Debt (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 2,464,064,000		$ 2,464,064,000		$ 2,473,927,000
stated liquidation amount of convertible debt	50		50
Interest rate swap agreements	(20,992,000)		(20,992,000)		(46,090,000)
Debt Instrument, Unamortized Discount	(450,018,000)		(450,018,000)		(462,274,000)
Debt, Current	(443,514,000)		(443,514,000)		(27,713,000)
Long-term Debt, Excluding Current Maturities	1,591,524,000		1,591,524,000		2,030,030,000
Debt Instrument, Interest Rate, Stated Percentage	7.75%		7.75%
Letters of Credit Outstanding, Amount	8,000,000		8,000,000
Derivative, Basis Spread on Variable Rate	4.68%		4.68%
Amortization of Financing Costs	1,000,000	1,500,000	1,900,000	3,000,000
Current Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0		0		0
Senior Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	409,063,000		409,063,000		419,688,000
Debt Instrument, Interest Rate, Stated Percentage	1.95%		1.95%
7.75% Senior Subordinated Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	550,000,000		550,000,000		550,000,000
3.75% Convertible Senior Subordinated Notes, due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	318,054,000		318,054,000		318,054,000
Debt Instrument, Unamortized Discount	(110,944,000)		(110,944,000)		(113,446,000)
treasury stock method average share price to include dilutive securities			$ 27.05
4.00% Junior Subordinated Convertible Debentures, due 2033 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	345,000,000		345,000,000		345,000,000
Debt Instrument, Convertible, Conversion Price	$ 58.11		$ 58.11
Debt instrument, convertible, contingent interest rate	0.125%		0.125%
contingent cash interest per stated liquidation amount	0.07		0.07
Debt Instrument, Unamortized Discount	(137,359,000)		(137,359,000)		(138,734,000)
treasury stock method average share price to include dilutive securities			$ 40.82
3.25% Convertible Senior Debentures, Due 2035 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	427,500,000		427,500,000		427,500,000
Debt Instrument, Unamortized Discount	(42,191,000)		(42,191,000)		(49,718,000)
treasury stock method average share price to include dilutive securities			$ 78.29
3.75% Convertible Senior Subordinated Notes Due 2042 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	390,000,000		390,000,000		390,000,000
Debt Instrument, Unamortized Discount	(159,524,000)		(159,524,000)		(160,376,000)
treasury stock method average share price to include dilutive securities			$ 41.19
Capitalized Lease and Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 24,447,000		$ 24,447,000		$ 23,685,000