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

Equity - Additional Information (Detail)

v3.4.0.3

Equity - Additional Information (Detail) - 2013 Plan [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Restricted Common Stock [Member] \| Employees and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded	357,640
Restricted common shares vesting years	Vest in 2016 to 2019
Restricted Common Stock [Member] \| Certain Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares awarded	290,330
Restricted Incentive [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$ 2	$ 2
Unrecognized compensation expense	$ 19
Weighted-average term in which unrecognized compensation expense is expected to be recognized	2 years
Assumed forfeiture rate for calculation of equity-based compensation expense	5.00%

- Definition

Expected Forfeiture Rate In Determining Share Based Compensation Expense

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- Definition

Share Based Compensation Arrangement By Share Based Payment Restricted Stock Awards Vesting Date

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- Definition

Stock Based Compensation Not Yet Recognized Weighted Average Period Of Expected Recognition

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- Definition

Costs and payments related to employee benefits and equity-based compensation, such as pension expense and contributions, other postretirement benefits expense and payments, stock or unit options expense, and amortization of restricted stock or unit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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