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Income Taxes - Additional Information (Detail)
$ in Millions, $ in Millions
 12 Months Ended
Apr. 11, 2011
USD ($)
Apr. 11, 2011
MXN ($)
Dec. 31, 2018
Dec. 31, 2017
USD ($)
Dec. 31, 2017
MXN ($)
Dec. 31, 2016
MXN ($)
Dec. 31, 2015
MXN ($)
Dec. 31, 2014
USD ($)
Dec. 31, 2014
MXN ($)
Dec. 31, 2013
MXN ($)
Dec. 31, 2017
MXN ($)
Disclosure of Income Taxes [Line Items]                      
pre-tax income         $ 61,878            
Deferred income tax assets value           $ 3,562         $ 984
Applicable income tax rate       30.00% 30.00% 30.00% 30.00%        
Prior year tax loss carryforwards value               $ 547 $ 10,755    
Income tax liability settlement period                   10 years  
Payments incurred net of inflation adjustments                   $ 24,804  
Reduction in balance payable           $ 3,236 $ 16,244       $ 2,456
Tax loss carryforwards book value before discount             11,136        
Reduction in balance payable             $ 3,971        
Increase in tax to be paid $ 30 $ 593                  
Income tax penalty imposed $ 48 $ 948                  
United States [member]                      
Disclosure of Income Taxes [Line Items]                      
Deferred income tax assets value       $ 700              
Applicable income tax rate       35.00% 35.00% 35.00% 35.00%        
Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Increase (decrease) in net deferred tax assets       $ (124)              
Subsequent Event [Member] | United States [member]                      
Disclosure of Income Taxes [Line Items]                      
Applicable income tax rate     21.00%