Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

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-Section S99

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- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Interest rate stated in the contractual debt agreement.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

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-Paragraph 1

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

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

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- Definition

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of debt outstanding by type or by instrument at that time.

+ References

No definition available.

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- Definition

Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.8)

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-Name Regulation S-X (SX)

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-Section 03

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 34

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- Definition

The amount of cash paid for interest during the period.

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-Publisher FASB

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-Topic 230

-SubTopic 10

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- Definition

Income derived from investments in debt securities and on cash and cash equivalents the earnings of which reflect the time value of money or transactions in which the payments are for the use or forbearance of money.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Publisher SEC

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-Paragraph 2

-Subparagraph (SX 210.5-03.7(b))

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- Definition

Amount borrowed under the credit facility as of the balance sheet date.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

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- 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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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-Publisher FASB

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- Definition

Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer plus capital lease obligations due to be paid more than one year after the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section H

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Borrowings (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Borrowings
Total long-term debt	$ 752.6		$ 752.5
Total long-term debt, net of current portion	752.6		752.5
Cash payments for interest	17.4	13.5
Interest income	0.1	0.2
3.75% senior notes due 2022
Borrowings
Total long-term debt	349.0		348.9
Interest rate (as a percent)	3.75%
Unamortized discount	(1.0)		(1.1)
Par value of senior notes	350
3.75% senior notes due 2022 \| Significant Observable Inputs (Level 2)
Borrowings
Fair value of notes	340.9
5.125% senior notes due 2020
Borrowings
Total long-term debt	249.2		249.1
Interest rate (as a percent)	5.125%
Unamortized discount	(0.8)		(0.9)
Par value of senior notes	250
5.125% senior notes due 2020 \| Significant Observable Inputs (Level 2)
Borrowings
Fair value of notes	267.7
6.125% senior notes due 2016
Borrowings
Total long-term debt	149.6		149.6
Interest rate (as a percent)	6.125%
Unamortized discount	(0.4)		(0.4)
Par value of senior notes	150
6.125% senior notes due 2016 \| Significant Observable Inputs (Level 2)
Borrowings
Fair value of notes	166.9
Revolving credit facility
Borrowings
Interest on borrowings	0
Remaining borrowing capacity	600.0
Average interest rate (as a percent)		1.32%
Industrial development and revenue bonds through 2018
Borrowings
Total long-term debt	4.5		4.5
Other, including capital lease obligations
Borrowings
Total long-term debt	0.3		0.4
Uncommitted line of credit
Borrowings
Maximum borrowing capacity	45.0		45.0
Average interest rate (as a percent)		1.50%
Amount outstanding	$ 0