v3.20.4
Servicing of Financial Assets (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Mar. 27, 2019
Servicing Assets at Fair Value [Line Items]          
Unpaid principal balance   $ 34,454 $ 34,467    
Residential mortgage servicing rights at fair value   296 345    
Unpaid Principal Balance of Outstanding Underlying MSRs Purchased     409 $ 6,100  
Payments to Acquire Mortgage Servicing Rights (MSR)   59 24 71  
Flow Purchase price [Member] [Domain]          
Servicing Assets at Fair Value [Line Items]          
Payments to Acquire Mortgage Servicing Rights (MSR)   59 13    
Purchase price [Member]          
Servicing Assets at Fair Value [Line Items]          
Payments to Acquire Mortgage Servicing Rights (MSR)       $ 77  
Bulk Purchase price [Member] [Domain]          
Servicing Assets at Fair Value [Line Items]          
Payments to Acquire Mortgage Servicing Rights (MSR) $ 7   4    
Residential Real Estate [Member]          
Servicing Assets at Fair Value [Line Items]          
Servicing Asset         $ 2
DUS Portfolio [Member]          
Servicing Assets at Fair Value [Line Items]          
Unpaid principal balance   4,500 3,900    
Commercial Real Estate [Member]          
Servicing Assets at Fair Value [Line Items]          
Servicing Asset at Amortized Cost   74 59    
Residential mortgage servicing rights at fair value   $ 81 64    
Residential First Mortgage [Member]          
Servicing Assets at Fair Value [Line Items]          
Financing Receivable, Significant Sales     $ 167