Loans Held-for-Investment (Troubled Debt Restructuring Detail) (Details)
$ in Millions |
3 Months Ended |
6 Months Ended |
12 Months Ended |
|
Jun. 30, 2016
USD ($)
loan
|
Jun. 30, 2015
USD ($)
loan
|
Jun. 30, 2016
USD ($)
loan
|
Jun. 30, 2015
USD ($)
loan
|
Dec. 31, 2015
USD ($)
loan
|
Dec. 31, 2014
USD ($)
loan
|
Dec. 31, 2013
USD ($)
loan
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
28
|
237
|
128
|
420
|
698
|
520
|
1,211
|
| Pre-Modification Unpaid Principal Balance |
$ 3
|
$ 32
|
$ 12
|
$ 64
|
$ 102
|
$ 60
|
$ 138
|
| Post-Modification Recorded Investment |
3
|
30
|
11
|
61
|
98
|
58
|
121
|
| Increase (Decrease) in Allowance at Modification |
$ 0
|
$ (2)
|
$ 0
|
$ (1)
|
$ (2)
|
$ 3
|
$ 3
|
| Number of Accounts | loan |
|
1
|
5
|
1
|
8
|
25
|
100
|
| Unpaid Principal Balance |
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 8
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 2
|
| Residential first mortgage |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
3
|
77
|
16
|
191
|
325
|
165
|
322
|
| Pre-Modification Unpaid Principal Balance |
$ 1
|
$ 23
|
$ 3
|
$ 53
|
$ 81
|
$ 48
|
$ 86
|
| Post-Modification Recorded Investment |
1
|
22
|
4
|
52
|
80
|
47
|
75
|
| Increase (Decrease) in Allowance at Modification |
$ 0
|
$ (2)
|
$ 0
|
$ (1)
|
$ (2)
|
$ 3
|
$ 2
|
| Number of Accounts | loan |
|
|
1
|
|
3
|
2
|
26
|
| Unpaid Principal Balance |
|
|
$ 0
|
|
$ 0
|
$ 0
|
$ 6
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
|
$ 0
|
|
$ 0
|
$ 0
|
$ 1
|
| Second mortgage |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
5
|
35
|
26
|
68
|
97
|
325
|
571
|
| Pre-Modification Unpaid Principal Balance |
$ 0
|
$ 1
|
$ 1
|
$ 3
|
$ 4
|
$ 11
|
$ 22
|
| Post-Modification Recorded Investment |
0
|
1
|
1
|
2
|
3
|
10
|
20
|
| Increase (Decrease) in Allowance at Modification |
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 1
|
| Number of Accounts | loan |
|
1
|
|
1
|
2
|
18
|
41
|
| Unpaid Principal Balance |
|
$ 0
|
|
$ 0
|
$ 0
|
$ 0
|
$ 1
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
$ 0
|
|
$ 0
|
$ 0
|
$ 0
|
$ 1
|
| HELOC |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
20
|
122
|
85
|
158
|
273
|
30
|
313
|
| Pre-Modification Unpaid Principal Balance |
$ 2
|
$ 8
|
$ 6
|
$ 8
|
$ 17
|
$ 1
|
$ 27
|
| Post-Modification Recorded Investment |
2
|
7
|
5
|
7
|
15
|
1
|
23
|
| Increase (Decrease) in Allowance at Modification |
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
$ 0
|
| Number of Accounts | loan |
|
|
|
|
3
|
5
|
|
| Unpaid Principal Balance |
|
|
|
|
$ 0
|
$ 0
|
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
|
|
|
$ 0
|
$ 0
|
|
| Other |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
|
|
|
|
3
|
|
|
| Pre-Modification Unpaid Principal Balance |
|
|
|
|
$ 0
|
|
|
| Post-Modification Recorded Investment |
|
|
|
|
0
|
|
|
| Increase (Decrease) in Allowance at Modification |
|
|
|
|
$ 0
|
|
|
| Commercial real estate |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
|
|
|
|
|
|
5
|
| Pre-Modification Unpaid Principal Balance |
|
|
|
|
|
|
$ 3
|
| Post-Modification Recorded Investment |
|
|
|
|
|
|
3
|
| Increase (Decrease) in Allowance at Modification |
|
|
|
|
|
|
$ 0
|
| Number of Accounts | loan |
|
|
|
|
|
|
33
|
| Unpaid Principal Balance |
|
|
|
|
|
|
$ 1
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
|
|
|
|
|
$ 0
|
| Second Mortgage and Home Equity Line of Credit Loans | Reconsolidated as a Result of Litigation Settlements |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| New TDRs, number of accounts | loan |
|
|
|
|
|
|
463
|
| New TDRs, post-modification unpaid principal balance |
|
|
|
|
|
|
$ 31
|
| Other Consumer and Commercial Loans |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
|
3
|
|
3
|
|
|
|
| Pre-Modification Unpaid Principal Balance |
|
$ 0
|
|
$ 0
|
|
|
|
| Post-Modification Recorded Investment |
|
0
|
|
0
|
|
|
|
| Increase (Decrease) in Allowance at Modification |
|
$ 0
|
|
$ 0
|
|
|
|
| Commercial and industrial |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
|
|
1
|
|
|
|
|
| Pre-Modification Unpaid Principal Balance |
|
|
$ 2
|
|
|
|
|
| Post-Modification Recorded Investment |
|
|
1
|
|
|
|
|
| Increase (Decrease) in Allowance at Modification |
|
|
$ 0
|
|
|
|
|
| HELOC loans |
|
|
|
|
|
|
|
| Troubled Debt Restructurings [Line Items] |
|
|
|
|
|
|
|
| Number of Accounts | loan |
|
|
4
|
|
|
|
|
| Unpaid Principal Balance |
|
|
$ 0
|
|
|
|
|
| Increase (Decrease) in Allowance at Subsequent Default |
|
|
$ 0
|
|
|
|
|