Debt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total principal amount of debt	$ 2,221.8us-gaap_DebtInstrumentCarryingAmount	$ 3,001.8us-gaap_DebtInstrumentCarryingAmount
Debt Maturity Period	5 years
Senior Notes	2,221.8us-gaap_SeniorNotes
Debt Instrument, Maturity Date Range, Start	Sep. 01, 2016
Debt Instrument, Maturity Date Range, End	May 01, 2023
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	5.25%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	6.875%
Line of Credit [Member]
Debt Instrument [Line Items]
Total principal amount of debt	0	480.0
Long-term Debt, Weighted Average Interest Rate	2.23%	2.22%
Long-term Line of Credit	1,800.0
Letters of Credit Outstanding, Amount	3.7	3.8
Long-term Line of Credit		480.0
Term Loan due 2017 [Member]
Debt Instrument [Line Items]
Total principal amount of debt	0	300.0
Long-term Debt, Weighted Average Interest Rate	2.28%	2.22%
Long-term Line of Credit		600.0
Senior Notes Due 2016 [Member]
Debt Instrument [Line Items]
Total principal amount of debt	176.8	176.8
Debt Instrument, Maturity Date	Sep. 01, 2016
Debt Instrument, Interest Rate, Stated Percentage	6.05%
Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Total principal amount of debt	$ 134.0	$ 134.0
Debt Instrument, Maturity Date	Apr. 01, 2018
Debt Instrument, Interest Rate, Stated Percentage	6.80%

Debt Maturity Period

No definition available.

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- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

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-Number 210

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-Number 210

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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+ Details

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- Definition

Maximum contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Definition

Minimum contractual interest rate for funds borrowed, under the debt agreement.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Topic 210

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-Subparagraph (SX 210.5-02.22(a)(2))

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

+ References

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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-Publisher FASB

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- Definition

Weighted average interest rate of long-term debt outstanding.

+ References

No definition available.

+ Details

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

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