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Schedule I- Investments (Detail) $ in Millions | Dec. 31, 2017 USD ($)
--- | ---
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | $ 4,663
Fair Value | 4,655
Amount at which shown in the balance sheet | 4,655
Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 2,132
Fair Value | 2,777
Amount at which shown in the balance sheet | 2,751
Other Aggregated Investments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 2
Fair Value | 2
Amount at which shown in the balance sheet | 2
Loans Receivable [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 1,085
Fair Value | 1,679
Amount at which shown in the balance sheet | 1,679
Long-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 3,759
Fair Value | 3,743
Amount at which shown in the balance sheet | 3,743
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 | 985
Fair Value | 1,014
Amount at which shown in the balance sheet | 1,014
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 | 840
Fair Value | 857
Amount at which shown in the balance sheet | 857
Long-Term Available-For-Sale [Member] | Foreign Governments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 4
Fair Value | 4
Amount at which shown in the balance sheet | 4
Long-Term Available-For-Sale [Member] | Corporate Obligations [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 1,173
Fair Value | 1,117
Amount at which shown in the balance sheet | 1,117
Short-Term Available-For-Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 676
Fair Value | 676
Amount at which shown in the balance sheet | 676
Equity Available For Sale [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 3
Fair Value | 4
Amount at which shown in the balance sheet | 4
AFS Investments [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 4,438
Fair Value | 4,423
Amount at which shown in the balance sheet | 4,423
Investments At Fair Value [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 223
Fair Value | 230
Amount at which shown in the balance sheet | 230
Investments At Fair Value [Member] | Assets Of Consolidated VIEs [Member] |
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items] |
Cost | 157
Fair Value | 182
Amount at which shown in the balance sheet | 182
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 | 916
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 | 365
Fair Value | 362
Amount at which shown in the balance sheet | 362
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 | 35
Fair Value | 32
Amount at which shown in the balance sheet | 32
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 | 66
Fair Value | 66
Amount at which shown in the balance sheet | 66
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 | 116
Fair Value | 116
Amount at which shown in the balance sheet | 116
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 | 175
Fair Value | 175
Amount at which shown in the balance sheet | $ 175

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- Definition This element represents the carrying (reported) amount of the entity's investments as of the balance sheet date. This amount may represent the individual investment's or group of similar investments' original cost, fair value, or such other amount at which the investment is shown in the entity's balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010 + Details
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- Definition This item represents the original cost of the entity's investments including investments in equity securities and, as to fixed maturities, original cost reduced by repayments and adjusted for amortization of premiums or accrual of discounts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611379-123010 + Details
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