Debt (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 2,493,127,000	$ 2,500,434,000
stated liquidation amount of convertible debt	50
Interest rate swap agreements	19,766,000	18,671,000
Debt Instrument, Unamortized Discount	(566,927,000)	(573,082,000)
Debt, Current	(528,475,000)	(527,204,000)
Long-term Debt, Excluding Current Maturities	1,417,491,000	1,418,819,000
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Letters of Credit Outstanding, Amount	14,000,000
Derivative, Basis Spread on Variable Rate	4.20%
Amortization of Financing Costs	1,000,000
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	393,125,000	398,438,000
Debt Instrument, Interest Rate, Stated Percentage	1.91%
7.75% Senior Subordinated Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	400,000,000	400,000,000
3.75% Convertible Senior Subordinated Notes, due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	132,375,000	132,408,000
Debt Instrument, Unamortized Discount	(44,527,000)	(45,098,000)
treasury stock method average share price to include dilutive securities	$ 26.84
conversion threshold	34.89
4.00% Junior Subordinated Convertible Debentures, due 2033 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	307,122,000	307,153,000
Debt instrument, convertible, contingent interest rate	0.125%
contingent cash interest paid per stated liquidation amount	0.09
contingent cash interest per stated liquidation amount	0.09
Debt Instrument, Unamortized Discount	(120,349,000)	(121,017,000)
treasury stock method average share price to include dilutive securities	$ 40.82
4.0% Junior Subordinated debt due 2033 [Domain]
Debt Instrument [Line Items]
conversion threshold	53.07
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	(30,354,000)	(34,374,000)
treasury stock method average share price to include dilutive securities	$ 77.88
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	(164,535,000)	(164,986,000)
treasury stock method average share price to include dilutive securities	$ 41.05
conversion threshold	53.37
3.5% Convertible senior subordinated debt [Domain]
Debt Instrument [Line Items]
Long-term Debt, Gross	424,250,000	424,250,000
treasury stock method average share price to include dilutive securities	$ 70.00
Capitalized Lease and Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 18,755,000	$ 20,685,000