Stock-Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost	$ 243	$ 247	$ 457	$ 436
Income tax benefits	(69)	(52)	(121)	(96)
Net stock-based compensation cost	175	196	336	340
Pre-tax stock-based compensation cost increase (decrease)	(4)		21
Unrecognized compensation cost related to non-vested awards	$ 1,500		$ 1,500
Unrecognized compensation cost related to non-vested awards, weighted average period of recognition	2 years 3 months 18 days		2 years 3 months 18 days
Performance Share Units
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost increase (decrease)	$ (8)		$ 9
Restricted Stock Units
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost increase (decrease)	3		10
Cost
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost	41	40	82	67
SG&A expense
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost	152	155	275	272
Research, development and engineering
Stock-based compensation cost, allocation of recognized costs
Pre-tax stock-based compensation cost	$ 50	$ 52	$ 99	$ 97

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- Definition

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

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- Definition

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