Consolidating Financial Information - Schedule of Income Statement Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Net consumer and other product sales	$ 1,209.6	$ 1,086.5	$ 2,428.4	$ 2,175.3
Oil and natural gas	9.5	26.0	26.3	60.3
Net investment income	15.5	19.5	37.0	43.9
Net investment gains	33.1	9.7	7.2	4.8
Insurance and investment product fees and other	1.8	2.1	4.1	3.2
Revenues	1,269.5	1,143.8	2,503.0	2,287.5
Operating costs and expenses:
Cost of consumer products and other goods sold	746.8	707.0	1,524.9	1,419.0
Oil and natural gas direct operating costs	9.2	23.3	26.3	43.8
Benefits and other changes in policy reserves	35.7	30.6	43.8	50.3
Selling, acquisition, operating and general expenses	311.0	324.2	619.1	660.4
Asset Impairment Charges	27.6	214.6	90.8	464.4
Amortization of intangibles	23.4	21.2	47.0	41.7
Total operating costs and expenses	1,153.7	1,320.9	2,351.9	2,679.6
Operating income	115.8	(177.1)	151.1	(392.1)
Interest expense	(95.8)	(81.1)	(193.3)	(157.5)
Other income, net	0.5	14.1	1.6	46.9
Income (loss) from continuing operations before income taxes	20.5	(244.1)	65.0	(361.5)
Income tax expense (benefit)	8.9	(0.8)	10.8	5.2
Income (Loss) from Continuing Operations Attributable to Parent	(19.9)	(236.9)	(8.8)	(360.4)
Net income (loss)	(1.5)	(237.5)	5.5	(343.9)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			(48.7)	22.8
Less: Net income (loss) attributable to noncontrolling interest	33.3	(9.2)	74.2	(5.8)
Net income (loss) attributable to controlling interest	(34.8)	(228.3)	(68.7)	(338.1)
Net income (loss) attributable to common and participating preferred stockholders	(34.8)	(228.3)	(68.7)	(338.1)
Gain (Loss) on Disposition of Oil and Gas Property	0.0	0.0	105.6	0.0
Consolidated Entities [Member]
Revenues:
Net consumer and other product sales			2,428.4	2,175.3
Oil and natural gas				60.3
Net investment income			37.0	43.9
Net investment gains			7.2	4.8
Insurance and investment product fees and other			4.1	3.2
Revenues			2,503.0	2,287.5
Operating costs and expenses:
Cost of consumer products and other goods sold			1,524.9	1,419.0
Oil and natural gas direct operating costs				43.8
Benefits and other changes in policy reserves			43.8	50.3
Selling, acquisition, operating and general expenses			619.1	660.4
Asset Impairment Charges			90.8	464.4
Amortization of intangibles			47.0	41.7
Total operating costs and expenses			2,351.9	2,679.6
Operating income			151.1	(392.1)
Interest expense			(193.3)	(157.5)
Other income, net			1.6	46.9
Income (loss) from continuing operations before income taxes			65.0
Income tax expense (benefit)			10.8	5.2
Income (Loss) from Continuing Operations Attributable to Parent				(366.7)
Net income (loss)			54.2
Less: Net income (loss) attributable to noncontrolling interest			74.2	(5.8)
Net income (loss) attributable to controlling interest			(68.7)	(338.1)
Gain (Loss) on Disposition of Oil and Gas Property			105.6
Gain on contingent purchase price reduction				141.2
Intersegment elimination [Member]
Revenues:
Net investment income			28.8	24.9
Net investment gains			(20.9)	15.1
Insurance and investment product fees and other			3.2	3.2
Revenues	9.2	65.1	11.1	43.2
Operating costs and expenses:
Benefits and other changes in policy reserves			15.6	8.5
Selling, acquisition, operating and general expenses			1.2	2.0
Asset Impairment Charges			0.1	5.0
Total operating costs and expenses			16.9	15.5
Operating income	13.2	43.9	(5.8)	27.7
Equity in net income (losses) of subsidiaries			(23.7)	201.7
Interest expense			(2.3)	(3.2)
Affiliated interest income			(7.6)	(21.1)
Other income, net			(0.3)	(8.2)
Income (loss) from continuing operations before income taxes			(24.5)	239.1
Income tax expense (benefit)			(10.7)	7.6
Income (Loss) from Continuing Operations Attributable to Parent				231.5
Net income (loss)			(13.8)	231.5
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Net income (loss) attributable to controlling interest			(13.8)	231.5
Gain (Loss) on Disposition of Oil and Gas Property			0.0
Gain on contingent purchase price reduction				0.0
Corporate and Other [Member]
Revenues:
Net consumer and other product sales				40.5
Revenues		19.5		40.5
Operating costs and expenses:
Cost of consumer products and other goods sold				29.1
Selling, acquisition, operating and general expenses			22.8	99.5
Asset Impairment Charges				60.2
Total operating costs and expenses			22.8	188.8
Operating income	(8.2)	(24.5)	(22.8)	(148.3)
Equity in net income (losses) of subsidiaries			23.7	(201.7)
Interest expense			(71.4)	(56.3)
