Goodwill and Other Intangible Assets - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) ReportableSegment	Dec. 31, 2023 USD ($) ReportableSegment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Goodwill And Other Intangible Assets [Line Items]
Amortization of core deposit and other intangible assets		$ 62,000,000	$ 56,000,000	$ 10,000,000
Changes to goodwill assigned to reporting unit	$ 0
Number of reportable segments | ReportableSegment	3	3
Impairment of goodwill		$ 0
Minimum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	3 years	3 years
Maximum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	7 years	7 years
Core Deposit and Other Intangible Assets [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	6 years	6 years
Amortization of core deposit and other intangible assets		$ 62,000,000	$ 56,000,000	$ 10,000,000
Core Deposit and Other Intangible Assets [Member] | Minimum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	3 years	3 years
Core Deposit and Other Intangible Assets [Member] | Maximum [Member]
Goodwill And Other Intangible Assets [Line Items]
Estimated useful lives	7 years	7 years