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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024 | Dec. 31, 2023
Derivative [Line Items] |  |  |  |
Notional Amount | $ 32,819 |  | $ 36,184 |
Reduction in estimated fair value of interest rate contracts in asset position | (533) |  | (686) |
Reduction in estimated fair value of interest rate contracts in liability position | (27) |  | (15) |
Aggregate fair value of derivative financial instruments in asset position | 105 |  | 157 |
Collateral relating to net asset positions | 106 |  | 157 |
Cash Flow Hedges |  |  |  |
Derivative [Line Items] |  |  |  |
Equity, Attributable to Parent, Before Tax | 9 | $ (359) | (135) | $ (203)
Clearinghouse Credit Facilities |  |  |  |
Derivative [Line Items] |  |  |  |
Amount of initial margin posted | 240 |  | 257 |
Interest Income |  |  |  |
Derivative [Line Items] |  |  |  |
Change in cash flow hedges derivative instruments, fair value net | (53) | (87) |  |
Interest rate swap agreements |  |  |  |
Derivative [Line Items] |  |  |  |
Cash flow hedge reclassification before tax | (62) | $ (100) |  |
Interest rate swap agreements | Maturity Period 2025 |  |  |  |
Derivative [Line Items] |  |  |  |
Equity, Attributable to Parent, Before Tax | 15 |  |  |
Interest rate swap agreements | Maturity Period 2026 |  |  |  |
Derivative [Line Items] |  |  |  |
Equity, Attributable to Parent, Before Tax | 12 |  |  |
Interest rate swap agreements | Maturity Period 2027 |  |  |  |
Derivative [Line Items] |  |  |  |
Equity, Attributable to Parent, Before Tax | 39 |  |  |
Interest rate swap agreements | Maturity Period 2028 |  |  |  |
Derivative [Line Items] |  |  |  |
Equity, Attributable to Parent, Before Tax | (3) |  |  |
Interest Rate Contracts | Not Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Amount | 40,800 |  | 40,500 |
Foreign exchange and other option and futures contracts | Not Designated as Hedging Instrument |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Amount | 1,500 |  | 1,600 |
Forward-Starting Interest Rate Swap Agreements | Fair value hedges: |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Amount | 2,500 |  | 3,400 |
Forward-Starting Interest Rate Swap Agreements | Cash flow hedges: |  |  |  |
Derivative [Line Items] |  |  |  |
Notional Amount | $ 8,500 |  | $ 10,000 |

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- Definition The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4H + Details
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- Definition Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 55 -Paragraph 9 -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-9 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 20 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-8 + Details
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