Derivative Financial Instruments and Hedging Activities (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	$ (521)	$ (392)	$ (35)
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	818	987
Fair Value of Derivative Liabilities	2,141	3,026
Derivative, Collateral, Obligation to Return Cash	40	210
Derivative, Collateral, Right to Reclaim Cash	126	193
Derivative Asset, Not Offset, Policy Election Deduction	516	166
Derivative, Notional Amount	104,707	91,832
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	37	390	(3)
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	73,134	63,210
Interest Rate Contract [Member] \| Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Net interest settlements and accruals excluded from the assessment of hedge effectiveness	(507)	(45)	393
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	196	(1,875)	(1,001)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(260)	1,893	957
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	12,119	16,883
Interest Rate Contract [Member] \| Currency Swap [Member] \| Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Net interest settlements and accruals excluded from the assessment of hedge effectiveness	(79)	(27)	(8)
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	96	(111)	(93)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(96)	113	82
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	(35)	50	145
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	10,276	4,219
Cross Currency Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	127	(780)	$ (507)
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	7,100	6,635
Cross Currency Interest Rate Contract [Member] \| Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	2,078	885
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	465	931
Fair Value of Derivative Liabilities	1,036	483
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Interest Rate Contract [Member] \| Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	106	0
Fair Value of Derivative Liabilities	633	1,653
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	59	41
Fair Value of Derivative Liabilities	116	76
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Cross Currency Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	119	15
Fair Value of Derivative Liabilities	252	653
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Cross Currency Interest Rate Contract [Member] \| Fair Value Hedging [Member] \| Designated as Hedging Instrument [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	69	0
Fair Value of Derivative Liabilities	$ 104	$ 161

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Income Effect of Derivative Financial Instruments [Abstract]

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and contract can be net settled by means outside contract or delivery of asset, subject to master netting arrangement or similar agreement and not elected or qualified to offset, deducted from derivative asset.

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Fair value, before effects of master netting arrangements, of a 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. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or 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. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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