Stock Compensation Plans Stock Awards (Details 2) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation by Share-based Payment Award
Stock plans, vesting period	3 years
Stock awards, outstanding, weighted average remaining contractual terms	1 year 4 months 24 days	10 months 24 days	9 months 18 days	1 year
Stock issued, settlement of fully vested stock awards, fair value grant date	$ 118	$ 119	$ 93
Stock Award Activity (Table)
Stock awards - outstanding at period start	701	796	938
Stock awards - granted	262	339	376
Stock awards - vested	(296)	(383)	(455)
Stock awards - forfeited	(64)	(51)	(63)
Stock awards - outstanding at period end	603	701	796	938
Stock Awards, Weighted Average Grant Date Fair Value [Table]
Weighted-average grant date fair value - outstanding at period start	$ 278	$ 244	$ 192
Weighted-average grant date fair value - granted	350	274	321
Weighted-average grant date fair value - vested	305	222	181
Weighted-average grant date fair value - forfeited	303	280	250
Weighted-average grant date fair value - outstanding at period end	$ 311	$ 278	$ 244	$ 192
Amended 2011 Plan [Domain]
Share-based Compensation by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	5,100
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	2,400
2011 Long-Term Incentive Stock Plan [Member]
Share-based Compensation by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	5,200

Stock Issued During Period, Fair Value Grant Date, Share-based Compensation

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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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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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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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Weighted average remaining contractual term for equity-based awards excluding options, 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 equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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 additional 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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