Derivative Financial Instruments - Exposure to Credit Loss on Call Options Held (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Fair Value	$ 977	$ 546
Not Designated as Hedging Instrument \| Call options
Derivatives, Fair Value [Line Items]
Notional Amount	29,968	23,297
Fair Value	796	244
Collateral	775	219
Net Credit Risk	39	33
Not Designated as Hedging Instrument \| Call options \| Merrill Lynch
Derivatives, Fair Value [Line Items]
Notional Amount	4,408	3,563
Fair Value	96	23
Collateral	59	0
Net Credit Risk	37	23
Not Designated as Hedging Instrument \| Call options \| Morgan Stanley
Derivatives, Fair Value [Line Items]
Notional Amount	3,466	1,699
Fair Value	102	14
Collateral	116	19
Net Credit Risk	0	0
Not Designated as Hedging Instrument \| Call options \| Barclay's Bank
Derivatives, Fair Value [Line Items]
Notional Amount	6,236	6,049
Fair Value	102	65
Collateral	100	59
Net Credit Risk	2	6
Not Designated as Hedging Instrument \| Call options \| Canadian Imperial Bank of Commerce
Derivatives, Fair Value [Line Items]
Notional Amount	5,983	5,169
Fair Value	147	68
Collateral	148	64
Net Credit Risk	0	4
Not Designated as Hedging Instrument \| Call options \| Wells Fargo
Derivatives, Fair Value [Line Items]
Notional Amount	1,443	1,361
Fair Value	58	17
Collateral	60	17
Net Credit Risk	0	0
Not Designated as Hedging Instrument \| Call options \| Goldman Sachs
Derivatives, Fair Value [Line Items]
Notional Amount	1,919	1,133
Fair Value	45	9
Collateral	45	10
Net Credit Risk	0	0
Not Designated as Hedging Instrument \| Call options \| Credit Suisse
Derivatives, Fair Value [Line Items]
Notional Amount	92	1,039
Fair Value	4	5
Collateral	4	5
Net Credit Risk	0	0
Not Designated as Hedging Instrument \| Call options \| Truist
Derivatives, Fair Value [Line Items]
Notional Amount	2,759	2,489
Fair Value	124	35
Collateral	124	36
Net Credit Risk	0	0
Not Designated as Hedging Instrument \| Call options \| Citibank
Derivatives, Fair Value [Line Items]
Notional Amount	1,073	795
Fair Value	27	8
Collateral	28	9
Net Credit Risk	0	$ 0
Not Designated as Hedging Instrument \| Call options \| JP Morgan
Derivatives, Fair Value [Line Items]
Notional Amount	2,589
Fair Value	91
Collateral	91
Net Credit Risk	$ 0

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

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