v3.19.3.a.u2
Servicing of Financial Assets (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2019
Jun. 30, 2019
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Mar. 27, 2019
Servicing Assets at Fair Value [Line Items]            
Payments to Acquire Mortgage Servicing Rights (MSR)   $ 7 $ 24 $ 71 $ 41  
Unpaid Principal Balance of Outstanding Underlying MSRs Purchased     409 6,100 2,700  
Unpaid principal balance     34,467 36,450    
Residential mortgage servicing rights at fair value     345 418    
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     3,900 3,600    
Commercial Real Estate [Member]            
Servicing Assets at Fair Value [Line Items]            
Servicing Asset at Amortized Cost     59 56    
Residential mortgage servicing rights at fair value     64 59    
Purchase price [Member]            
Servicing Assets at Fair Value [Line Items]            
Payments to Acquire Mortgage Servicing Rights (MSR)       $ 77 $ 30  
Bulk Purchase price [Member] [Domain]            
Servicing Assets at Fair Value [Line Items]            
Payments to Acquire Mortgage Servicing Rights (MSR)     4      
Flow Purchase price [Member] [Domain]            
Servicing Assets at Fair Value [Line Items]            
Payments to Acquire Mortgage Servicing Rights (MSR)     $ 13      
Residential First Mortgage [Member]            
Servicing Assets at Fair Value [Line Items]            
Financing Receivable, Significant Sales $ 167