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Segments - Additional Information (Detail) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) | Jun. 30, 2019 USD ($) | Mar. 31, 2019 USD ($) | Jun. 30, 2020 Segment
Segment Reporting Information [Line Items] |  |  |  |  |
Number of reportable segments | Segment |  |  |  |  | 3
Severance, Inventory Impairments, Facility Closures and Other Items [Member] |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Charges/ (reversals) | $ 102 |  |  |  |
Goodwill, Indefinite-lived and Finite-Lived Intangible and Long-Lived Tangible Assets [Member] |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Charges/ (reversals) |  | $ 1,891 | $ 5,373 |  |
Inventory Charges [Member] |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Charges/ (reversals) |  | 114 | 302 |  |
Severance, Facility Closures And Other Items [Member] |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Charges/ (reversals) |  | $ 18 | 5 | $ 11 |
Voluntary Early Retirement Program [Member] |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Charges/ (reversals) |  |  | $ 89 |  |

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