Share-Based Associate Compensation Plans (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2015 USD ($) peers_exceeded Peers compensation_plans shares	Dec. 31, 2014 USD ($) peers_exceeded Peers shares	Dec. 31, 2013 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award
Number of equity compensation plans \| compensation_plans	4
Maximum number of shares awarded to each full-time employee for their service \| shares	10
Share based compensation	$ 14	$ 13	$ 12
Tax benefit from compensation expense	6	6	6
Options exercised, intrinsic value	15	13	17
Options vested, intrinsic value	7	$ 9	15
Unrecognized compensation costs related to non-vested awards	$ 23
Expected weighted-average period to recognize the unrecognized compensation costs related to non-vested awards	1 year 8 months 18 days
Number of peers exceeded \| peers_exceeded	4	6
Number of peers 2013 \| Peers	10
Number of peers 2012 \| Peers		10
Proceeds from stock options exercised	$ 24	$ 22	25
Shares of common stock granted in period \| shares	386,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Awards exercise peirod	10 years
Awards vesting period	3 years
Proceeds from stock options exercised	$ 24	$ 22	$ 25
Shares repurchased \| shares	292,414	378,276	577,745
Shares repurchased, value	$ 16	$ 19	$ 28
Weighted average remaining contractual term	8 years 6 months 10 days
Weighted-average remaining contractual life for exercisable awards	3 years 7 months 10 days
Shares authorized to be granted under the shareholder-approved plans \| shares	17,300,000
Shares available for future issuance under the plans \| shares	4,700,000
Stock Options \| Directors
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock granted in period \| shares	20,880
Restricted Stock Units \| Service Based Shares
Share-based Compensation Arrangement by Share-based Payment Award
Awards vesting period	3 years
Awards other than options vested, intrinsic value	$ 26	14	15
Restricted Stock Units \| Performance Based Shares
Share-based Compensation Arrangement by Share-based Payment Award
Awards vesting period	3 years
share based performance metric for performance shares	3 years
Awards other than options vested, intrinsic value	$ 6	$ 3	$ 3
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum	13.78%	18.69%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum	34.69%	41.21%
Risk-free rates, minimum	0.00%	0.00%	0.00%
Risk-free rates, maximum	200.00%	200.00%	200.00%
Number of shares issued \| shares	103,586
Expected volatility	2 years 10 months 18 days	2 years 10 months 18 days
Dividend yield	3.52%	3.74%
Risk-free rates	0.99%	0.66%

Maximum number of shares awarded to each full-time employee for their service

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Number of equity compensation plans

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Number of peers 2012

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Number of peers 2013

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Number of peers exceeded

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Amount of difference between fair value of the underlying shares vested during the period.

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share based performance metric for performance shares

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The amount of expense, net of income tax, 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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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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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 cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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 estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the maximum 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 estimated measure of the minimum 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 maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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

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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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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

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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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