| Label | Element | Value |
|---|---|---|
| Advisor Class | Mortgage-Backed Securities [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 44.00% |
| Advisor Class | U.S. Government and Agency Securities [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 29.30% |
| Advisor Class | Agency Commercial Mortgage-Backed Securities [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 19.30% |
| Advisor Class | Short-Term Investments [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 7.40% |