Fair Value of Financial Instruments - Assets and Liabilities Carrying at Fair Value on Non-Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Mar. 31, 2014	Sep. 30, 2013		Mar. 31, 2013	Sep. 30, 2012
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 930.6		$ 502.7		$ 930.6		$ 502.7		$ 755.6	$ 523.5		$ 419.0	$ 206.0
Document Period End Date					Jun. 30, 2014
Assets
Cash and cash equivalents	1,455.9		1,243.7		1,455.9		1,243.7			1,899.7			1,470.7
Derivatives, Assets
Derivatives	324.7				324.7					221.8
Fixed maturity securities, available-for-sale:
Asset-backed loans	724.3				724.3					560.4
Derivatives, Liabilities
Equity conversion feature of preferred stock										330.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	1.5				2.1		(0.3)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	15.9		(10.8)		20.5		(9.6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	191.0		106.3		425.3		394.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(1.0)				(1.0)		(9.6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(13.5)		(11.8)		(15.9)		(25.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	(18.9)	[1],[2]		[1]	(23.9)	[1],[2]	(53.0)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	2,019.4		1,733.2		2,019.4		1,733.2		2,234.5	1,875.2		1,842.3	1,782.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	112.9		(106.3)		340.9		(46.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0		0		150.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(328.0)		(2.8)		(347.3)		(2.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	0		0		0	[2]		[1]
Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	5.9		5.1		5.9		5.1		10.7	5.0		5.3	15.9
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0		(0.1)		(0.3)		(0.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				5.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		(0.1)		0		(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	(4.8)	[2]		[1]	(3.8)	[2]	(10.5)	[1]
Commercial mortgage-backed securities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	83.9		5.9		83.9		5.9			5.7		6.2	5.0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.1		(0.3)		0.4		(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	83.8				83.8		1.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net		[2]		[1]	(6.0)	[2]		[1]
Corporates [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	745.2		439.0		745.2		439.0		657.0	461.1		356.5	135.3
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0				0		(0.3)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	14.4		(12.0)		18.4		(10.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	88.9		106.2		283.2		383.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	(1.0)				(1.0)		(9.6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		(11.7)		(2.4)		(25.4)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	(14.1)	[2]		[1]	(14.1)	[2]	(33.8)	[1]
Hybrids [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value													8.8
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)							(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net							(8.7)	[1]
Municipals [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	36.5				36.5				35.6
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.9				1.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				35.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0					[2]
Held for trading [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0				0				10.8	10.7
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0				1.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	1.5				1.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(13.5)				(13.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	[2]			0	[2]
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	6.0		11.7		6.0		11.7		0	0		10.0	0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	1.2		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.5		1.6		0.5		1.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	5.5		0.1		5.5		10.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	[2]	0	[2]	0	[2]	0	[2]
Nomura Fund Linked Note [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	11.6				11.6				0	0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	11.3				11.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	[2]			0	[2]
Embedded Derivative Financial Instruments [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0.3				0.3
Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	174.3				174.3					31.2
Recurring [Member]
Assets
Cash and cash equivalents	1,455.9	[3],[4]			1,455.9	[3],[4]				1,899.7	[3],[4]
Contingent purchase price reduction receivable	41.5	[3]			41.5	[3]				41.0	[3]
Derivatives, Liabilities
