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Schedule I- Investments (Detail) $ in Millions | Dec. 31, 2020 USD ($)
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Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | $ 2,549
Fair Value | 2,736
Amount at which shown in the balance sheet | 2,736
Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 220
Fair Value | 197
Amount at which shown in the balance sheet | 197
Loans Receivable [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 124
Fair Value | 120
Amount at which shown in the balance sheet | 120
Long-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 2,080
Fair Value | 2,258
Amount at which shown in the balance sheet | 2,258
Long-Term Available-For-Sale [Member] | U.S. Treasury And Government Agency [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 556
Fair Value | 631
Amount at which shown in the balance sheet | 631
Long-Term Available-For-Sale [Member] | US States And Political Subdivisions [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 162
Fair Value | 194
Amount at which shown in the balance sheet | 194
Long-Term Available-For-Sale [Member] | Foreign Governments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 9
Fair Value | 10
Amount at which shown in the balance sheet | 10
Long-Term Available-For-Sale [Member] | Corporate Obligations [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 767
Fair Value | 830
Amount at which shown in the balance sheet | 830
Short-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 280
Fair Value | 281
Amount at which shown in the balance sheet | 281
AFS Investments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 2,360
Fair Value | 2,539
Amount at which shown in the balance sheet | 2,539
Investments At Fair Value [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 189
Fair Value | 197
Amount at which shown in the balance sheet | 197
Investments At Fair Value [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 96
Fair Value | 77
Amount at which shown in the balance sheet | 77
Mortgage-backed [Member] | Long-Term Available-For-Sale [Member] | Residential Mortgage Backed Agency [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 305
Fair Value | 312
Amount at which shown in the balance sheet | 312
Mortgage-backed [Member] | Long-Term Available-For-Sale [Member] | Residential Mortgage-Backed Non-Agency [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 23
Fair Value | 25
Amount at which shown in the balance sheet | 25
Mortgage-backed [Member] | Long-Term Available-For-Sale [Member] | Commercial Mortgage-Backed [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 17
Fair Value | 17
Amount at which shown in the balance sheet | 17
Asset-backed [Member] | Long-Term Available-For-Sale [Member] | Collateralized Debt Obligations [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 120
Fair Value | 118
Amount at which shown in the balance sheet | 118
Asset-backed [Member] | Long-Term Available-For-Sale [Member] | Other Asset-Backed [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 121
Fair Value | 121
Amount at which shown in the balance sheet | $ 121

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