Derivative Instruments - Asset and Liability Management Derivative Positions of Company (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Notional Value	$ 768,000
Asset and Liability Management Positions [Member]
Derivative [Line Items]
Notional Value	116,117	$ 118,061
Fair Value, Assets	350	449
Fair Value, Liabilities	409	548
Asset and Liability Management Positions [Member] \| Other Derivatives [Member]
Derivative [Line Items]
Notional Value	1,792	1,879
Fair Value, Assets		1
Fair Value, Liabilities	125	183
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value	9,653	11,971
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value	7,033	8,616
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Futures and Forwards [Member] \| Purchased [Member]
Derivative [Line Items]
Notional Value	9,322	18,356
Fair Value, Assets	10	73
Fair Value, Liabilities	16	5
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Futures and Forwards [Member] \| Written [Member]
Derivative [Line Items]
Notional Value	29,348	39,416
Fair Value, Assets	25	48
Fair Value, Liabilities	27	157
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Options [Member] \| Purchased [Member]
Derivative [Line Items]
Notional Value	18,570	11,610
Fair Value, Assets	256	121
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Interest Rate Contracts [Member] \| Options [Member] \| Written [Member]
Derivative [Line Items]
Notional Value	9,662	12,843
Fair Value, Assets	52	202
Fair Value, Liabilities	231	198
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	735	633
Fair Value, Assets	2	1
Fair Value, Liabilities	6	2
Asset and Liability Management Positions [Member] \| Other Economic Hedges [Member] \| Equity Contracts [Member]
Derivative [Line Items]
Notional Value	209	172
Fair Value, Assets	5	3
Asset and Liability Management Positions [Member] \| Fair Value Hedges [Member] \| Interest Rate Contracts [Member] \| Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value	12,350	8,400
Asset and Liability Management Positions [Member] \| Fair Value Hedges [Member] \| Interest Rate Contracts [Member] \| Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value	16,650	100
Asset and Liability Management Positions [Member] \| Cash Flow Hedges [Member] \| Interest Rate Contracts [Member] \| Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value		3,250
Asset and Liability Management Positions [Member] \| Net Investment Hedges [Member] \| Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Notional Value	793	815
Fair Value, Liabilities	$ 4	$ 3

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 not subject to a master netting arrangement and elected not to be offset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226052-175313

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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 not subject to a master netting arrangement and elected not to be offset.

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

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