Regulation and Capital Adequacy - Risk-Based Capital and Leverage Requirements (Detail)	Oct. 01, 2023	Sep. 30, 2023	Dec. 31, 2022
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum required CET1 ratio applicable to advanced approach banking institutions		4.50%	4.50%
Minimum required Tier 1 capital ratio applicable to advanced approach banking institutions		6.00%	6.00%
Minimum required Total capital ratio applicable to advanced approach banking institutions		8.00%	8.00%
Banking Regulation, global systemically important bank (GSIB) surcharge		0.030	0.025
Counter-cyclical capital buffer		0	0
Standardized
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital ratio		0.138	0.133
Tier 1 capital ratio		0.153	0.148
Total capital ratio		0.173	0.168
Standardized risk based ratios stress capital buffer		6.30%	6.30%
Standardized | Forecast
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Standardized risk based ratios stress capital buffer	5.50%
Advanced
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital ratio		0.100	0.095
Tier 1 capital ratio		0.115	0.110
Total capital ratio		0.135	0.130
Capital conservation buffer		2.50%	2.50%