Condensed Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Net Income (Loss) Attributable to Parent [Abstract]
Sales	$ 569	$ 514	$ 1,114	$ 1,003
Cost of sales	362	316	712	620
Gross profit	207	198	402	383
Selling, general and administrative expenses	111	97	218	192
Legacy and separation-related expenses, net	8	6	17	12
Equity and other income	(12)	(5)	(21)	(15)
Operating income	100	100	188	194
Net pension and other postretirement plan non-service income and remeasurement adjustments	(10)	(17)	(20)	(43)
Net interest and other financing expenses	16	8	30	18
Income before income taxes	94	109	178	219
Income tax expense	27	38	121	76
Net income	$ 67	$ 71	$ 57	$ 143
NET INCOME PER SHARE
Basic (usd per share)	$ 0.33	$ 0.35	$ 0.28	$ 0.70
Diluted (usd per share)	$ 0.33	$ 0.35	$ 0.28	$ 0.70
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic (shares)	200	205	201	205
Diluted (shares)	200	205	202	205
Dividends paid per common share (usd per share)	$ 0.07	$ 0.05	$ 0.15	$ 0.10
COMPREHENSIVE INCOME
Net income	$ 67	$ 71	$ 57	$ 143
Other comprehensive income (loss), net of tax
Unrealized translation gain (loss)	3	6	4	(3)
Amortization of pension and other postretirement plan prior service credit	(2)	(2)	(4)	(4)
Other comprehensive gain (loss)	1	4	0	(7)
Comprehensive income	$ 68	$ 75	$ 57	$ 136