Document and Entity Information |
6 Months Ended |
|---|---|
Jun. 30, 2016 | |
| Document and Entity Information [Abstract] | |
| Entity Registrant Name | FLAGSTAR BANCORP INC |
| Entity Central Index Key | 0001033012 |
| Document Type | S-4 |
| Document Period End Date | Jun. 30, 2016 |
| Amendment Flag | false |
| Entity Filer Category | Accelerated Filer |