Non-controlling interests (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 03, 2016	Mar. 29, 2015
Noncontrolling Interest [Line Items]
Balance	[1]	$ 937.7
Net income		34.8	$ 36.0
Other comprehensive income (loss)		11.2	$ (26.4)
Dividends declared		(1.7)
Dividends to non-controlling interest		(0.1)
Purchase of treasury stock		(2.3)
Issuance of shares pursuant to employee stock compensation plans		0.5
Income tax benefit arising from employee stock compensation plans		(0.6)
Stock based compensation		(0.1)
Balance	[2]	979.4
Common Stock [Member]
Noncontrolling Interest [Line Items]
Balance		4.8
Net income		0.0
Other comprehensive income (loss)		0.0
Dividends declared		0.0
Dividends to non-controlling interest		0.0
Purchase of treasury stock		0.0
Issuance of shares pursuant to employee stock compensation plans		0.0
Income tax benefit arising from employee stock compensation plans		0.0
Stock based compensation		0.0
Balance		4.8
Additional Paid-in Capital [Member]
Noncontrolling Interest [Line Items]
Balance		387.6
Net income		0.0
Other comprehensive income (loss)		0.0
Dividends declared		0.0
Dividends to non-controlling interest		0.0
Purchase of treasury stock		0.0
Issuance of shares pursuant to employee stock compensation plans		0.5
Income tax benefit arising from employee stock compensation plans		(0.6)
Stock based compensation		(0.1)
Balance		387.4
Retained Earnings [Member]
Noncontrolling Interest [Line Items]
Balance		1,292.7
Net income		33.9
Other comprehensive income (loss)		0.0
Dividends declared		(1.7)
Dividends to non-controlling interest		0.0
Purchase of treasury stock		0.0
Issuance of shares pursuant to employee stock compensation plans		0.0
Income tax benefit arising from employee stock compensation plans		0.0
Stock based compensation		0.0
Balance		1,324.9
Accumulated Other Comprehensive Income (Loss) [Member]
Noncontrolling Interest [Line Items]
Balance		(180.9)
Net income		0.0
Other comprehensive income (loss)		11.0
Dividends declared		0.0
Dividends to non-controlling interest		0.0
Purchase of treasury stock		0.0
Issuance of shares pursuant to employee stock compensation plans		0.0
Income tax benefit arising from employee stock compensation plans		0.0
Stock based compensation		0.0
Balance		(169.9)
Treasury Stock [Member]
Noncontrolling Interest [Line Items]
Balance		(593.7)
Net income		0.0
Other comprehensive income (loss)		0.0
Dividends declared		0.0
Dividends to non-controlling interest		0.0
Purchase of treasury stock		(2.3)
Issuance of shares pursuant to employee stock compensation plans		0.0
Income tax benefit arising from employee stock compensation plans		0.0
Stock based compensation		0.0
Balance		(596.0)
Non-controlling Interests [Member]
Noncontrolling Interest [Line Items]
Balance		27.2
Net income		0.9
Other comprehensive income (loss)		0.2
Dividends declared		0.0
Dividends to non-controlling interest		(0.1)
Purchase of treasury stock		0.0
Issuance of shares pursuant to employee stock compensation plans		0.0
Income tax benefit arising from employee stock compensation plans		0.0
Stock based compensation		0.0
Balance		$ 28.2

[1] Condensed from audited financial statements

[2] Unaudited