Annual report pursuant to Section 13 and 15(d)

Nonrecourse Debt - Schedule of Outstanding Amounts under Each Nonrecourse Asset-Backed Debt Agreements and Bank Loans and Value of Assets Pledged as Security (Detail)

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Nonrecourse Debt - Schedule of Outstanding Amounts under Each Nonrecourse Asset-Backed Debt Agreements and Bank Loans and Value of Assets Pledged as Security (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Debt issuance costs $ (12)  
Nonrecourse Asset-Backed Debt Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Debt issuance costs (16) $ (2)
Outstanding Balance 563 206
Nonrecourse Asset-Backed Debt Agreement [Member] | HASI Sustainable Yield Bond 2013-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance 83 92
Value of Assets Pledged, Financing receivables $ 99 104
Description of Assets Pledged Financing receivables  
Nonrecourse Asset-Backed Debt Agreement [Member] | ABS Loan Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 102 116
Value of Assets Pledged, Equity interest $ 117 $ 144
Description of Assets Pledged Equity interest in Strong Upwind Holdings I, LLC  
Nonrecourse Asset-Backed Debt Agreement [Member] | HASI Sustainable Yield Bond 2015-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 100  
Description of Assets Pledged Financing receivables, real estate and real estate intangibles  
Value of Assets Pledged, Financing receivables, real estate and real estate intangibles $ 139  
Nonrecourse Asset-Backed Debt Agreement [Member] | HASI SYB Loan Agreement 2015-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance 90  
Value of Assets Pledged, Equity interest $ 117  
Description of Assets Pledged Equity interest in Strong Upwind Holdings II and III, LLC, related interest rate swap  
Nonrecourse Asset-Backed Debt Agreement [Member] | HASI SYB Loan Agreement 2015-2 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 42  
Value of Assets Pledged, Equity interest $ 71  
Description of Assets Pledged Equity interest in Buckeye Wind Energy Class B Holdings LLC, related interest rate swap  
Nonrecourse Asset-Backed Debt Agreement [Member] | HASI SYB Loan Agreement 2015-3 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 162  
Value of Assets Pledged, Financing receivables $ 175  
Description of Assets Pledged Residential Solar Financing receivables