Fair Value Measurements (Fair Value Option Disclosures) (Details) - USD ($)
$ in Millions |
6 Months Ended |
12 Months Ended |
|
|
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
$ 3,034
|
$ 2,585
|
$ 1,380
|
$ 1,378
|
| Total assets at fair value |
3,159
|
2,652
|
1,407
|
1,379
|
| Assets, fair value over/(under) UPB |
125
|
67
|
27
|
1
|
| Long-term debt, fair value |
|
0
|
(84)
|
|
| DOJ Agreement |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Litigation settlement payment amount |
118
|
118
|
|
|
| DOJ Agreement | Subsequent Payments |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Litigation settlement payment amount |
(118)
|
|
|
|
| Loans held-for-sale |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
2,922
|
2,452
|
1,144
|
1,110
|
| Total assets at fair value |
3,071
|
2,541
|
1,196
|
1,141
|
| Assets, fair value over/(under) UPB |
149
|
89
|
52
|
31
|
| Loans held-for-investment |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
112
|
133
|
236
|
268
|
| Total assets at fair value |
88
|
111
|
211
|
238
|
| Assets, fair value over/(under) UPB |
(24)
|
(22)
|
(25)
|
(30)
|
| Long-term debt |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Liabilities, unpaid principal balance (UPB) |
|
0
|
(88)
|
(117)
|
| Long-term debt, fair value |
|
0
|
(84)
|
(106)
|
| Liabilities, fair value over/(under) UPB |
|
0
|
4
|
11
|
| DOJ Agreement |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Liabilities, unpaid principal balance (UPB) |
(118)
|
(118)
|
(118)
|
(118)
|
| Long-term debt, fair value |
(84)
|
(84)
|
(82)
|
(93)
|
| Liabilities, fair value over/(under) UPB |
34
|
34
|
36
|
25
|
| Nonperforming |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
23
|
22
|
11
|
11
|
| Total assets at fair value |
11
|
10
|
5
|
4
|
| Assets, fair value over/(under) UPB |
(12)
|
(12)
|
(6)
|
(7)
|
| Nonperforming | Loans held-for-sale |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
1
|
1
|
0
|
0
|
| Total assets at fair value |
1
|
0
|
0
|
0
|
| Assets, fair value over/(under) UPB |
0
|
(1)
|
0
|
0
|
| Nonperforming | Loans held-for-investment |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
22
|
21
|
11
|
11
|
| Total assets at fair value |
10
|
10
|
5
|
4
|
| Assets, fair value over/(under) UPB |
(12)
|
(11)
|
(6)
|
(7)
|
| Performing |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
3,011
|
2,563
|
1,369
|
1,367
|
| Total assets at fair value |
3,148
|
2,642
|
1,402
|
1,375
|
| Assets, fair value over/(under) UPB |
137
|
79
|
33
|
8
|
| Performing | Loans held-for-sale |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
2,921
|
2,451
|
1,144
|
1,110
|
| Total assets at fair value |
3,070
|
2,541
|
1,196
|
1,141
|
| Assets, fair value over/(under) UPB |
149
|
90
|
52
|
31
|
| Performing | Loans held-for-investment |
|
|
|
|
| Fair Value, Option, Quantitative Disclosures [Line Items] |
|
|
|
|
| Assets, unpaid principal balance (UPB) |
90
|
112
|
225
|
257
|
| Total assets at fair value |
78
|
101
|
206
|
234
|
| Assets, fair value over/(under) UPB |
$ (12)
|
$ (11)
|
$ (19)
|
$ (23)
|