Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v2.4.1.9
Document and Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Mar. 03, 2015
Jun. 30, 2014
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2014    
Document Fiscal Year Focus 2014    
Document Fiscal Period Focus FY    
Trading Symbol HASI    
Entity Registrant Name Hannon Armstrong Sustainable Infrastructure Capital, Inc.    
Entity Central Index Key 0001561894    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Accelerated Filer    
Entity Common Stock, Shares Outstanding   27,370,719dei_EntityCommonStockSharesOutstanding  
Entity Public Float     $ 304dei_EntityPublicFloat