Divestitures Divestitures - Schedule of components of net income (loss) from discontinued operations (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Funds Withheld Receivable		$ 1,679.4		$ 1,679.4		$ 1,710.1
Other assets		149.1		149.1		134.3
Disposal Group, Including Discontinued Operation, Assets, Current		25,544.0		25,544.0		24,984.5
Assets		35,455.1		35,455.1		35,034.0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(13.1)	$ 5.8	(48.7)	$ 22.8
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent				(48.7)	22.8
Insurance reserves		1,824.8		1,824.8		1,856.0
Debt		6,232.0		6,232.0		6,310.5	[1],[2]
Accounts payable and other current liabilities		847.5		847.5		1,095.6
Other liabilities		71.6		71.6		95.5
Disposal Group, Including Discontinued Operation, Liabilities, Current		23,988.1		23,988.1		23,420.9
Total liabilities		33,947.2		33,947.2		33,445.9
FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		232.9	210.5	565.5	508.8
Disposal Group, Including Discontinued Operation, Benefits and other changes in policy reserves		188.1	171.9	369.0	395.6
Disposal Group, Including Discontinued Operation, General and Administrative Expense		27.1	28.3	55.3	57.5
Disposal Group, Including Discontinued Operation, Impairments		1.3	(0.4)	1.3	0.1
Disposal Group, Including Discontinued Operation, Depreciation and Amortization		(0.4)	(3.0)	(33.9)	(8.3)
Disposal Group, Including Discontinued Operation, Operating Expense		216.9	196.8	459.5	461.5
Disposal Group, Including Discontinued Operation, Operating Income (Loss)		16.0	13.7	106.0	47.3
Disposal Group, Including Discontinued Operation, Interest Expense		(5.9)	(5.9)	(11.8)	(11.8)
Disposal Group, Including Discontinued Operation, Other Income		2.5		2.5
Disposal Group, Including Discontinued Operation, Other Expense			(5.0)		(5.0)
Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax		23.5	0.0	23.5	0.0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax		(10.9)	2.8	73.2	30.5
Discontinued Operation, Tax Effect of Discontinued Operation	[3]	2.2	(3.0)	121.9	7.7
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(13.1)	5.8	(48.7)	22.8
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest		1.8	(2.8)	11.2	0.5
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent		(14.9)	8.6	(59.9)	22.3
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		16.2	14.2	31.6	25.8
FGL [Member] | Investment Income [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue	[4]	226.7	207.6	448.9	416.0
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		(41.7)	(33.4)	24.5	25.1
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		31.7	$ 22.1	60.5	$ 41.9
Majority-Owned Subsidiary, Unconsolidated [Member] | FGL [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Funds Withheld Receivable		993.0		993.0		1,058.0
Other assets		15.6		15.6		15.9
Disposal Group, Including Discontinued Operation, Assets, Current		1,618.7		1,618.7		1,769.8
Assets		2,627.3		2,627.3		2,843.7
Insurance reserves		1,170.8		1,170.8		1,226.8
Debt		217.5		217.5		330.7
Accounts payable and other current liabilities		1.1		1.1		1.6
Other liabilities		12.7		12.7		11.0
Disposal Group, Including Discontinued Operation, Liabilities, Current		1,225.2		1,225.2		1,273.6
Total liabilities		$ 2,627.3		$ 2,627.3		$ 2,843.7

[1] The carrying amounts of cash and cash equivalents, trade receivables, accounts payable and accrued investment income approximate fair value due to their short duration and, accordingly, they are not presented in the tables above.

[2] The fair values of debt set forth above are generally based on quoted or observed market prices.

[3] (b) Included in the income tax expense for the six months ended March 31, 2016 was a $90.9 of net income tax expense related to the establishment of a deferred tax liability of $328.6 at March 31, 2016 as a result of classifying the Company’s ownership interest in FGL as held for sale. The deferred tax liability was partially offset by a $237.7 reduction of valuation allowance on HRG’s net operating and capital loss carryforwards expected to offset the FGL taxable gain at March 31, 2016. The remaining liability is expected to be offset by current year losses recognized in Continuing Operations except for $13.0 of estimated alternative minimum taxes.

[4] (a) Included in the net investment income attributable to FGL is interest income of $1.2 and $0.6 for the three months ended March 31, 2016 and 2015, respectively and $2.3 and $2.3 for the six months ended March 31, 2016 and 2015, 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 Condensed Consolidated Statements of Operations.