Income Taxes - Uncertain tax positions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Unrecognized tax benefits [Roll Forward]
Balance as of beginning of period	$ 12.9	$ 13.3
Additions attributable to Sealy on date of acquisition	9.2
Additions based on tax positions related to current period	2.3	1.1
Additions for tax positions of prior years	7.2	0
Settlements of uncertain tax positions with tax authorities	(5.5)	(1.5)
Balance as of end of period	26.1	12.9	13.3
Unrecognized tax benefits that would impact effective tax rate	22.2
Interest and penalties related to unrecognized tax benefits recorded in income tax expense	1.8	3.0	(0.3)
Accrued interest and penalties	$ 11.0	$ 5.8	$ 2.8