Debt (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 2,468,154,000		$ 2,473,927,000
Interest rate swap agreements	(39,961,000)		(46,090,000)
Debt Instrument, Unamortized Discount	456,205,000		462,274,000
Debt, Current	233,919,000		27,713,000
Long-term Debt, Excluding Current Maturities	1,817,991,000		2,030,030,000
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Letters of Credit Outstanding, Amount	8,000,000
Derivative, Basis Spread on Variable Rate	4.71%
Amortization of Financing Costs	1,000,000	1,500,000
Current Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0		0
Senior Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	414,375,000		419,688,000
Debt Instrument, Interest Rate, Stated Percentage	1.96%
7.75% Senior Subordinated Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	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
Debt Instrument, Unamortized Discount	112,208,000		113,446,000
treasury stock method average share price to include dilutive securities	$ 27.11
4.00% Junior Subordinated Convertible Debentures, due 2033 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	345,000,000		345,000,000
Debt Instrument, Unamortized Discount	138,053,000		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
Debt Instrument, Unamortized Discount	45,990,000		49,718,000
treasury stock method average share price to include dilutive securities	$ 78.49
3.75% Convertible Senior Subordinated Notes Due 2042 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	390,000,000		390,000,000
Debt Instrument, Unamortized Discount	159,954,000		160,376,000
treasury stock method average share price to include dilutive securities	$ 41.26
Capitalized Lease and Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 23,225,000		$ 23,685,000