Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues:
Total revenues	$ 1,353	$ 1,039
Transaction-based expenses:
Revenues less transaction-based expenses	701	634
Operating expenses:
Compensation and benefits	195	175
Professional and contract services	27	37
Computer operations and data communications	35	33
Occupancy	25	24
General, administrative and other	61	16
Marketing and advertising	9	10
Depreciation and amortization	48	48
Regulatory	7	7
Merger and strategic initiatives	7	9
Restructuring charges	12	0
Total operating expenses	426	359
Operating income	275	275
Interest income	2	3
Interest expense	(26)	(37)
Net gain on divestiture of business	0	27
Other income	5	0
Net income from unconsolidated investees	17	45
Income before income taxes	273	313
Income tax provision	70	66
Net income attributable to Nasdaq	$ 203	$ 247
Per share information:
Basic earnings per share (in dollars per share)	$ 1.23	$ 1.49
Diluted earnings per share (in dollars per share)	1.22	1.48
Cash dividends declared per common share (in dollars per share)	$ 0.47	$ 0.44
Transaction rebates
Transaction-based expenses:
Transaction-based expenses	$ (479)	$ (331)
Brokerage, clearance and exchange fees
Transaction-based expenses:
Transaction-based expenses	(173)	(74)
Operating Segments | Market Services
Revenues:
Total revenues	933	638
Transaction-based expenses:
Revenues less transaction-based expenses	281	233
Operating expenses:
Operating income	178	135
Operating Segments | Corporate Services
Revenues:
Total revenues	128	121
Transaction-based expenses:
Revenues less transaction-based expenses	128	121
Operating expenses:
Operating income	45	44
Operating Segments | Information Services
Revenues:
Total revenues	211	193
Operating Segments | Market Technology
Revenues:
Total revenues	81	77
Other Revenues
Revenues:
Total revenues	$ 0	10
Transaction-based expenses:
Revenues less transaction-based expenses		$ 10