Annual report pursuant to Section 13 and 15(d)

Cover Page

v3.21.1
Cover Page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2020
Mar. 23, 2021
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K/A    
Document Annual Report true    
Document Period End Date Dec. 31, 2020    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 001-35877    
Entity Registrant Name HANNON ARMSTRONG SUSTAINABLEINFRASTRUCTURE CAPITAL, INC.    
Entity Incorporation, State or Country Code MD    
Entity Tax Identification Number 46-1347456    
Entity Address, Address Line One 1906 Towne Centre Blvd    
Entity Address, Address Line Two Suite 370    
Entity Address, City or Town Annapolis    
Entity Address, State or Province MD    
Entity Address, Postal Zip Code 21401    
City Area Code 410    
Local Phone Number 571-9860    
Title of 12(b) Security Common Stock, $0.01 par value per share    
Trading Symbol HASI    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Public Float     $ 2.0
Entity Common Stock, Shares Outstanding   78,662,832  
Documents Incorporated by Reference Portions of the registrant’s proxy statement for the 2021 annual meeting of stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K.    
Amendment Flag true    
Amendment Description Amendment to file financial statements of significant non-consolidated investees in accordance with Regulation S-X, Rule 3-09.    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Entity Central Index Key 0001561894