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Segment Information - Operating Income by Reportable Segment (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | $ 993 | $ 214 | $ 109
Product Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 1,056 | 365 | 250
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) | 365 | 46 | 27
Operating Segments [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | 1,056 | 365 | 250
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) | 289 | 211 | 194
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) | 402 | 108 | 29
Segment Reconciling Items [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | (63) | (151) | (141)
Segment Reconciling Items [Member] | Others [Member] |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |
Operating income (loss) | $ (63) | $ (151) | $ (141)

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