Derivative Financial Instruments and Hedging Activities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Derivative [Line Items]
Debt Carrying Value Fair Value	$ 42,200,000,000		$ 42,200,000,000		$ 38,700,000,000
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	(36,000,000)	$ (221,000,000)	(351,000,000)	$ (483,000,000)
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	1,388,000,000		1,388,000,000		818,000,000
Fair Value of Derivative Liabilities	1,712,000,000		1,712,000,000		2,141,000,000
Derivative, Notional Amount	114,769,000,000		114,769,000,000		104,707,000,000
Derivative, Collateral, Obligation to Return Cash	35,000,000		35,000,000		40,000,000
Derivative, Collateral, Right to Reclaim Cash	145,000,000		145,000,000		126,000,000
Derivative Asset, Not Offset, Policy Election Deduction	843,000,000		843,000,000		516,000,000
Derivative Liability, Not Offset, Policy Election Deduction	843,000,000		843,000,000		516,000,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Net interest settlements and accruals excluded from the assessment of hedge effectiveness	(92,000,000)	(137,000,000)	(294,000,000)	(407,000,000)
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	585,000,000	(219,000,000)	316,000,000	(285,000,000)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(553,000,000)	210,000,000	(316,000,000)	223,000,000
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	15,029,000,000		15,029,000,000		12,119,000,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Currency Swap
Income Effect of Derivative Financial Instruments [Abstract]
Net interest settlements and accruals excluded from the assessment of hedge effectiveness	(33,000,000)	(23,000,000)	(97,000,000)	(56,000,000)
Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments	266,000,000	(46,000,000)	155,000,000	(48,000,000)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(261,000,000)	44,000,000	(159,000,000)	47,000,000
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	3,802,000,000		3,802,000,000		2,078,000,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member] | Fair Value Hedging [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	329,000,000		329,000,000		106,000,000
Fair Value of Derivative Liabilities	382,000,000		382,000,000		633,000,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member] | Currency Swap
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	212,000,000		212,000,000		69,000,000
Fair Value of Derivative Liabilities	76,000,000		76,000,000		104,000,000
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	(153,000,000)	28,000,000	(102,000,000)	125,000,000
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	78,632,000,000		78,632,000,000		73,134,000,000
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	419,000,000		419,000,000		465,000,000
Fair Value of Derivative Liabilities	995,000,000		995,000,000		1,036,000,000
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member] | Affiliated Entity
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	91,000,000		91,000,000
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Income Effect of Derivative Financial Instruments [Abstract]
Derivative, Gain (Loss) on Derivative, Net	(5,000,000)	59,000,000	132,000,000	30,000,000
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	11,658,000,000		11,658,000,000		10,276,000,000
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Affiliated Entity
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	5,700,000,000		5,700,000,000
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	174,000,000		174,000,000		59,000,000
Fair Value of Derivative Liabilities	127,000,000		127,000,000		116,000,000
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member] | Affiliated Entity
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Liabilities	91,000,000		91,000,000
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	210,000,000	$ (137,000,000)	14,000,000	$ (112,000,000)
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Derivative, Notional Amount	5,648,000,000		5,648,000,000		7,100,000,000
Cross Currency Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Level 2 [Member] | Fair Value, Recurring [Member]
Balance Sheet Effect of Derivative Financial Instruments [Abstract]
Fair Value of Derivative Assets	254,000,000		254,000,000		119,000,000
Fair Value of Derivative Liabilities	$ 132,000,000		$ 132,000,000		$ 252,000,000