Information by Segment - Summary of Inter Segment Policies for Segment (Parenthetical) (Detail) - Mexico and Central America [member] $ in Millions	Dec. 31, 2017 MXN ($)
Disclosure of operating segments [line items]
Assets of discontinued operations	$ 28,272
Liabilities of discontinued operations	$ 9,945

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

Name:	ifrs-full_DisclosureOfOperatingSegmentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration