Amount of deferred tax expense from write-off of the deferred tax asset related to deductible stock options at exercise.

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Unrecognized cost of unvested share-based compensation awards.

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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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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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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).

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

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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Amount of stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Share based compensation arrangement by share based payment award equity instruments other than options forfeited in period weighted average grant date fair value.

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Common Equity Common Equity 5 (Details) - USD ($)	3 Months Ended		6 Months Ended
Common Equity Common Equity 5 (Details) - USD ($)	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other Comprehensive Income (Loss), Net of Tax	$ 11,300,000	$ 0	$ 11,300,000	$ 0
Stock Repurchased During Period, Shares			600,000	1,300,000
Stock Repurchased During Period, Value			$ 32,000,000	$ 57,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Share Based Compensation Arrangement By Share Based Payment Award Award Percentage To Vest Each Year After Grant Date			33.00%
Share Repurchase Plan, 2013 [Member] [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount	$ 300,000,000		$ 300,000,000
Stock Repurchased During Period, Shares			0
Stock Repurchased During Period, Value			$ 0
Share Repurchase Plan, 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchased During Period, Shares				400,000
Stock Repurchased During Period, Value				$ 18,600,000
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value			$ 3,700,000	2,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	147,214		155,479
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0		60,164
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0		(68,429)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0		0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	147,214		147,214
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 0.00		$ 53.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	0.00		36.95
Share Based Compensation Arrangement By Share Based Payment Awards Equity Instruments Other Than Options Forfeited In Period Weighted Average Grant Date Fair Value	$ 0.00		$ 0.00
Tax Benefit from Stock Options Exercised			$ 1,300,000	$ 1,000,000.00
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 4,600,000		$ 4,600,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			24 months
Share Repurchases to Fulfill Exercised Stock Options and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchased During Period, Shares			600,000	900,000
Stock Repurchased During Period, Value			$ 32,000,000	$ 38,700,000