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Schedule I - Summary Of Investments (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
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SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost | $ 2,734 |
Investments | 2,955 |
Available-for-sale Securities, Amortized Cost Basis | 2,140 | $ 2,807
Other Investments | 690 | 595
Available-for-sale Securities | 2,265 |
Investments | 2,955 | 3,544
Short-term Investments [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 415 | 492
Available-for-sale Securities | 414 | 492
ShortTermInvestmentsMember, including Pledged |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 520 |
Available-for-sale Securities | 519 |
Other Investments [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 594 |
Available-for-sale Securities | 683 |
Other Investments [Member] | Fixed Income Funds |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities | 690 |
Fixed Income Securities [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 1,605 | 2,175
Available-for-sale Securities | 1,730 | 2,317
Fixed Income Securities [Member] | Municipal Bonds [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 315 | 321
Available-for-sale Securities | 340 | 358
Fixed Income Securities [Member] | Corporate Debt Securities [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 612 | 1,059
Available-for-sale Securities | 613 | 1,077
Fixed Income Securities [Member] | Debt Security, Government, Non-US [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 89 | 97
Available-for-sale Securities | 87 | 98
Fixed Income Securities [Member] | Residential Mortgage-Backed Securities [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 182 | 256
Available-for-sale Securities | 252 | 302
Fixed Income Securities [Member] | Collateralized Debt Obligations [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 128 | 74
Available-for-sale Securities | 128 | 74
Fixed Income Securities [Member] | Asset-backed Securities [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 234 | 263
Available-for-sale Securities | 265 | 303
Fixed Income Securities [Member] | U S Government Obligations [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 60 |
Available-for-sale Securities | 60 |
Fixed Income Securities [Member] | US Government Debt Securities [Member] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 45 | 105
Available-for-sale Securities | 45 | $ 106
Fixed Income Securities [Member] | Corporate Obligations, Excluding Related Party Investments |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Available-for-sale Securities, Amortized Cost Basis | 612 |
Available-for-sale Securities | 613 |
Fair Value Amount, Excluding Related Party Investments [Domain] |  |
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] |  |
Investments | $ 2,947 |

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