Divestitures - Schedule of (loss) income for discontinued operations (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ 45.8	$ (234.5)	$ (40.6)	$ 5.0	$ (32.1)	$ (16.7)	$ (152.4)	$ (20.3)	$ (224.3)	$ (221.5)	$ 87.3
Net Income (Loss) Attributable to Parent		(7.3)	(132.9)	(24.7)	(33.9)	(143.1)	(75.6)	(228.3)	(109.8)	(198.8)	(556.8)	(10.3)
Less: Net income attributable to noncontrolling interest										164.9	44.4	112.0
Net (loss) income		$ 36.2	$ (93.0)	$ 15.9	$ 7.0	$ (127.1)	$ (41.4)	$ (237.5)	$ (106.4)	(33.9)	(512.4)	101.7
Other income (expense), net										1.0	10.2	(11.9)
Interest Expense										(397.1)	(401.6)	(298.8)
Consolidated operating income										628.0	45.8	427.4
Costs and Expenses										4,587.4	4,663.9	4,207.3
Asset Impairment Charges										27.1	153.3	2.1
Selling, acquisition, operating and general expenses										1,243.6	1,301.3	1,181.0
Compass Production Partners G.P. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue										40.2	107.4	147.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax										53.6	0.0	0.0
Oil and Gas Production Expense										38.2	85.9	69.6
Gain (Loss) on Disposition of Oil and Gas Property										105.6	0.0	0.0
Equity Method Investment, Realized Gain (Loss) Upon Step Acquisition										0.0	141.2	0.0
Net Income (Loss) Attributable to Parent										40.7	(367.5)	(67.7)
Less: Net income attributable to noncontrolling interest										0.1	(1.1)
Net (loss) income										40.8	(368.6)	(67.7)
Other income (expense), net										1.5	25.7	(6.4)
Interest Expense										(5.9)	(9.9)	(7.7)
Consolidated operating income										(114.0)	(525.6)	(53.6)
Costs and Expenses										154.2	633.0	200.6
Asset Impairment Charges										93.2	485.1	81.0
Selling, acquisition, operating and general expenses										22.8	62.0	50.0
FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Other Income										4.8
Disposal Group, Including Discontinued Operation, Revenue										1,147.0	996.5	1,190.8
Disposal Group, Including Discontinued Operation, Benefits and other changes in policy reserves										790.9	578.4	787.5
Disposal Group, Including Discontinued Operation, General and Administrative Expense										118.3	112.8	102.3
Disposal Group, Including Discontinued Operation, Depreciation and Amortization										78.6	41.8	97.5
Disposal Group, Including Discontinued Operation, Operating Expense										987.8	733.0	987.3
Disposal Group, Including Discontinued Operation, Operating Income (Loss)										159.2	263.5	203.5
Disposal Group, Including Discontinued Operation, Interest Expense										22.0	23.6	22.5
Disposal Group, Including Discontinued Operation, Other Expense											5.0	4.0
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax	[1]									362.8	0.0	0.0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax										(220.8)	234.9	177.0
Discontinued Operation, Tax Effect of Discontinued Operation	[2]									44.3	87.8	22.0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest										(265.1)	147.1	155.0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest										19.0	23.1	12.9
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent										(284.1)	124.0	142.1
FGL [Member] | Insurance Premiums [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue										69.9	58.5	55.6
FGL [Member] | Net Investment Income
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue	[3]									922.7	850.8	760.2
FGL [Member] | Gain (Loss) on Investments [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue	[4]									27.6	(2.0)	306.7
FGL [Member] | Insurance and investment product fees [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue										$ 126.8	$ 89.2	$ 68.3

[1] (c) FGL’s net income during Fiscal 2016 and the increase in unrealized gains on FGL’s investment portfolio resulted in an increase of the Company’s carrying value in FGL that was above the fair value that the Company expects to receive as part of the sale which write-down of carrying value of the assets of business held for sale to fair value less cost to sell of $362.8. Such write-down could be partially reversed if the carrying value of FGL decreases in future reporting periods. Upon completion of the FGL Merger, the amount of AOCI related to FGL will be recognized through (loss) income from discontinued operations on the statement of operations and could result in a gain from discontinued operations.

[2] (d) Included in the income tax expense for Fiscal 2016 was $15.2 of income tax expense primarily related to the establishment of a deferred tax liability of $367.9 at September 30, 2016 as a result of classifying HRG’s ownership interest in FGL as held for sale, partially offset by the recognition of a $94.7 deferred tax asset related to realized capital losses primarily from the Compass Sale and $258.0 reduction of valuation allowances on HRG’s net operating and capital loss carryforwards expected to offset the tax effects of the FGL Merger. The excess deferred tax liability of $15.2 was mainly related to the Company’s estimated alternative minimum taxes.

[3] (a) Included in the net investment income attributable to FGL is interest income of $4.1, $4.5 and $4.5 for Fiscal 2016, 2015 and 2014, respectively, on debt instruments issued by entities consolidated by HRG as they will continue to exist following the closing of the FGL Merger. The corresponding interest expense is recorded in continuing operations in the accompanying Consolidated Statements of Operations.

[4] (b) Included in “Net investment gains (losses)” are charges related to the change in expected recovery rates of asset-based loans. Such charges are presented as “Impairments and bad debt expense” on the Company’s accompanying Consolidated Statements of Operations.