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Schedule I (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Other Investments | $ 5,277 | $ 4,672
Cost or Amortized Cost | 101,697 |
Fair Value | 100,668 |
Amount at Which Shown in the Balance Sheet | 100,844 |
All Related Party [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Other Investments | 124 |
Fixed maturities available for sale |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 79,323 |
Fair Value | 78,470 |
Amount at Which Shown in the Balance Sheet | 78,470 |
Fixed maturities available for sale | U.S. Treasury and agency |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 4,158 |
Fair Value | 4,145 |
Amount at Which Shown in the Balance Sheet | 4,145 |
Fixed maturities available for sale | Foreign |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 21,370 |
Fair Value | 21,416 |
Amount at Which Shown in the Balance Sheet | 21,416 |
Fixed maturities available for sale | Corporate securities |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 27,183 |
Fair Value | 26,583 |
Amount at Which Shown in the Balance Sheet | 26,583 |
Fixed maturities available for sale | Mortgage-backed securities |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 15,758 |
Fair Value | 15,540 |
Amount at Which Shown in the Balance Sheet | 15,540 |
Fixed maturities available for sale | States, municipalities, and political subdivisions |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 10,854 |
Fair Value | 10,786 |
Amount at Which Shown in the Balance Sheet | 10,786 |
Fixed maturities held to maturity |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 13,435 |
Fair Value | 13,259 |
Amount at Which Shown in the Balance Sheet | 13,435 |
Fixed maturities held to maturity | U.S. Treasury and agency |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 1,185 |
Fair Value | 1,182 |
Amount at Which Shown in the Balance Sheet | 1,185 |
Fixed maturities held to maturity | Foreign |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 1,549 |
Fair Value | 1,542 |
Amount at Which Shown in the Balance Sheet | 1,549 |
Fixed maturities held to maturity | Corporate securities |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 2,601 |
Fair Value | 2,508 |
Amount at Which Shown in the Balance Sheet | 2,601 |
Fixed maturities held to maturity | Mortgage-backed securities |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 2,524 |
Fair Value | 2,486 |
Amount at Which Shown in the Balance Sheet | 2,524 |
Fixed maturities held to maturity | States, municipalities, and political subdivisions |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 5,576 |
Fair Value | 5,541 |
Amount at Which Shown in the Balance Sheet | 5,576 |
Industrial, miscellaneous, and all others |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 770 |
Fair Value | 770 |
Amount at Which Shown in the Balance Sheet | 770 |
Short-term investments |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 3,016 |
Fair Value | 3,016 |
Amount at Which Shown in the Balance Sheet | 3,016 |
Other investments |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Cost or Amortized Cost | 5,153 |
Fair Value | 5,153 |
Amount at Which Shown in the Balance Sheet | $ 5,153 |

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