| Fair Value Disclosures [Abstract] | Period [Axis] |
|---|
2016-01-01 - 2016-12-31 |
|---|
Fair Value Disclosures [Abstract] | |
Assets and liabilities measured at fair value on a recurring basis | Assets and liabilities measured at fair value on a recurring basis are presented in the following tables. | | | | | | | | | | | | | | | | | December 31, 2016 | | | | | | | Total Assets/Liabilities at Fair Value | (In millions) | Level 1 | | Level 2 | | Level 3 | | Assets | | | | | | | | Fixed maturity securities: | | | | | | | | Corporate and other bonds | $ | — |
| | $ | 18,840 |
| | $ | 130 |
| | $ | 18,970 |
| States, municipalities and political subdivisions | — |
| | 13,239 |
| | 1 |
| | 13,240 |
| Asset-backed: | | | | | | | | Residential mortgage-backed | — |
| | 4,944 |
| | 129 |
| | 5,073 |
| Commercial mortgage-backed | — |
| | 2,027 |
| | 13 |
| | 2,040 |
| Other asset-backed | — |
| | 968 |
| | 57 |
| | 1,025 |
| Total asset-backed | — |
| | 7,939 |
| | 199 |
| | 8,138 |
| U.S. Treasury and obligations of government-sponsored enterprises | 93 |
| | — |
| | — |
| | 93 |
| Foreign government | — |
| | 445 |
| | — |
| | 445 |
| Redeemable preferred stock | 19 |
| | — |
| | — |
| | 19 |
| Total fixed maturity securities | 112 |
| | 40,463 |
| | 330 |
| | 40,905 |
| Equity securities | 91 |
| | — |
| | 19 |
| | 110 |
| Other invested assets | — |
| | 5 |
| | — |
| | 5 |
| Short term investments | 475 |
| | 853 |
| | — |
| | 1,328 |
| Life settlement contracts, included in Other assets | — |
| | — |
| | 58 |
| | 58 |
| Total assets | $ | 678 |
| | $ | 41,321 |
| | $ | 407 |
| | $ | 42,406 |
| Liabilities | | | | | |
| | |
| Other liabilities | $ | — |
| | $ | (3 | ) | | $ | — |
| | $ | (3 | ) | Total liabilities | $ | — |
| | $ | (3 | ) | | $ | — |
| | $ | (3 | ) |
| | | | | | | | | | | | | | | | | December 31, 2015 | | | | | | | Total Assets/Liabilities at Fair Value | (In millions) | Level 1 | | Level 2 | | Level 3 | | Assets | | | | | | | | Fixed maturity securities: | | | | | | | | Corporate and other bonds | $ | — |
| | $ | 17,592 |
| | $ | 168 |
| | $ | 17,760 |
| States, municipalities and political subdivisions | — |
| | 13,172 |
| | 2 |
| | 13,174 |
| Asset-backed: | | | | | | | |
| Residential mortgage-backed | — |
| | 4,938 |
| | 134 |
| | 5,072 |
| Commercial mortgage-backed | — |
| | 2,175 |
| | 22 |
| | 2,197 |
| Other asset-backed | — |
| | 868 |
| | 53 |
| | 921 |
| Total asset-backed | — |
| | 7,981 |
| | 209 |
| | 8,190 |
| U.S. Treasury and obligations of government-sponsored enterprises | 66 |
| | 1 |
| | — |
| | 67 |
| Foreign government | — |
| | 346 |
| | — |
| | 346 |
| Redeemable preferred stock | 35 |
| | — |
| | — |
| | 35 |
| Total fixed maturity securities | 101 |
| | 39,092 |
| | 379 |
| | 39,572 |
| Equity securities | 177 |
| | — |
| | 20 |
| | 197 |
| Other invested assets | — |
| | 17 |
| | — |
| | 17 |
| Short term investments | 448 |
| | 1,134 |
| | — |
| | 1,582 |
| Life settlement contracts, included in Other assets | — |
| | — |
| | 74 |
| | 74 |
| Total assets | $ | 726 |
| | $ | 40,243 |
| | $ | 473 |
| | $ | 41,442 |
| Liabilities | | | | | |
| | |
| Other liabilities | $ | — |
