Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Summary of Significant Accounting Principles - New Accounting Standards (Details)
 3 Months Ended
Jan. 01, 2020
USD ($)
Mar. 31, 2020
USD ($)
portfolio_segment
Dec. 31, 2019
USD ($)
Mar. 31, 2019
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Allowance for credit losses   $ 17,126,000,000   $ 10,379,000,000
Retained earnings   $ (155,866,000,000) $ (156,319,000,000)  
Number of portfolio segments | portfolio_segment   3    
Expected credit losses   $ 0    
ASU 2020-04        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Cumulative effect of new accounting principle $ 0      
Accounting Standards Update 2016-13        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Cumulative effect of new accounting principle (2,406,000,000)      
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13        
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%      
Retained earnings $ 2,400,000,000