OTHER COMPREHENSIVE INCOME (Amounts Reclassified from Accumulated Other Comprehensive Income to Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense									$ 137,977	$ 295,522	$ 134,076
Other nonoperating income									13,000	13,357	14,624
Benefit from income taxes									105,449	(232,075)	124,851
Total	$ 124,023	$ 179,151	$ 159,652	$ 52,979	$ 327,546	$ 108,579	$ 120,139	$ 44,921	515,805	601,185	419,491
Reclassification From AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total									4,591	4,016	1,276
Interest Rate Hedge Losses [Member] | Reclassification From AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense									306	3,070	2,008
Benefit from income taxes									(80)	(1,208)	(814)
Total									226	1,862	1,194
Pension and Postretirement Plan Actuarial Loss and Prior Service Cost [Member] | Reclassification From AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating income									5,906	2,915	134
Benefit from income taxes									(1,541)	(761)	(52)
Total									$ 4,365	$ 2,154	$ 82