Equity conversion feature of preferred stock										330.8	[3]
Liabilities, Fair Value Disclosure, Recurring	2,031.2	[3]			2,031.2	[3]				1,888.6
Funds Withheld Receivable	158.5	[3]			158.5	[3]
Assets, Fair Value Disclosure, Recurring	19,524.4	[3]			19,524.4	[3]				17,820.9
Recurring [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	410.5	[3]			410.5	[3]				1,001.8	[3]
Recurring [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives	0.9	[3]			0.9	[3]				1.8	[3]
Derivatives, Liabilities
Derivative Liability	5.6	[3]			5.6	[3]				10.0	[3]
Recurring [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives	1.4	[3]			1.4	[3]				4.1	[3]
Derivatives, Liabilities
Derivative Liability	4.3	[3]			4.3	[3]				2.4	[3]
Recurring [Member] | Call options [Member]
Derivatives, Assets
Derivatives	324.7	[3]			324.7	[3]				221.8	[3]
Recurring [Member] | Available-for-sale embedded derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	663.4	[3]			663.4	[3]				271.0	[4]
Recurring [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability	1,864.5	[3]			1,864.5	[3]				1,544.4	[3]
Recurring [Member] | Future contracts [Member]
Derivatives, Liabilities
Derivative Liability										1.0	[3]
Recurring [Member] | Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Derivative Liability	154.9	[3]			154.9	[3]
Recurring [Member] | Interest Rate Contract [Member]
Derivatives, Liabilities
Derivative Liability	1.9	[3]			1.9	[3]
Recurring [Member] | Asset-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,737.7	[3]			1,737.7	[3]				1,523.1	[3]
Recurring [Member] | Commercial mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	610.2	[3]			610.2	[3]				454.4	[3]
Recurring [Member] | Corporates [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	10,297.8	[3]			10,297.8	[3]				9,418.3	[3]
Recurring [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	481.6	[3]			481.6	[3]				428.8	[3]
Recurring [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,255.7	[3]			1,255.7	[3]				1,007.0	[3]
Recurring [Member] | Agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	99.5	[3]			99.5	[3]				98.6	[3]
Recurring [Member] | Non-agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,874.1	[3]			1,874.1	[3]				1,368.0	[3]
Recurring [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	97.3	[3]			97.3	[3]				81.5	[4]
Recurring [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	13.7				13.7
Recurring [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	1,455.9	[3],[4]			1,455.9	[3],[4]				1,899.7	[3],[4]
Contingent purchase price reduction receivable											[3]
Fixed maturity securities, available-for-sale:
Asset-backed loans
Total financial assets	0				0					0
Liabilities
Total debt		[5]				[5]				0	[5]
Derivatives, Liabilities
Equity conversion feature of preferred stock											[3]
Redeemable preferred stock, excluding equity conversion feature
Liabilities Related to Investment Contracts, Fair Value Disclosure
Financial Liabilities Fair Value Disclosure	0				0					0
Liabilities, Fair Value Disclosure, Recurring	0	[3]			0	[3]				0
Funds Withheld Receivable	0	[3]			0	[3]
Assets, Fair Value Disclosure, Recurring	1,812.6	[3]			1,812.6	[3]				2,761.4
Recurring [Member] | Level 1 [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	209.4	[3]			209.4	[3]				790.9	[3]
Recurring [Member] | Level 1 [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Call options [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Available-for-sale embedded derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	50.0	[3]			50.0	[3]					[4]
Recurring [Member] | Level 1 [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Future contracts [Member]
Derivatives, Liabilities
Derivative Liability											[3]
Recurring [Member] | Level 1 [Member] | Interest Rate Contract [Member]
Derivatives, Liabilities
Derivative Liability		[3]				[3]
Recurring [Member] | Level 1 [Member] | Asset-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Commercial mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Corporates [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Non-agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 1 [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	97.3	[3]			97.3	[3]				70.8	[4]
Recurring [Member] | Level 1 [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets
Recurring [Member] | Level 1 [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	0				0
Recurring [Member] | Level 2 [Member]
Assets
Cash and cash equivalents		[3],[4]				[3],[4]				0	[3],[4]
Contingent purchase price reduction receivable											[3]
Fixed maturity securities, available-for-sale:
Asset-backed loans
Total financial assets	0				0					0
Liabilities
Total debt	5,526.1	[5]			5,526.1	[5]				4,773.2	[5]
