| Document and Entity Information | Sep. 29, 2021 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001841304 |
| Document Type | 8-K |
| Document Period End Date | Sep. 29, 2021 |
| Entity Registrant Name | Kensington Capital Acquisition Corp. II |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40114 |
| Entity Tax Identification Number | 86-1326226 |
| Entity Address, Address Line One | 1400 Old Country Road |
| Entity Address, Address Line Two | Suite 301 |
| Entity Address, City or Town | Westbury |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 11590 |
| City Area Code | (703) |
| Local Phone Number | 674-6514 |
| Written Communications | false |
| Soliciting Material | true |
| 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 Par Value 0.0001 Per Share And One Fourth 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, par value $0.0001 per share, and one-fourth of one redeemable warrant |
| Trading Symbol | KCAC.U |
| Security Exchange Name | NYSE |
| Class 160 A 160common 160stock 160included 160as 160part 160of 160the 160units [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A common stock included as part of the units |
| Trading Symbol | KCAC |
| Security Exchange Name | NYSE |
| Redeemable Warrants Included As Part Of The Units Each Whole Warrant Exercisable For One Share Of Class A Common Stock At An Exercise Price Of 11.50 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Redeemable warrants included as part of the units, each whole warrant exercisable for one share of Class A common stock at an exercise price of $11.50 |
| Trading Symbol | KCAC WS |
| Security Exchange Name | NYSE |
