Investments in Unconsolidated Affiliates (Details 3) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Changes in carrying value of investment in Symetra
Carrying value at the beginning of the period			$ 389,700,000
Equity in earnings of Symetra	7,900,000	5,300,000	14,600,000	(6,300,000)
Carrying value at the end of the period	422,900,000		422,900,000
Symetra
Changes in carrying value of investment in Symetra
Carrying value at the beginning of the period	392,800,000	329,000,000	387,500,000	307,700,000
Equity in earnings of Symetra	8,600,000	5,300,000	15,900,000	(6,200,000)
Net unrealized gains from investee's fixed maturity portfolio	24,000,000	50,000,000	24,100,000	82,800,000
Dividends received	(1,000,000)	(900,000)	(1,900,000)	(900,000)
(Decrease) increase in value of warrants	(3,400,000)	(10,900,000)	(4,600,000)	(10,900,000)
Carrying value at the end of the period	421,000,000	372,500,000	421,000,000	372,500,000
Symetra \| Common shareholders' equity
Changes in carrying value of investment in Symetra
Carrying value at the beginning of the period	356,900,000	290,500,000	350,400,000	269,200,000
Equity in earnings of Symetra	8,600,000	5,300,000	15,900,000	(6,200,000)
Net unrealized gains from investee's fixed maturity portfolio	24,000,000	50,000,000	24,100,000	82,800,000
Dividends received	(1,000,000)	(900,000)	(1,900,000)	(900,000)
Carrying value at the end of the period	388,500,000	344,900,000	388,500,000	344,900,000
Tax on equity in earnings	700,000	0	1,300,000	0
Equity in net unrealized gains	87,700,000	74,000,000	87,700,000	74,000,000
Tax on equity in net unrealized gains	7,100,000	0	7,100,000	0
Loss from dilutive effect resulting from public offering				17,900,000
Loss from dilutive effect resulting from dividend and issuance of restricted shares		300,000		600,000
Gain from dilutive effect resulting from public offering				1,900,000
Symetra \| Warrants
Changes in carrying value of investment in Symetra
Carrying value at the beginning of the period	35,900,000	38,500,000	37,100,000	38,500,000
Dividends received	(600,000)		(1,000,000)
(Decrease) increase in value of warrants	(3,400,000)	(10,900,000)	(4,600,000)	(10,900,000)
Carrying value at the end of the period	$ 32,500,000	$ 27,600,000	$ 32,500,000	$ 27,600,000

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 19
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 6
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 11
-Article 7

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 9

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.12)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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Dividends received on warrants included in net investment income.

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Represents the equity in unrealized gains or losses from investments in unconsolidated affiliates.

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Tax effect related to the accumulated equity in unrealized gains or losses from investments in unconsolidated affiliates.

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The net unrealized gains (losses) from Symetra's fixed maturity portfolio.

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Gain from the dilutive effect of Symetra's public offering included in the net unrealized gains from Symetra's fixed maturity portfolio.

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The increase (decrease) in the fair value of warrants included in other revenue.

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Tax effect on the equity in earnings of an unconsolidated affiliate.

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Total investments in (A) companies that are accounted for using the equity method and (B) warrants to acquire additional shares of an unconsolidated affiliate that are carried at fair value.

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- Definition

Loss resulting from the dilutive effect of dividend payments and issuance of restricted shares by an equity method investee.

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Loss from the dilutive effect of Symetra's public offering included in the equity in earnings of Symetra.

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