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Fair Value of Financial Instruments (Fair Value Hierarchy Table Presents The Company's Assets And Liabilities At Fair Value Not Recorded On The Company's Consolidated Balance Sheet) (Detail) - Value Disclosed At Fair Value Not Recorded At Fair Value [Member] - Fair Value Measurements Nonrecurring [Member] - USD ($) $ in Millions | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Carrying Reported Amount Fair Value Disclosure [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Other investments | $ 1 |  | $ 1 |
Total assets | 1 |  | 1 |
Long-term debt | 2,814 |  | 2,741 |
Medium-term notes | 416 | [1] | 403 | [2]
Investment agreements | 203 |  | 204 |
Total liabilities | 3,439 |  | 3,360 |
Gross liability (recoverable) | 527 |  | 540 |
Ceded recoverable (liability) | 17 |  | 18 |
Fair Value [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Other investments | 1 |  | 1 |
Total assets | 1 |  | 1 |
Long-term debt | 311 |  | 305 |
Medium-term notes | 225 |  | 217 |
Investment agreements | 218 |  | 217 |
Total liabilities | 760 |  | 751 |
Gross liability (recoverable) | 758 |  | 764 |
Ceded recoverable (liability) | 17 |  | 19 |
Fair Value [Member] | Fair Value Inputs Level 1 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Other investments | 0 |  | 0 |
Total assets | 0 |  | 0 |
Long-term debt | 0 |  | 0 |
Medium-term notes | 0 |  | 0 |
Investment agreements | 0 |  | 0 |
Total liabilities | 0 |  | 0 |
Gross liability (recoverable) | 0 |  | 0 |
Ceded recoverable (liability) | 0 |  | 0 |
Fair Value [Member] | Fair Value Inputs Level 2 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Other investments | 0 |  | 0 |
Total assets | 0 |  | 0 |
Long-term debt | 311 |  | 305 |
Medium-term notes | 0 |  | 0 |
Investment agreements | 0 |  | 0 |
Total liabilities | 311 |  | 305 |
Gross liability (recoverable) | 0 |  | 0 |
Ceded recoverable (liability) | 0 |  | 0 |
Fair Value [Member] | Fair Value Inputs Level 3 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Other investments | 1 |  | 1 |
Total assets | 1 |  | 1 |
Long-term debt | 0 |  | 0 |
Medium-term notes | 225 |  | 217 |
Investment agreements | 218 |  | 217 |
Total liabilities | 449 |  | 446 |
Gross liability (recoverable) | 758 |  | 764 |
Ceded recoverable (liability) | 17 |  | 19 |
Liabilities Of Consolidated Vies [Member] | Carrying Reported Amount Fair Value Disclosure [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Variable interest entity loans payable | 6 |  | 12 |
Liabilities Of Consolidated Vies [Member] | Fair Value [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Variable interest entity loans payable | 6 |  | 12 |
Liabilities Of Consolidated Vies [Member] | Fair Value [Member] | Fair Value Inputs Level 1 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Variable interest entity loans payable | 0 |  | 0 |
Liabilities Of Consolidated Vies [Member] | Fair Value [Member] | Fair Value Inputs Level 2 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Variable interest entity loans payable | 0 |  | 0 |
Liabilities Of Consolidated Vies [Member] | Fair Value [Member] | Fair Value Inputs Level 3 [Member] |  |  |  |
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items] |  |  |  |
Variable interest entity loans payable | $ 6 |  | $ 12 |
[1] | The carry value includes the complex interest calculations embedded in an MTN elected to be accounted for as a separate derivative that is reported together with the host contract. As of June 30, 2025, the Company had an embedded derivative liability of $1 million.
[2] | The carry value includes the complex interest calculations embedded in an MTN elected to be accounted for as a separate derivative that is reported together with the host contract. As of December 31, 2024, the Company had an embedded derivative liability of $2 million.

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- Definition Fair value portion of investments in an entity not consolidated. Includes, but is not limited to, investments in an entity that is affiliated with the reporting entity by means of direct or indirect ownership, an entity in which the reporting entity shares control of the entity with another party or group, an entity which the company has significant influence, but does not have control and subsidiaries that are not required to be consolidated and are accounted for using the equity or cost method. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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