| | $ | (5 | ) | | $ | — |
| | $ | (5 | ) | Total liabilities | $ | — |
| | $ | (5 | ) | | $ | — |
| | $ | (5 | ) |
|
Table of reconciliation for assets and liablities measured at fair value on a recurring basis using significant unobservable inputs | The tables below present a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Level 3 (In millions) | Balance as of January 1, 2016 | | Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)* | | Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) | | Purchases | | Sales | | Settlements | | Transfers into Level 3 | | Transfers out of Level 3 | | Balance as of December 31, 2016 | | Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2016 recognized in Net income (loss)* | Fixed maturity securities: | | | | | | | | | | | | | | | | | | | | Corporate and other bonds | $ | 168 |
| | $ | 1 |
| | $ | 1 |
| | $ | 163 |
| | $ | (36 | ) | | $ | (103 | ) | | $ | — |
| | $ | (64 | ) | | $ | 130 |
| | $ | — |
| States, municipalities and political subdivisions | 2 |
| | — |
| | — |
| | — |
| | — |
| | (1 | ) | | — |
| | — |
| | 1 |
| | — |
| Asset-backed: | | | | | | | | | | | | | | | | | |
| | | Residential mortgage-backed | 134 |
| | 3 |
| | (5 | ) | | 15 |
| | — |
| | (14 | ) | | 56 |
| | (60 | ) | | 129 |
| | — |
| Commercial mortgage-backed | 22 |
| | (1 | ) | | (1 | ) | | 32 |
| | — |
| | (17 | ) | | 3 |
| | (25 | ) | | 13 |
| | — |
| Other asset-backed | 53 |
| | (2 | ) | | 1 |
| | 86 |
| | (25 | ) | | (1 | ) | | 2 |
| | (57 | ) | | 57 |
| | — |
| Total asset-backed | 209 |
| | — |
| | (5 | ) | | 133 |
| | (25 | ) | | (32 | ) | | 61 |
| | (142 | ) | | 199 |
| | — |
| Total fixed maturity securities | 379 |
| | 1 |
| | (4 | ) | | 296 |
| | (61 | ) | | (136 | ) | | 61 |
| | (206 | ) | | 330 |
| | — |
| Equity securities | 20 |
| | (1 | ) | | — |
| | — |
| | — |
| | — |
| | — |
| | — |
| | 19 |
| | (2 | ) | Life settlement contracts | 74 |
| | 5 |
| | — |
| | — |
| | — |
| | (21 | ) | | — |
| | — |
| | 58 |
| | (3 | ) | Total | $ | 473 |
| | $ | 5 |
| | $ | (4 | ) | | $ | 296 |
| | $ | (61 | ) | | $ | (157 | ) | | $ | 61 |
| | $ | (206 | ) | | $ | 407 |
| | $ | (5 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Level 3 (In millions) | Balance as of January 1, 2015 | | Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)* | | Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) | | Purchases | | Sales | | Settlements | | Transfers into Level 3 | | Transfers out of Level 3 | | Balance as of December 31, 2015 | | Unrealized gains (losses) on Level 3 assets and liabilities held as of December 31, 2015 recognized in Net income (loss)* | Fixed maturity securities: | | | | | | | | | | | | | | | | | | | | Corporate and other bonds | $ | 162 |
| | $ | (2 | ) | | $ | (3 | ) | | $ | 65 |
| | $ | (13 | ) | | $ | (35 | ) | | $ | 40 |
| | $ | (46 | ) | | $ | 168 |
| | $ | (2 | ) | States, municipalities and political subdivisions | 94 |
| | 1 |
| | — |
| | — |
| | — |
| | (10 | ) | | — |
| | (83 | ) | | 2 |
| | — |
| Asset-backed: | | | | | | | | | | | | | | | | | |
| | | Residential mortgage-backed | 189 |
| | 5 |
| | (3 | ) | | 81 |
| | — |
| | (35 | ) | | 14 |
