Quarterly Financial Information (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									9 Months Ended	12 Months Ended
	Jan. 02, 2016 USD ($) $ / shares shares	Oct. 03, 2015 USD ($) $ / shares shares	Jul. 04, 2015 USD ($) $ / shares shares	Apr. 04, 2015 USD ($) $ / shares shares	Jan. 03, 2015 USD ($) segment $ / shares shares	Sep. 27, 2014 USD ($) $ / shares shares	Jun. 28, 2014 USD ($) $ / shares shares	Mar. 29, 2014 USD ($) $ / shares shares	Dec. 28, 2013 segment	Sep. 27, 2014 USD ($)	Jan. 02, 2016 USD ($) segment $ / shares shares	Jan. 03, 2015 USD ($) $ / shares shares	Dec. 28, 2013 USD ($) $ / shares shares
Interim Period, Costs Not Allocable [Line Items]
Net Sales	$ 773.5	$ 882.3	$ 942.2	$ 911.7	$ 775.6	$ 829.8	$ 850.4	$ 801.2			$ 3,509.7	$ 3,257.1	$ 3,095.7
Gross profit	219.8	241.1	251.4	220.9	188.1	203.8	211.0	194.4			933.2	797.3	783.2
Income (loss) from operations	(14.1)	100.1	103.2	63.6	(110.6)	74.7	87.7	69.7			252.8	121.5	208.0
Net Income	(18.6)	64.3	64.9	37.9	(115.8)	48.8	58.1	45.0			148.5	36.1	126.0
Net Income Attributable to Regal Beloit Corporation	$ (19.3)	$ 63.4	$ 62.8	$ 36.4	$ (116.5)	$ 47.5	$ 56.2	$ 43.8			$ 143.3	$ 31.0	$ 120.0
Basic (in dollars per shares) | $ / shares	$ (0.43)	$ 1.42	$ 1.40	$ 0.81	$ (2.61)	$ 1.06	$ 1.24	$ 0.97			$ 3.21	$ 0.69	$ 2.66
Assuming Dilution (in dollars per share) | $ / shares	$ (0.43)	$ 1.41	$ 1.39	$ 0.81	$ (2.61)	$ 1.05	$ 1.24	$ 0.96			$ 3.18	$ 0.69	$ 2.64
Basic (in shares) | shares	44.7	44.8	44.8	44.7	44.7	44.9	45.2	45.1			44.7	45.0	45.0
Assuming Dilution (in shares) | shares	44.7	45.1	45.2	45.1	44.7	45.2	45.5	45.4			45.1	45.3	45.4
Number of reported segments | segment					3				2		3
Goodwill Impairment	$ 79.9				$ 118.5					$ 1.0	$ 79.9	$ 119.5	$ 76.3
Goodwill, Impairment Loss, Net of Tax	58.1
Asset Impairment and Other, Net of Tax					40.0
Goodwill, Asset, and Other Impairment, Net of Tax					146.3
Commercial and Industrial Systems
Interim Period, Costs Not Allocable [Line Items]
Net Sales	370.7	$ 426.8	$ 441.0	$ 456.4	451.2	$ 472.3	$ 479.0	$ 453.5			1,694.9	1,856.1	1,746.6
Income (loss) from operations	(59.7)	38.8	41.5	33.3	(84.2)	33.6	47.0	37.2
Goodwill Impairment											79.9	100.7
Climate Solutions
Interim Period, Costs Not Allocable [Line Items]
Net Sales	210.3	264.4	286.1	280.4	256.2	290.0	303.5	285.1			1,041.2	1,134.8	1,098.6
Income (loss) from operations	28.9	40.7	43.7	33.4	7.1	33.1	33.1	26.3
Goodwill Impairment											0.0	7.7
Power Transmission Solutions
Interim Period, Costs Not Allocable [Line Items]
Net Sales	192.5	191.1	215.1	174.9	68.2	67.5	67.9	62.6			773.6	$ 266.2	250.5
Income (loss) from operations	$ 16.7	$ 20.6	$ 18.0	$ (3.1)	$ (33.5)	$ 8.0	$ 7.6	$ 6.2
Goodwill Impairment											$ 0.0		$ 11.1