Investment Securities (Fair Value Measurement by Level) (Details) (USD $) In Millions, unless otherwise specified																																																																																																																																																																																																																																																																																											9 Months Ended
	Sep. 30, 2012 Fair Value		Dec. 31, 2011 Fair Value		Sep. 30, 2011 Fair Value		Dec. 31, 2010 Fair Value		Sep. 30, 2012 Level 1 Inputs	Dec. 31, 2011 Level 1 Inputs	Sep. 30, 2011 Level 1 Inputs	Dec. 31, 2010 Level 1 Inputs	Sep. 30, 2012 Level 2 Inputs	Dec. 31, 2011 Level 2 Inputs	Sep. 30, 2011 Level 2 Inputs	Dec. 31, 2010 Level 2 Inputs	Dec. 31, 2010 Level 3 Inputs	Sep. 30, 2012 Debt securities issued by corporations	Dec. 31, 2011 Debt securities issued by corporations	Sep. 30, 2012 Mortgage-backed and asset-backed securities Fair Value	Dec. 31, 2011 Mortgage-backed and asset-backed securities Fair Value	Sep. 30, 2012 Mortgage-backed and asset-backed securities Level 2 Inputs	Dec. 31, 2011 Mortgage-backed and asset-backed securities Level 2 Inputs	Sep. 30, 2012 Mortgage-backed and asset-backed securities Level 3 Inputs	Dec. 31, 2011 Mortgage-backed and asset-backed securities Level 3 Inputs	Sep. 30, 2012 Fixed maturity investments. Level 3 Inputs	Dec. 31, 2011 Fixed maturity investments. Level 3 Inputs	Sep. 30, 2011 Fixed maturity investments. Level 3 Inputs	Dec. 31, 2010 Fixed maturity investments. Level 3 Inputs	Sep. 30, 2012 Common equity securities Level 3 Inputs	Dec. 31, 2011 Common equity securities Level 3 Inputs	Sep. 30, 2011 Common equity securities Level 3 Inputs	Dec. 31, 2010 Common equity securities Level 3 Inputs	Sep. 30, 2012 Convertible fixed maturity investments Level 3 Inputs	Dec. 31, 2011 Convertible fixed maturity investments Level 3 Inputs	Sep. 30, 2011 Convertible fixed maturity investments Level 3 Inputs	Sep. 30, 2012 Other long-term investments Level 3 Inputs		Dec. 31, 2011 Other long-term investments Level 3 Inputs		Sep. 30, 2011 Other long-term investments Level 3 Inputs		Dec. 31, 2010 Other long-term investments Level 3 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis U.S. Government and agency obligations Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis U.S. Government and agency obligations Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis U.S. Government and agency obligations Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis U.S. Government and agency obligations Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis U.S. Government and agency obligations Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis U.S. Government and agency obligations Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis U.S. Government and agency obligations Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis U.S. Government and agency obligations Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Consumer Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Industrial Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Financials Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Financials Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Financials Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Communications Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Communications Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Communications Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Basic materials Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Energy Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Energy Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Energy Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Utilities Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Technology Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Technology Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Technology Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Debt securities issued by corporations Diversified Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Municipal obligations Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Municipal obligations Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Municipal obligations Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Municipal obligations Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Municipal obligations Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Municipal obligations Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Municipal obligations Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Municipal obligations Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Mortgage-backed and asset-backed securities Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Foreign government, agency and provincial obligations Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Non-cumulative perpetual preference shares Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Fixed maturity investments. Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Fixed maturity investments. Fair Value		Sep. 30, 2012 Fair value measured on a recurring basis Fixed maturity investments. Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Fixed maturity investments. Level 1 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Fixed maturity investments. Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Fixed maturity investments. Level 2 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Fixed maturity investments. Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Fixed maturity investments. Level 3 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Short-term investments Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Short-term investments Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Short-term investments Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Short-term investments Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Short-term investments Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Short-term investments Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Short-term investments Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Short-term investments Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Consumer Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Consumer Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Consumer Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Consumer Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Consumer Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Consumer Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Consumer Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Consumer Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Financials Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Financials Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Financials Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Financials Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Financials Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Financials Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Financials Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Financials Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Basic materials Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Basic materials Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Basic materials Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Basic materials Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Basic materials Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Basic materials Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Basic materials Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Basic materials Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Energy Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Energy Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Energy Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Energy Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Energy Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Energy Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Energy Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Energy Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Utilities Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Utilities Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Utilities Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Utilities Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Utilities Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Utilities Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Utilities Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Utilities Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Technology Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Technology Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Technology Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Technology Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Technology Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Technology Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Technology Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Technology Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Other: Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Other: Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Other: Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Other: Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Other: Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Other: Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Other: Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Other: Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Common equity securities Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Common equity securities Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Convertible fixed maturity investments Fair Value	Dec. 31, 2011 Fair value measured on a recurring basis Convertible fixed maturity investments Fair Value	Sep. 30, 2012 Fair value measured on a recurring basis Convertible fixed maturity investments Level 1 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Convertible fixed maturity investments Level 1 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Convertible fixed maturity investments Level 2 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Convertible fixed maturity investments Level 2 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Convertible fixed maturity investments Level 3 Inputs	Dec. 31, 2011 Fair value measured on a recurring basis Convertible fixed maturity investments Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Other long-term investments Fair Value		Dec. 31, 2011 Fair value measured on a recurring basis Other long-term investments Fair Value		Sep. 30, 2012 Fair value measured on a recurring basis Other long-term investments Level 1 Inputs		Dec. 31, 2011 Fair value measured on a recurring basis Other long-term investments Level 1 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Other long-term investments Level 2 Inputs		Dec. 31, 2011 Fair value measured on a recurring basis Other long-term investments Level 2 Inputs		Sep. 30, 2012 Fair value measured on a recurring basis Other long-term investments Level 3 Inputs		Dec. 31, 2011 Fair value measured on a recurring basis Other long-term investments Level 3 Inputs		Sep. 30, 2011 Fair value measured on a recurring basis Other long-term investments Level 3 Inputs	Dec. 31, 2010 Fair value measured on a recurring basis Other long-term investments Level 3 Inputs	Sep. 30, 2012 Fair value measured on a recurring basis Forward Contracts [Member] Level 2 Inputs	Sep. 30, 2012 Segment, Discontinued Operations [Member]	Dec. 31, 2011 Segment, Discontinued Operations [Member]
