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Revenues - Summary of Deductions from Revenue (Parenthetical) (Detail) - USD ($) $ in Millions |  |  | 12 Months Ended
--- | --- | --- | ---
Jan. 01, 2016 | Dec. 31, 2015 | Dec. 31, 2017
Revenue [abstract] |  |  |
Tax credits regularization plan amount |  |  | $ 532
Impact on income due to change in tax rate | 25.00% | 18.00% |

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- Definition Tax credits regularization plan amount. + References No definition available. + Details
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