Asset backed loans and other invested assets.

No definition available.

Name:	hrg_AssetBackedLoansAndOtherInvestedAssets
Namespace Prefix:	hrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available For Sale Debt Securities Fair Value Disclosure [Abstract]

+ References

No definition available.

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- Definition

Funds Withheld Receivable

+ References

No definition available.

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Namespace Prefix:	hrg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3044-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13476-108611

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Fair Value of Financial Instruments - Assets and Liabilities Carrying at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Assets
Cash and cash equivalents	$ 270.1	$ 465.2	$ 643.2	$ 673.6
Fixed maturity securities, available-for-sale:
Funds Withheld Receivable		0.0
Estimate of Fair Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Asset Backed Loans And Other Invested Assets		33.3
Liabilities
Debt Instrument, Fair Value Disclosure	5,931.0	5,761.8
Reported Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Asset Backed Loans And Other Invested Assets		33.3
Liabilities
Debt Instrument, Fair Value Disclosure	5,705.1	5,465.6
Fair Value, Inputs, Level 2 [Member]
Liabilities
Debt Instrument, Fair Value Disclosure	5,839.0	5,639.9
Fair Value, Inputs, Level 3 [Member]
Fixed maturity securities, available-for-sale:
Asset Backed Loans And Other Invested Assets		33.3
Liabilities
Debt Instrument, Fair Value Disclosure	92.0	121.9
Fair Value, Measurements, Recurring \| Estimate of Fair Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Assets, Fair Value Disclosure, Recurring	1.5	0.2
Derivatives, Liabilities
Liabilities, Fair Value Disclosure, Recurring	3.3	1.7
Fair Value, Measurements, Recurring \| Fair Value, Inputs, Level 1
Fixed maturity securities, available-for-sale:
Assets, Fair Value Disclosure, Recurring	0.0	0.0
Derivatives, Liabilities
Liabilities, Fair Value Disclosure, Recurring	0.0	0.0
Fair Value, Measurements, Recurring \| Fair Value, Inputs, Level 2 [Member]
Fixed maturity securities, available-for-sale:
Assets, Fair Value Disclosure, Recurring	1.5	0.2
Derivatives, Liabilities
Liabilities, Fair Value Disclosure, Recurring	3.3	1.7
Fair Value, Measurements, Recurring \| Fair Value, Inputs, Level 3 [Member]
Fixed maturity securities, available-for-sale:
Assets, Fair Value Disclosure, Recurring	0.0	0.0
Derivatives, Liabilities
Liabilities, Fair Value Disclosure, Recurring	$ 0.0	$ 0.0