Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Principles - New Accounting Standards (Details)

v3.20.2
Summary of Significant Accounting Principles - New Accounting Standards (Details)
Loan in Thousands
 9 Months Ended
Jan. 01, 2020
USD ($)
Sep. 30, 2020
USD ($)
Loan
portfolio_segment
Jun. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Dec. 31, 2018
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Impact of adoption   $ 268,850,000,000 $ 265,637,000,000 $ 264,810,000,000 $ 268,387,000,000 $ 271,408,000,000 $ 265,325,000,000
Allowance for credit losses   21,506,000,000     $ 10,242,000,000    
Retained earnings   $ (160,447,000,000)   (156,319,000,000)      
Number of portfolio segments | portfolio_segment   3          
Expected credit losses   $ 0          
Number of loans funded under Paycheck Protection Program, CARES Act | Loan   343          
Loans and leases   $ 955,172,000,000   983,426,000,000      
Cumulative Effect, Period of Adoption, Adjustment              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Allowance for credit losses $ 3,300,000,000            
Loans and leases receivable, percentage increase in allowance 32.00%            
Smalll Business Administration (SBA), CARES Act, Paycheck Protection Program              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Loans and leases   $ 24,700,000,000          
ASU 2020-04              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Impact of adoption $ 0            
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment              
New Accounting Pronouncements or Change in Accounting Principle [Line Items]              
Impact of adoption       $ (2,406,000,000)      
Allowance for credit losses 3,300,000,000            
Retained earnings $ 2,400,000,000