Major Accounting Policies - Changes in AOCI Balances by Component (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in AOCI balances by component (after-tax)
BALANCE	$ 3,223,830	$ 3,880,823	$ 3,427,094
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	50,170	(193,320)	(41,123)
BALANCE	3,113,499	3,223,830	3,880,823
Accumulated Other Comprehensive Income (Loss)
Changes in AOCI balances by component (after-tax)
BALANCE	(484,212)	(298,201)	(257,850)
Other comprehensive income (loss) before reclassifications	(127,119)	(204,634)	(52,161)
Amounts reclassified from AOCI	178,556	18,623	11,810
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	51,437	(186,011)	(40,351)
BALANCE	(432,775)	(484,212)	(298,201)
Foreign Currency Translation
Changes in AOCI balances by component (after-tax)
BALANCE	(119,416)	(164)	45,899
Other comprehensive income (loss) before reclassifications	(109,361)	(119,252)	(46,063)
Amounts reclassified from AOCI	6,208
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(103,153)	(119,252)	(46,063)
BALANCE	(222,569)	(119,416)	(164)
Ownership Share of Equity Method Investees' Other Comprehensive Income (Loss)
Changes in AOCI balances by component (after-tax)
BALANCE	(30,436)	(32,274)	(43,019)
Other comprehensive income (loss) before reclassifications	(9,000)	(7,958)	10,745
Amounts reclassified from AOCI	1,487	9,796
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(7,513)	1,838	10,745
BALANCE	(37,949)	(30,436)	(32,274)
Defined Benefit Pension and Postretirement Plans
Changes in AOCI balances by component (after-tax)
BALANCE	(325,145)	(258,297)	(252,724)
Other comprehensive income (loss) before reclassifications	(5,382)	(74,924)	(13,655)
Amounts reclassified from AOCI	167,997	8,076	8,082
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	162,615	(66,848)	(5,573)
BALANCE	(162,530)	(325,145)	(258,297)
Unrealized Gain (Loss) on Derivative Contracts
Changes in AOCI balances by component (after-tax)
BALANCE	(8,954)	(7,642)	(8,960)
Other comprehensive income (loss) before reclassifications	(3,260)	(2,151)	(2,536)
Amounts reclassified from AOCI	2,959	839	3,854
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(301)	(1,312)	1,318
BALANCE	(9,255)	(8,954)	(7,642)
Unrealized Gain (Loss) on Available-for-Sale Securities
Changes in AOCI balances by component (after-tax)
BALANCE	(261)	176	954
Other comprehensive income (loss) before reclassifications	(116)	(349)	(652)
Amounts reclassified from AOCI	(95)	(88)	(126)
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(211)	(437)	(778)
BALANCE	(472)	(261)	176
Noncontrolling interests
Changes in AOCI balances by component (after-tax)
BALANCE	112,959	123,836	85,799
Other comprehensive income (loss) before reclassifications	(1,543)	(7,352)	(776)
Amounts reclassified from AOCI	276	43	4
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(1,267)	(7,309)	(772)
BALANCE	116,152	112,959	123,836
Accumulated Other Comprehensive Income (Loss) Attributable to Noncontrolling Interests
Changes in AOCI balances by component (after-tax)
BALANCE	643	7,952	8,724
BALANCE	(624)	643	7,952
Foreign Currency Translation Attributable to Noncontrolling Interests
Changes in AOCI balances by component (after-tax)
BALANCE	1,328	7,885	8,723
Other comprehensive income (loss) before reclassifications	(1,442)	(6,557)	(838)
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(1,442)	(6,557)	(838)
BALANCE	(114)	1,328	7,885
Unrealized Gain (Loss) on Derivative Contracts Attributable Noncontrolling Interests
Changes in AOCI balances by component (after-tax)
BALANCE	(685)	67	1
Other comprehensive income (loss) before reclassifications	(101)	(795)	62
Amounts reclassified from AOCI	276	43	4
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	175	(752)	66
BALANCE	$ (510)	$ (685)	$ 67