Investments (Details 12) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010
Changes in mortgage loan valuation allowance
Beginning balance, Mortgage loan valuation allowance	$ 114.3	$ 121.1
Provision: Mortgage loan valuation allowance	7.8	34.8
Charge-offs: Mortgage loan valuation allowance	(11.8)	(47.2)
Recoveries: Mortgage loan valuation allowance	1.1	2.7
Effect of exchange rates: Mortgage loan valuation allowance	(0.2)	(0.2)
Ending balance, Mortgage loan valuation allowance	111.2	111.2
Individually evaluated for impairment, Mortgage loan valuation allowance	7.9	7.9
Collectively evaluated for impairment, Mortgage loan valuation allowance	103.3	103.3
Individually evaluated for impairment, Mortgage loans	44.9	44.9
Collectively evaluated for impairment, Mortgage loans	10,926.7	10,926.7
Mortgage loans, Total amortized cost	10,971.6	10,971.6	11,246.2
Commercial mortgage loans
Mortgage loan valuation allowance disclosures
Mortgage loans, Days delinquent to be analyzed for valuation allowance (in days)		60
Changes in mortgage loan valuation allowance
Beginning balance, Mortgage loan valuation allowance	75.6	80.6
Provision: Mortgage loan valuation allowance	0.4	13.5
Charge-offs: Mortgage loan valuation allowance	(4.2)	(22.4)
Recoveries: Mortgage loan valuation allowance		0.1
Ending balance, Mortgage loan valuation allowance	71.8	71.8
Individually evaluated for impairment, Mortgage loan valuation allowance	4.1	4.1
Collectively evaluated for impairment, Mortgage loan valuation allowance	67.7	67.7
Individually evaluated for impairment, Mortgage loans	19.1	19.1
Collectively evaluated for impairment, Mortgage loans	9,557.1	9,557.1
Mortgage loans, Total amortized cost	9,576.2	9,576.2	9,689.6
Residential mortgage loans
Changes in mortgage loan valuation allowance
Beginning balance, Mortgage loan valuation allowance	38.7	40.5
Provision: Mortgage loan valuation allowance	7.4	21.3
Charge-offs: Mortgage loan valuation allowance	(7.6)	(24.8)
Recoveries: Mortgage loan valuation allowance	1.1	2.6
Effect of exchange rates: Mortgage loan valuation allowance	(0.2)	(0.2)
Ending balance, Mortgage loan valuation allowance	39.4	39.4
Individually evaluated for impairment, Mortgage loan valuation allowance	3.8	3.8
Collectively evaluated for impairment, Mortgage loan valuation allowance	35.6	35.6
Individually evaluated for impairment, Mortgage loans	25.8	25.8
Collectively evaluated for impairment, Mortgage loans	1,369.6	1,369.6
Mortgage loans, Total amortized cost	$ 1,395.4	$ 1,395.4	$ 1,556.6

The numbers of days for which a mortgage loan has been delinquent such that it is analyzed to determine if a valuation allowance is needed.

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- Definition

Amount of foreign currency translation adjustment increasing or decreasing the valuation allowance for financing receivables.

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- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953423-111524

-Subparagraph (c)(1)

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Charge to expense for financing receivables that are expected to be uncollectible.

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- Definition

Reduction to the allowance for credit losses related to collections on financing receivables which have been partially or fully charged off as bad debts.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Reduction to the allowance for credit losses related to financing receivables deemed uncollectible.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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- Definition

For an unclassified balance sheet, an amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date(s). Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10(3))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 10

-Subparagraph 3

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