Segment and Georgraphic Data - Additional Information (Detail) $ in Millions	12 Months Ended
Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Asset Impairment Charges	$ 27.1	$ 153.3	$ 2.1
Consolidated operating income	$ 628.0	45.8	427.4
Number of reporting segments	2
Insurance Segment [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges		57.1	0.0
Consolidated operating income	$ (12.4)	(68.7)	40.1
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges	(1.1)	5.2	(0.2)
Consolidated operating income	68.1	(62.9)	32.5
Front Street Re (Delaware) Ltd. [Member] \| Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Consolidated operating income	$ 59.7	$ (115.4)	$ 45.1

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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.

+ References

No definition available.

+ Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=hrg_InsuranceSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_IntersegmentEliminationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=hrg_FrontStreetReDelawareLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: