Label	Element	Value
Western Asset SMASh Series C Fund \| Financials [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	26.10%
Western Asset SMASh Series C Fund \| Energy [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	14.30%
Western Asset SMASh Series C Fund \| Communication Services [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	12.30%
Western Asset SMASh Series C Fund \| Health Care [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	8.40%
Western Asset SMASh Series C Fund \| Sovereign Bonds [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	7.00%
Western Asset SMASh Series C Fund \| Asset-Backed Securities [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	6.90%
Western Asset SMASh Series C Fund \| Utilities [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	6.80%
Western Asset SMASh Series C Fund \| Industrials [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	5.20%
Western Asset SMASh Series C Fund \| Information Technology [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	3.70%
Western Asset SMASh Series C Fund \| Materials [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	2.90%
Western Asset SMASh Series C Fund \| Consumer Discretionary [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	2.80%
Western Asset SMASh Series C Fund \| Consumer Staples [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	2.10%
Western Asset SMASh Series C Fund \| U.S. Government & Agency Obligations [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	1.00%
Western Asset SMASh Series C Fund \| Real Estate [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	0.10%
Western Asset SMASh Series C Fund \| Short-Term Investments [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	0.40%