Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents at beginning of year	$ 1,137,303	$ 2,269,756
Cash flows from operating activities:
Net income	449,611	176,346
Adjustments to reconcile net income to cash flows from operating activities:
Depreciation and amortization	100,804	94,192
Gain on acquisition	0	(7,433)
Gain on sale of business	(218,705)	0
Stock-based compensation	8,076	9,492
Equity in net income of unconsolidated investments (net of tax)	(39,646)	(36,219)
Dividends received from unconsolidated investments and nonmarketable securities	30,045	8,454
Pension and postretirement benefit	(1,793)	(7)
Pension and postretirement contributions	(7,089)	(6,288)
Unrealized gain on investments in marketable securities	(625)	(1,553)
Loss on early extinguishment of debt	0	52,801
Deferred income taxes	30,708	(3,204)
Working capital changes	(91,189)	(353,138)
Other, net	(36,340)	12,102
Net cash provided by (used in) operating activities	223,857	(54,455)
Cash flows from investing activities:
Acquisitions, net of cash acquired	(7,643)	(39,525)
Capital expenditures	(280,945)	(97,765)
Cash proceeds from divestitures, net	416,711	6,857
Sales of marketable securities, net	(439)	208
Repayments from joint ventures	0	1,250
Investments in equity and other corporate investments	(1,979)	0
Net cash provided by (used in) investing activities	125,705	(128,975)
Cash flows from financing activities:
Repayments of long-term debt	0	(751,209)
Other (repayments) borrowings, net	(211,833)	58,886
Fees related to early extinguishment of debt	0	(46,959)
Dividends paid to shareholders	(72,484)	(69,762)
Dividends paid to noncontrolling interests	(7,378)	(17,930)
Repurchases of common stock	(250,000)	(250,000)
Proceeds from exercise of stock options	1,288	3,337
Withholding taxes paid on stock-based compensation award distributions	(16,460)	(8,169)
Net cash used in financing activities	(556,867)	(1,081,806)
Net effect of foreign exchange on cash and cash equivalents	(21,854)	2,425
Decrease in cash and cash equivalents	(229,159)	(1,262,811)
Cash and cash equivalents at end of period	$ 908,144	$ 1,006,945