v2.4.0.8
Document and Entity Information
6 Months Ended
Jun. 30, 2015
Jul. 24, 2015
Common Stock [Member]
Jul. 24, 2015
Restricted Stock [Member]
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Jun. 30, 2015    
Document Fiscal Year Focus 2015    
Document Fiscal Period Focus Q2    
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   102,180,775 817,684