HA Sustainable Infrastructure Capital, Inc. Quarterly report pursuant to Section 13 or 15(d)

Securitization of Financial Assets - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Managed assets	$ 6,200,000,000		$ 6,200,000,000
Securitization credit losses	0	$ 0
Securitization assets	121,929,000		123,979,000
Greater than 90 Days Past Due
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Securitization assets	0
Asset-backed Securities, Securitized Loans and Receivables
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Managed receivables	$ 4,100,000,000		$ 4,100,000,000
Maximum
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Annual servicing fees	0.20%
Maximum \| Measurement Input, Discount Rate
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Discount rates to determine fair market value of underlying assets	0.07
Minimum \| Measurement Input, Discount Rate
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Discount rates to determine fair market value of underlying assets	0.03