Nasdaq Stockholders' Equity (Common Stock in Treasury) (Details) - Share repurchase program $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2026 USD ($) $ / shares shares
Dividends Payable [Line Items]
Number of shares of common stock repurchased (in shares) | shares	10,392,733
Average price paid per share (in dollars per share) | $ / shares	$ 86.91
Total purchase price (in millions) | $	$ 903