Quarterly report pursuant to Section 13 or 15(d)

Long-term Debt - Schedule of Outstanding Non-Recourse Asset-Backed Debt and Bank Loans (Detail)

v3.8.0.1
Long-term Debt - Schedule of Outstanding Non-Recourse Asset-Backed Debt and Bank Loans (Detail) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Debt issuance costs $ (21)  
Value of Assets Pledged, Equity interest $ 29 $ 41
Minimum [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 2.26%  
Non-recourse Asset-Backed Debt, Maturity Date 2017-12  
Maximum [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 7.45%  
Non-recourse Asset-Backed Debt, Maturity Date 2046-12  
HASI Sustainable Yield Bond 2013-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 2.79%  
Non-recourse Asset-Backed Debt, Maturity Date 2019-12  
Non-recourse Asset-Backed Debt, Anticipated Balance at Maturity $ 57  
ABS Loan Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 5.74%  
Non-recourse Asset-Backed Debt, Maturity Date 2021-09  
Non-recourse Asset-Backed Debt, Anticipated Balance at Maturity $ 17  
HASI Sustainable Yield Bond 2015-1A [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 4.28%  
Non-recourse Asset-Backed Debt, Maturity Date 2034-10  
HASI Sustainable Yield Bond 2015-1B [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 5.41%  
Non-recourse Asset-Backed Debt, Maturity Date 2034-10  
2017 Credit Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 3.55%  
Non-recourse Asset-Backed Debt, Maturity Date 2024-06  
HASI SYB Loan Agreement 2015-2 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 5.41%  
Non-recourse Asset-Backed Debt, Maturity Date 2023-12  
HASI SYB Loan Agreement 2015-3 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 4.92%  
Non-recourse Asset-Backed Debt, Maturity Date 2020-12  
Non-recourse Asset-Backed Debt, Anticipated Balance at Maturity $ 127  
HASI SYB Loan Agreement 2016-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 4.37%  
Non-recourse Asset-Backed Debt, Maturity Date 2021-11  
Non-recourse Asset-Backed Debt, Anticipated Balance at Maturity $ 101  
HASI SYB Trust 2016-2 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 4.35%  
Non-recourse Asset-Backed Debt, Maturity Date 2037-04  
2017 Master Repurchase Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 3.96%  
Non-recourse Asset-Backed Debt, Maturity Date 2019-07  
Non-recourse Asset-Backed Debt, Anticipated Balance at Maturity $ 31  
HASI ECON 101 Trust [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Non-recourse Asset-Backed Debt, Interest Rate 3.57%  
Non-recourse Asset-Backed Debt, Maturity Date 2041-05  
Asset-Backed Nonrecourse Debt Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Other non-recourse debt $ 85 84
Debt issuance costs (21) (17)
Outstanding Balance 1,076 692
Value of Assets Pledged, Equity interest $ 224 81
Description of Assets Pledged Financing receivables  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI Sustainable Yield Bond 2013-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 68 75
Value of Assets Pledged, Equity interest $ 87 93
Description of Assets Pledged Financing receivables  
Asset-Backed Nonrecourse Debt Agreement [Member] | ABS Loan Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 79 90
Value of Assets Pledged, Equity interest $ 80 97
Description of Assets Pledged Equity interest in Strong Upwind Holdings I, LLC  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI Sustainable Yield Bond 2015-1A [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 95 97
Non-recourse Asset-Backed Debt, Interest Rate 4.28%  
Non-recourse Asset-Backed Debt, Maturity Date 2034-10  
Value of Assets Pledged, Equity interest $ 137 138
Description of Assets Pledged Financing receivables, real estate and real estate intangibles  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI Sustainable Yield Bond 2015-1B [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 14  
Non-recourse Asset-Backed Debt, Interest Rate 5.00%  
Non-recourse Asset-Backed Debt, Maturity Date 2034-10  
Value of Assets Pledged, Equity interest $ 137  
Description of Assets Pledged Class B Bond of HASI Sustainable Yield Bond 2015-1  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI SYB Loan Agreement 2015-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance   74
Value of Assets Pledged, Equity interest   96
Description of Assets Pledged Equity interest in Strong Upwind Holdings II and III, LLC, related interest rate swap  
Asset-Backed Nonrecourse Debt Agreement [Member] | 2017 Credit Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 198  
Value of Assets Pledged, Equity interest $ 243  
Description of Assets Pledged Equity interests in Strong Upwind Holdings I, II, III, and IV LLC, and Northern Frontier, LLC  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI SYB Loan Agreement 2015-2 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 37 41
Value of Assets Pledged, Equity interest $ 67 70
Description of Assets Pledged Equity interest in Buckeye Wind Energy Class B Holdings LLC, related interest rate swap  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI SYB Loan Agreement 2015-3 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 146 150
Value of Assets Pledged, Equity interest $ 172 175
Description of Assets Pledged Residential solar financing receivables, related interest rate swaps  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI SYB Loan Agreement 2016-1 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 118 98
Value of Assets Pledged, Equity interest $ 138 $ 114
Description of Assets Pledged Residential solar financing receivables, related interest rate swaps  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI SYB Trust 2016-2 [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 86  
Value of Assets Pledged, Equity interest $ 88  
Description of Assets Pledged Financing receivables  
Asset-Backed Nonrecourse Debt Agreement [Member] | 2017 Master Repurchase Agreement [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 37  
Value of Assets Pledged, Equity interest $ 41  
Description of Assets Pledged Financing receivables and investments  
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI ECON 101 Trust [Member]    
Financial Instruments Owned and Pledged as Collateral [Line Items]    
Outstanding Balance $ 134  
Value of Assets Pledged, Equity interest $ 139  
Description of Assets Pledged Financing receivables and investments