Derivative Financial Instruments - Information about Interest Rate Swap Agreements (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Notional Amount	$ 27,277	$ 26,977
Fair Value Hedges [Member]
Derivative [Line Items]
Impact of estimated fair value gain (losses) on hedging instruments	104	43
Fair Value Hedges [Member] \| Forward-Starting Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Notional Amount	1,800	1,000
Cash Flow Hedges [Member]
Derivative [Line Items]
Impact of estimated fair value gain (losses) on hedging instruments	361	214
Cash Flow Hedges [Member] \| Forward-Starting Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Notional Amount	$ 6,000	$ 9,000

Impact in estimated fair value gain (losses ) on hedging instruments.

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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 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-5

+ Details

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A

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- Details

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