Debt Cost Incurred (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 29, 2012
Debt Instrument [Line Items]
Interest incurred	$ 147.7	[1]	$ 185.2	[1]	$ 198.6	[1]
Interest capitalized	(2.7)		(1.4)		(2.3)
Interest expensed	145.0		183.8		196.3
Noncash interest expense and amortization of debt discount
Debt Instrument [Line Items]
Non-cash interest expense			$ 11.2		$ 19.0

[1] Interest incurred includes total non-cash interest of $11.2 million and $19.0 million in 2013 and 2012, respectively, related to the €500 million convertible note and the $575 million convertible note. Interest incurred also includes the change in fair value of the embedded conversion feature related to €500 million convertible note of $5.4 million expense and $8.0 million income for 2013 and 2012, respectively, as well as amortization of debt discounts and issuance costs.