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 (Parenthetical) (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 (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Transactions
Financing Receivable, Recorded Investment [Line Items]  
Number of transactions 73hasi_NumberOfTransactions
Financial receivable outstanding, Average Remaining Balance $ 10hasi_FinanceReceivableOutstandingAverageRemainingBalance
Total aggregate remaining balance 21hasi_FinanceReceivableAggregateRemainingAmount
U.S. Federal Government [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Total financing receivable 261us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= hasi_UsFederalGovernmentMember
State, Local, Institutions [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Total financing receivable 83us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Investment Grade By Independent Rating Agency [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Total financing receivable 59us-gaap_FinancingReceivableRecordedInvestmentPastDue
/ us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis
= hasi_InvestmentGradeByIndependentRatingAgencyMember
Maximum [Member]  
Financing Receivable, Recorded Investment [Line Items]  
Financial receivable outstanding, Average Remaining Balance $ 1hasi_FinanceReceivableOutstandingAverageRemainingBalance
/ us-gaap_RangeAxis
= us-gaap_MaximumMember