Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net (loss) earnings including noncontrolling interest	$ (104.2)	$ 301.2	$ 1,001.8
Depreciation, depletion and amortization	665.5	711.2	739.8
Deferred and other income taxes	612.4	(182.6)	47.4
Equity in net loss of nonconsolidated companies, net of dividends	34.4	32.6	28.0
Accretion expense for asset retirement obligations	25.7	40.4	32.4
Share-based compensation expense	28.0	30.5	41.3
Loss on write-down of long-lived asset	0.0	43.5	7.9
Unrealized loss (gain) on derivatives	8.3	(70.1)	33.4
(Gain) loss on disposal of fixed assets	(25.5)	27.0	26.6
Other	7.8	18.2	12.9
Changes in assets and liabilities, net of acquisitions:
Receivables, net	(91.2)	3.5	(60.7)
Inventories, net	(155.7)	263.0	(53.7)
Other current assets and noncurrent assets	(23.7)	239.8	(82.6)
Accounts payable and accrued liabilities	(65.7)	(243.9)	262.0
Other noncurrent liabilities	19.4	45.9	1.8
Net cash provided by operating activities	935.5	1,260.2	2,038.3
Cash Flows from Investing Activities
Capital expenditures	(820.1)	(843.1)	(1,000.3)
Purchases of available-for-sale securities - restricted	(1,676.3)	(1,659.4)	0.0
Proceeds from sale of available-for-sale securities - restricted	1,658.1	1,029.3	0.0
Proceeds from sale of assets	300.7	0.9	5.6
Proceeds from adjustment to acquisition of business	0.0	0.0	47.9
Investments in nonconsolidated companies	(62.5)	(244.0)	(227.1)
Investments in consolidated affiliate	(49.5)	(169.0)	0.0
Return of investment from nonconsolidated companies	0.0	0.0	54.4
Other	(18.2)	19.3	1.1
Net cash (used in) investing activities	(667.8)	(1,866.0)	(1,118.4)
Cash Flows from Financing Activities
Payments of short-term debt	(601.4)	(421.3)	(367.2)
Proceeds from issuance of short-term debt	631.4	397.0	379.7
Payments of structured accounts payable arrangements	(418.5)	(792.2)	(395.7)
Proceeds from structured accounts payable arrangements	666.8	433.6	635.2
Payments of long-term debt	(102.2)	(769.1)	(59.6)
Proceeds from issuance of long-term debt	1,251.4	720.0	4.7
Payments of Financing Costs	(15.4)	0.0	0.0
Repurchases of stock	0.0	(75.0)	(709.5)
Cash dividends paid	(210.6)	(385.1)	(384.7)
Other	(0.7)	3.5	3.7
Net cash provided by (used in) financing activities	1,200.8	(888.6)	(893.4)
Effect of exchange rate changes on cash	14.5	68.8	(264.1)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	1,483.0	(1,425.6)	(237.6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - Beginning of Period	711.4	2,137.0	2,374.6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - End of Period	2,194.4	711.4	2,137.0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	2,153.5	673.1	1,276.3
Restricted cash in other current assets	8.3	7.0	9.3
Restricted cash in other assets	32.6	31.3	851.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - End of Period	$ 2,194.4	$ 711.4	$ 2,137.0