Financial Instruments Level 3 Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Mar. 31, 2012	Dec. 31, 2011		Mar. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Separate Account Assets										$ 45,295.2
Fixed maturities, including securities pledged, Fair Value	19,900.0				19,900.0
Equity securities, available-for-sale	144.7				144.7					144.9
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in Net income, Assets	0	[1]	0.4	[1]	0.3	[1]	0.5	[1]
Separate Accounts | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in OCI, Assets	0	[1]	0	[1]	0	[1]	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	[1]			1.1	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			0.1	[1]			0.1	[1]
Change in unrealized gains (losses) included in earnings	(0.2)	[1],[2]	(0.6)	[1]	(0.6)	[1]	(0.7)	[1]
Equity securities, available-for-sale	23.1	[1]			16.1	[1]
Separate Account Assets			20.1	[1]			22.3	[1]
Issuances, Assets	0	[1]			0	[1]
Sales, Assets	(14.4)	[1]			(9.0)	[1]
Settlements, Assets	0	[1]	(2.0)	[1]	0	[1]	(2.7)	[1]
Transfers in to Level 3, Assets	0	[1],[3]	0	[1],[3]	0.2	[1],[3]	0	[1],[3]
Transfers out of Level 3, Asset	0	[1],[3]	5.1	[1],[3]	0	[1],[3]	6.7	[1],[3]
Derivatives, excluding Product Guarantee and Fixed Indexed Annuity | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in Net income, Liability			(1.7)				(4.0)
Total realized/unrealized gains (losses) included in OCI, Liability			0				0
Purchases, Liability			0				0
Settlements, Liability			0				(0.1)
Transfers Into Level 3, Liability			0	[3]			0	[3]
Transfers out of Level 3, Liability			0	[3]			0	[3]
Change in unrealized gains (losses) included in earnings			(1.7)				(3.9)
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Asset (Liability) Value	0				0				0	(12.7)
Fair Value, Assets (Liabilities) Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Earnings	0	[2]			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Gain (Loss) Included in Earnings	0				(1.7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Gain (Loss) Included in Other Comprehensive Income (Loss)	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Purchases	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Issues	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Sales	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Settlements	0				14.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Transfers Into Level 3	0	[3]			0	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Transfers out of Level 3	0	[3]			0	[3]
Derivatives, net												(11.4)	(13.6)
Derivatives, Fair Value Disclosure			9.7				9.7
Product guarantees | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in Net income, Liability	59.8	[4]	(3.2)	[4]	(90.8)	[4]	3.1	[4]
Total realized/unrealized gains (losses) included in OCI, Liability	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	(1.2)				(2.8)
Purchases, Liability			(1.3)				(2.6)
Issues, Liability	0				0
Sales, Liability	0				0
Settlements, Liability	0		0		0		0
Transfers Into Level 3, Liability	0	[3]	0	[3]	0	[3]	0	[3]
Transfers out of Level 3, Liability	0	[3]	0	[3]	0	[3]	0	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	(133.0)				(133.0)				(72.0)	(221.0)
Change in unrealized gains (losses) included in earnings	0	[2]	0		0		0
Derivatives, Fair Value Disclosure	(133.0)		(2.5)		(133.0)		(2.5)			(221.0)		2.0	(3.0)
Fixed indexed annuities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in Net income, Liability	(0.3)	[4]	(3.4)	[4]	1.3	[4]	(6.2)	[4]
Total realized/unrealized gains (losses) included in OCI, Liability	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0				0
Purchases, Liability			0				0
Issues, Liability	0				0
Sales, Liability	0				0
Settlements, Liability	0		0		0		0
Transfers Into Level 3, Liability	0	[3]	0	[3]	0	[3]	0	[3]
Transfers out of Level 3, Liability	0	[3]	0	[3]	0	[3]	0	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	(17.6)				(17.6)				(17.9)	(16.3)
Change in unrealized gains (losses) included in earnings	0	[2]	0		0		0
Derivatives, Fair Value Disclosure	(17.6)		(11.8)		(17.6)		(11.8)			(16.3)		(8.4)	(5.6)
U.S. corporate, state and municipalities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged	146.6				129.1
Total realized/unrealized gains (losses) included in Net income, Assets	0		(0.1)		(0.2)		0
Total realized/unrealized gains (losses) included in OCI, Assets	4.0		(4.5)		3.2		(3.2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	6.8				7.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			0				13.9
Change in unrealized gains (losses) included in earnings	0	[2]	0		0.2		(0.1)
Issuances, Assets	0				0
Sales, Assets	0				0
Settlements, Assets	(15.1)		(11.6)		(6.0)		(15.5)
Transfers in to Level 3, Assets	27.9	[3]	126.8	[3]	28.3	[3]	120.7	[3]
Transfers out of Level 3, Asset	(10.6)	[3]	0	[3]	(3.6)	[3]	0	[3]
Fixed maturities, including securities pledged, Fair Value	151.6		133.5		151.6		133.5			129.1		13.9	11.2
Foreign securities government
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged, Fair Value	453.4	[5]			453.4	[5]				345.2	[5]
