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Stockholders' Equity - Summary of Common Stock (Parenthetical) (Detail) - shares | Dec. 31, 2020 | Dec. 31, 2019
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Disclosure of Classes of Share Capital [Line Items] |  |
Fixed portion of shares issued | 13,068,000,000 | 13,068,000,000
Variable portion of shares issued | 36,985,072,077 | 38,765,385,003
Series A [Member] |  |
Disclosure of Classes of Share Capital [Line Items] |  |
Percentage of capital stock | 64.00% |
Series B [Member] |  |
Disclosure of Classes of Share Capital [Line Items] |  |
Percentage of capital stock | 36.00% |

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