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				12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Sep. 30, 2014		Sep. 30, 2013
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 1,160.8		$ 709.5		$ 1,066.0		$ 523.5
Assets
Cash and cash equivalents	1,311.4		1,293.8		1,319.2		1,899.7
Derivatives, Assets
Derivatives	306.2				296.3
Fixed maturity securities, available-for-sale:
Asset-backed loans	791.9				811.6
Other invested assets	247.0				165.0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0.5		0.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	11.1		(6.7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	92.2		192.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(3.1)		(0.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	(5.9)	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	2,636.6		2,172.6		2,059.4		1,875.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	230.8		146.8
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	346.9		150.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(0.5)		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	0		0
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	34.6		9.8		37.0		5.0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0		(0.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	3.5		5.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	(5.9)	[1]			(5.9)	[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	120.4		6.0		83.1		5.7
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.8		0.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	36.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(0.3)
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	907.6		607.1		850.0		461.1
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	8.4		(6.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	51.9		152.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(2.6)		(0.5)
Hybrids [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			34.3
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)			(0.7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases			35.0
Municipals [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	38.8				37.2
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	1.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(0.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0
Held for trading [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0
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	6.1		10.8		6.0		10.7
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings			0.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0.1		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		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	[1]	0	[1]
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	11.8				11.2
Derivatives, Liabilities
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		[1]
Embedded Derivative Financial Instruments [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0.6
Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Trading Securities					165.0
Level 2 [Member]
Liabilities
Total debt	5,842.6	[2]			5,308.5	[2]
Level 3 [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans	791.9				151.7
Derivatives, Liabilities
Liabilities Related to Investment Contracts, Fair Value Disclosure	13,442.9				13,108.8
Level 3 [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	233.2				811.6
Recurring [Member]
Assets
Contingent Purchase Price Reduction Receivable Fair Value Disclosure	41.5	[3]			41.5	[3]
Derivatives, Liabilities
Liabilities, Fair Value Disclosure, Recurring	2,643.9	[3]			2,062.2	[3]
Funds Withheld Receivable	512.6	[3]			154.4	[3]
Assets, Fair Value Disclosure, Recurring	19,307.1	[3]			18,501.7	[3]
Recurring [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	583.6	[3]			296.0	[3]
Recurring [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives					12.8	[3]
Derivatives, Liabilities
Derivative Liability	2.6	[3]			0.4	[3]
Recurring [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives	19.9	[3]			3.2	[3]
Derivatives, Liabilities
Derivative Liability	0.9	[3]			0.5	[3]
Recurring [Member] | Call options [Member]
Derivatives, Assets
Derivatives	306.2	[3]			296.3	[3]
Recurring [Member] | Available For Sale Embedded Derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	625.9	[3]			663.6	[3]
Recurring [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability	2,140.2	[3]			1,908.1	[3]
Recurring [Member] | Future Contracts [Member]
Derivatives, Liabilities
Derivative Liability	1.9
Recurring [Member] | Interest Rate Contract [Member]
Derivatives, Assets
Derivatives	0.6	[3]			0.6	[3]
Recurring [Member] | Interest Rate Swap [Member]
Derivatives, Liabilities
Derivative Liability	1.9	[3]			1.8	[3]
Recurring [Member] | Asset-backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,839.1	[3]			1,792.9	[3]
Recurring [Member] | Commercial Mortgage Backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	668.4	[3]			636.9	[3]
Recurring [Member] | Corporate Debt Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	9,721.4	[3]			9,795.8	[3]
Recurring [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,301.5	[3]			1,316.1	[3]
