Nasdaq Stockholders' Equity (Schedule of Dividends Declared) (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2026 |
Jun. 30, 2026 |
Mar. 31, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Equity [Abstract] | ||||||
| Dividend per common share (in dollars per share) | $ 0.31 | $ 0.31 | $ 0.27 | $ 0.27 | $ 0.89 | $ 0.78 |
| Total Amount Paid | $ 173 | $ 174 | $ 153 | $ 500 | ||