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Share-Based Compensation (Details 3) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Long-Term Equity Incentive Plan
Stock option and incentive plans
Period during which cash flow deferred	7 years
Restricted stock
Restricted Stock
Units outstanding at the beginning of the period (in shares)	0.4
Units granted (in shares)	0.2
Units issued (in shares)	(0.2)
Units forfeitured (in shares)	0
Units outstanding at the end of the period (in shares)	0.4
Weighted Average Grant Date Value
Units outstanding at the beginning of the period (in dollars per share)	52.66
Units granted (in dollars per share)	127.33
Units issued (in dollars per share)	48.54
Units forfeitured (in dollars per share)	52.33
Units outstanding at the end of the period (in dollars per share)	84.53
Long-Term Stock and Investment Plan | Minimum
Stock option and incentive plans
Number of specified measurement funds in which deferred compensation can be notionally invested	1
Number of specified measurement funds in which cash awards can be notionally invested	1

X

- Definition

Represents the number of specified measurement funds in which cash awards granted by the entity can be notionally invested.

+ References

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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- Definition

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 as a result of the occurrence of a terminating event.

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- Definition

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

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

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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