Repossessed Assets (Details)
$ in Millions
12 Months Ended
Dec. 31, 2015
USD ($)
family
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Repossessed Assets [Line Items]      
Repossessed assets $ 19 $ 37 $ 121
Repossessed Assets [Roll Forward]      
Beginning balance 19 37 121
Additions/transfers in 42 40 78
Disposals (27) (46) (116)
Write-down and other changes (10) (10) (11)
Transfers out (7) (2) (35)
Ending balance 17 19 $ 37
One-to-four family properties      
Repossessed Assets [Line Items]      
Repossessed assets 18 18  
Repossessed Assets [Roll Forward]      
Beginning balance 18    
Ending balance 12 18  
Commercial properties      
Repossessed Assets [Line Items]      
Repossessed assets 1 1  
Repossessed Assets [Roll Forward]      
Beginning balance 1    
Ending balance $ 5 $ 1  
Minimum      
Repossessed Assets [Line Items]      
Number of families the property can house | family 1    
Maximum      
Repossessed Assets [Line Items]      
Number of families the property can house | family 4