Income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
U.S. federal	$ 63.2	$ 71.8	$ 82.6
Foreign	20.1	28.0	31.2
State and local	5.2	8.0	11.3
Total current tax expense	88.5	107.8	125.1
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Total deferred tax expense	26.2	14.2	(0.5)
Provision for income taxes	114.7	122.0	124.6
Net deferred tax liabilities	216.2	168.6
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1.2	1.5	0.4
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
U.S. income before income taxes	283.6	260.1	255.3
Non-U.S. income before income taxes	67.3	103.8	108.4
Income from continuing operations before income taxes	350.9	363.9	363.7
Components of Deferred Tax Assets [Abstract]
Accounts receivable, principally due to allowances for returns and doubtful accounts	4.1	4.4
Inventories, principally due to additional costs inventories for tax purposes	22.9	19.8
Employee compensation and benefits accrued for financial reporting purposes	60.6	92.1
Foreign net operating losses	25.7	21.7
Foreign tax credits	24.1	24.1
Other	12.8	12.0
Total deferred tax assets	150.2	174.1
Less valuation allowance	(40.3)	(42.0)
Total deferred tax assets after valuation allowance	109.9	132.1
Components of Deferred Tax Liabilities [Abstract]
Plant and equipment, principally due to differences in depreciation, capitalized interest, and capitalized overhead	130.9	123.1
Goodwill and intangible assets, principally due to differences in amortization	195.2	177.6
Total deferred tax liabilities	326.1	300.7
Deferred tax liabilities, net	216.2	168.6
Deferred Tax Assets, Net, Classification [Abstract]
Deferred tax liabilities	219.7	172.4
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed expected tax expense on income before taxes at federal statutory rate	122.8	127.4	127.3
Increase (Decrease) Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
State and local income taxes net of federal income tax benefit	5.6	5.6	6.8
Foreign tax rate differential	(7.4)	(7.5)	(7.4)
Manufacturing tax benefits	(5.8)	(6.7)	(7.5)
Other	(0.5)	3.2	5.4
Actual income tax expense	$ 114.7	$ 122.0	$ 124.6
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal statutory rate	35.00%	35.00%	35.00%
Increase (Decrease) Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
State and local income taxes net of federal income tax benefit	1.60%	1.50%	1.90%
Foreign tax rate differential	(2.10%)	(2.10%)	(2.00%)
Manufacturing tax benefits	(1.70%)	(1.80%)	(2.10%)
Other	(0.10%)	0.90%	1.50%
Effective tax rate	32.70%	33.50%	34.30%
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 30.7	$ 24.1
Additions based on tax positions related to the current year	2.3	2.6
Additions for tax positions of prior years	7.0	11.5
Reductions for tax positions of prior years	(4.5)	(1.6)
Reductions due to a lapse of the statute of limitations	(1.7)	(4.7)
Settlements	(0.9)	(1.2)
Balance at end of year	32.9	30.7	$ 24.1
Operating loss carryforwards	85.3
Operating loss carryforwards subject to expiration	23.9
Foreign tax credit carryforward	24.1
Valuation allowance	40.3	42.0
Undistributed foreign subsidiaries earnings	287.5
Unrecognized tax benefits that would impact effective tax rate	32.9	30.7
Interest and penalties	13.2	11.8
Unrecognized Tax Benefits, Increase Resulting from Acquisition	2.6	6.8
Interest and penalties resulting from acquisitions	2.5	7.2
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	6.0
Continuing Operations [Member]
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
U.S. federal	26.7	11.5	1.0
Foreign	(3.9)	2.1	(0.7)
State and local	3.4	0.6	(0.8)
Total deferred tax expense	26.2	14.2	$ (0.5)
Deferred charges and other assets [Member]
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Net deferred tax liabilities	3.5	3.8
Components of Deferred Tax Liabilities [Abstract]
Deferred tax liabilities, net	$ 3.5	$ 3.8