Derivatives, Liabilities
Equity conversion feature of preferred stock											[3]
Redeemable preferred stock, excluding equity conversion feature
Liabilities Related to Investment Contracts, Fair Value Disclosure
Financial Liabilities Fair Value Disclosure	5,526.1				5,526.1					4,773.2
Liabilities, Fair Value Disclosure, Recurring	11.8	[3]			11.8	[3]				13.4
Funds Withheld Receivable	158.5	[3]			158.5	[3]
Assets, Fair Value Disclosure, Recurring	16,781.2	[3]			16,781.2	[3]				14,536.0
Recurring [Member] | Level 2 [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	201.1	[3]			201.1	[3]				210.9	[3]
Recurring [Member] | Level 2 [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives	0.9	[3]			0.9	[3]				1.8	[3]
Derivatives, Liabilities
Derivative Liability	5.6	[3]			5.6	[3]				10.0	[3]
Recurring [Member] | Level 2 [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives	1.4	[3]			1.4	[3]				4.1	[3]
Derivatives, Liabilities
Derivative Liability	4.3	[3]			4.3	[3]				2.4	[3]
Recurring [Member] | Level 2 [Member] | Call options [Member]
Derivatives, Assets
Derivatives	324.7	[3]			324.7	[3]				221.8	[3]
Recurring [Member] | Level 2 [Member] | Available-for-sale embedded derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	607.4	[3]			607.4	[3]				271.0	[4]
Recurring [Member] | Level 2 [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 2 [Member] | Future contracts [Member]
Derivatives, Liabilities
Derivative Liability										1.0	[3]
Recurring [Member] | Level 2 [Member] | Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Derivative Liability		[3]				[3]
Recurring [Member] | Level 2 [Member] | Interest Rate Contract [Member]
Derivatives, Liabilities
Derivative Liability	1.9	[3]			1.9	[3]
Recurring [Member] | Level 2 [Member] | Asset-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,731.8	[3]			1,731.8	[3]				1,518.1	[3]
Recurring [Member] | Level 2 [Member] | Commercial mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	526.3	[3]			526.3	[3]				448.7	[3]
Recurring [Member] | Level 2 [Member] | Corporates [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	9,552.6	[3]			9,552.6	[3]				8,957.2	[3]
Recurring [Member] | Level 2 [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	481.6	[3]			481.6	[3]				428.8	[3]
Recurring [Member] | Level 2 [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,219.2	[3]			1,219.2	[3]				1,007.0	[3]
Recurring [Member] | Level 2 [Member] | Agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	99.5	[3]			99.5	[3]				98.6	[3]
Recurring [Member] | Level 2 [Member] | Non-agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,874.1	[3]			1,874.1	[3]				1,368.0	[3]
Recurring [Member] | Level 2 [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading		[3]				[3]					[4]
Recurring [Member] | Level 2 [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets
Recurring [Member] | Level 2 [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	2.1	[3]			2.1	[3]
Recurring [Member] | Level 3 [Member]
Assets
Cash and cash equivalents		[3],[4]				[3],[4]					[3],[4]
Contingent purchase price reduction receivable	41.5	[3]			41.5	[3]				41.0	[3]
Fixed maturity securities, available-for-sale:
Asset-backed loans	724.3				724.3					560.4
Total financial assets	884.9				884.9					591.6
Liabilities
Total debt		[5]				[5]					[5]
Derivatives, Liabilities
Equity conversion feature of preferred stock										330.8	[3]
Redeemable preferred stock, excluding equity conversion feature										377.1
Liabilities Related to Investment Contracts, Fair Value Disclosure	12,891.5				12,891.5					12,378.6
Financial Liabilities Fair Value Disclosure	12,891.5				12,891.5					12,755.7
Liabilities, Fair Value Disclosure, Recurring	2,019.4	[3]			2,019.4	[3]				1,875.2
Funds Withheld Receivable	0	[3]			0	[3]
Assets, Fair Value Disclosure, Recurring	930.6	[3]			930.6	[3]				523.5
Recurring [Member] | Level 3 [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Derivatives, Liabilities
Derivative Liability		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Call options [Member]
Derivatives, Assets
Derivatives		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Available-for-sale embedded derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	6.0	[3]			6.0	[3]					[4]
Recurring [Member] | Level 3 [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability	1,864.5	[3]			1,864.5	[3]				1,544.4	[3]
Recurring [Member] | Level 3 [Member] | Future contracts [Member]
Derivatives, Liabilities
Derivative Liability											[3]
Recurring [Member] | Level 3 [Member] | Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Derivative Liability	154.9	[3]			154.9	[3]
Recurring [Member] | Level 3 [Member] | Interest Rate Contract [Member]
