Equity Compensation Plans (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of shares available for grant	13
Weighted average fair value per option granted	$ 13.99	$ 8.90	$ 13.23
Stock option expense reduced operating earnings	$ 59	$ 74	$ 88
Stock option expense earnings per share	$ 0.11	$ 0.14	$ 0.16
Unrecognized compensation cost related to stock	42
Total intrinsic value of options exercised	340	154	112
Cash received from the exercise of stock options	547	583	146
Restricted Stock [Member]
Awards of stock options vest over number of years	4 years
Stock Options
Awards of stock options vest over number of years	2 years
Recognition period for unrecognized compensation cost for restricted stock and RSUs	1 year
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	47	63	28
Stock option expense reduced operating earnings	69	46	26
Stock option expense earnings per share	$ 0.13	$ 0.09	$ 0.05
Restricted Stock and Restricted Stock Units (RSUs)
Unrecognized compensation cost related to stock	$ 32
Recognition period for unrecognized compensation cost for restricted stock and RSUs	2 years 0 months 75 days
Maximum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	7 years
Minimum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	5 years
Share-based Compensation Award, Vesting In One Year [Member]
Percentage of stock options vesting in a period of one year	50.00%
Share-based Compensation Award, Vesting In Second Year [Member]
Percentage of stock options vesting in a period of one year	50.00%

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Stock Option Expense Reduced Operating Earnings

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Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements.

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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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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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Percentage of vesting of share-based compensation awards.

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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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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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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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