RETIREMENT PENSION PLANS - Changes in Level 3, Pension Plan Investments (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Return on Plan Assets: Attributable to Assets Held at Period End	$ 66	$ 248
U.S. Plans
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Return on Plan Assets: Attributable to Assets Held at Period End	65	79
U.S. Plans | Level 3 | Private equity
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value, beginning of period	11	15
Return on Plan Assets: Attributable to Assets Held at Period End	4	(4)
Purchases	4	0
Settlements	0	0
Net Transfers Into (Out of) Level 3		0
Fair Value, end of period	19	11
U.S. Plans | Level 3 | Partnerships Fixed Income
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value, beginning of period	1	1
Return on Plan Assets: Attributable to Assets Held at Period End	0	0
Purchases	0	0
Settlements	(1)	0
Net Transfers Into (Out of) Level 3		0
Fair Value, end of period	0	1
U.S. Plans | Level 3 | Alternatives – Partnerships
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value, beginning of period	77	84
Return on Plan Assets: Attributable to Assets Held at Period End	4	(5)
Purchases	1	0
Settlements	(5)	(2)
Net Transfers Into (Out of) Level 3		0
Fair Value, end of period	77	77
U.S. Plans | Level 3 | Total Level 3 fair value
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value, beginning of period	89	100
Return on Plan Assets: Attributable to Assets Held at Period End	8	(9)
Purchases	5	0
Settlements	(6)	(2)
Net Transfers Into (Out of) Level 3	0	0
Fair Value, end of period	$ 96	$ 89