PROPERTY, PLANT & EQUIPMENT (Property Plant and Equipment) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant & equipment	$ 6,608,842,000		$ 6,933,602,000
Reserve for depreciation, depletion and amortization	3,537,212,000		3,621,585,000
Property, plant & equipment, net	3,071,630,000		3,312,017,000
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	2,273,874,000	[1]	2,295,087,000	[1]
Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	126,833,000		149,982,000
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	3,952,423,000		4,248,100,000
Leaseholds [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	13,451,000		11,692,000
Deferred Asset Retirement Costs [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	163,644,000		151,973,000
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	78,617,000		76,768,000
Depletable Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant & equipment	$ 1,287,225		$ 1,258,982

[1] Includes depletable land, as follows: December 31, 2014 — $1,287,225 thousand and December 31, 2013 — $1,258,982 thousand.