Derivative Financial Instruments - Exposure to Credit Loss on Call Options Held (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Fair Value	$ 849	$ 575
Not Designated as Hedging Instrument \| Call options
Derivatives, Fair Value [Line Items]
Notional Amount	19,404	15,909
Fair Value	816	548
Collateral	790	491
Maximum amount of loss due to credit risk	42	58
Not Designated as Hedging Instrument \| Call options \| Merrill Lynch
Derivatives, Fair Value [Line Items]
Notional Amount	3,307	1,932
Fair Value	128	75
Collateral	86	32
Maximum amount of loss due to credit risk	42	43
Not Designated as Hedging Instrument \| Call options \| Morgan Stanley
Derivatives, Fair Value [Line Items]
Notional Amount	2,184	1,503
Fair Value	86	40
Collateral	92	41
Maximum amount of loss due to credit risk	0	0
Not Designated as Hedging Instrument \| Call options \| Barclay's Bank
Derivatives, Fair Value [Line Items]
Notional Amount	5,197	4,639
Fair Value	231	180
Collateral	233	169
Maximum amount of loss due to credit risk	0	11
Not Designated as Hedging Instrument \| Call options \| Canadian Imperial Bank of Commerce
Derivatives, Fair Value [Line Items]
Notional Amount	2,936	2,276
Fair Value	147	86
Collateral	151	85
Maximum amount of loss due to credit risk	0	1
Not Designated as Hedging Instrument \| Call options \| Wells Fargo
Derivatives, Fair Value [Line Items]
Notional Amount	2,445	2,900
Fair Value	89	106
Collateral	90	105
Maximum amount of loss due to credit risk	0	1
Not Designated as Hedging Instrument \| Call options \| Goldman Sachs
Derivatives, Fair Value [Line Items]
Notional Amount	307	634
Fair Value	10	15
Collateral	10	15
Maximum amount of loss due to credit risk	0	0
Not Designated as Hedging Instrument \| Call options \| Credit Suisse
Derivatives, Fair Value [Line Items]
Notional Amount	1,485	1,373
Fair Value	74	27
Collateral	75	25
Maximum amount of loss due to credit risk	0	2
Not Designated as Hedging Instrument \| Call options \| Truist
Derivatives, Fair Value [Line Items]
Notional Amount	1,543	652
Fair Value	51	19
Collateral	53	19
Maximum amount of loss due to credit risk	$ 0	$ 0

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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Fair value, after effects of master netting arrangements, of 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 offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Nominal or face amount used to calculate payment on derivative.

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No definition available.

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