v3.26.1
DWS Government and Agency Securities Portfolio Average Annual Total Returns - Service Shares [Member] - Service 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   3.34% 2.53% 1.50%
Performance Inception Date Dec. 03, 1990