Consolidating Guarantor Financial Information (Schedule of Consolidating Cash Flow Statements) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 803	$ 893	$ 862
Investing Activities
Capital expenditures on property, plant and equipment	(267)	(246)	(232)
Acquisitions, net of cash acquired	(269)	(178)	(6)
Proceeds from sale of businesses and assets, net	1	12	4
Capital expenditures related to Fairway Methanol LLC	0	0	(288)
Return of capital from subsidiary	0	0	0
Contributions to subsidiary	0	0	0
Intercompany loan receipts (disbursements)	0	0	0
Other, net	(14)	(27)	(36)
Net cash provided by (used in) investing activities	(549)	(439)	(558)
Financing Activities
Short-term borrowings (repayments), net	111	(352)	350
Proceeds from short-term borrowings	182	53	80
Repayments of short-term borrowings	(124)	(90)	(83)
Proceeds from long-term debt	351	1,509	0
Repayments of long-term debt	(77)	(1,127)	(24)
Purchases of treasury stock, including related fees	(500)	(500)	(420)
Dividends to parent	0	0	0
Contributions from parent	0	0	0
Stock option exercises	1	6	3
Series A common stock dividends	(241)	(201)	(174)
Return of capital to parent	0	0	0
(Distributions to) contributions from noncontrolling interests	(27)	(24)	214
Other, net	(27)	(33)	(12)
Net cash provided by (used in) financing activities	(351)	(759)	(66)
Exchange rate effects on cash and cash equivalents	35	(24)	(51)
Net increase (decrease) in cash and cash equivalents	(62)	(329)	187
Cash and cash equivalents as of beginning of period	638	967	780
Cash and cash equivalents as of end of period	576	638	967
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	740	695	591
Investing Activities
Capital expenditures on property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from sale of businesses and assets, net	0	0	0
Capital expenditures related to Fairway Methanol LLC	0	0	0
Return of capital from subsidiary	0	0	0
Contributions to subsidiary	0	0	0
Intercompany loan receipts (disbursements)	0	0	0
Other, net	0	0	0
Net cash provided by (used in) investing activities	0	0	0
Financing Activities
Short-term borrowings (repayments), net	0	0	0
Proceeds from short-term borrowings	0	0	0
Repayments of short-term borrowings	0	0	0
Proceeds from long-term debt	0	0	0
Repayments of long-term debt	0	0	0
Purchases of treasury stock, including related fees	(500)	(500)	(420)
Dividends to parent	0	0	0
Contributions from parent	0	0	0
Stock option exercises	1	6	3
Series A common stock dividends	(241)	(201)	(174)
Return of capital to parent	0	0	0
(Distributions to) contributions from noncontrolling interests	0	0	0
Other, net	0	0	0
Net cash provided by (used in) financing activities	(740)	(695)	(591)
Exchange rate effects on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents as of beginning of period	0	0	0
Cash and cash equivalents as of end of period	0	0	0
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	868	711	536
Investing Activities
Capital expenditures on property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	(11)	0	0
Proceeds from sale of businesses and assets, net	0	0	0
Capital expenditures related to Fairway Methanol LLC	0	0	0
Return of capital from subsidiary	16	145	0
Contributions to subsidiary	0	0	0
Intercompany loan receipts (disbursements)	(530)	(283)	(333)
Other, net	0	0	0
Net cash provided by (used in) investing activities	(525)	(138)	(333)
Financing Activities
Short-term borrowings (repayments), net	56	(371)	383
Proceeds from short-term borrowings	0	0	0
Repayments of short-term borrowings	0	0	0
Proceeds from long-term debt	351	1,589	15
Repayments of long-term debt	(6)	(1,083)	(9)
Purchases of treasury stock, including related fees	0	0	0
Dividends to parent	741	695	592
Contributions from parent	0	0	0
Stock option exercises	0	0	0
Series A common stock dividends	0	0	0
Return of capital to parent	0	0	0
(Distributions to) contributions from noncontrolling interests	0	0	0
Other, net	(3)	(13)	0
Net cash provided by (used in) financing activities	(343)	(573)	(203)
Exchange rate effects on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents as of beginning of period	0	0	0
Cash and cash equivalents as of end of period	0	0	0
