Loans and Allowance for Credit Losses - Summary of Financing Receivable credit losses charged-off by portfolio class (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2023	Mar. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing receivable charge offs relating to uncollectible amount on acquired loans		$ 91
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing receivables charge off relating to balance sheet repositioning and capital management actions	$ 117
Other Retail Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing receivable charge off relating to balance sheet repositioning and capital management actions one	$ 192