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Segments - Additional Information (Detail) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) Segment	Jun. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment				3
Charges/ (reversals)	$ 5,769			$ 5,780	$ (12)
Goodwill, Indefinite-lived and Finite-Lived Intangible and Long-Lived Tangible Assets [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	5,373
Inventory Charges [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	302
Voluntary Early Retirement Program [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	89
Severance, Facility Closures And Other Items [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)	$ 5	$ 11
Severance, Facility Closures And Reserve Adjustments [Member]
Segment Reporting Information [Line Items]
Charges/ (reversals)			$ 12

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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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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