Affiliated interest income			(0.3)	2.6
Other income, net			3.0	36.5
Income (loss) from continuing operations before income taxes			(67.2)	(372.4)
Income tax expense (benefit)			1.5	(13.3)
Net income (loss)			(68.7)	(359.1)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Less: Net income (loss) attributable to noncontrolling interest				(21.0)
Net income (loss) attributable to controlling interest			(68.7)	(338.1)
Gain (Loss) on Disposition of Oil and Gas Property			0.0
Gain on contingent purchase price reduction				0.0
Discontinued Operations, Held-for-sale [Member]
Operating costs and expenses:
Operating income			0.0	0.0
Net income (loss)			(48.7)	22.8
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			(48.7)	22.8
Less: Net income (loss) attributable to noncontrolling interest			11.2	0.5
Net income (loss) attributable to controlling interest	(14.9)	8.6	(59.9)	22.3
Gain (Loss) on Disposition of Oil and Gas Property			0.0
Gain on contingent purchase price reduction				0.0
Other Financial Services [Member]
Operating costs and expenses:
Operating income	(9.2)	(67.3)
Gain on contingent purchase price reduction				0.0
Asset Management segment [Member]
Revenues:
Net investment income			6.7	13.1
Insurance and investment product fees and other			0.9
Revenues	1.6	5.1	7.6	13.1
Operating costs and expenses:
Selling, acquisition, operating and general expenses			10.8	19.0
Asset Impairment Charges			15.1	62.6
Total operating costs and expenses			25.9	81.6
Operating income			(18.3)	(68.5)
Affiliated interest income			3.4	14.0
Other income, net			0.9	(1.5)
Income (loss) from continuing operations before income taxes			(20.8)	(84.0)
Net income (loss)			(20.8)	(84.0)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Less: Net income (loss) attributable to noncontrolling interest				(17.2)
Net income (loss) attributable to controlling interest			(20.8)	(66.8)
Gain (Loss) on Disposition of Oil and Gas Property			0.0
Energy Segment [Member]
Revenues:
Oil and natural gas			26.3	60.3
Revenues	9.5	26.0	26.3	60.3
Operating costs and expenses:
Oil and natural gas direct operating costs			26.3	43.8
Selling, acquisition, operating and general expenses			15.6	36.2
Asset Impairment Charges	21.2	146.6	75.6	336.6
Total operating costs and expenses			117.5	416.6
Operating income	(26.7)	(161.3)	(91.2)	(356.3)
Interest expense			(3.7)	(4.4)
Affiliated interest income			4.5	4.5
Other income, net			2.3	24.0
Income (loss) from continuing operations before income taxes			8.5	(200.0)
Net income (loss)			8.5	(200.0)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Less: Net income (loss) attributable to noncontrolling interest				(0.5)
Net income (loss) attributable to controlling interest			8.5	(199.5)
Gain (Loss) on Disposition of Oil and Gas Property			105.6
Gain on contingent purchase price reduction				141.2
Insurance Segment [Member]
Revenues:
Net investment income			1.5	5.9
Net investment gains			28.1	(10.3)
Revenues	39.6	(38.9)	29.6	(4.4)
Operating costs and expenses:
Benefits and other changes in policy reserves			28.2	41.8
Selling, acquisition, operating and general expenses			3.2	4.5
Total operating costs and expenses			31.4	46.3
Operating income	(1.8)	(56.3)	(1.8)	(50.7)
Income (loss) from continuing operations before income taxes			(1.8)	(50.7)
Income tax expense (benefit)			(1.8)	(17.7)
Net income (loss)			0.0	(33.0)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Net income (loss) attributable to controlling interest				(33.0)
Gain (Loss) on Disposition of Oil and Gas Property			0.0
Gain on contingent purchase price reduction				0.0
Consumer Products Segment [Member]
Revenues:
Net consumer and other product sales			2,428.4	2,134.8
Revenues	1,209.6	1,067.0	2,428.4	2,134.8
Operating costs and expenses:
Cost of consumer products and other goods sold			1,524.9	1,389.9
Selling, acquisition, operating and general expenses			565.5	499.2
Amortization of intangibles			47.0	41.7
Total operating costs and expenses			2,137.4	1,930.8
Operating income	$ 148.5	$ 88.4	291.0	204.0
Interest expense			(115.9)	(93.6)
Other income, net			(4.3)	(3.9)
Income (loss) from continuing operations before income taxes			170.8	106.5
Income tax expense (benefit)			21.8	28.6
Net income (loss)			149.0	77.9
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	0.0
Less: Net income (loss) attributable to noncontrolling interest			63.0	32.4
Net income (loss) attributable to controlling interest			86.0	45.5
Gain (Loss) on Disposition of Oil and Gas Property			$ 0.0
Gain on contingent purchase price reduction				$ 0.0