Fair Value Measurements - Quantitative Information about Recurring Fair Value Measurement of Assets and Liabilities Classified as Level 3 (Detail) $ in Millions		Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Mortgage servicing rights		$ 16	$ 7
Domestic deposits		(535)	(646)
Long-term debt	[1]	(17,236)	(19,979)
Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Long-term debt		(1,853)	(448)
Asset-backed securities
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Asset-backed securities available-for-sale		120	131
Residential mortgages
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Asset-backed securities available-for-sale			15
Interest rate contracts
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative assets (liability		0	34
Foreign exchange contracts
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative assets (liability		(2)	9
Equity contracts
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative assets (liability		46	119
Credit contracts
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative assets (liability		(2)	63
Other Contracts
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Derivative assets (liability		$ (33)	$ (59)
Probability to fund for rate lock commitments | Interest rate contracts | Recurring | Minimum | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.36	0.41
Probability to fund for rate lock commitments | Interest rate contracts | Recurring | Maximum | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.99	1
Probability to fund for rate lock commitments | Interest rate contracts | Recurring | Weighted Average | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.83	0.78
Interest rate yield curve | Interest rate contracts | Recurring | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08
Interest rate yield curve | Interest rate contracts | Recurring | Minimum | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.04
Interest rate yield curve | Interest rate contracts | Recurring | Maximum | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.07
Interest rate yield curve | Interest rate contracts | Recurring | Weighted Average | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.06
Implied volatility of currency pairs | Recurring | Minimum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.09
Implied volatility of currency pairs | Recurring | Minimum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0	0.09
Implied volatility of currency pairs | Recurring | Maximum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.11
Implied volatility of currency pairs | Recurring | Maximum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.09	0.11
Implied volatility of currency pairs | Recurring | Weighted Average | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.10
Implied volatility of currency pairs | Recurring | Weighted Average | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.06	0.10
Implied volatility of currency pairs | Foreign exchange contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0	0.09
Implied volatility of currency pairs | Foreign exchange contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.09	0.11
Implied volatility of currency pairs | Foreign exchange contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.06	0.10
Cross-currency basis | Foreign exchange contracts | Recurring | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		(0.0086)
Cross-currency basis | Foreign exchange contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			(0.0009)
Cross-currency basis | Foreign exchange contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.0040
Cross-currency basis | Foreign exchange contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.0024
Equity / Equity Index volatility | Recurring | Minimum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08	0
Equity / Equity Index volatility | Recurring | Minimum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08	0
Equity / Equity Index volatility | Recurring | Maximum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.21	0.42
Equity / Equity Index volatility | Recurring | Maximum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.71	0.67
Equity / Equity Index volatility | Recurring | Weighted Average | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.15	0.15
Equity / Equity Index volatility | Recurring | Weighted Average | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.31	0.23
Equity / Equity Index volatility | Equity contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08	0
Equity / Equity Index volatility | Equity contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.85	0.67
Equity / Equity Index volatility | Equity contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.40	0.27
Equity / Equity and Equity / Index correlation | Recurring | Minimum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.49	0.43
Equity / Equity and Equity / Index correlation | Recurring | Minimum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.44	0.32
Equity / Equity and Equity / Index correlation | Recurring | Maximum | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.85	0.47
Equity / Equity and Equity / Index correlation | Recurring | Maximum | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.98	0.62
Equity / Equity and Equity / Index correlation | Recurring | Weighted Average | Option adjusted discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.62	0.45
Equity / Equity and Equity / Index correlation | Recurring | Weighted Average | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.82	0.52
Equity / Equity and Equity / Index correlation | Equity contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.44	0.17
Equity / Equity and Equity / Index correlation | Equity contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.98	0.62
Equity / Equity and Equity / Index correlation | Equity contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.81	0.30
Equity dividend yields and forward price | Equity contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		(0.04)	(0.01)
Equity dividend yields and forward price | Equity contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.01	0
Equity dividend yields and forward price | Equity contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0	0
Credit default swap spreads | Recurring | Option adjusted discounted cash flows | Structured notes
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.0798
Credit default swap spreads | Credit contracts | Recurring | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.0150
Credit default swap spreads | Credit contracts | Recurring | Minimum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.0076
Credit default swap spreads | Credit contracts | Recurring | Maximum | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.0325
Credit default swap spreads | Credit contracts | Recurring | Weighted Average | Option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.0234
Conversion rate | Other Contracts | Recurring | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		1.6	1.6
Expected duration | Other Contracts | Recurring | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		1	2
Market assumptions related to yields for comparable instruments | Asset-backed securities | Recurring | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.04
Market assumptions related to yields for comparable instruments | Asset-backed securities | Recurring | Minimum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.03
Market assumptions related to yields for comparable instruments | Asset-backed securities | Recurring | Maximum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.04
Market assumptions related to yields for comparable instruments | Asset-backed securities | Recurring | Weighted Average | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.03
Constant prepayment rates | Recurring | Minimum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.10	0.17
Constant prepayment rates | Recurring | Maximum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.16	0.26
Constant prepayment rates | Recurring | Weighted Average | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.12	0.19
Constant prepayment rates | Residential mortgages | Recurring | Broker quotes or consensus pricing and, where applicable, discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.10
Discount rate | Recurring | Minimum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08	0.09
Discount rate | Recurring | Maximum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.13	0.10
Discount rate | Recurring | Weighted Average | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		0.08	0.09
Estimated annualized costs to service | Recurring | Minimum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		72	73
Estimated annualized costs to service | Recurring | Maximum | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		85	157
Estimated annualized costs to service | Recurring | Weighted Average | Discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs		75	76
Conditional default rates | Residential mortgages | Recurring | Broker quotes or consensus pricing and, where applicable, discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.05
Loss severity rates | Residential mortgages | Recurring | Broker quotes or consensus pricing and, where applicable, discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.65
Discount margin | Residential mortgages | Recurring | Broker quotes or consensus pricing and, where applicable, discounted cash flows
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.0500
Likelihood of transaction being executed | Interest rate contracts | Recurring | Market comparable adjusted for probability to fund and, where applicable, discounted cash flows or option pricing model
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Range of Inputs			0.90

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2021 and 2020. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20212020(in millions)AssetsLoans$46 $10 Other assets55 79 Total assets$101 $89 LiabilitiesInterest, taxes and other liabilities$9 $10 Total liabilities$9 $10