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v3.20.4

Other Comprehensive Income - Schedule of Comprehensive Income (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Equity [Abstract] |  |  |  |
Other Comprehensive Income (Loss), Tax | $ 15.6 | $ 15.6 | $ 12.4 | $ (3.3)
Other Comprehensive Income (Loss), Transfers From Available-For-Sale To Held-To-Maturity Securities, Net Of Tax |  |  |  | 1.2
Other Comprehensive Income (Loss), Net of Tax | 45.6 |  | 35.6 |
Before Tax Amount |  |  |  |
Change in net unrealized gains during period |  | 61.8 | 54.9 | (13.9)
Reclassification adjustment for net gains included in net income |  | (0.3) | (0.1) | 0.1
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Investment Transferred from Available-for-sale to Equity Method, Tax |  |  | (1.6) |
Change in net unrealized loss on derivatives |  | 0.2 |  |
Change in net actuarial gains |  | (0.5) | (0.8) | (0.6)
Total other comprehensive income |  |  |  | (12.8)
Tax Expense (Benefit) |  |  |  |
Change in net unrealized gains during period |  | 15.8 | 14.1 | (3.6)
Reclassification adjustment for net gains included in net income |  | (0.1) | 0.0 | 0.0
Change in net unrealized loss on derivatives |  | 0.0 |  |
Change in net actuarial gains |  | (0.1) | (0.1) | (0.1)
Total other comprehensive income (loss) |  |  |  | (3.3)
Net of Tax Amount |  |  |  |
Change in net unrealized loss during period |  | 46.0 | 40.8 | (10.3)
Reclassification adjustment for net loss included in net income |  | (0.2) | (0.1) | 0.1
Change in net unrealized loss on derivatives |  | 0.2 |  |
Change in net actuarial loss |  | (0.4) | (0.7) | (0.5)
Other comprehensive income (loss), net of tax |  | 45.6 | 35.6 | (9.5)
Other comprehensive income (loss), before tax | $ 61.2 | 61.2 | 48.0 | (12.8)
Change in unamortized loss on available-for-sale investment securities transferred into held-to-maturity |  | 0.0 | 0.0 | 1.6
Other Comprehensive Income (Loss), Transfers From Available-For-Sale To Held-To-Maturity Securities, Tax |  |  |  | 0.4
Reclassification adjustment for securities transferred from held-to-maturity to available-for-sale |  | 0.0 | (6.0) | 0.0
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax |  |  | (4.4) |
Change in net unrealized loss on derivatives |  | $ (0.2) | $ 0.0 | $ 0.0

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- Definition Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563 + Details
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- Definition Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580 + Details
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