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Schedule I - Investments (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	$ 2,938
Fair Value	2,676
Amount at which shown in the balance sheet	2,676
Assets Of Consolidated VIEs [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	176
Fair Value	125
Amount at which shown in the balance sheet	125
Loans Receivable [Member] | Assets Of Consolidated VIEs [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	113
Fair Value	78
Amount at which shown in the balance sheet	78
Long-Term Available-For-Sale [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,044
Fair Value	1,812
Amount at which shown in the balance sheet	1,812
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	427
Fair Value	394
Amount at which shown in the balance sheet	394
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	173
Fair Value	164
Amount at which shown in the balance sheet	164
Long-Term Available-For-Sale [Member] | Foreign Governments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	18
Fair Value	15
Amount at which shown in the balance sheet	15
Long-Term Available-For-Sale [Member] | Corporate Obligations [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	862
Fair Value	715
Amount at which shown in the balance sheet	715
Short-Term Available-For-Sale [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	119
Fair Value	119
Amount at which shown in the balance sheet	119
AFS Investments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,163
Fair Value	1,931
Amount at which shown in the balance sheet	1,931
Investments At Fair Value [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	775
Fair Value	745
Amount at which shown in the balance sheet	745
Investments At Fair Value [Member] | Assets Of Consolidated VIEs [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	63
Fair Value	47
Amount at which shown in the balance sheet	47
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	217
Fair Value	195
Amount at which shown in the balance sheet	195
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	96
Fair Value	88
Amount at which shown in the balance sheet	88
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	24
Fair Value	23
Amount at which shown in the balance sheet	23
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	117
Fair Value	112
Amount at which shown in the balance sheet	112
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	110
Fair Value	106
Amount at which shown in the balance sheet	$ 106

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Amount of investment held by insurance company, excluding investment in related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 7
-Subparagraph (SX 210.12-15(Column D))
-URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611379-123010

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 7
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