DEBT (Debt) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Feb. 28, 2018	Jan. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Debt Instrument [Line Items]
Total short-term debt		$ 133,000,000			$ 0
Total long-term debt - face value		2,846,396,000			2,881,529,000
Unamortized discounts and debt issuance costs		(67,016,000)			(26,664,000)
Total long-term debt - book value		2,779,380,000			2,854,865,000
Less current maturities		23,000			41,383,000
Total long-term debt - reported value		2,779,357,000			2,813,482,000
Estimated fair value of long-term debt		2,695,802,000			2,983,419,000
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Total short-term debt	[1],[2]	$ 133,000,000			0
Maturity date		Dec. 31, 2021
Effective interest rate	[1],[2]	1.25%
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Total long-term debt - face value	[1]	$ 0			250,000,000
Maturity date		Dec. 31, 2021
Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 2,846,396,000
Notes [Member] | Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value	[3]	$ 0			350,000,000
Maturity year		2018
Notes [Member] | Floating-Rate Notes Due 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 250,000,000			250,000,000
Maturity year		2020
Effective interest rate		3.50%
Notes [Member] | Floating-Rate Notes Due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 500,000,000			0	$ 600,000,000
Interest rate						7.50%
Maturity year		2021
Effective interest rate		3.71%
Notes [Member] | 7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 0			35,111,000
Interest rate		7.50%		7.50%
Maturity year		2021
Notes [Member] | 8.85% notes due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 6,000,000			6,000,000
Interest rate		8.85%
Maturity year		2021
Effective interest rate		8.88%
Notes [Member] | Term loan due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value							$ 250,000,000
Notes [Member] | Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 0			250,000,000
Maturity year		2021
Notes [Member] | 4.50% notes due 2025 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 400,000,000			400,000,000
Interest rate		4.50%
Maturity year		2025
Effective interest rate		4.65%
Notes [Member] | 3.90% notes due 2027 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 400,000,000			400,000,000
Interest rate		3.90%					3.90%	3.90%
Maturity year		2027
Effective interest rate		4.00%
Notes [Member] | 7.15% notes due 2037 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 129,239,000			240,188,000
Interest rate		7.15%
Maturity year		2037
Effective interest rate		8.05%
Notes [Member] | 4.50% notes due 2047 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 700,000,000			700,000,000
Interest rate		4.50%					4.50%
Maturity year		2047
Effective interest rate		4.59%
Notes [Member] | 4.70% notes due 2048 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 460,949,000			0
Interest rate		4.70%	4.70%
Maturity year		2048
Effective interest rate		5.42%
Other Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 208,000			$ 230,000
Effective interest rate		6.46%

[1] Borrowings on the bank line of credit are classified as short-term debt if we intend to repay within twelve months and as long-term debt if we have the intent and ability to extend payment beyond twelve months.

[2] The effective interest rate reflects the margin above LIBOR for LIBOR-based borrowings. We also paid upfront fees that are amortized to interest expense and pay fees for unused borrowing capacity and standby letters of credit.

[3] This short-term loan was refinanced on a long-term basis in February 2018 as discussed below. Thus, it was classified as long-term debt as of December 31, 2017.