Recurring [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,361.9	[3]			1,259.8	[3]
Recurring [Member] | Residential Mortgage Backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	2,201.9	[3]			2,114.0	[3]
Recurring [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Trading Securities	91.5	[3]			104.5	[3]
Recurring [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Other invested assets	13.8				13.3
Recurring [Member] | Level 1 [Member]
Fixed maturity securities, available-for-sale:
Total financial assets	1,311.4				1,319.2
Derivatives, Liabilities
Financial Liabilities Fair Value Disclosure	0				0
Liabilities, Fair Value Disclosure, Recurring	0	[3]			0	[3]
Funds Withheld Receivable	0	[3]			0	[3]
Assets, Fair Value Disclosure, Recurring	550.2	[3]			279.3	[3]
Recurring [Member] | Level 1 [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	401.6	[3]			115.6	[3]
Recurring [Member] | Level 1 [Member] | Available For Sale Embedded Derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	57.1	[3]			59.2	[3]
Recurring [Member] | Level 1 [Member] | Fixed Maturities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	1,311.4				1,319.2	[3]
Recurring [Member] | Level 1 [Member] | Equity [Member]
Fixed maturity securities, available-for-sale:
Trading Securities	91.5	[3]			104.5	[3]
Recurring [Member] | Level 1 [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Other invested assets	0				0
Recurring [Member] | Level 2 [Member]
Fixed maturity securities, available-for-sale:
Total financial assets	0				0
Derivatives, Liabilities
Financial Liabilities Fair Value Disclosure	5,842.6				5,308.5
Liabilities, Fair Value Disclosure, Recurring	7.3	[3]			2.8	[3]
Funds Withheld Receivable	512.6	[3]			154.4	[3]
Assets, Fair Value Disclosure, Recurring	17,596.1	[3]			17,156.4	[3]
Recurring [Member] | Level 2 [Member] | U.S. Government securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	182.0	[3]			180.4	[3]
Recurring [Member] | Level 2 [Member] | Foreign exchange forward agreements [Member]
Derivatives, Assets
Derivatives					12.8	[3]
Derivatives, Liabilities
Derivative Liability	2.6	[3]			0.4	[3]
Recurring [Member] | Level 2 [Member] | Commodity Option [Member]
Derivatives, Assets
Derivatives	19.9	[3]			3.2	[3]
Derivatives, Liabilities
Derivative Liability	0.9	[3]			0.5	[3]
Recurring [Member] | Level 2 [Member] | Call options [Member]
Derivatives, Assets
Derivatives	306.2	[3]			296.3	[3]
Recurring [Member] | Level 2 [Member] | Available For Sale Embedded Derivatives [Member]
Fixed maturity securities, available-for-sale:
Equity securities - available-for-sale	562.7	[3]			598.4	[3]
Recurring [Member] | Level 2 [Member] | Future Contracts [Member]
Derivatives, Liabilities
Derivative Liability	1.9				0.1
Recurring [Member] | Level 2 [Member] | Interest Rate Contract [Member]
Derivatives, Assets
Derivatives	0.6	[3]			0.6	[3]
Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Derivatives, Liabilities
Derivative Liability	1.9	[3]			1.8	[3]
Recurring [Member] | Level 2 [Member] | Asset-backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,804.5	[3]			1,755.9	[3]
Recurring [Member] | Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	548.0	[3]			553.8	[3]
Recurring [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	8,813.8	[3]			8,945.8	[3]
Recurring [Member] | Level 2 [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,301.5	[3]			1,316.1	[3]
Recurring [Member] | Level 2 [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	1,323.1	[3]			1,222.6	[3]
Recurring [Member] | Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	2,201.9	[3]			2,114.0	[3]
Recurring [Member] | Level 2 [Member] | Fixed Maturities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0				0	[3]
Recurring [Member] | Level 2 [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Other invested assets	2.0	[3]			2.1	[3]
Recurring [Member] | Level 3 [Member]
Fixed maturity securities, available-for-sale:
Total financial assets	1,025.1				963.3
Derivatives, Liabilities
Financial Liabilities Fair Value Disclosure	13,442.9				13,108.8
Liabilities, Fair Value Disclosure, Recurring	2,636.6	[3]			2,059.4	[3]
Funds Withheld Receivable	0	[3]			0	[3]
Assets, Fair Value Disclosure, Recurring	1,160.8	[3]			1,066.0	[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]
Recurring [Member] | Level 3 [Member] | FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Derivative Liability	2,140.2	[3]			1,908.1	[3]
Recurring [Member] | Level 3 [Member] | Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Derivative Liability	496.4	[3]			151.3	[3]
Recurring [Member] | Level 3 [Member] | Corporate Debt Securities [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	907.6	[3]			850.0	[3]
Recurring [Member] | Level 3 [Member] | Hybrids [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities	0	[3]			0	[3]
Recurring [Member] | Level 3 [Member] | Municipals [Member]
Fixed maturity securities, available-for-sale:
Available-for-sale Securities					37.2	[3]
Recurring [Member] | Level 3 [Member] | Fixed Maturities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0				0	[3]
