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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-Name Accounting Standards Codification

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Unrecognized cost of unvested share-based compensation awards.

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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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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 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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock Compensation Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Stock Compensation Plans (Details) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 20	$ 14	$ 58	$ 41
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted in period (in shares)	2,400	11,100	1,267,900	1,228,500
Equity Award Vesting Period (in years)			3 years
Options expiration period (in years)			10 years
Unrecognized compensation cost	$ 100		$ 100
Remaining period over which to recognize unrecognized compensation expense (in years)			2 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity other than stock options granted in period (in shares)	0	0	6,900	9,100
Unrecognized compensation cost	$ 4		$ 4
Remaining period over which to recognize unrecognized compensation expense (in years)			1 year
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity other than stock options granted in period (in shares)	500	2,300	153,200	152,700
Equity Award Vesting Period (in years)			3 years
Unrecognized compensation cost	$ 35		$ 35
Remaining period over which to recognize unrecognized compensation expense (in years)			2 years
Minimum [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			3 years
Minimum [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			1 year
Minimum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			3 years
Maximum [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			4 years
Maximum [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			4 years
Maximum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Award Vesting Period (in years)			4 years