Investment securities
Fair value investments	$ 7,626.4	[1]	$ 8,346.8	[1],[2]	$ 7,265.9	[1]	$ 7,901.6	[1]	$ 2,225.8	$ 1,879.1	$ 1,755.2	$ 1,894.4	$ 5,016.0	$ 6,088.2	$ 4,969.5	$ 5,477.4	$ 0	$ 2,281.3	$ 2,135.1	$ 2,047.4	$ 3,222.9	$ 2,041.9	$ 3,207.8	$ 5.5	$ 15.1	$ 76.1	$ 78.9	$ 216.9	$ 128.4	$ 35.9	$ 32.3	$ 32.1	$ 71.2	$ 0	$ 0	$ 0	$ 272.6	[1]	$ 268.3	[1]	$ 292.2	[1]	$ 330.2	[1]	$ 7,626.4	$ 8,346.8	$ 2,225.8	$ 1,879.1	$ 5,016.0	$ 6,088.2	$ 384.6	$ 379.5	$ 394.7	$ 305.0	$ 340.5	$ 296.2	$ 54.2	$ 8.8	$ 0	$ 0	$ 2,281.3	$ 2,135.1	$ 1.1	$ 3.8	$ 2,280.2	$ 2,131.3	$ 0	$ 0	$ 597.2	$ 790.7	$ 0	$ 0	$ 597.2	$ 790.7	$ 0	$ 0	$ 488.1	$ 359.4	$ 0	$ 0	$ 488.1	$ 359.4	$ 0	$ 0	$ 405.4	$ 239.6	$ 1.1	$ 3.8	$ 404.3	$ 235.8	$ 0	$ 0	$ 217.1	$ 225.8	$ 0	$ 0	$ 217.1	$ 225.8	$ 0	$ 0	$ 175.1	$ 195.7	$ 0	$ 0	$ 175.1	$ 195.7	$ 0	$ 0	$ 172.9	$ 155.8	$ 0	$ 0	$ 172.9	$ 155.8	$ 0	$ 0	$ 204.4	$ 140.1	$ 0	$ 0	$ 204.4	$ 140.1	$ 0	$ 0	$ 21.1	$ 24.5	$ 0	$ 0	$ 21.1	$ 24.5	$ 0	$ 0	$ 0	$ 3.5	$ 0	$ 0	$ 0	$ 3.5	$ 0	$ 0	$ 3.8	$ 2.7	$ 0	$ 0	$ 3.8	$ 2.7	$ 0	$ 0	$ 2,047.4	$ 3,222.9	$ 0	$ 0	$ 2,041.9	$ 3,207.8	$ 5.5	$ 15.1	$ 476.4	$ 589.2	$ 56.9	$ 65.7	$ 419.5	$ 523.5	$ 0	$ 0	$ 86.1	$ 78.8	$ 0	$ 0	$ 15.5	$ 15.0	$ 70.6	$ 63.8	$ 5,289.7	$ 6,333.7	[3]	$ 398.5	$ 365.7	[3]	$ 4,815.1	$ 5,889.1	[3]	$ 76.1	$ 78.9	[3]	$ 917.3	$ 846.0	$ 917.3	$ 846.0	$ 0	$ 0	$ 0	$ 0	$ 249.7	$ 188.8	$ 249.6	$ 188.5	$ 0.1	$ 0.3	$ 0	$ 0	$ 316.1	$ 219.2	$ 277.9	$ 185.8	$ 2.3	$ 1.5	$ 35.9	$ 31.9	$ 118.2	$ 121.0	$ 118.2	$ 119.9	$ 0	$ 1.1	$ 0	$ 0	$ 96.8	$ 72.6	$ 96.8	$ 72.6	$ 0	$ 0	$ 0	$ 0	$ 42.9	$ 42.0	$ 42.7	$ 41.8	$ 0.2	$ 0.2	$ 0	$ 0	$ 51.6	$ 25.8	$ 51.6	$ 25.8	$ 0	$ 0	$ 0	$ 0	$ 129.5	$ 85.6	$ 73.2	$ 33.0	$ 56.3	$ 52.2	$ 0	$ 0.4	$ 1,004.8	$ 755.0	$ 910.0	$ 667.4	$ 58.9	$ 55.3	$ 35.9	$ 32.3	$ 142.0	$ 143.8	$ 0	$ 0	$ 142.0	$ 143.8	$ 0	$ 0	$ 272.6	[3]	$ 268.3	[4]	$ 0	[3]	$ 0	[4]	$ 0	[3]	$ 0	[4]	$ 272.6	[3]	$ 268.3	[4]
Carrying value of investment accounted for using the equity method																																																																																																																																																																																																																																																																																					34.3		33.0		36.6	41.9
Derivative, Gain (Loss) on Derivative, Net																																																																																																																																																																																																																																																																																											0.3
Fixed maturity investments reclassified to assets held for sale																																																																																																																																																																																																																																																																																												$ 377.3	$ 111.8

[1] (1) Excludes carrying value of $33.0 and $34.3 at January 1, 2012 and September 30, 2012 associated with other long-term investments accounted for using the equity method

[2] (2) Carrying value includes $111.8 and $377.3 at January 1, 2012 and September 30, 2012 that is classified as assets held for sale relating to discontinued operations. Level 3 Investments MillionsLevel 1InvestmentsLevel 2InvestmentsFixedMaturitiesCommonequitysecuritiesConvertiblefixedmaturitiesOther long-terminvestments Total Balance at January 1, 2011$1,894.4$5,477.4$128.4$71.2$—$330.2(1) $7,901.6(1) Total realized and unrealized gains (losses)(50.5)115.9(10.6)(4.9)—22.5 72.4 Foreign currency gains (losses) through OCI.3(84.4)(4.4)1.6—(5.0) (91.9) Amortization/Accretion2.4(40.7)(.1)——— (38.4) Purchases6,690.73,987.4212.819.7—27.9 10,938.5 Sales(6,782.1)(4,596.9)1.6(55.5)—(83.4) (11,516.3) Transfers in—111.81.0——— 112.8 Transfers out—(1.0)(111.8)——— (112.8) Balance at September 30, 2011$1,755.2$4,969.5$216.9$32.1$—$292.2(1) $7,265.9(1) (1) Excludes carrying value o

[3] September 30, 2012MillionsFair value Level 1 Inputs Level 2 Inputs Level 3 InputsFixed maturity investments: US Government and agency obligations$394.7 $340.5 $54.2 $— Debt securities issued by corporations: Consumer597.2 — 597.2 —Industrial488.1 — 488.1 —Financials405.4 1.1 404.3 —Communications217.1 — 217.1 —Basic materials175.1 — 175.1 —Energy172.9 — 172.9 —Utilities204.4 — 204.4 —Technology21.1 — 21.1 —Diversified— — — —Total debt securities issued by corporations:2,281.3 1.1 2,280.2 — Municipal obligations3.8 — 3.8 —Mortgage-backed and asset-backed securities2,047.4 — 2,041.9 5.5Foreign government, agency and provincial obligations476.4 56.9 419.5 —Preferred stocks86.1 — 15.5 70.6Total fixed maturity investments (1)5,289.7 398.5 4,815.1 76.1 Short-term investments917.3 917.3 — — Common equity securities: Financials316.1 277.9 2.3 35.9Consumer249.7 249.6 .1 —Basic materials118.2 118.2 — —Energy96.8 96.8 — —Technology51.6 51.6 — —Utilities42.9 42.7 .2 —Other129.5 73.2 56.3 —Total common equity securities1,004.8 910.0 58.9 35.9 Convertible fixed maturity investments142.0 — 142.0 —Other long-term investments (2) 272.6 — — 272.6Total investments$7,626.4 $2,225.8 $5,016.0 $384.6 (1) Carrying value includes $377.3 that is classified as assets held for sale relating to discontinued operations. (2) Excludes carrying value of $34.3 associated with other long-term investment limited partnerships accounted for using the equity method and $0.3 related to forward contrac

[4]