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Fair Value Measurements - Level 3 Inputs Reconciliation (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | $ 449.2 | $ 1,044.2
Total Gains (Losses): |  |
Included in Consolidated Statement of Income | 2.8 | (9.3)
Included in Other Comprehensive Income (Loss) | 1.4 | (5.1)
Purchases | 140.2 | 240.2
Settlements | (0.1) | (0.1)
Sales | (138.3) | (192.1)
Transfers into Level 3 | 19.8 | 9.0
Transfers out of Level 3 | (223.6) | (637.6)
Balance at End of Year | 251.4 | 449.2
Fair Value | 7,986.9 | 7,605.9
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 830.6 | 858.5
Other Short-term Investments, Fair Value Disclosure | 284.1 | 875.4
Redeemable Preferred Stocks |  |
Total Gains (Losses): |  |
Fair Value | 7.4 | 7.5
United States Government and Government Agencies and Authorities |  |
Total Gains (Losses): |  |
Fair Value | 637.4 | 585.3
States and Political Subdivisions |  |
Total Gains (Losses): |  |
Fair Value | 1,890.1 | 1,589.5
Foreign Governments |  |
Total Gains (Losses): |  |
Fair Value | 5.5 | 5.2
Corporate Bonds and Notes |  |
Total Gains (Losses): |  |
Fair Value | 4,386.9 | 4,425.4
Collateralized Loan Obligations |  |
Total Gains (Losses): |  |
Fair Value | 752.1 | 767.7
Other Mortgage- and Asset-backed |  |
Total Gains (Losses): |  |
Fair Value | 307.5 | 225.3
Fair Value, Recurring |  |
Total Gains (Losses): |  |
Convertible securities at fair value | 46.4 | 39.9
Investments, Fair Value Disclosure | 8,863.9 | 8,504.3
Fair Value, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Investments, Fair Value Disclosure | 586.6 | 639.5
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Convertible securities at fair value | 46.4 | 39.9
Investments, Fair Value Disclosure | 7,700.9 | 7,123.4
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Investments, Fair Value Disclosure | 251.4 | 449.2
Fair Value, Recurring | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Investments, Fair Value Disclosure | 325.0 | 292.2
Fair Value, Recurring | Redeemable Preferred Stocks |  |
Total Gains (Losses): |  |
Fair Value | 7.4 |
Fair Value, Recurring | Redeemable Preferred Stocks | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value |  | 0.0
Fair Value, Recurring | Redeemable Preferred Stocks | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value |  | 1.3
Fair Value, Recurring | Redeemable Preferred Stocks | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value |  | 6.2
Fair Value, Recurring | Redeemable Preferred Stocks | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value |  | 0.0
Fair Value, Recurring | United States Government and Government Agencies and Authorities |  |
Total Gains (Losses): |  |
Fair Value | 637.4 | 585.3
Fair Value, Recurring | United States Government and Government Agencies and Authorities | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 132.8 | 134.0
Fair Value, Recurring | United States Government and Government Agencies and Authorities | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 504.6 | 451.3
Fair Value, Recurring | United States Government and Government Agencies and Authorities | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | United States Government and Government Agencies and Authorities | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | States and Political Subdivisions |  |
Total Gains (Losses): |  |
Fair Value | 1,890.1 | 1,589.5
Fair Value, Recurring | States and Political Subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | States and Political Subdivisions | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 1,890.1 | 1,589.5
Fair Value, Recurring | States and Political Subdivisions | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | States and Political Subdivisions | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Foreign Governments |  |
Total Gains (Losses): |  |
Fair Value | 5.5 | 5.2
Fair Value, Recurring | Foreign Governments | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Foreign Governments | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 5.5 | 5.2
Fair Value, Recurring | Foreign Governments | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Foreign Governments | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Corporate Bonds and Notes |  |
Total Gains (Losses): |  |
Fair Value | 4,386.9 | 4,425.4
Fair Value, Recurring | Corporate Bonds and Notes | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Corporate Bonds and Notes | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 4,150.1 | 3,992.4
Fair Value, Recurring | Corporate Bonds and Notes | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 236.8 | 433.0
