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Long-Term Investments - Additional Information (Detail) - USD ($) |  | 12 Months Ended |
--- | --- | --- | ---
Sep. 09, 2013 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Feb. 03, 2009
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Fair value of retained noncontrolling interest | $ 55,000,000 |  |  |  |
Funding commitment letters capped amount |  | $ 149,000,000 |  |  |
Income (loss) on equity-method investments |  | $ (2,000,000) | $ 7,000,000 | $ 2,000,000 |
ST-Ericsson SA [Member] |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Controlling share held by Ericsson |  |  |  |  | 50.00%
Sale of Stock | 1 |  |  |  |
Deconsolidated gain or loss | $ 0 |  |  |  |
Liquidation date |  | Apr. 15, 2014 |  |  |
ST-Ericsson SA [Member] | Maximum [Member] |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Income (loss) on equity-method investments |  | $ 1,000,000 | $ 1,000,000 | $ 1,000,000 |

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