Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 1,414	$ 1,096	$ 4,165	$ 3,197
Transaction-based expenses:
Revenues less transaction-based expenses	715	632	2,115	1,889
Operating expenses:
Compensation and benefits	198	175	582	518
Professional and contract services	38	31	96	99
Computer operations and data communications	39	33	109	98
Occupancy	29	24	80	72
General, administrative and other	13	40	99	95
Marketing and advertising	7	8	20	29
Depreciation and amortization	51	47	149	143
Regulatory	2	8	16	23
Merger and strategic initiatives	1	10	12	25
Restructuring charges	11	30	36	30
Total operating expenses	389	406	1,199	1,132
Operating income	326	226	916	757
Interest income	0	3	4	8
Interest expense	(24)	(29)	(77)	(97)
Net gain on divestiture of business	0	0	0	27
Other income	1	0	5	1
Net income from unconsolidated investees	54	15	97	71
Income before income taxes	357	215	945	767
Income tax provision	93	65	237	196
Net income attributable to Nasdaq	$ 264	$ 150	$ 708	$ 571
Per share information:
Basic earnings per share (in dollars per share)	$ 1.61	$ 0.91	$ 4.31	$ 3.46
Diluted earnings per share (in dollars per share)	1.58	0.90	4.25	3.42
Cash dividends declared per common share (in dollars per share)	$ 0.49	$ 0.47	$ 1.45	$ 1.38
Transaction rebates
Transaction-based expenses:
Transaction-based expenses	$ (518)	$ (349)	$ (1,526)	$ (1,012)
Brokerage, clearance and exchange fees
Transaction-based expenses:
Transaction-based expenses	(181)	(115)	(524)	(296)
Operating Segments | Market Services
Revenues:
Total revenues	958	690	2,867	1,995
Transaction-based expenses:
Revenues less transaction-based expenses	259	226	817	687
Operating expenses:
Operating income	154	129	509	392
Operating Segments | Corporate Services
Revenues:
Total revenues	132	124	386	368
Transaction-based expenses:
Revenues less transaction-based expenses	132	124	386	368
Operating expenses:
Operating income	51	45	145	134
Operating Segments | Information Services
Revenues:
Total revenues	238	198	661	585
Operating Segments | Market Technology
Revenues:
Total revenues	86	84	251	239
Other Revenues
Revenues:
Total revenues	$ 0	$ 0	$ 0	10
Transaction-based expenses:
Revenues less transaction-based expenses				$ 10