Long-Term Debt (Senior Notes Due 2021) (Details) (Senior Notes [Member], USD $) In Millions, unless otherwise specified	0 Months Ended	6 Months Ended
Jan. 14, 2011	Jun. 30, 2011
Senior Notes [Member]
Debt instrument offering date	January 14, 2011
Face amount of senior notes	$ 500	$ 500
Interest rate of notes	4.875%
Percentage of face value of debt instrument pricing	99.297%
Maturity date of 4.875% Senior Notes	Jan. 14, 2021
Number of days in annual interest calculation period	360
Debt instrument call feature	Prior to October 14, 2020, the 4.875% Senior Notes are redeemable in whole, at any time, or in part, from time to time, at the Company's option upon not less than 30 nor more than 60 days' notice at a redemption price, plus any accrued and unpaid interest to, but not including, the redemption date, equal to the greater of: · 100% of the principal amount thereof; or · the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the applicable Treasury Yield (as defined in the indenture governing the 4.875% Senior Notes) plus 25 basis points.
Debt instrument minimum number of days callable	30
Debt instrument maximum number of days callable	60
Percentage principal amount of debt that can be redeemed by the company	100.00%
Basis points added to treasury yield to determine redemption price of debt	25
Percentage principal amount of debt redeemable upon change in control	101.00%
Senior notes, net carrying amount		496.6
Senior notes, unamortized discount		$ 3.4
Debt instrument covenant compliance		The 4.875% Senior Notes are subject to certain customary, positive and negative covenants, with which the Company complied as of June 30, 2011.

Long-Term Debt (Senior Notes Due 2021) (Details) (Senior Notes [Member], USD $)
In Millions, unless otherwise specified

0 Months Ended

6 Months Ended

Jan. 14, 2011

Jun. 30, 2011

Senior Notes [Member]

Debt instrument offering date

January 14, 2011

Face amount of senior notes

$ 500

Interest rate of notes

4.875%

Percentage of face value of debt instrument pricing

99.297%

Maturity date of 4.875% Senior Notes

Jan. 14, 2021

Number of days in annual interest calculation period

360

Debt instrument call feature

Prior to October 14, 2020, the 4.875% Senior Notes are redeemable in whole, at any time, or in part, from time to time, at the Company's option upon not less than 30 nor more than 60 days' notice at a redemption price, plus any accrued and unpaid interest to, but not including, the redemption date, equal to the greater of:

· 100% of the principal amount thereof; or

· the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the applicable Treasury Yield (as defined in the indenture governing the 4.875% Senior Notes) plus 25 basis points.

Debt instrument minimum number of days callable

Debt instrument maximum number of days callable

Percentage principal amount of debt that can be redeemed by the company

100.00%

Basis points added to treasury yield to determine redemption price of debt

Percentage principal amount of debt redeemable upon change in control

101.00%

Senior notes, net carrying amount

496.6

Senior notes, unamortized discount

$ 3.4

Debt instrument covenant compliance

The 4.875% Senior Notes are subject to certain customary, positive and negative covenants, with which the Company complied as of June 30, 2011.

- Definition

As described in the Indenture governing the notes, the fewest number of days notice the Company must give to call the notes.

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+ References

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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.

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