v2.4.0.8
Document and Entity Information
6 Months Ended
Jun. 30, 2015
Jul. 31, 2015
Document and Entity Information [Abstract]    
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 American Capital Agency Corp  
Entity Central Index Key 0001423689  
Entity Filer Category Large Accelerated Filer  
Current Fiscal Year End Date --12-31  
Entity Common Stock, Shares Outstanding   348,802,157
Trading Symbol AGNC