Earnings Per Share - Denominator of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income attributable to The Timken Company	$ 53.1	$ 88.8	$ 61.9	$ 80.7	$ 113.5	$ 64.2	$ 92.5	$ 91.9	$ 284.5	$ 362.1	$ 302.8
Less: undistributed earnings allocated to nonvested stock									0.0	0.0	0.0
Net income available to common shareholders for basic and diluted earnings per share									$ 284.5	$ 362.1	$ 302.8
Denominator:
Weighted-average number of shares outstanding - basic (in shares)									75,354,280	75,758,123	77,119,602
Effect of dilutive securities:
Stock options and awards - based on the treasury stock method (in shares)									1,047,086	1,138,442	1,217,879
Weighted-average number of shares outstanding, assuming dilution of stock options and awards (in shares)									76,401,366	76,896,565	78,337,481
Basic earnings per share (in dollars per share)	$ 0.70	$ 1.18	$ 0.82	$ 1.07	$ 1.51	$ 0.85	$ 1.22	$ 1.21	$ 3.78	$ 4.78	$ 3.93
Diluted earnings per share (in dollars per share)	$ 0.69	$ 1.16	$ 0.82	$ 1.06	$ 1.48	$ 0.84	$ 1.20	$ 1.19	$ 3.72	$ 4.71	$ 3.86