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Fair Value of Financial Instruments (Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) - Fair Value Inputs Level 3 [Member] - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value assets |  | $ 96 |  | $ 146 |
Total gains/(losses) included in earnings, assets |  | $ 1 |  | $ (4) |
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] |  | Other Income |  | Other Income |
Unrealized gains/(losses) included in OCI, assets |  | $ 0 | [1] | $ 0 | [2]
Purchases, assets |  | 0 |  | 6 |
Issuances, assets |  | 0 |  | 0 |
Settlements, assets |  | 0 |  | (1) |
Sales, assets |  | 0 |  | 0 |
Transfers into level 3, assets |  | 0 |  | 0 |
Transfers out of level 3, assets |  | 0 |  | 0 |
Ending balance, fair value assets |  | 97 |  | 147 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets |  | 1 |  | (4) |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets |  | 0 | [1] | 0 | [2]
Beginning balance, fair value liabilities |  | 72 |  | 132 |
Total (gains)/losses included in earnings, liabilities |  | $ 4 |  | $ 24 |
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Liability, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] |  | Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, before Tax |  | Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, before Tax |
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] |  | Other Income |  | Other Income |
Unrealized (gains)/losses included in OCI, liabilities |  | $ 0 | [3] | $ (22) | [4]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] |  | Other Income |  | Other Income |
Purchases, liabilities |  | $ 0 |  | $ 0 |
Issuances, liabilities |  | 0 |  | 0 |
Settlements, liabilities |  | 6 |  | (37) |
Sales, liabilities |  | 0 |  | 0 |
Transfers into Level 3, liabilities |  | 0 |  | 0 |
Transfers out of Level 3, liabilities |  | 0 |  | 0 |
Ending balance, fair value liabilities |  | 70 |  | 97 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities |  | 2 |  | (1) |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held |  | 0 | [3] | (3) | [4]
Loans receivable - residential [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value assets |  | 28 |  | 35 |
Total gains/(losses) included in earnings, assets |  | 2 |  | 2 |
Unrealized gains/(losses) included in OCI, assets |  | 0 | [1] | 0 | [2]
Purchases, assets |  | 0 |  | 0 |
Issuances, assets |  | 0 |  | 0 |
Settlements, assets |  | 0 |  | (1) |
Sales, assets |  | 0 |  | 0 |
Transfers into level 3, assets |  | 0 |  | 0 |
Transfers out of level 3, assets |  | 0 |  | 0 |
Ending balance, fair value assets |  | 30 |  | 36 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets |  | 2 |  | 2 |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets |  | 0 | [1] | 0 | [2]
Corporate Obligations [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value assets |  | 16 |  | 1 |
Unrealized gains/(losses) included in earnings, assets |  | (1) |  |  |
Total gains/(losses) included in earnings, assets |  |  |  | 0 |
Unrealized gains/(losses) included in OCI, assets |  | 0 | [1] | 0 | [2]
Purchases, assets |  | 0 |  | 6 |
Issuances, assets |  | 0 |  | 0 |
Settlements, assets |  | 0 |  | 0 |
Sales, assets |  | 0 |  | 0 |
Transfers into level 3, assets |  | 0 |  | 0 |
Transfers out of level 3, assets |  | 0 |  | 0 |
Ending balance, fair value assets |  | 15 | [5] | 7 | [6]
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets |  | (1) |  | 0 |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets |  | 0 | [1] | 0 | [2]
Equity investments [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value assets |  | 52 |  | 108 |
Total gains/(losses) included in earnings, assets |  | 0 |  | (6) |
Unrealized gains/(losses) included in OCI, assets |  | 0 | [1] | 0 | [2]
Purchases, assets |  | 0 |  | 0 |
Issuances, assets |  | 0 |  | 0 |
Settlements, assets |  | 0 |  | 0 |
Sales, assets |  | 0 |  | 0 |
Transfers into level 3, assets |  | 0 |  | 0 |
Transfers out of level 3, assets |  | 0 |  | 0 |
Ending balance, fair value assets |  | 52 |  | 102 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets |  | 0 |  | (6) |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets |  | 0 | [1] | 0 | [2]
