| Document and Entity Information | Mar. 02, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001408100 |
| Document Type | 8-K |
| Document Period End Date | Mar. 2, 2021 |
| Entity Registrant Name | KENNEDY-WILSON HOLDINGS, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-33824 |
| Entity Tax Identification Number | 26-0508760 |
| Entity Address, Address Line One | 151 S. El Camino Drive |
| Entity Address, City or Town | Beverly Hills |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90212 |
| City Area Code | (310) |
| Local Phone Number | 887-6400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, $.0001 par value |
| Trading Symbol | KW |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
