Quarterly Financial Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Jan. 02, 2016	Oct. 03, 2015	Jul. 04, 2015	Apr. 04, 2015	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Interim Period, Costs Not Allocable [Line Items]
Net Sales	$ 758.1	$ 809.6	$ 838.6	$ 818.2	$ 773.5	$ 882.3	$ 942.2	$ 911.7	$ 3,224.5	$ 3,509.7	$ 3,257.1
Gross Profit	193.2	231.7	222.9	217.4	219.8	241.1	251.4	220.9	865.2	933.2	797.3
Income from Operations	70.1	89.8	91.4	69.3	(14.1)	100.1	103.2	63.6	320.6	252.8	121.5
Net Income	47.1	61.1	58.4	42.7	(18.6)	64.3	64.9	37.9	209.3	148.5	36.1
Net Income Attributable to Regal Beloit Corporation	$ 45.6	$ 59.6	$ 56.6	$ 41.6	$ (19.3)	$ 63.4	$ 62.8	$ 36.4	$ 203.4	$ 143.3	$ 31.0
Basic (in dollars per shares)	$ 1.02	$ 1.33	$ 1.27	$ 0.93	$ (0.43)	$ 1.42	$ 1.40	$ 0.81	$ 4.55	$ 3.21	$ 0.69
Assuming Dilution (in dollars per share)	$ 1.01	$ 1.32	$ 1.26	$ 0.93	$ (0.43)	$ 1.41	$ 1.39	$ 0.81	$ 4.52	$ 3.18	$ 0.69
Basic (in shares)	44.8	44.8	44.7	44.7	44.7	44.8	44.8	44.7	44.7	44.7	45.0
Assuming Dilution (in shares)	45.1	45.0	45.0	45.0	44.7	45.1	45.2	45.1	45.0	45.1	45.3
Goodwill Impairment					$ 79.9				$ 0.0	$ 79.9	$ 119.5
Goodwill impairment (net of tax)					58.1
Commercial and Industrial Systems
Interim Period, Costs Not Allocable [Line Items]
Net Sales	$ 369.2	$ 389.4	$ 394.7	$ 377.6	370.7	$ 426.8	$ 441.0	$ 456.4	1,530.9	1,694.9	1,856.1
Income from Operations	20.5	36.2	25.1	21.7	(59.7)	38.8	41.5	33.3
Goodwill Impairment										79.9
Climate Solutions
Interim Period, Costs Not Allocable [Line Items]
Net Sales	215.2	250.5	254.5	239.8	210.3	264.4	286.1	280.4	960.0	1,041.2	1,134.8
Income from Operations	27.0	42.2	36.1	24.6	28.9	40.7	43.7	33.4
Goodwill Impairment										0.0
Power Transmission Solutions
Interim Period, Costs Not Allocable [Line Items]
Net Sales	173.7	169.7	189.4	200.8	192.5	191.1	215.1	174.9	$ 733.6	773.6	$ 266.2
Income from Operations	$ 22.6	$ 11.4	$ 30.2	$ 23.0	$ 16.7	$ 20.6	$ 18.0	$ (3.1)
Goodwill Impairment										$ 0.0