Medium Term Notes [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value liabilities |  | 35 |  | 40 |
Total (gains)/losses included in earnings, liabilities |  | 2 |  | (2) |
Unrealized (gains)/losses included in OCI, liabilities |  | 0 | [3] | (2) | [4]
Purchases, liabilities |  | 0 |  | 0 |
Issuances, liabilities |  | 0 |  | 0 |
Settlements, liabilities |  | 0 |  |  |
Sales, liabilities |  | 0 |  | 0 |
Transfers into Level 3, liabilities |  | 0 |  | 0 |
Transfers out of Level 3, liabilities |  | 0 |  | 0 |
Ending balance, fair value liabilities |  | 37 |  | 36 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities |  | 2 |  | 2 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held |  | 0 | [3] | (2) | [4]
Variable Interest Entity Notes [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value liabilities |  | 31 |  | 78 |
Total (gains)/losses included in earnings, liabilities |  | 2 |  | 25 |
Unrealized (gains)/losses included in OCI, liabilities |  | 0 | [3] | (20) | [4]
Purchases, liabilities |  | 0 |  | 0 |
Issuances, liabilities |  | 0 |  | 0 |
Settlements, liabilities |  | 6 |  | (37) |
Sales, liabilities |  | 0 |  | 0 |
Transfers into Level 3, liabilities |  | 0 |  | 0 |
Transfers out of Level 3, liabilities |  | 0 |  | 0 |
Ending balance, fair value liabilities |  | 27 |  | 46 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities |  | 0 |  | 0 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held |  | 0 | [3] | (1) | [4]
Currency Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value liabilities |  | 6 |  | 14 |
Total (gains)/losses included in earnings, liabilities |  | 0 |  | 1 |
Unrealized (gains)/losses included in OCI, liabilities |  | 0 | [3] | 0 | [4]
Purchases, liabilities |  | 0 |  | 0 |
Issuances, liabilities |  | 0 |  | 0 |
Settlements, liabilities |  | 0 |  | 0 |
Sales, liabilities |  | 0 |  | 0 |
Transfers into Level 3, liabilities |  | 0 |  | 0 |
Transfers out of Level 3, liabilities |  | 0 |  | 0 |
Ending balance, fair value liabilities |  | 6 |  | 15 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities |  | 0 |  | 1 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held |  | $ 0 | [3] | 0 | [4]
Other Assets [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Beginning balance, fair value assets |  |  |  | 2 |
Total gains/(losses) included in earnings, assets |  |  |  | 0 |
Unrealized gains/(losses) included in OCI, assets | [2] |  |  | 0 |
Purchases, assets |  |  |  | 0 |
Issuances, assets |  |  |  | 0 |
Settlements, assets |  |  |  | 0 |
Sales, assets |  |  |  | 0 |
Transfers into level 3, assets |  |  |  | 0 |
Transfers out of level 3, assets |  |  |  | 0 |
Ending balance, fair value assets |  |  |  | 2 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets |  |  |  | 0 |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets | [2] |  |  | $ 0 |
[1] | Reported within the "Unrealized gains (losses) on available-for-sale securities" on the Company's consolidated statements of comprehensive income (loss).
[2] | Reported within the "Unrealized gains (losses) on available-for-sale securities" on the Company's consolidated statements of comprehensive income (loss).
[3] | Reported within the "Instrument-specific credit risk of liabilities measured at fair value" on the Company's consolidated statements of comprehensive income (loss).
[4] | Reported within the "Instrument-specific credit risk of liabilities measured at fair value" on the Company's consolidated statements of comprehensive income (loss).
[5] | Includes loans carried at fair value of $14 million.
[6] | Includes loans carried at fair value of $6 million

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- Definition Amount of unrealized gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of unrealized gain (loss) recognized in other comprehensive income (OCI) from liability measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 101 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-101 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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