| Document and Entity Information | Nov. 24, 2021 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001836833 |
| Document Type | 8-K |
| Document Period End Date | Nov. 24, 2021 |
| Entity Registrant Name | dMY Technology Group, Inc. IV |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40166 |
| Entity Tax Identification Number | 85-2992192 |
| Entity Address, City or Town | 1180 North Town Center Drive |
| Entity Address, Address Line One | Suite 100 |
| Entity Address, Address Line Two | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89144 |
| City Area Code | (702) |
| Local Phone Number | 781-4313 |
| 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 |
| Units Each Consisting Of One Share Of Class A Common Stock And One Fifth Of One Redeemable Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Units, each consisting of one share of Class A common stock and one-fifth of one redeemable warrant |
| Trading Symbol | DMYQ.U |
| Security Exchange Name | NYSE |
| Class 160 A Common Stock Par Value 0.0001 Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A common stock, par value $0.0001 per share |
| Trading Symbol | DMYQ |
| Security Exchange Name | NYSE |
| Warrants Each Whole Warrant Exercisable For One Share Of Class A Common Stock Each At An Exercise Price Of 11.50 Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Warrants, each whole warrant exercisable for one share of Class A common stock, each at an exercise price of $11.50 per share |
| Trading Symbol | DMYQ WS |
| Security Exchange Name | NYSE |
