Loans Held-for-Investment (Troubled Debt Restructurings) (Details) - USD ($)
$ in Millions |
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
$ 94
|
$ 136
|
$ 408
|
| Allowance for loan losses on TDR loans |
|
15
|
81
|
| TDR loans under fair value option |
30
|
32
|
30
|
| Consumer loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
93
|
|
407
|
| Allowance for loan losses on TDR loans |
12
|
15
|
|
| Consumer loans | Residential first mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
34
|
76
|
350
|
| Consumer loans | Second mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
31
|
33
|
36
|
| Consumer loans | HELOC |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
28
|
27
|
21
|
| Commercial loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
1
|
|
|
| Commercial loans | Commercial real estate |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
|
|
1
|
| Commercial loans | Commercial and industrial |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
1
|
|
|
| Performing |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
73
|
101
|
362
|
| Performing | Consumer loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
72
|
|
361
|
| Performing | Consumer loans | Residential first mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
21
|
49
|
306
|
| Performing | Consumer loans | Second mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
30
|
32
|
35
|
| Performing | Consumer loans | HELOC |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
21
|
20
|
20
|
| Performing | Commercial loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
1
|
|
|
| Performing | Commercial loans | Commercial real estate |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
|
|
1
|
| Performing | Commercial loans | Commercial and industrial |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
1
|
|
|
| Nonperforming |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
21
|
35
|
46
|
| Nonperforming | Consumer loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
21
|
|
46
|
| Nonperforming | Consumer loans | Residential first mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
13
|
27
|
44
|
| Nonperforming | Consumer loans | Second mortgage |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
1
|
1
|
1
|
| Nonperforming | Consumer loans | HELOC |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
7
|
$ 7
|
1
|
| Nonperforming | Commercial loans |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
0
|
|
|
| Nonperforming | Commercial loans | Commercial real estate |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
|
|
$ 0
|
| Nonperforming | Commercial loans | Commercial and industrial |
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
| TDR balance |
$ 0
|
|
|