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Derivative Financial Instruments - Mark-to-Market Impact of Derivatives on Statements of Income (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | $ 11 | $ 171 | $ 64
Interest Expense and Derivative Instruments Hedging Activities [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | (35) | 254 | 152
Designated as Hedging Instrument [Member] | Fair Value [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | (46) | 83 | 88
Designated as Hedging Instrument [Member] | Fair Value [Member] | Interest Rate Swaps [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Gains (losses) recognized in net income on derivatives | 104 | (610) | (310)
Gains (losses) recognized in net income on hedged items | (86) | 96 | (55)
Net fair value hedge ineffectiveness gains (losses) | (24) | 50 | 39
Designated as Hedging Instrument [Member] | Fair Value [Member] | Cross-Currency Interest Rate Swaps [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Gains (losses) recognized in net income on derivatives | 64 | (63) | 104
Gains (losses) recognized in net income on hedged items | (128) | 660 | 349
Net fair value hedge ineffectiveness gains (losses) | (22) | 33 | 49
Designated as Hedging Instrument [Member] | Cash Flow [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | 0 | 0 | 0
Trading [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | 11 | 171 | 64
Trading [Member] | Interest Rate Swaps [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | 11 | 130 | 30
Trading [Member] | Floor Income Contracts [Member] |  |  |
Derivative Instruments Gain Loss [Line Items] |  |  |
Mark-to-market gains (losses) recognized | $ 0 | $ 41 | $ 34

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- Definition Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 25 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480238/815-25-50-1 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4E -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4E + Details
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- Definition The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -Subparagraph (a)(1),(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480238/815-25-50-1 + Details
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- Definition Amount of gain (loss) from the ineffectiveness of the hedge. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4C -Subparagraph (d)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 815 -SubTopic 25 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480238/815-25-50-1 + Details
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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A + Details
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