Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015
Accumulated other comprehensive income [Roll Forward]
Beginning balance			$ 8,128
Ending balance	$ 7,955		7,955
Accumulated other comprehensive income (loss)	(1,564)	$ (1,056)	(1,564)	$ (1,056)	$ (1,617)
Foreign currency translation [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(651)	(560)	(622)	171
Other comprehensive income (loss)	(10)	190	(39)	(541)
Ending balance	(661)	(370)	(661)	(370)
Pension and post retirement [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(899)	(690)	(952)	(746)
Amortization of deferred actuarial losses into earnings	25	27	78	83
Ending balance	(874)	(663)	(874)	(663)
Cash Flow Hedges [Member]
Accumulated other comprehensive income [Roll Forward]
Beginning balance	(32)	(23)	(43)	0
Deferral of gains (losses) arising during the period	(11)	(6)	(22)	(35)
Reclassification of realized (gains) losses to sales and cost of sales	14	6	36	12
Ending balance	$ (29)	$ (23)	$ (29)	$ (23)