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

Our Portfolio - Allowance Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance			$ 36
Ending balance	$ 37		37
Allowance for loss on receivables	37		37
Performance Rating 3
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	8		8
Allowance for loss on receivables	8		8
Cumulative effect adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loss on receivables					$ 17
Government receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	$ 0	0	$ 0
Provision for loss on receivables	0	0	0	0
Ending balance	0	0	0	0
Allowance for loss on receivables	0	0	0	0
Commercial receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	36	26	36	26
Provision for loss on receivables	1	3	1	3
Ending balance	37	29	37	29
Allowance for loss on receivables	37	$ 29	37	$ 29
Commercial receivables \| Performance Rating 3
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance	8		8
Allowance for loss on receivables	$ 8		$ 8

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.