Quarterly report pursuant to Section 13 or 15(d)

Our Portfolio - Financing Receivables, Investments, Real Estate and Equity Method Investments - Analysis of Portfolio by Type of Obligor and Credit Quality (Detail)

v2.4.1.9
Our Portfolio - Financing Receivables, Investments, Real Estate and Equity Method Investments - Analysis of Portfolio by Type of Obligor and Credit Quality (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Financing Receivable, Recorded Investment [Line Items]  
Financing receivables $ 554us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Financing receivables held-for-sale 40us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet
Investments 23us-gaap_Investments
Real estate 130hasi_RealEstateInvestmentsAndIntangibleLeasesAssets
Equity method investment 138us-gaap_PaymentsToAcquireInvestments
Total 885us-gaap_LoansAndLeasesReceivableNetReportedAmount
Average Remaining Balance 10hasi_FinanceReceivableOutstandingAverageRemainingBalance
Commercial Investment Grade [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Financing receivables 249us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Investments 9us-gaap_Investments
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Real estate 130hasi_RealEstateInvestmentsAndIntangibleLeasesAssets
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Total 388us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Average Remaining Balance 9hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Commercial Non-Investment Grade [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Financing receivables 1us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Investments 14us-gaap_Investments
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Total 15us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Average Remaining Balance 14hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Debt and Real Estate Portfolio [Member]  
Financing Receivable, Recorded Investment [Line Items]  
% of Debt and Real Estate Portfolio 98.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember
Debt and Real Estate Portfolio [Member] | Commercial Investment Grade [Member]  
Financing Receivable, Recorded Investment [Line Items]  
% of Debt and Real Estate Portfolio 52.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingInvestmentGradeMember
Debt and Real Estate Portfolio [Member] | Commercial Non-Investment Grade [Member]  
Financing Receivable, Recorded Investment [Line Items]  
% of Debt and Real Estate Portfolio 2.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember
/ us-gaap_ExternalCreditRatingByGroupingAxis
= us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Government [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Financing receivables 304us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USTreasuryAndGovernmentMember
Financing receivables held-for-sale 40us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USTreasuryAndGovernmentMember
Total 344us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USTreasuryAndGovernmentMember
Average Remaining Balance 11hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USTreasuryAndGovernmentMember
Government [Member] | Debt and Real Estate Portfolio [Member]  
Financing Receivable, Recorded Investment [Line Items]  
% of Debt and Real Estate Portfolio 46.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USTreasuryAndGovernmentMember
Subtotal, Debt and Real Estate [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Financing receivables 554us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Financing receivables held-for-sale 40us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Investments 23us-gaap_Investments
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Real estate 130hasi_RealEstateInvestmentsAndIntangibleLeasesAssets
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Total 747us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Average Remaining Balance 10hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Subtotal, Debt and Real Estate [Member] | Debt and Real Estate Portfolio [Member]  
Financing Receivable, Recorded Investment [Line Items]  
% of Debt and Real Estate Portfolio 100.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_SubtotalDebtAndRealEstateMember
Equity Method Investment [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Equity method investment 138us-gaap_PaymentsToAcquireInvestments
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_EquityMethodInvestmentsMember
Total 138us-gaap_LoansAndLeasesReceivableNetReportedAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_EquityMethodInvestmentsMember
Average Remaining Balance $ 14hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_EquityMethodInvestmentsMember