Foreign securities government | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged	19.7				51.1
Total realized/unrealized gains (losses) included in Net income, Assets	0		0		0.9		0.9
Total realized/unrealized gains (losses) included in OCI, Assets	0.3		0.2		1.2		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, Purchases and Issuances			2.2				2.3
Change in unrealized gains (losses) included in earnings	0	[2]	0		0		0
Issuances, Assets	0				0
Sales, Assets	0				(5.7)
Settlements, Assets	0		0		0		(5.2)
Transfers in to Level 3, Assets	0	[3]	22.3	[3]	0	[3]	22.3	[3]
Transfers out of Level 3, Asset	0	[3]	7.0	[3]	(25.7)	[3]	5.8	[3]
Fixed maturities, including securities pledged, Fair Value	19.4		24.9		19.4		24.9			51.1		7.6	11.4
Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged, Fair Value	2,257.2				2,257.2					2,247.1
Residential mortgage-backed | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged	11.0				41.0
Total realized/unrealized gains (losses) included in Net income, Assets	1.1		(0.2)		0.8		(0.7)
Total realized/unrealized gains (losses) included in OCI, Assets	(1.6)		0.4		(1.8)		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			0				3.0
Change in unrealized gains (losses) included in earnings	0.1	[2]	0.2		0.4		1.7
Issuances, Assets	0				0
Sales, Assets	(6.0)				(6.0)
Settlements, Assets	0		(0.3)		0		(0.8)
Transfers in to Level 3, Assets	0	[3]	0	[3]	0	[3]	0	[3]
Transfers out of Level 3, Asset	(1.7)	[3]	106.7	[3]	(31.6)	[3]	243.9	[3]
Fixed maturities, including securities pledged, Fair Value	6.0		12.3		6.0		12.3			41.0		119.9	254.7
Asset-backed Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged	28.7				27.7
Total realized/unrealized gains (losses) included in Net income, Assets	0.2		0.1		0.4		(1.7)
Total realized/unrealized gains (losses) included in OCI, Assets	0.5		0.3		(0.5)		(3.7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			0				0
Change in unrealized gains (losses) included in earnings	(0.2)	[2]	(0.2)		(0.4)		3.5
Issuances, Assets	0				0
Sales, Assets	0				0
Settlements, Assets	(0.5)		(1.0)		(1.1)		(1.4)
Transfers in to Level 3, Assets	2.2	[3]	0	[3]	2.6	[3]	1.5	[3]
Transfers out of Level 3, Asset	0	[3]	1.7	[3]	0	[3]	200.7	[3]
Fixed maturities, including securities pledged, Fair Value	30.1		49.1		30.1		49.1			27.7		52.0	247.7
Fixed maturities, available-for-sale, including securities pledged | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Fixed maturities, including securities pledged	206.0				248.9
Total realized/unrealized gains (losses) included in Net income, Assets	1.3		(0.2)		1.9		(1.5)
Total realized/unrealized gains (losses) included in OCI, Assets	3.2		(3.6)		2.1		(5.9)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	6.8				7.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			2.2				19.2
Change in unrealized gains (losses) included in earnings	(0.1)	[2]	0		0.2		5.1
Issuances, Assets	0				0
Sales, Assets	(6.0)				(11.7)
Settlements, Assets	(15.6)		(12.9)		(7.1)		(22.9)
Transfers in to Level 3, Assets	30.1	[3]	149.1	[3]	30.9	[3]	144.5	[3]
Transfers out of Level 3, Asset	(12.3)	[3]	115.4	[3]	(60.9)	[3]	450.4	[3]
Fixed maturities, including securities pledged, Fair Value			219.8				219.8					193.4	525.0
Equity securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Inputs Reconciliation, Calculation [Roll Forward]
Total realized/unrealized gains (losses) included in Net income, Assets	0		0.1		0		0.2
Total realized/unrealized gains (losses) included in OCI, Assets	0		(0.1)		0.1		(0.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				0.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases and Issuances			1.7				4.0
Change in unrealized gains (losses) included in earnings	0	[2]	0		0		0
Equity securities, available-for-sale	18.5				19.0
Issuances, Assets	0				0
Sales, Assets	0				(1.1)
Settlements, Assets	0		(1.3)		0		(1.3)
Transfers in to Level 3, Assets	0	[3]	0	[3]	0	[3]	0	[3]
Transfers out of Level 3, Asset	0	[3]	8.7	[3]	0	[3]	9.0	[3]
Equity securities, available-for-sale	$ 18.5		$ 21.7		$ 18.5		$ 21.7			$ 19.0		$ 29.8	$ 27.7

[1] The investment income and realized gains (losses) and change in unrealized gains (losses) included in net income (loss) for separate account assets are offset by an equal amount for separate account liabilities, which result in a net zero impact on net income (loss) for the Company.

[2] For financial instruments still held as of June 30, amounts are included in Net investment income and Other net realized capital gains (losses) in the Condensed Consolidated Statements of Operations.

[3] The Company’s policy is to recognize transfers in and transfers out as of the beginning of the reporting period.

[4] All gains and losses on Level 3 are classified as realized gains (losses) for the purpose of this disclosure because it is impracticable to track realized and unrealized gains (losses) separately on a contract-by-contract basis. These amounts are included in Other net realized capital gains (losses) in the Condensed Consolidated Statements of Operations.

[5] Primarily U.S. dollar denominated.