Share-Based Associate Compensation Plans (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) peers_exceeded Peers compensation_plans shares	Dec. 31, 2019 USD ($) Peers peers_exceeded shares	Dec. 31, 2018 USD ($) peers_exceeded Peers 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
Number of peers exceeded \| peers_exceeded	8	5	4
Number of peers in peer group \| Peers	9	9	9
Share based compensation	$ 25	$ 24	$ 23
Tax benefit from compensation expense	6	6	5
Options exercised, intrinsic value	15	26	15
Options vested, intrinsic value	7	23	6
Unrecognized compensation costs related to non-vested awards	$ 34
Expected weighted-average period to recognize the unrecognized compensation costs related to non-vested awards	1 year 8 months 12 days
Proceeds from stock options exercised		11	9
Shares of common stock granted in period (in shares) \| shares	508,000
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	$ 7	$ 11	$ 9
Shares repurchased \| shares	50,751	103,237	69,649
Shares repurchased, value	$ 5	$ 9	$ 5
Weighted average remaining contractual term	8 years 4 months 17 days
Shares authorized to be granted under the shareholder-approved plans \| shares	17,300,000
Shares available for future issuance under the plans \| shares	7,100,000
Stock Options \| Directors
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock granted in period (in shares) \| shares	12,928
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	2.15%	2.61%	2.81%
Weighted-average expected term	2 years 10 months 9 days	2 years 10 months 9 days	2 years 10 months 20 days
Risk-free rates	1.30%	2.48%	2.22%
Performance Shares \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Shares, Issued \| shares	56,722	20,549
Awards vesting period	3 years	3 years
Risk-free rates, minimum	0.00%	0.00%	0.00%
Risk-free rates, maximum	200.00%	200.00%	200.00%
share based performance metric for performance shares	3 years
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Intrinsic Value Aggregate	$ 5	$ 2	$ 6
Service Based Shares \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Awards vesting period	3 years
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Intrinsic Value Aggregate	$ 30	$ 25	$ 24

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

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Amount, after tax, of expense for award under share-based payment arrangement.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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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 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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Number of shares authorized for issuance under share-based payment arrangement.

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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 award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents 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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