Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2014
Accumulated other comprehensive income [Roll Forward]
Accumulated other comprehensive income (loss)	$ (1,273)	$ (128)	$ (1,273)	$ (128)	$ (575)
Foreign currency translation [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(133)	521	171	504
Other comprehensive income (loss)	(427)	(4)	(731)	13
Purchase of noncontrolling interest	0	8	0	8
Ending balance	(560)	525	(560)	525
Pension and post retirement [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(718)	(669)	(746)	(692)
Amortization of deferred actuarial losses into earnings	27	24	55	47
Divestiture of business	1	0	1	0
Ending balance	(690)	(645)	(690)	(645)
Cash Flow Hedges [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(24)	2	0	(1)
Deferred gains (losses) arising during the period	(3)	(11)	(29)	(8)
Reclassification of realized (gain) loss to sales and cost of sales	4	1	6	1
Ending balance	$ (23)	$ (8)	$ (23)	$ (8)