Share Based Compensation (Details 1) (Employee Stock Option, USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Employee Stock Option
Options Activity, Number of Options
Outstanding at January 1	4,489
Exercised	(420)
Canceled	(69)
Forfeited	(18)
Outstanding at December 31	3,982	4,489
Exercisable at December 31	3,560
Option Activity, Weighted Average Exercise Price
Outstanding at January 1	$ 25.54
Exercised	$ 11.51
Canceled	$ 39.70
Forfeited	$ 15.36
Outstanding at December 31	$ 26.81	$ 25.54
Exercisable at December 31	$ 28.12
Options Activity, Weighted Remaining Contractual Term and Aggregate Intrisic Value
Weighted Average Remaining Contractual Term, Outstanding at January 1	4 years 1 month 20 days	5 years 2 months 15 days
Weighted Average Remaining Contractual Term, Outstanding at December 31	4 years 1 month 20 days	5 years 2 months 15 days
Weighted Average Remaining Contractual Term, Exercisable at December 31	4 years 9 months 6 days
Aggregate Intrinsic Value, Outstanding at January 1	$ 39
Aggregate Intrinsic Value, Outstanding at December 31	31	39
Aggregate Intrinsic Value, Exercisable at December 31	26
Vested or expected to vest at December 31, 2014
Number of Options (000)	3,982
Weighted Average Exercise Price	$ 26.77
Weighted Average Remaining Contractual Term (years)	4 years 2 months 1 day
Aggregate Intrinsic Value (millions)	$ 31

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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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 vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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

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