Share-Based Compensation Other Share-Based Compensation Data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before tax	$ 679	$ 697	$ 638
Share-based compensation expense, net of tax effects	619	641	587
Income tax benefit realized from share-based award exercises	208	$ 201	$ 239
Unrecognized compensation expense related to share awards	$ 805
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 4 months 25 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of shares granted, per share	$ 54	$ 46	$ 43
Total intrinsic value of stock options exercised	$ 1,736	$ 1,398	$ 1,431
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value per share	$ 303	$ 259	$ 229
Total fair value of restricted shares vested	$ 574	$ 545	$ 521
Employee Stock Purchase Plan (ESPP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares purchased	1	1	2

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 from exercise of option under share-based payment arrangement.

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Amount of noncash expense for share-based payment arrangement.

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The weighted average fair value at grant date for nonvested equity-based awards issued 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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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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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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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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Number of shares issued during the period as a result of an employee stock purchase plan.

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