Fair Value, Recurring | Corporate Bonds and Notes | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Redeemable Preferred Stock |  |
Total Gains (Losses): |  |
Fair Value |  | 7.5
Fair Value, Recurring | Redeemable Preferred Stock | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 |
Fair Value, Recurring | Redeemable Preferred Stock | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 1.3 |
Fair Value, Recurring | Redeemable Preferred Stock | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 6.1 |
Fair Value, Recurring | Redeemable Preferred Stock | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 |
Fair Value, Recurring | Collateralized Loan Obligations |  |
Total Gains (Losses): |  |
Fair Value | 752.1 | 767.7
Fair Value, Recurring | Collateralized Loan Obligations | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Collateralized Loan Obligations | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 752.1 | 767.7
Fair Value, Recurring | Collateralized Loan Obligations | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Collateralized Loan Obligations | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Other Mortgage- and Asset-backed |  |
Total Gains (Losses): |  |
Fair Value | 307.5 | 225.3
Fair Value, Recurring | Other Mortgage- and Asset-backed | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Other Mortgage- and Asset-backed | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 300.5 | 215.3
Fair Value, Recurring | Other Mortgage- and Asset-backed | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 7.0 | 10.0
Fair Value, Recurring | Other Mortgage- and Asset-backed | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Investments in Fixed Maturities |  |
Total Gains (Losses): |  |
Fair Value | 7,986.9 | 7,605.9
Fair Value, Recurring | Investments in Fixed Maturities | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Fair Value | 132.8 | 134.0
Fair Value, Recurring | Investments in Fixed Maturities | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Fair Value | 7,604.2 | 7,022.7
Fair Value, Recurring | Investments in Fixed Maturities | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Fair Value | 249.9 | 449.2
Fair Value, Recurring | Investments in Fixed Maturities | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Fair Value | 0.0 | 0.0
Fair Value, Recurring | Preferred Stocks | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 34.2 | 43.7
Fair Value, Recurring | Preferred Stocks | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 17.6 | 15.4
Fair Value, Recurring | Preferred Stocks | Quoted Prices in Active Markets for Identical Assets (Level 1) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Preferred Stocks | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Preferred Stocks | Significant Other Observable Inputs (Level 2) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 34.2 | 43.7
Fair Value, Recurring | Preferred Stocks | Significant Other Observable Inputs (Level 2) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 16.1 | 15.4
Fair Value, Recurring | Preferred Stocks | Significant Unobservable Inputs (Level 3) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Preferred Stocks | Significant Unobservable Inputs (Level 3) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 1.5 | 0.0
Fair Value, Recurring | Preferred Stocks | Measured at Net Asset Value | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Preferred Stocks | Measured at Net Asset Value | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Common Stock | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 18.9 | 10.4
Fair Value, Recurring | Common Stock | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 2.9 | 0.4
Fair Value, Recurring | Common Stock | Quoted Prices in Active Markets for Identical Assets (Level 1) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 18.9 | 8.7
Fair Value, Recurring | Common Stock | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 2.9 | 0.4
Fair Value, Recurring | Common Stock | Significant Other Observable Inputs (Level 2) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 1.7
Fair Value, Recurring | Common Stock | Significant Other Observable Inputs (Level 2) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) |  | 0.0
Fair Value, Recurring | Common Stock | Significant Unobservable Inputs (Level 3) | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Common Stock | Significant Unobservable Inputs (Level 3) | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) |  | 0.0
Fair Value, Recurring | Common Stock | Measured at Net Asset Value | Finance, Insurance and Real Estate |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Common Stock | Measured at Net Asset Value | Other Industries |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) |  | 0.0
