Variable Interest Entities (VIEs) (Consolidated VIEs) (Details) - USD ($) $ in Millions |
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|
| Private-label Securitizations [Line Items] | |||
| Loans held-for-investment | $ 6,107 | $ 6,650 | $ 5,279 |
| Long-term debt | $ 247 | $ 247 | 331 |
| Variable Interest Entity, Primary Beneficiary | HELOC Securitizations | |||
| Private-label Securitizations [Line Items] | |||
| Loans held-for-investment | 132 | ||
| Long-term debt | 84 | ||
| FSTAR 2005-1 HELOC Securitization | Variable Interest Entity, Primary Beneficiary | HELOC Securitizations | |||
| Private-label Securitizations [Line Items] | |||
| Loans held-for-investment | 63 | ||
| Long-term debt | 42 | ||
| FSTAR 2006-2 HELOC Securitization | Variable Interest Entity, Primary Beneficiary | HELOC Securitizations | |||
| Private-label Securitizations [Line Items] | |||
| Loans held-for-investment | 69 | ||
| Long-term debt | $ 42 |