v3.21.2
Regulation and Capital Adequacy - Risk-based Capital (Detail) - USD ($)
$ in Millions
Sep. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Preferred stock $ 9,953 $ 11,203  
Standardized Capital Rules [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
Common shareholders' equity 96,344 84,729  
Impact of CECL transition 1,059 1,126  
Deduction for goodwill (3,652) (3,652)  
Deduction for identifiable intangible assets (478) (601)  
Other adjustments 19 39  
CET1 capital 93,292 81,641 $ 74,850
Preferred stock 9,953 11,203  
Deduction for investments in covered funds (662) (106)  
Other adjustments (3) (8)  
Tier 1 capital 102,580 92,730 85,440
Qualifying subordinated debt 12,044 12,196  
Junior subordinated debt 94 188  
Allowance for credit losses 2,896 3,095  
Other adjustments (52) (55)  
Tier 2 capital 14,982 15,424 14,925
Total capital 117,562 108,154  
Advanced Capital Rules [Member]      
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]      
CET1 capital 93,292 81,641 74,850
Tier 1 capital 102,580 92,730 85,440
Standardized Tier 2 capital 14,982 15,424  
Allowance for credit losses (2,896) (3,095)  
Other adjustments 539 950  
Tier 2 capital 12,625 13,279 $ 13,473
Total capital $ 115,205 $ 106,009