Compensation Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3,300	$ 2,800	$ 10,100	$ 8,600
Awards expected to be settled with stock	3,117	$ 2,621	9,636	$ 8,150
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 24,600		$ 24,600
Weighted average recognition period for unrecognized stock-based compensation expense			2 years 7 months 6 days

Share-based Payment Arrangement, Noncash Expense, Including Liabilities Settled

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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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