RETIREMENT PENSION PLANS - Schedule of Pension Costs Recognized in Other Comprehensive Loss (Details) - Net Actuarial Loss - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Settlements		$ (6)
Pension Plan
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning	$ 578	611
Net actuarial loss for the year	133	(8)
Amortization for the year	(24)	(29)
Deferred tax impact	(20)	10
Balance, ending	667	578
U.S.
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Settlements		0
U.S. | Pension Plan
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning	394	418
Net actuarial loss for the year	113	(11)
Amortization for the year	(20)	(23)
Deferred tax impact	(20)	10
Balance, ending	467	394
Non-U.S.
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Settlements		(6)
Non-U.S. | Pension Plan
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning	184	193
Net actuarial loss for the year	20	3
Amortization for the year	(4)	(6)
Deferred tax impact	0	0
Balance, ending	$ 200	$ 184