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Schedule I- Investments (Detail) $ in Millions | Dec. 31, 2018 USD ($)
--- | ---
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | $ 4,118
Fair Value | 4,072
Amount at which shown in the balance sheet | 4,072
Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 1,192
Fair Value | 1,254
Amount at which shown in the balance sheet | 1,219
Other Aggregated Investments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 1
Fair Value | 1
Amount at which shown in the balance sheet | 1
Loans Receivable [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 159
Fair Value | 172
Amount at which shown in the balance sheet | 172
Long-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 3,618
Fair Value | 3,582
Amount at which shown in the balance sheet | 3,582
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 | 916
Fair Value | 932
Amount at which shown in the balance sheet | 932
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 | 641
Fair Value | 727
Amount at which shown in the balance sheet | 727
Long-Term Available-For-Sale [Member] | Foreign Governments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 3
Fair Value | 3
Amount at which shown in the balance sheet | 3
Long-Term Available-For-Sale [Member] | Corporate Obligations [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 1,457
Fair Value | 1,332
Amount at which shown in the balance sheet | 1,332
Short-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 199
Fair Value | 199
Amount at which shown in the balance sheet | 199
Equity Available For Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 0
Fair Value | 0
Amount at which shown in the balance sheet | 0
AFS Investments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 3,817
Fair Value | 3,781
Amount at which shown in the balance sheet | 3,781
Investments At Fair Value [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 300
Fair Value | 290
Amount at which shown in the balance sheet | 290
Investments At Fair Value [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 143
Fair Value | 157
Amount at which shown in the balance sheet | 157
Held-To-Maturity [Member] | Corporate Obligations [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 890
Fair Value | 925
Amount at which shown in the balance sheet | 890
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 | 218
Fair Value | 214
Amount at which shown in the balance sheet | 214
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 | 30
Fair Value | 27
Amount at which shown in the balance sheet | 27
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 | 53
Fair Value | 51
Amount at which shown in the balance sheet | 51
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 | 122
Fair Value | 119
Amount at which shown in the balance sheet | 119
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 | 178
Fair Value | 177
Amount at which shown in the balance sheet | $ 177

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