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	425	(21)	529
Investing Activities
Capital expenditures on property, plant and equipment	(176)	(139)	(128)
Acquisitions, net of cash acquired	(12)	0	(3)
Proceeds from sale of businesses and assets, net	9	1	0
Capital expenditures related to Fairway Methanol LLC	0	0	(20)
Return of capital from subsidiary	241	758	0
Contributions to subsidiary	0	0	(120)
Intercompany loan receipts (disbursements)	(25)	19	(33)
Other, net	(2)	(10)	(12)
Net cash provided by (used in) investing activities	35	629	(316)
Financing Activities
Short-term borrowings (repayments), net	15	1	0
Proceeds from short-term borrowings	0	0	0
Repayments of short-term borrowings	0	0	0
Proceeds from long-term debt	530	746	406
Repayments of long-term debt	(2)	(635)	(74)
Purchases of treasury stock, including related fees	0	0	0
Dividends to parent	802	669	624
Contributions from parent	0	0	0
Stock option exercises	0	0	0
Series A common stock dividends	0	0	0
Return of capital to parent	0	0	0
(Distributions to) contributions from noncontrolling interests	0	0	0
Other, net	(22)	(21)	(10)
Net cash provided by (used in) financing activities	(281)	(578)	(302)
Exchange rate effects on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	179	30	(89)
Cash and cash equivalents as of beginning of period	51	21	110
Cash and cash equivalents as of end of period	230	51	21
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	593	872	422
Investing Activities
Capital expenditures on property, plant and equipment	(91)	(107)	(104)
Acquisitions, net of cash acquired	(274)	(178)	(3)
Proceeds from sale of businesses and assets, net	20	11	4
Capital expenditures related to Fairway Methanol LLC	0	0	(268)
Return of capital from subsidiary	0	0	0
Contributions to subsidiary	0	0	0
Intercompany loan receipts (disbursements)	0	90	(15)
Other, net	(12)	(17)	(24)
Net cash provided by (used in) investing activities	(357)	(201)	(410)
Financing Activities
Short-term borrowings (repayments), net	51	(1)	0
Proceeds from short-term borrowings	182	53	80
Repayments of short-term borrowings	(124)	(90)	(83)
Proceeds from long-term debt	14	0	0
Repayments of long-term debt	(69)	(42)	(14)
Purchases of treasury stock, including related fees	0	0	0
Dividends to parent	280	0	0
Contributions from parent	0	0	120
Stock option exercises	0	0	0
Series A common stock dividends	0	0	0
Return of capital to parent	(257)	(903)	0
(Distributions to) contributions from noncontrolling interests	(27)	(24)	214
Other, net	(2)	1	(2)
Net cash provided by (used in) financing activities	(512)	(1,006)	315
Exchange rate effects on cash and cash equivalents	35	(24)	(51)
Net increase (decrease) in cash and cash equivalents	(241)	(359)	276
Cash and cash equivalents as of beginning of period	587	946	670
Cash and cash equivalents as of end of period	346	587	946
Consolidation Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(1,823)	(1,364)	(1,216)
Investing Activities
Capital expenditures on property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	28	0	0
Proceeds from sale of businesses and assets, net	(28)	0	0
Capital expenditures related to Fairway Methanol LLC	0	0	0
Return of capital from subsidiary	(257)	(903)	0
Contributions to subsidiary	0	0	120
Intercompany loan receipts (disbursements)	555	174	381
Other, net	0	0	0
Net cash provided by (used in) investing activities	298	(729)	501
Financing Activities
Short-term borrowings (repayments), net	(11)	19	(33)
Proceeds from short-term borrowings	0	0	0
Repayments of short-term borrowings	0	0	0
Proceeds from long-term debt	(544)	(826)	(421)
Repayments of long-term debt	0	633	73
Purchases of treasury stock, including related fees	0	0	0
Dividends to parent	(1,823)	(1,364)	(1,216)
Contributions from parent	0	0	(120)
Stock option exercises	0	0	0
Series A common stock dividends	0	0	0
Return of capital to parent	257	903	0
(Distributions to) contributions from noncontrolling interests	0	0	0
Other, net	0	0	0
Net cash provided by (used in) financing activities	1,525	2,093	715
Exchange rate effects on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents as of beginning of period	0	0	0
Cash and cash equivalents as of end of period	$ 0	$ 0	$ 0