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Segment Information - Operating Income by Reportable Segment (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | $ 1,323 | $ 1,203 | $ 1,400
Product Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 1,496 | 1,307 | 1,466
Analog, MEMS & Sensors Group (AMS) [Member] | Product Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 810 | 596 | 488
Operating Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 1,496 | 1,307 | 1,466
Operating Segments [Member] | Automotive and Discrete Group (ADG) [Member] | Product Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 182 | 357 | 431
Operating Segments [Member] | Microcontrollers and Digital ICs Group (MDG) [Member] | Product Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 504 | 354 | 547
Segment Reconciling Items [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | (173) | (104) | (66)
Segment Reconciling Items [Member] | Others [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | $ (173) | $ (104) | $ (66)

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