| Document and Entity Information | Sep. 30, 2021 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 30, 2021 |
| Entity Registrant Name | IonQ, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39694 |
| Entity Tax Identification Number | 84-2992192 |
| Entity Address, Address Line One | 4505 Campus Drive |
| Entity Address, City or Town | College Park |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20740 |
| City Area Code | 301 |
| Local Phone Number | 298-7997 |
| Entity Information, Former Legal or Registered Name | dMY Technology Group, Inc. III |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0001824920 |
| Former Address [Member] | |
| Entity Information [Line Items] | |
| Entity Address, Address Line One | 1180 North Town Center Drive |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89144 |
| Common Stock [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | IONQ |
| Security Exchange Name | NYSE |
| Warrant [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one share of Common Stock at an exercise price of $11.50 per share |
| Trading Symbol | IONQ WS |
| Security Exchange Name | NYSE |
