6504192

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-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=6504226

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References+ Details

- Definition

The amount that relates to an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

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

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-Name Statement of Financial Accounting Standard (FAS)

-Number 106

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-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 FASB

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-Number 132R

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

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+ Details