Derivatives, Liabilities
Derivative Liability		[3]				[3]
Recurring [Member] | Level 3 [Member] | Asset-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	5.9	[3]			5.9	[3]				5.0	[3]
Recurring [Member] | Level 3 [Member] | Commercial mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	83.9	[3]			83.9	[3]				5.7	[3]
Recurring [Member] | Level 3 [Member] | Corporates [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	745.2	[3]			745.2	[3]				461.1	[3]
Recurring [Member] | Level 3 [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	0	[3]			0	[3]					[3]
Recurring [Member] | Level 3 [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	36.5	[3]			36.5	[3]					[3]
Recurring [Member] | Level 3 [Member] | Agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Non-agency residential mortgage-backed securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities		[3]				[3]					[3]
Recurring [Member] | Level 3 [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading		[3]				[3]				10.7	[4]
Recurring [Member] | Level 3 [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	160.6				160.6					31.2
Recurring [Member] | Level 3 [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Equity securities - trading	11.6				11.6
Contingent purchase price reduction receivable [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	41.5		41.0		41.5		41.0		41.5	41.0		41.0	41.0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings					0.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net		[2]		[1]		[2]		[1]
FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	1,864.5		1,585.9		1,864.5		1,585.9		1,718.7	1,544.4		1,639.6	1,550.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	145.8		(53.7)		320.1		35.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net		[2]	0			[2]		[1]
Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	154.9				154.9				151.0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	5.1				8.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)					0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases					150.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales					0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(1.2)				(3.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net		[2]			0	[2]
Equity conversion feature of preferred stock [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			147.3				147.3		364.8	330.8		202.7	232.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(38.0)		(52.6)		12.7		(81.9)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(326.8)		(2.8)		(343.5)		(2.8)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net		[2]	0			[2]		[1]
Reported Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans	724.3				724.3
Total financial assets	884.9				884.9
Liabilities
Total debt	5,303.4	[5]			5,303.4	[5]
Derivatives, Liabilities
Liabilities Related to Investment Contracts, Fair Value Disclosure	14,353.4				14,353.4
Financial Liabilities Fair Value Disclosure	19,656.8				19,656.8
Reported Value Measurement [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	160.6				160.6
Reported Value Measurement [Member] | Recurring [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans										560.4
Total financial assets										591.6
Liabilities
Total debt										4,896.1	[5]
Derivatives, Liabilities
Redeemable preferred stock, excluding equity conversion feature										329.4
Liabilities Related to Investment Contracts, Fair Value Disclosure										13,703.8
Financial Liabilities Fair Value Disclosure										18,929.3
Reported Value Measurement [Member] | Recurring [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets										31.2
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans	724.3				724.3					560.4
Total financial assets	884.9				884.9					591.6
Liabilities
Total debt	5,526.1	[5]			5,526.1	[5]				4,773.2	[5]
Derivatives, Liabilities
Redeemable preferred stock, excluding equity conversion feature										377.1
Liabilities Related to Investment Contracts, Fair Value Disclosure	12,891.5				12,891.5					12,378.6
Financial Liabilities Fair Value Disclosure	18,417.6				18,417.6					17,528.9
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	$ 160.6				$ 160.6					$ 31.2

[1] (a)The net transfers in and out of Level 3 during the nine months ended June 30, 2013 were exclusively to or from Level 2.

[2] This includes a $6.0 transfer to asset-backed securities from commercial mortgage-backed securities, the remaining transfers were from level 3 to level 2.

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

[4] The fair values of cash equivalents and equity investments set forth above are generally based on quoted or observed market prices.

[5] (a)