v2.4.0.8
Document and Entity Information
9 Months Ended
Sep. 30, 2014
Oct. 31, 2014
Common Stock [Member]
Oct. 31, 2014
Restricted Stock [Member]
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Sep. 30, 2014    
Document Fiscal Year Focus 2014    
Document Fiscal Period Focus Q3    
Entity Registrant Name MRC GLOBAL INC.    
Entity Central Index Key 0001439095    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   102,064,907 242,223