XML 198 R156.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stockholders' Equity - Summary of Common Stock (Detail) - shares
Dec. 31, 2017
Dec. 31, 2016
Series A [Member]    
Disclosure of Classes of Share Capital [Line Items]    
Subscribed and paid shares 30,214,469,912 28,121,583,148
Unissued shares authorized for executives' stock compensation programs 531,739,616 638,468,154
Shares that guarantee the issuance of convertible securities 4,529,605,020 5,218,899,920
Number of shares issued 35,275,814,548 33,978,951,222
Series B [Member]    
Disclosure of Classes of Share Capital [Line Items]    
Subscribed and paid shares 15,107,234,956 14,060,791,574
Unissued shares authorized for executives' stock compensation programs 265,869,808 319,234,077
Shares that guarantee the issuance of convertible securities 2,264,802,510 2,609,449,960
Number of shares issued 17,637,907,274 16,989,475,611