Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Total revenues	$ 1,652	$ 1,353
Transaction-based expenses:
Revenues less transaction-based expenses	851	701
Operating expenses:
Compensation and benefits	239	195
Professional and contract services	27	27
Computer operations and data communications	44	35
Occupancy	28	25
General, administrative and other	13	61
Marketing and advertising	10	9
Depreciation and amortization	63	48
Regulatory	7	7
Merger and strategic initiatives	45	7
Restructuring charges	10	12
Total operating expenses	486	426
Operating income	365	275
Interest income	1	2
Interest expense	(29)	(26)
Other income	1	5
Net income from unconsolidated investees	57	17
Income before income taxes	395	273
Income tax provision	97	70
Net income attributable to Nasdaq	$ 298	$ 203
Per share information:
Basic earnings per share (in dollars per share)	$ 1.81	$ 1.23
Diluted earnings per share (in dollars per share)	1.78	1.22
Cash dividends declared per common share (in dollars per share)	$ 0.49	$ 0.47
Transaction rebates
Transaction-based expenses:
Transaction-based expenses	$ (654)	$ (479)
Brokerage, clearance and exchange fees
Transaction-based expenses:
Transaction-based expenses	(147)	(173)
Operating Segments | Market Services
Revenues:
Total revenues	1,139	933
Transaction-based expenses:
Revenues less transaction-based expenses	338	281
Operating expenses:
Operating income	228	178
Operating Segments | Corporate Platforms
Revenues:
Total revenues	155	128
Transaction-based expenses:
Revenues less transaction-based expenses	155	128
Operating expenses:
Operating income	65	45
Operating Segments | Investment Intelligence
Revenues:
Total revenues	258	211
Transaction-based expenses:
Revenues less transaction-based expenses	258	211
Operating expenses:
Operating income	167	134
Operating Segments | Market Technology
Revenues:
Total revenues	100	81
Transaction-based expenses:
Revenues less transaction-based expenses	100	81
Operating expenses:
Operating income	$ (2)	$ 8