v3.26.1
DWS Government and Agency Securities Portfolio Average Annual Total Returns - Government Cash Managed Shares [Member] - Government Cash Managed Shares - Return Before Taxes[Member]
12 Months Ended 60 Months Ended 120 Months Ended
Jul. 28, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Prospectus [Line Items]        
Average Annual Return, Percent   3.99% 3.01% 1.94%
Performance Inception Date Feb. 16, 2007