| Cover | Feb. 16, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Feb. 16, 2021 |
| Entity File Number | 001-07283 |
| Entity Registrant Name | Regal Beloit Corp |
| Entity Central Index Key | 0000082811 |
| Entity Tax Identification Number | 39-0875718 |
| Entity Incorporation, State or Country Code | WI |
| Entity Address, Address Line One | 200 State Street |
| Entity Address, City or Town | Beloit |
| Entity Address, State or Province | WI |
| Entity Address, Postal Zip Code | 53511 |
| City Area Code | 608 |
| Local Phone Number | 364-8800 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | RBC |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
