For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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+ Details

Fair Value (Fair Value Of Assets On A Recurring Basis) (Details) (USD $) In Millions	9 Months Ended																																													9 Months Ended	12 Months Ended													9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Sep. 30, 2011 U.S. Treasury And Government Agencies [Member] Level 1 [Member] Fixed Maturities [Member]	Dec. 31, 2010 U.S. Treasury And Government Agencies [Member] Level 1 [Member] Fixed Maturities [Member]	Sep. 30, 2011 U.S. Treasury And Government Agencies [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 U.S. Treasury And Government Agencies [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 U.S. Treasury And Government Agencies [Member] Fixed Maturities [Member]	Dec. 31, 2010 U.S. Treasury And Government Agencies [Member] Fixed Maturities [Member]	Sep. 30, 2011 Foreign Governments [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Foreign Governments [Member] Fixed Maturities [Member]	Sep. 30, 2011 Municipal [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Municipal [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Municipal [Member] Level 3 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Municipal [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Municipal [Member] Fixed Maturities [Member]	Dec. 31, 2010 Municipal [Member] Fixed Maturities [Member]	Sep. 30, 2011 Corporate [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Corporate [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Corporate [Member] Level 3 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Corporate [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Corporate [Member] Fixed Maturities [Member]	Dec. 31, 2010 Corporate [Member] Fixed Maturities [Member]	Sep. 30, 2011 Residential Mortgage-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Residential Mortgage-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Residential Mortgage-Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Residential Mortgage-Backed [Member] Fixed Maturities [Member]	Dec. 31, 2010 Residential Mortgage-Backed [Member] Fixed Maturities [Member]	Sep. 30, 2011 Residential Mortgage-Backed Securities, U.S. Agency Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Residential Mortgage-Backed Securities, U.S. Agency Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Residential Mortgage-Backed Securities, U.S. Agency Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Residential Mortgage-Backed Securities, U.S. Agency Backed [Member] Fixed Maturities [Member]	Dec. 31, 2010 Residential Mortgage-Backed Securities, U.S. Agency Backed [Member] Fixed Maturities [Member]	Sep. 30, 2011 Commercial Mortgage-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Commercial Mortgage-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Commercial Mortgage-Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Commercial Mortgage-Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Commercial Mortgage-Backed [Member] Fixed Maturities [Member]	Dec. 31, 2010 Commercial Mortgage-Backed [Member] Fixed Maturities [Member]	Sep. 30, 2011 Asset-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Asset-Backed [Member] Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Asset-Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Asset-Backed [Member] Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Asset-Backed [Member] Fixed Maturities [Member]	Dec. 31, 2010 Asset-Backed [Member] Fixed Maturities [Member]	Sep. 30, 2011 FHLBB Borrowings [Member]	Dec. 31, 2010 FHLBB Borrowings [Member]	Sep. 30, 2011 Equity Securities [Member]	Sep. 30, 2011 Equity Securities [Member] Level 1 [Member]	Sep. 30, 2011 Equity Securities [Member] Level 3 [Member]	Dec. 31, 2010 Level 1 [Member] Equity Securities [Member]	Sep. 30, 2011 Level 2 [Member] Equity Securities [Member]	Dec. 31, 2010 Level 2 [Member] Equity Securities [Member]	Dec. 31, 2010 Level 3 [Member] Equity Securities [Member]	Dec. 31, 2010 Equity Securities [Member]	Sep. 30, 2011 Level 1 [Member]	Dec. 31, 2010 Level 1 [Member]	Sep. 30, 2011 Level 1 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Level 1 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Level 2 [Member]	Dec. 31, 2010 Level 2 [Member]	Sep. 30, 2011 Level 2 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Level 2 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Level 3 [Member]	Dec. 31, 2010 Level 3 [Member]	Sep. 30, 2011 Level 3 [Member] Fixed Maturities [Member]	Dec. 31, 2010 Level 3 [Member] Fixed Maturities [Member]	Sep. 30, 2011 Fixed Maturities [Member]	Dec. 31, 2010 Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities	$ 6,227.6	$ 4,797.9	$ 4,797.9	$ 153.0	$ 124.0	$ 126.0	$ 137.2	$ 279.0	$ 261.2	$ 302.9	$ 302.9	$ 1,017.1	$ 938.1	$ 15.8	$ 16.6	$ 1,032.9	$ 954.7	$ 3,268.9	$ 2,392.2	$ 22.5	$ 28.2	$ 3,291.4	$ 2,420.4	$ 701.0	$ 132.9	$ 0.8	$ 701.0	$ 133.7	$ 158.2	$ 600.4	$ 5.5	$ 163.7	$ 600.4	$ 333.9	$ 361.1	$ 12.2	$ 5.5	$ 346.1	$ 366.6	$ 88.8	$ 47.4	$ 21.8	$ 13.5	$ 110.6	$ 60.9													$ 153.0	$ 124.0			$ 5,996.8	$ 4,609.3			$ 77.8	$ 64.6	$ 6,227.6	$ 4,797.9
Equity securities																																																237.4	122.9	25.5	106.6	89.0	10.5	2.9	120.0
Total investment assets at fair value	6,608.9	4,917.9																																																						275.9	230.6			6,229.7	4,619.8			103.3	67.5
Other investments	143.9																																																											143.9
Derivative instruments	5.4																																																											5.4
Excluded FHLBB common stock																																														$ 8.9	$ 8.6