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Goodwill - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Goodwill [Line Items] |  |  |
Goodwill acquired | $ 149,000,000 | $ 43,000,000 |
Accumulated impairment losses, net | 102,000,000 | 102,000,000 |
Impairment loss of goodwill | 0 | 0 | $ 0
Norstel AB [Member] |  |  |
Goodwill [Line Items] |  |  |
Increase in goodwill | 14,000,000 |  |
ADG and MDG Segments [Member] |  |  |
Goodwill [Line Items] |  |  |
Goodwill acquired | 135,000,000 |  |
Microcontrollers and Digital ICs Group (MDG) [Member] |  |  |
Goodwill [Line Items] |  |  |
Goodwill acquired | 111,000,000 |  |
Accumulated impairment losses, net | 96,000,000 | 96,000,000 |
Others [Member] |  |  |
Goodwill [Line Items] |  |  |
Accumulated impairment losses, net | $ 6,000,000 | $ 6,000,000 |

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