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		41.5		41.5		41.0
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings			0.5
Contingent Purchase Price Reduction Receivable [Member] | Recurring [Member] | Level 3 [Member]
Assets
Contingent Purchase Price Reduction Receivable Fair Value Disclosure	41.5	[3]			41.5	[3]
FIA embedded derivatives, included in contractholder funds [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	2,140.2		1,644.7		1,908.1		1,544.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	232.1		100.3
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			0
Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	496.4		149.9		151.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(1.3)		(0.7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	346.9		150.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(0.5)
Equity conversion feature of preferred stock [Member]
Derivatives, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			378.0				330.8
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings			47.2
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			0
Reported Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans	791.9				151.7
Total financial assets	2,336.5
Liabilities
Total debt	5,666.0	[2]			5,157.8	[2]
Derivatives, Liabilities
Liabilities Related to Investment Contracts, Fair Value Disclosure	15,019.9				14,555.4
Financial Liabilities Fair Value Disclosure	20,685.9
Reported Value Measurement [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	233.2				811.6
Reported Value Measurement [Member] | Recurring [Member]
Fixed maturity securities, available-for-sale:
Total financial assets					2,282.5
Derivatives, Liabilities
Financial Liabilities Fair Value Disclosure					19,713.2
Reported Value Measurement [Member] | Recurring [Member] | Fixed Maturities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	1,311.4				1,319.2
Estimate of Fair Value Measurement [Member]
Fixed maturity securities, available-for-sale:
Asset-backed loans	791.9				151.7
Liabilities
Total debt	5,842.6	[2]			5,308.5	[2]
Derivatives, Liabilities
Liabilities Related to Investment Contracts, Fair Value Disclosure	13,442.9				13,108.8
Estimate of Fair Value Measurement [Member] | Policy loans [Member]
Fixed maturity securities, available-for-sale:
Policy loans and other invested assets	233.2				811.6
Estimate of Fair Value Measurement [Member] | Recurring [Member]
Fixed maturity securities, available-for-sale:
Total financial assets	2,336.5				2,282.5
Derivatives, Liabilities
Financial Liabilities Fair Value Disclosure	19,285.5				18,417.3
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Future Contracts [Member]
Derivatives, Liabilities
Derivative Liability					0.1
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Front Street Future Policyholder Benefits Reserve [Member]
Derivatives, Liabilities
Derivative Liability	496.4	[3]			151.3	[3]
Estimate of Fair Value Measurement [Member] | Recurring [Member] | Fixed Maturities [Member]
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	1,311.4				1,319.2	[3]
Option Pricing [Member] | Recurring [Member] | Level 3 [Member] | Other Invested Assets [Member] | Other Invested Assets [Member]
Fixed maturity securities, available-for-sale:
Other invested assets					$ 11.2

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmViNzU2N2Q0OTYxMTQyNzFiMTJmYjdjMmM4YTJkM2ZlfFRleHRTZWxlY3Rpb246OUNENEUyQTc3QzdGNTE4MDlDRjNFNjY1RTQyMjIzMUIM}

[2] (a)

[3] December 31, 2014 September 30, 2014 Level 1 Level 2 Level 3 Fair Value Level 1 Level 2 Level 3 Fair ValueAssets Contingent purchase price reduction receivable$— $— $41.5 $41.5 $— $— $41.5 $41.5Derivatives: Interest rate contracts— 0.6 — 0.6 — 0.6 — 0.6Commodity swap and option agreements— 19.9 — 19.9 — 3.2 — 3.2Foreign exchange forward agreements— 17.3 — 17.3 — 12.8 — 12.8Call options and futures contracts— 306.2 — 306.2 — 296.3 — 296.3Fixed maturity securities, available-for-sale: Asset-backed securities— 1,804.5 34.6 1,839.1 — 1,755.9 37.0 1,792.9Commercial mortgage-backed securities— 548.0 120.4 668.4 — 553.8 83.1 636.9Corporates— 8,813.8 907.6 9,721.4 — 8,945.8 850.0 9,795.8Hybrids— 1,301.5 — 1,301.5 — 1,316.1 — 1,316.1Municipals— 1,323.1 38.8 1,361.9 — 1,222.6 37.2 1,259.8Residential mortgage-backed securities— 2,201.9 — 2,201.9 — 2,114.0 — 2,114.0U.S. Government401.6 182.0 — 583.6 115.6 180.4 — 296.0Equity securities: Available-for-sale57.1 562.7 6.1 625.9 59.2 598.4 6.0 663.6Trading91.5 — — 91.5 104.5 — — 104.5Other invested assets— 2.0 11.8 13.8 — 2.1 11.2 13.3Funds withheld receivable (a)— 512.6 — 512.6 — 154.4 — 154.4Total financial assets$550.2 $17,596.1 $1,160.8 $19,307.1 $279.3 $17,156.4 $1,066.0 $18,501.7 Liabilities Derivatives: FIA embedded derivatives, included in contractholder funds$— $— $2,140.2 $2,140.2 $— $— $1,908.1 $1,908.1Front Street future policyholder benefit liability— — 496.4 496.4 — — 151.3 151.3Foreign exchange forward agreements and contracts— 2.6 — 2.6 — 0.1 — 0.1Futures contracts— 1.9 — 1.9 — 0.4 — 0.4Commodity contracts— 0.9 — 0.9 — 0.5 — 0.5Interest rate contracts— 1.9 — 1.9 — 1.8 — 1.8Total financial liabilities$— $7.3 $2,636.6 $2,643.9 $— $2.8 $2,059.4 $2,062.2