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Fair Value Measurements - Valuation of Assets Measured at Fair Value (Details) - USD ($) | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Convertible Debt, Fair Value Disclosures |  | $ 0
Fair Value Option Investments | $ 0 | 77,500,000
Trading Securities at Fair Value | 0 | 6,700,000
Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Trading Securities at Fair Value |  | 6,700,000
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value |  | (800,000)
Investments, Fair Value Disclosure | 7,140,100,000 |
Assets, Fair Value Disclosure |  | 5,992,100,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Trading Securities at Fair Value |  | 6,700,000
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value |  | 0
Investments, Fair Value Disclosure | 594,200,000 |
Assets, Fair Value Disclosure |  | 349,700,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Trading Securities at Fair Value |  | 0
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value |  | (800,000)
Investments, Fair Value Disclosure | 5,456,500,000 |
Assets, Fair Value Disclosure |  | 4,839,800,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Trading Securities at Fair Value |  | 0
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value |  | 0
Investments, Fair Value Disclosure | 897,400,000 |
Assets, Fair Value Disclosure |  | 556,600,000
Investments in Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 6,424,200,000 | 5,382,700,000
Investments in Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 156,500,000 | 115,800,000
Investments in Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 5,370,300,000 | 4,772,100,000
Investments in Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 897,400,000 | 494,800,000
US Government and Government Agencies and Authorities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 865,700,000 | 556,100,000
US Government and Government Agencies and Authorities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 156,500,000 | 115,800,000
US Government and Government Agencies and Authorities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 709,200,000 | 440,300,000
US Government and Government Agencies and Authorities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 1,619,100,000 | 1,701,800,000
States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 1,619,100,000 | 1,701,800,000
States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Debt Security, Government, Non-US [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 5,900,000 | 3,200,000
Debt Security, Government, Non-US [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Debt Security, Government, Non-US [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 5,900,000 | 3,200,000
Debt Security, Government, Non-US [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Corporate Bonds and Notes [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 3,393,800,000 | 2,980,600,000
Corporate Bonds and Notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Corporate Bonds and Notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 3,011,200,000 | 2,579,100,000
Corporate Bonds and Notes [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 382,600,000 | 401,500,000
Redeemable Preferred Stocks [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 100,000
Redeemable Preferred Stocks [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Redeemable Preferred Stocks [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Redeemable Preferred Stocks [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 100,000
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 524,000,000 | 139,800,000
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 19,100,000 | 46,600,000
Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 504,900,000 | 93,200,000
Other Mortgage and Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 15,700,000 | 1,100,000
Other Mortgage and Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Other Mortgage and Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 5,800,000 | 1,100,000
Other Mortgage and Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 9,900,000 | 0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 526,000,000
Equity, Fair Value Disclosure | 684,400,000 |
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 227,200,000
Equity, Fair Value Disclosure | 437,700,000 |
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 68,500,000
Equity, Fair Value Disclosure | 54,700,000 |
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 61,800,000
Equity, Fair Value Disclosure | 0 |
Preferred Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 55,700,000
Equity, Fair Value Disclosure | 41,200,000 |
Preferred Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity Securities at Fair Value | 0 |
Preferred Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 55,700,000
Equity, Fair Value Disclosure | 41,200,000 |
Preferred Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0 |
Preferred Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 23,100,000
Equity, Fair Value Disclosure | 13,000,000 |
Preferred Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0 |
Preferred Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 12,300,000
Equity, Fair Value Disclosure | 13,000,000 |
Preferred Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 10,800,000
Equity, Fair Value Disclosure | 0 |
Common Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 7,100,000
Equity, Fair Value Disclosure | 10,200,000 |
Common Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 7,000,000
Equity, Fair Value Disclosure | 10,200,000 |
Common Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 100,000
Equity, Fair Value Disclosure | 0 |
Common Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0 |
Common Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 17,700,000
Equity, Fair Value Disclosure | 700,000 |
Common Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 700,000
Equity, Fair Value Disclosure | 200,000 |
Common Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 400,000
Equity, Fair Value Disclosure | 500,000 |
Common Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 16,600,000
Equity, Fair Value Disclosure | 0 |
Exchange Traded Funds [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 219,500,000
Equity, Fair Value Disclosure | 427,300,000 |
Exchange Traded Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 219,500,000
Equity, Fair Value Disclosure | 427,300,000 |
Exchange Traded Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0 |
Exchange Traded Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Unfunded commitments | 148,200,000 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 202,900,000
Convertible Debt, Fair Value Disclosures | 31,500,000 |
Equity, Fair Value Disclosure | 192,000,000 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Convertible Debt, Fair Value Disclosures | 0.0 |
Equity, Fair Value Disclosure | 0 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Convertible Debt, Fair Value Disclosures | 31,500,000 |
Equity, Fair Value Disclosure | 0 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 34,400,000
Convertible Debt, Fair Value Disclosures | 0 |
Equity, Fair Value Disclosure | 0 |
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair Value Option Investments |  | 77,500,000
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair Value Option Investments |  | 0
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair Value Option Investments |  | 0
Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair Value Option Investments |  | 0
Fair Value, Inputs, Net Asset Value [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Trading Securities at Fair Value |  | 0
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value |  | 0
Investments, Fair Value Disclosure | 192,000,000 |
Assets, Fair Value Disclosure |  | 246,000,000
Fair Value, Inputs, Net Asset Value [Member] | Investments in Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | US Government and Government Agencies and Authorities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | Debt Security, Government, Non-US [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | Corporate Bonds and Notes [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | Redeemable Preferred Stocks [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Fair Value, Inputs, Net Asset Value [Member] | Collateralized Loan Obligations [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | Other Mortgage and Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities | 0 | 0
Fair Value, Inputs, Net Asset Value [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 168,500,000
Equity, Fair Value Disclosure | 192,000,000 |
Fair Value, Inputs, Net Asset Value [Member] | Preferred Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0.0 |
Fair Value, Inputs, Net Asset Value [Member] | Preferred Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0.0 |
Fair Value, Inputs, Net Asset Value [Member] | Common Stock [Member] | Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0.0 |
Fair Value, Inputs, Net Asset Value [Member] | Common Stock [Member] | All Industries Other than Finance, Insurance and Real Estate [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0.0 |
Fair Value, Inputs, Net Asset Value [Member] | Exchange Traded Funds [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 0
Equity, Fair Value Disclosure | 0.0 |
Fair Value, Inputs, Net Asset Value [Member] | Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale Securities |  | 168,500,000
Convertible Debt, Fair Value Disclosures | 0.0 |
Equity, Fair Value Disclosure | $ 192,000,000 |
Fair Value, Inputs, Net Asset Value [Member] | Limited Liability Companies and Limited Partnerships [Member] | Fair Value, Measurements, Recurring [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fair Value Option Investments |  | $ 77,500,000

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- Definition Amount of investments reported under the Fair Value Option method of accounting. + References No definition available. + Details
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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
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- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959 + Details
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- Definition Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock. + References No definition available. + Details
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- Definition Fair value of the entity's equity. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=99377789&loc=SL6742756-110258 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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