Contingencies - Legal Proceedings (Details) (Pricing Investigation by Korea Fair Trade Commission)	Mar. 31, 2012 location
Pricing Investigation by Korea Fair Trade Commission
Loss Contingencies [Line Items]
Number of hotels included in pricing investigation, managed by Company	2

Loss Contingency, Number of Company-managed Hotels Included in Pricing Investigation

No definition available.

Name:	mar_LossContingencyNumberOfCompanyManagedHotelsIncludedInPricingInvestigation
Namespace Prefix:	mar_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant