Debt Debt, Textuals (Details) (USD $)	0 Months Ended	3 Months Ended		6 Months Ended
	Jul. 02, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	May 28, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate		6.24%		6.24%			6.28%
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate		87.00%		87.00%			87.00%
Financing Commitment						$ 1,825,000,000
Line of Credit Facility, Maximum Borrowing Capacity		500,000,000		500,000,000
Consent Solitication Fee		0.25%
Long-term Line of Credit						600,000,000
Pending Divestiture Proceeds	200,000,000
Leverage Ratio with payment terms	375.00%
Bridge Loan						725,000,000
Pending Leverage Ratio		500.00%		500.00%
Credit Facility, Maximum Borrowing Capacity	1,100,000,000
Letters of Credit, Maximum Borrowing Capacity		175,000,000		175,000,000
Line of Credit Facility, Amount Outstanding		86,600,000		86,600,000			86,600,000
Letters of Credit Outstanding, Amount		31,700,000		31,700,000
Repayments of Debt and Capital Lease Obligations				13,100,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.30%
Line of Credit Facility, Remaining Borrowing Capacity	468,300,000	381,700,000		381,700,000
Repayments of Long-term Capital Lease Obligations				12,967,000	12,823,000
Repayments of Debt				100,000
Gains (Losses) on Extinguishment of Debt		468,000	0	468,000	0
Capital Lease Obligations Incurred				28,500,000	51,000,000
Proceeds from Issuance of Long-term Debt	425,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.375%
Unsecured Debt [Member] | February 2013 [Member]
Debt Instrument [Line Items]
Senior Notes		0		0			4,757,000
Unsecured Debt [Member] | April 2015 [Member]
Debt Instrument [Line Items]
Senior Notes		136,465,000		136,465,000			136,465,000
Unsecured Debt [Member] | April 2016 [Member]
Debt Instrument [Line Items]
Senior Notes		197,377,000		197,377,000			197,377,000
Unsecured Debt [Member] | June 2017 [Member]
Debt Instrument [Line Items]
Senior Notes		295,000,000		295,000,000			295,000,000
Unsecured Debt [Member] | October 2018 [Member]
Debt Instrument [Line Items]
Senior Notes		250,000,000		250,000,000			250,000,000
Unsecured Debt [Member] | May 2019 [Member]
Debt Instrument [Line Items]
Senior Notes		250,000,000		250,000,000			250,000,000
Unsecured Debt [Member] | November 2020 [Member]
Debt Instrument [Line Items]
Senior Notes		200,000,000		200,000,000			200,000,000
Unsecured Debt [Member] | November 2021 [Member]
Debt Instrument [Line Items]
Senior Notes		150,000,000		150,000,000			150,000,000
Unsecured Debt [Member] | April 2027 [Member]
Debt Instrument [Line Items]
Senior Notes		$ 200,000,000		$ 200,000,000			$ 200,000,000