| Document and Entity Information | Jan. 29, 2020 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001120193 |
| Document Type | 8-K |
| Document Period End Date | Jan. 29, 2020 |
| Entity Registrant Name | Nasdaq, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38855 |
| Entity Tax Identification Number | 52-1165937 |
| Entity Address, Address Line One | 151 W. 42nd Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10036 |
| City Area Code | 212 |
| Local Phone Number | 401 8700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock .01parvaluepershare [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $0.01 par value per share |
| Trading Symbol | NDAQ |
| Security Exchange Name | NASDAQ |
| One Point Seven Five Percent Senior Notes Due 2029 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 1.75% Senior Notes due 2029 |
| Trading Symbol | NDAQ29 |
| Security Exchange Name | NASDAQ |
| Three Point Eight Seven Five Percent Senior Notes Due 2021 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 3.875% Senior Notes due 2021 |
| Trading Symbol | NDAQ21 |
| Security Exchange Name | NASDAQ |
| One Point Seven Five Percent Senior Note Due 2023 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 1.750% Senior Notes due 2023 |
| Trading Symbol | NDAQ23 |
| Security Exchange Name | NASDAQ |
