Significant Accounting Policies Revenue Recognition (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 896,200,000	$ 914,000,000.0	$ 1,000,000,000.0	$ 979,700,000	$ 910,100,000	$ 881,300,000	$ 906,300,000	$ 883,100,000	$ 3,789,900,000	$ 3,580,800,000	$ 3,003,800,000
Cost of Goods and Services Sold									2,648,100,000	2,540,700,000	2,191,700,000
Selling, General and Administrative Expense	159,200,000	148,000,000.0	158,700,000	152,700,000	148,300,000	142,000,000.0	141,800,000	148,600,000	618,600,000	580,700,000	508,300,000
Income Before Income Taxes									472,400,000	408,100,000	259,900,000
Income Tax Expense (Benefit)									97,700,000	102,600,000	57,600,000
Net Income	117,800,000	66,700,000	94,900,000	95,300,000	60,800,000	72,300,000	91,900,000	80,500,000	374,700,000	305,500,000	202,300,000
Contract with Customer, Asset, after Allowance for Credit Loss	129,200,000				116,600,000				129,200,000	116,600,000
Inventory, Net	842,000,000.0				835,700,000				842,000,000.0	835,700,000
Other Assets, Current	105,400,000				77,000,000.0				105,400,000	77,000,000.0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	71,800,000				59,000,000.0				71,800,000	59,000,000.0
Other Liabilities, Current	172,300,000				171,000,000.0				172,300,000	171,000,000.0
Retained Earnings (Accumulated Deficit)	1,907,400,000				1,630,200,000				1,907,400,000	1,630,200,000	1,408,400,000	$ 1,289,300,000
Unbilled Receivables, Current	545,100,000				546,600,000				545,100,000	546,600,000
Net Income (Loss) Attributable to The Timken Company	$ 113,500,000	$ 64,200,000	$ 92,500,000	$ 91,900,000	$ 60,000,000.0	$ 71,600,000	$ 91,000,000.0	$ 80,200,000	$ 362,100,000	$ 302,800,000	$ 203,400,000
Earnings Per Share, Basic	$ 1.51	$ 0.85	$ 1.22	$ 1.21	$ 0.78	$ 0.93	$ 1.18	$ 1.03	$ 4.78	$ 3.93	$ 2.62
Earnings Per Share, Diluted	$ 1.48	$ 0.84	$ 1.20	$ 1.19	$ 0.77	$ 0.91	$ 1.16	$ 1.02	$ 4.71	$ 3.86	$ 2.58
Operating Income (Loss)									$ 516,400,000	$ 454,500,000	$ 299,500,000
Other Nonoperating Income (Expense)									13,000,000.0	9,400,000	9,600,000
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component									(10,200,000)	6,200,000	$ 15,000,000.0
Contracts Accounted for under Percentage of Completion [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									0.80
Transferred over Time [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									0.12	$ 0.10
Minimum [Member] | Transferred at Point in Time [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									85
Minimum [Member] | Transferred over Time [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									10
Maximum [Member] | Transferred at Point in Time [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									90
Maximum [Member] | Transferred over Time [Member]
Change in Accounting Estimate [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 15