Derivative Financial Instruments - Summary of Gain (Loss) Recognized in Income on Derivatives (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Commodity contracts [Member] | Other (expense) income, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Three months ended March 31,	$ 0.8	$ 5.3	$ 2.5	$ 24.0
Foreign Exchange Contract [Member] | Other (expense) income, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Three months ended March 31,	2.9	(5.7)	0.8	(7.4)
Call options [Member] | Net investment gains [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Three months ended March 31,	(1.4)	(0.5)	0.5	2.2
Embedded Derivatives in Reinsurance Contracts [Member] | Net investment gains [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Three months ended March 31,	3.4	1.1	5.8	(5.1)
Spectrum Brands [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(5.4)	9.3	(0.8)	17.1
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.7	7.0	0.9	11.8
Spectrum Brands [Member] | Interest Rate Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(0.6)	(1.4)	(0.3)	(2.0)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(0.5)	(0.5)	(1.0)	(0.9)
Spectrum Brands [Member] | Commodity contracts [Member] | Cost Of Goods Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	1.8	(0.5)	0.8	(1.7)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(1.6)	(0.1)	(3.0)	0.3
Spectrum Brands [Member] | Foreign Exchange Contract [Member] | Cost Of Goods Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(6.6)	11.3	(1.2)	20.8
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2.8	7.6	4.9	12.4
Spectrum Brands [Member] | Foreign Exchange Contract [Member] | Sales Revenue, Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	0.0	(0.1)	(0.1)	0.0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0.0	$ 0.0	$ 0.0	$ 0.0