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Investment Securities Investment Securities (Net Realized Investment Gain (losses) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | $ 121.8 | $ 76.7 | $ 117.0
Foreign Currency Transaction Gain (Loss), Realized | (17.3) | (8.6) | (48.7)
Net realized investment gains, pre-tax | 104.5 | 68.1 | 68.3
Trading securities, Tax on Realized Holding Gain (Loss) on Investments | (30.0) | (23.8) | (37.0)
Trading Securities, Tax on Realized Foreign Currency Transaction Gain (Loss) Tax | 5.5 | 2.2 | 12.8
Tax on Net Realized Gain (Loss) and Foreign Currency Gain (Loss) on Trading Securities | (24.5) | (21.6) | (24.2)
Trading Securities Realized Holding Gain (Loss) on Investments after Tax | 91.8 | 52.9 | 80.0
Trading Securities, Realized Foreign Currency Gain (Loss) Net of Tax | (11.8) | (6.4) | (35.9)
Net Realized Gain (Loss) and Foreign Currency Gain (Loss) on Trading Securities Net of Tax | 80.0 | 46.5 | 44.1
Fixed maturity investments |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 8.6 | 82.5 | 49.4
Foreign Currency Transaction Gain (Loss), Realized | (15.0) | (2.5) | (38.3)
Net realized investment gains, pre-tax | (6.4) | 80.0 | 11.1
Short-term investments |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 0.1 | 0 | 0
Foreign Currency Transaction Gain (Loss), Realized | 0 | (4.3) | (9.9)
Net realized investment gains, pre-tax | 0.1 | (4.3) | (9.9)
Common equity securities |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 104.5 | 1.3 | 34.6
Foreign Currency Transaction Gain (Loss), Realized | (3.7) | 0 | 0
Net realized investment gains, pre-tax | 100.8 | 1.3 | 34.6
Convertible fixed maturity investments |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 1.0 | (8.2) | (2.2)
Foreign Currency Transaction Gain (Loss), Realized | 0 | (1.8) | 0
Net realized investment gains, pre-tax | 1.0 | (10.0) | (2.2)
Other long-term investments |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 7.5 | 1.4 | 35.2
Foreign Currency Transaction Gain (Loss), Realized | 1.4 | 0 | (0.5)
Net realized investment gains, pre-tax | 8.9 | 1.4 | 34.7
Forward contracts |  |  |
Investment securities |  |  |
Trading Securities, Realized Gain (Loss) | 0.1 | (0.3) |
Foreign Currency Transaction Gain (Loss), Realized | 0 | 0 |
Net realized investment gains, pre-tax | $ 0.1 | $ (0.3) |

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- Definition Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30690-110894 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30700-110894 + Details
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- Definition This item represents the gain (loss) realized during the period from the sale of trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Subparagraph c -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
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