Derivatives - Derivative Balance Sheet Classification (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 7,689	$ 12,363
Fair Value	25	7
Asset Derivatives	71	57
Liability Derivatives	(46)	(50)
Available-for-sale Securities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	657	645
Fair Value	0	0
Asset Derivatives	0	0
Liability Derivatives	0	0
Other investments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,286	1,662
Fair Value	47	(1)
Asset Derivatives	56	18
Liability Derivatives	(9)	(19)
Other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	5,746	10,056
Fair Value	(22)	8
Asset Derivatives	15	39
Liability Derivatives	(37)	(31)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,582	8,269
Fair Value	(1)	(5)
Asset Derivatives	31	27
Liability Derivatives	(32)	(32)
Interest rate swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	3,450	3,450
Fair Value	(1)	(1)
Asset Derivatives	1	1
Liability Derivatives	(2)	(2)
Interest rate swaps \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,300	6,600
Foreign currency swaps \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	657	644
Fair Value	27	13
Asset Derivatives	39	29
Liability Derivatives	(12)	(16)
Total cash flow hedges
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	4,107	4,094
Fair Value	26	12
Asset Derivatives	40	30
Liability Derivatives	(14)	(18)
Interest rate swaps and futures \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,929	6,626
Fair Value	(1)	(5)
Asset Derivatives	0	0
Liability Derivatives	(1)	(5)
Foreign currency swaps and forwards \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	657	645
Fair Value	0	0
Asset Derivatives	0	0
Liability Derivatives	0	0
Credit derivatives in offsetting positions \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	996	998
Fair Value	0	0
Asset Derivatives	31	27
Liability Derivatives	$ (31)	$ (27)

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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- Definition

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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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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- Definition

Nominal or face amount used to calculate payment on derivative.

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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.

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