DWS S&P 500 Index Fund Average Annual Total Returns		12 Months Ended	60 Months Ended	105 Months Ended	120 Months Ended
DWS S&P 500 Index Fund Average Annual Total Returns	Apr. 28, 2026	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		17.88%	14.42%		14.82%
Class A \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent		10.69%	11.21%		12.06%
Class A \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent		7.66%	9.79%		10.85%
Class A \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		11.95%	12.76%		13.69%
Performance Inception Date	Feb. 15, 2005
Class C \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		15.36%	12.98%		13.40%
Performance Inception Date	Feb. 15, 2005
Class R6 \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		17.58%	14.15%	14.59%
Performance Inception Date	Mar. 31, 2017
Class R6 \| S&P 500® Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		17.88%	14.42%	14.79%
Class S \| Return Before Taxes[Member]
Prospectus [Line Items]
Average Annual Return, Percent		17.52%	14.09%		14.51%
Performance Inception Date	Aug. 29, 1997