Long-term Equity-based Compensation Plans - Fair Value Assumptions (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]
Options, Outstanding, Weighted Average Remaining Contractual Term	5
Options, Outstanding, Intrinsic Value	$ 6.3
Options, Vested and Expected to Vest, Outstanding, Number	3,796,343
Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 9.12	$ 7.70
Options, Exercised in Period, Total Intrinsic Value	0.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding at Beginning of the Year	4,004,546
Options, Outstanding, Weighted Average Exercise Price, Beginning of the Year	$ 42.34
Options, Granted in Period	308,750
Options, Granted in Period, Weighted Average Exercise Price	$ 28.10
Options, Exercised in Period	(12,000)
Options, Exercised in Period, Weighted Average Exercise Price	$ 19.43
Options, Forfeited and Expired in Period	(467,494)
Options, Forfeited and Expired in Period, Weighted Average Exercise Price	$ 46.72
Options, Outstanding at End of the Period	3,833,802
Options, Outstanding, Weighted Average Exercise Price, End of the Year	$ 40.73
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	5
Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	6.2
Options, Vested and Expected to Vest, Exercised, Number	3,082,926
Options, Vested and Expected to Vest, Exercised, Weighted Average Exercise Price	$ 44.44
Options, Vested and Expected to Vest, Exercised, Weighted Average Remaining Contractual Term	4
Options, Vested and Expected to Vest, Exercised, Aggregate Intrinsic Value	$ 2.6
Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 40.87
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	9,950,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Restricted Stock, Nonvested Balance at Beginning of the Year	218,156
Restricted Stock, Nonvested Balance at Beginning of the Year	$ 23.72
Nonvested Restricted Stock, Granted in Period	123,075
Nonvested Restricted Stock, Granted in Period, Weighted Average Grant Date Fair Value	$ 33.25
Nonvested Restricted Stock, Forfeited in Period	(613)
Nonvested Restricted Stock, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 22.07
Restricted Stock, Nonvested Balance at End of the Period	340,618
Restrited Stock, Nonvested Balance at End of the Period	$ 27.17
Time Vested Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested Restricted Stock, Granted in Period	57,600
Restricted Stock, Nonvested Balance at End of the Period	164,418
Performance Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested Restricted Stock, Granted in Period	65,475
Restricted Stock, Nonvested Balance at End of the Period	176,200

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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- Definition

The weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect during the reporting period as a result of the occurrence of a terminating event specified in the contractual agreement of the plan.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(2)(c)
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

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Net number of share options (or share units) granted during the period.

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The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

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As of the balance sheet date, the total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options that are exercisable.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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The weighted-average period between the balance sheet date and expiration date for fully vested and expected to vest options that are exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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The weighted-average period between the balance sheet date and expiration date for fully vested and expected to vest options outstanding, which may be expressed in a decimal value for number of years.

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Number of share options (or share units) exercised during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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