Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income (loss)	$ (221)	$ 186	$ (74)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	158	148	149
Impairment of investment in equity affiliate		11
Long-lived asset impairment charge			162
Goodwill impairment charge			92
Deferred tax provision (benefit)	130	(27)	91
Employee benefit plan settlement	4	7
Gain on sale of land			(39)
Gain on sale of investments			(10)
Equity in net income of affiliated companies	(3)	(1)	(2)
Non-cash compensation	9	11	22
Other non-cash (income) expense	8	(3)	16
Cash dividends received from equity affiliates	1	2	9
Changes in assets and liabilities:
Accounts and notes receivable	126	73	(127)
Inventories	114	27	(105)
Prepaid expenses and other current assets	(7)	18	(27)
Accounts payable and accrued liabilities	(55)	(75)	122
Income taxes payable	(5)	(6)	7
Other liabilities	(11)	(37)	12
Cash provided by operating activities	377	363	298
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(200)	(224)	(229)
Proceeds from sale of business		135
Cash paid for acquisition of business, net of cash acquired of $1, $— and $1	(92)	(3)	(64)
Proceeds from the sale of land			39
Proceeds from sales of investments			11
Other	4	(2)	(3)
Cash used in investing activities	(288)	(94)	(246)
Cash Flows from Financing Activities:
Borrowings under financing arrangements		29
Repayments under financing arrangements		(29)	(4)
Increase (decrease) in short-term borrowings, net			(4)
Proceeds from (repayments of) issuance of commercial paper, net	(19)	(216)	249
Proceeds from long-term debt, net of issuance costs	444	352	90
Repayments of long-term debt	(410)	(75)	(251)
Repayments of redeemable preferred stock		(25)
Purchases of common stock	(44)	(173)	(142)
Proceeds from sales of common stock	3	4	22
Cash dividends paid to noncontrolling interests	(26)	(23)	(21)
Cash dividends paid to common stockholders	(80)	(80)	(80)
Cash used in financing activities	(132)	(236)	(141)
Effects of exchange rate changes on cash	25	(39)	(16)
Increase (decrease) in cash and cash equivalents	(18)	(6)	(105)
Cash and cash equivalents at beginning of year	169	175	280
Cash and cash equivalents at end of year	151	169	175
Non-cash investing activities and supplemental cash flow information:
Additions to property, plant and equipment included in Accounts payable and accrued liabilities	29	23	29
Income taxes paid	71	99	84
Interest paid	48	47	$ 47
Marshall Mine [Member]
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Loss on sale and asset impairment charge	$ 129
Specialty Fluids [Member]
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Loss on sale and asset impairment charge		$ 29