Long-term debt Long-Term Debt - Additional Information (Details) (USD $)	9 Months Ended			9 Months Ended			9 Months Ended
	Sep. 28, 2014	Sep. 28, 2014 Unsecured Fixed Rate Notes 9.375 Percent Due November 2017 [Member]	Dec. 29, 2013 Unsecured Fixed Rate Notes 9.375 Percent Due November 2017 [Member]	Sep. 28, 2014 Unsecured Fixed Rate Notes 4.875 Percent Due September 2021 [Member]	Sep. 08, 2014 Unsecured Fixed Rate Notes 4.875 Percent Due September 2021 [Member]	Dec. 29, 2013 Unsecured Fixed Rate Notes 4.875 Percent Due September 2021 [Member]	Sep. 28, 2014 Unsecured Fixed Rate Notes 5.500 Percent Due September 2024 [Member]	Sep. 08, 2014 Unsecured Fixed Rate Notes 5.500 Percent Due September 2024 [Member]	Dec. 29, 2013 Unsecured Fixed Rate Notes 5.500 Percent Due September 2024 [Member]	Oct. 01, 2014 Classified Ventures [Member] Subsequent Event [Member]
Debt Instrument [Line Items]
Increase in Long Term Debt Net of Repayments and Discount Amortization	$ 399,700,000
Proceeds in Issuance of Long Term Debt	675,000,000
Debt Instrument, Interest Rate, Stated Percentage		9.375%		4.875%	4.875%		5.50%	5.50%
Debt Instrument Offering Price Percentage					98.531%			99.038%
Debt Instrument Yield To Maturity					5.125%			5.625%
Debt Instrument, Maturity Date		Nov. 15, 2017		Sep. 15, 2021			Sep. 15, 2024
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		104.688%
Interest Expense Saved from Early Redemption		19,400,000
Debt Instrument, Face Amount		0	250,000,000	350,000,000	350,000,000	0	325,000,000	325,000,000	0
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,270,000,000									$ 617,500,000