| | (117 | ) | | 134 |
| | — |
| Commercial mortgage-backed | 83 |
| | 7 |
| | (4 | ) | | 23 |
| | — |
| | (17 | ) | | 17 |
| | (87 | ) | | 22 |
| | — |
| Other asset-backed | 655 |
| | 3 |
| | 3 |
| | 130 |
| | (263 | ) | | (52 | ) | | 7 |
| | (430 | ) | | 53 |
| | — |
| Total asset-backed | 927 |
| | 15 |
| | (4 | ) | | 234 |
| | (263 | ) | | (104 | ) | | 38 |
| | (634 | ) | | 209 |
| | — |
| Total fixed maturity securities | 1,183 |
| | 14 |
| | (7 | ) | | 299 |
| | (276 | ) | | (149 | ) | | 78 |
| | (763 | ) | | 379 |
| | (2 | ) | Equity securities | 16 |
| | — |
| | (1 | ) | | 4 |
| | — |
| | — |
| | 1 |
| | — |
| | 20 |
| | — |
| Life settlement contracts | 82 |
| | 25 |
| | — |
| | — |
| | — |
| | (33 | ) | | — |
| | — |
| | 74 |
| | 1 |
| Total | $ | 1,281 |
| | $ | 39 |
| | $ | (8 | ) | | $ | 303 |
| | $ | (276 | ) | | $ | (182 | ) | | $ | 79 |
| | $ | (763 | ) | | $ | 473 |
| | $ | (1 | ) |
|
Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets | The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurements of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to the Company. The valuation of life settlement contracts as of December 31, 2016 was based on the terms of the pending sale of the contracts to a third party, therefore the contracts are not included in the table below. | | | | | | | | | | | December 31, 2016 | Estimated Fair Value (In millions) | | Valuation Technique(s) | | Unobservable Input(s) | | Range (Weighted Average) | Fixed maturity securities | $ | 106 |
| | Discounted cash flow | | Credit spread | | 2% - 40% (4%) |
| | | | | | | | | | | December 31, 2015 | Estimated Fair Value
(In millions) | | Valuation Technique(s) | | Unobservable Input(s) | | Range (Weighted Average) | Fixed maturity securities | $ | 138 |
| | Discounted cash flow | | Credit spread | | 3% - 184% (6%) | Life settlement contracts | 74 |
| | Discounted cash flow | | Discount rate risk premium | | 9% | |
|
| | | | Mortality assumption | | 55% - 1676% (164%) |
|
Carrying amount and estimated fair value of financial instrument assets and liabilities not measured at fair value | The carrying amount and estimated fair value of the Company's financial assets and liabilities which are not measured at fair value on the Consolidated Balance Sheets are presented in the following tables. | | | | | | | | | | | | | | | | | | | | | December 31, 2016 | Carrying Amount | | Estimated Fair Value | (In millions) | | Level 1 | | Level 2 | | Level 3 | | Total | Assets | | | | | | | | | | Mortgage loans | $ | 591 |
| | $ | — |
| | $ | — |
| | $ | 594 |
| | $ | 594 |
| Liabilities | | | | | | | | | | Long term debt | $ | 2,710 |
| | $ | — |
| | $ | 2,952 |
| | $ | — |
| | $ | 2,952 |
|
| | | | | | | | | | | | | | | | | | | | | December 31, 2015 | Carrying
Amount | | Estimated Fair Value | (In millions) | | Level 1 | | Level 2 | | Level 3 | | Total | Assets | | | | | | | | | | Mortgage loans | $ | 678 |
| | $ | — |
| | $ | — |
| | $ | 688 |
| | $ | 688 |
| Liabilities | | | | | | | | | | Short term debt | $ | 350 |
| | $ | — |
| | $ | 360 |
| | $ | — |
| | $ | 360 |
| Long term debt | 2,210 |
| | — |
| | 2,433 |
| | — |
| | 2,433 |
|
|