Fair Value, Recurring | Bond Exchange Traded Funds |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 432.0 | 496.4
Fair Value, Recurring | Bond Exchange Traded Funds | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 432.0 | 496.4
Fair Value, Recurring | Bond Exchange Traded Funds | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 |
Fair Value, Recurring | Bond Exchange Traded Funds | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 |
Fair Value, Recurring | Bond Exchange Traded Funds | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 |
Fair Value, Recurring | Limited Liability Companies and Limited Partnerships |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 325.0 | 292.2
Fair Value, Recurring | Limited Liability Companies and Limited Partnerships | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 |
Fair Value, Recurring | Limited Liability Companies and Limited Partnerships | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Limited Liability Companies and Limited Partnerships | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 0.0 | 0.0
Fair Value, Recurring | Limited Liability Companies and Limited Partnerships | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 325.0 | 292.2
Fair Value, Recurring | Dividends on Equity Securities Excluding Alternative Investments |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 830.6 | 858.5
Fair Value, Recurring | Dividends on Equity Securities Excluding Alternative Investments | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 453.8 | 505.5
Fair Value, Recurring | Dividends on Equity Securities Excluding Alternative Investments | Significant Other Observable Inputs (Level 2) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 50.3 | 60.8
Fair Value, Recurring | Dividends on Equity Securities Excluding Alternative Investments | Significant Unobservable Inputs (Level 3) |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 1.5 | 0.0
Fair Value, Recurring | Dividends on Equity Securities Excluding Alternative Investments | Measured at Net Asset Value |  |
Total Gains (Losses): |  |
Equity Securities at Fair Value (Cost: 2021 - $618.7; 2020 - $684.1) | 325.0 | 292.2
Corporate Bonds and Notes |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | 433.0 | 409.1
Total Gains (Losses): |  |
Included in Consolidated Statement of Income | 2.8 | (9.0)
Included in Other Comprehensive Income (Loss) | 1.2 | 3.2
Purchases | 104.6 | 185.9
Settlements | 0.0 | 0.0
Sales | (128.1) | (165.2)
Transfers into Level 3 | 8.1 | 9.0
Transfers out of Level 3 | (184.8) | 0.0
Balance at End of Year | 236.8 | 433.0
States and Political Subdivisions |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | 0.0 | 0.0
Total Gains (Losses): |  |
Included in Consolidated Statement of Income |  | 0.0
Included in Other Comprehensive Income (Loss) |  | 0.1
Purchases |  | 0.6
Settlements |  | 0.0
Sales |  | 0.0
Transfers into Level 3 |  | 0.0
Transfers out of Level 3 |  | (0.7)
Balance at End of Year |  | 0.0
Redeemable Preferred Stocks |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | 6.2 | 6.7
Total Gains (Losses): |  |
Included in Consolidated Statement of Income | 0.0 | 0.0
Included in Other Comprehensive Income (Loss) | (0.1) | 0.5
Purchases | 0.0 | 0.2
Settlements | 0.0 | 0.0
Sales | 0.0 | 0.0
Transfers into Level 3 | 0.0 | 0.0
Transfers out of Level 3 | 0.0 | (1.2)
Balance at End of Year | 6.1 | 6.2
Collateralized Loan Obligations |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | 0.0 | 618.2
Total Gains (Losses): |  |
Included in Consolidated Statement of Income | 0.0 | (0.3)
Included in Other Comprehensive Income (Loss) | 0.1 | (9.3)
Purchases | 17.7 | 53.5
Settlements | 0.0 | 0.0
Sales | (10.0) | (26.4)
Transfers into Level 3 | 10.0 | 0.0
Transfers out of Level 3 | (17.8) | (635.7)
Balance at End of Year | 0.0 | 0.0
Other Mortgage- and Asset-backed |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Year | 10.0 | 10.2
Total Gains (Losses): |  |
Included in Consolidated Statement of Income | 0.0 | 0.0
Included in Other Comprehensive Income (Loss) | (0.5) | 0.4
Purchases | 16.2 | 0.0
Settlements | (0.1) | (0.1)
Sales | (0.2) | (0.5)
Transfers into Level 3 | 0.0 | 0.0
Transfers out of Level 3 | (18.4) | 0.0
Balance at End of Year | 7.0 | $ 10.0
Dividends on Equity Securities Excluding Alternative Investments |  |
Total Gains (Losses): |  |
Included in Other Comprehensive Income (Loss) | 0.7 |
Purchases | 1.7 |
Transfers into Level 3 | 1.7 |
Transfers out of Level 3 | (2.6) |
Balance at End of Year | $ 1.5 |

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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