Other Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Schedule Of Other Assets [Line Items]
Goodwill	$ 6,288		$ 6,288		$ 4,285
Accumulated depreciation and amortization	11,870		11,870		10,810
Property, leasehold improvements and equipment used for operation	7,200		7,200		6,710
Foreclosed real estate included in property, leasehold improvements and equipment	142		$ 142		194
Amortization period - capitalized costs of software developed or obtained for internal use			3 years
Investments in qualified affordable housing projects	751		$ 751		714
Assets classified as held for sale	1,510		1,510		$ 1,020
Property, leasehold improvements and equipment
Schedule Of Other Assets [Line Items]
Impairment of property leasehold improvements and equipment	106	$ 0	130	$ 134
Other
Schedule Of Other Assets [Line Items]
Identifiable intangible assets			$ 1,770
Identifiable intangible assets weighted average remaining life in years			13 years
2022 Acquisitions
Schedule Of Other Assets [Line Items]
Consideration transferred			$ 3,830
GreenSky, Inc
Schedule Of Other Assets [Line Items]
Goodwill	1,050		1,050
Intangible assets	710		710
Tangible assets	960		960
Liabilities assumed	990		990
NN Investment Partners
Schedule Of Other Assets [Line Items]
Goodwill	890		890
Intangible assets	900		900
Tangible assets	540		540
Liabilities assumed	510		510
Operating lease right-of-use assets
Schedule Of Other Assets [Line Items]
Right-of-use assets recognized	$ 52	$ 86	$ 168	$ 230