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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 | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Accounts Notes And Loans Receivable [Line Items] |  |  |  |
Beginning balance, fair value assets | $ 146 |  | $ 216 |
Total gains/(losses) included in earnings, assets | $ (62) |  | $ (36) |
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 | 17 |  | 0 |
Issuances, assets | 0 |  | 0 |
Settlements, assets | (3) |  | (9) |
Sales, assets | (2) |  | (26) |
Transfers into level 3, assets | 0 |  | 1 |
Transfers out of level 3, assets | 0 |  | 0 |
Ending balance, fair value assets | 96 |  | 146 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets | $ (62) |  | $ (7) |
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] | Other Income |  | Other Income |
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 | 132 |  | 219 |
Total (gains)/losses included in earnings, liabilities | $ 28 |  | $ 38 |
Fair Value, Liability, 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, liabilities | $ (28) | [3] | $ (44) | [4]
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 |
Purchases, liabilities | $ 0 |  | $ 0 |
Issuances, liabilities | 0 |  | 62 |
Settlements, liabilities | (40) |  | (46) |
Sales, liabilities | (20) |  | (97) |
Transfers into Level 3, liabilities | 0 |  | 0 |
Transfers out of Level 3, liabilities | 0 |  | 0 |
Ending balance, fair value liabilities | 72 |  | 132 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities | (12) |  | 15 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held | 0 | [3] | (4) | [4]
Loans receivable - residential [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |
Beginning balance, fair value assets | 35 |  | 78 |
Total gains/(losses) included in earnings, assets | (4) |  | (33) |
Unrealized gains/(losses) included in OCI, assets | 0 | [1] | 0 | [2]
Purchases, assets | 0 |  | 0 |
Issuances, assets | 0 |  | 0 |
Settlements, assets | (3) |  | (9) |
Sales, assets | 0 |  | (1) |
Transfers into level 3, assets | 0 |  | 0 |
Transfers out of level 3, assets | 0 |  | 0 |
Ending balance, fair value assets | 28 |  | 35 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets | (6) |  | 1 |
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 | 1 |  | 0 |
Total gains/(losses) included in earnings, assets | (2) |  | 0 |
Unrealized gains/(losses) included in OCI, assets | 0 | [1] | 0 | [2]
Purchases, assets | 17 |  | 0 |
Issuances, assets | 0 |  | 0 |
Settlements, assets | 0 |  | 0 |
Sales, assets | 0 |  | 0 |
Transfers into level 3, assets | 0 |  | 1 |
Transfers out of level 3, assets | 0 |  | 0 |
Ending balance, fair value assets | 16 | [5] | 1 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets | 0 |  | 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 | 108 |  | 115 |
Total gains/(losses) included in earnings, assets | (56) |  | (7) |
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 |  | 108 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets | (56) |  | (7) |
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 | 40 |  | 41 |
Total (gains)/losses included in earnings, liabilities | (4) |  | 5 |
Unrealized (gains)/losses included in OCI, liabilities | (1) | [3] | (6) | [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 | 35 |  | 40 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities | (4) |  | 5 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held | (1) | [3] | (6) | [4]
Variable Interest Entity Notes [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |
Beginning balance, fair value liabilities | 78 |  | 172 |
Total (gains)/losses included in earnings, liabilities | 40 |  | 25 |
Unrealized (gains)/losses included in OCI, liabilities | (27) | [3] | (38) | [4]
Purchases, liabilities | 0 |  | 0 |
Issuances, liabilities | 0 |  | 62 |
Settlements, liabilities | (40) |  | (46) |
Sales, liabilities | (20) |  | (97) |
Transfers into Level 3, liabilities | 0 |  | 0 |
Transfers out of Level 3, liabilities | 0 |  | 0 |
Ending balance, fair value liabilities | 31 |  | 78 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities | 0 |  | 2 |
Change in Unrealized Gains/ (Losses) for the Period Included in OCI for Liabilities still held | 1 | [3] | 2 | [4]
Currency Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |
Beginning balance, fair value liabilities | 14 |  | 6 |
Total (gains)/losses included in earnings, liabilities | (8) |  | 8 |
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 |  | 14 |
Change in unrealized gains/(losses) for the period included in earnings for liabilities still held, liabilities | (8) |  | 8 |
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 |  | 23 |
Total gains/(losses) included in earnings, assets | 0 |  | 4 |
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 | (2) |  | (25) |
Transfers into level 3, assets | 0 |  | 0 |
Transfers out of level 3, assets | 0 |  | 0 |
Ending balance, fair value assets | 0 |  | 2 |
Change in unrealized gains/(losses) for the period included in earnings for assets still held, assets | 0 |  | (1) |
Change in unrealized gains/(losses) for the period included in OCI for Assets still held, assets | $ 0 | [1] | $ 0 | [2]
[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 $15 million.

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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 transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy. + 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 (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3). + 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)(1a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy. + 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)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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