Represents the percentage the granted awards can potentially vest up to.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

+ References

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to differences in the deductibility of incentive stock options and other equity-based compensation costs in accordance with generally accepted accounting principles and enacted tax laws.

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- Definition

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

+ References

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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).

+ References

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- Definition

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).

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

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- Definition

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.

+ References

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- Definition

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.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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Equity-based Compensation (Details) (LTIP, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Weighted-Average Grant-Date Fair Value
Compensation expense not yet recognized	$ 164.9		$ 164.9
Weighted average period over which compensation expense is to be recognized			2 years 5 months 1 day
Number of shares remaining available for grant	5,400,000		5,400,000
Compensation agreement
Compensation expense recognized	18.1	17.6	37.0	38.9
Tax benefit	6.3	6.1	12.7	13.5
Tax shortfall	$ 6.9	$ 7.4	$ 6.9	$ 7.4
Service Vesting Restricted Stock Awards
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)			9,898,000
Granted (in shares)			351,000
Forfeited (in shares)			(187,000)
Vested (in shares)			(3,336,000)
Outstanding at the end of the period (in shares)	6,726,000		6,726,000
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)			$ 16.92
Granted (in dollars per share)			$ 10.73
Forfeited (in dollars per share)			$ 15.14
Vested (in dollars per share)			$ 17.27
Outstanding at the end of the period (in dollars per share)	$ 16.48		$ 16.48
Market/Service Vesting Restricted Stock Awards
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)			3,534,000
Forfeited (in shares)			(16,000)
Outstanding at the end of the period (in shares)	3,518,000		3,518,000
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)			$ 12.93
Forfeited (in dollars per share)			$ 8.21
Outstanding at the end of the period (in dollars per share)	$ 12.95		$ 12.95
Market/Service Vesting Restricted Stock Awards \| Minimum
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)			$ 6.70
Significant assumptions used to calculate fair values
Expected volatility (as a percent)			41.30%
Risk-free interest rate (as a percent)			0.50%
Market/Service Vesting Restricted Stock Awards \| Maximum
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)			$ 13.57
Significant assumptions used to calculate fair values
Expected volatility (as a percent)			56.70%
Risk-free interest rate (as a percent)			1.10%
Other disclosures
Vesting percentage of the awards granted			100.00%
Service Vesting Restricted Stock Units
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)			1,023,000
Granted (in shares)			1,310,000
Forfeited (in shares)			(56,000)
Vested (in shares)			(133,000)
Outstanding at the end of the period (in shares)	2,144,000		2,144,000
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)			$ 10.59
Granted (in dollars per share)			$ 10.83
Forfeited (in dollars per share)			$ 10.58
Vested (in dollars per share)			$ 10.98
Outstanding at the end of the period (in dollars per share)	$ 10.72		$ 10.72
Market/Service Vesting Restricted Stock Units
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)			825,000
Granted (in shares)			990,000
Forfeited (in shares)			(34,000)
Outstanding at the end of the period (in shares)	1,781,000		1,781,000
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)			$ 15.81
Granted (in dollars per share)			$ 15.44
Forfeited (in dollars per share)			$ 15.81
Outstanding at the end of the period (in dollars per share)	$ 15.60		$ 15.60
Market/Service Vesting Restricted Stock Units \| Minimum
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)			$ 15.44
Significant assumptions used to calculate fair values
Expected volatility (as a percent)			53.00%
Risk-free interest rate (as a percent)			0.50%
Market/Service Vesting Restricted Stock Units \| Maximum
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)			$ 15.81
Significant assumptions used to calculate fair values
Expected volatility (as a percent)			54.00%
Risk-free interest rate (as a percent)			0.70%
Other disclosures
Vesting percentage of the awards granted			200.00%