Income Taxes Significant Components of Company's Income Tax Provision from Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Tax expense at federal statutory rate				$ 555	$ 753	$ 671
State income taxes, net of federal benefit				3	(23)	7
Foreign income tax expense at different rates and foreign losses without tax benefits				(190)	(198)	(196)
U.S. tax on foreign income				(354)	(203)	(222)
Reserve and valuation allowance adjustments				0	(99)	34
U.S. credits and incentives				(20)	(12)	(9)
Business divestitures				2,149	354	71
Restructuring and impairment costs				126	52	75
Change in assertion over permanently reinvested earnings		$ 780
Other	$ (85)		$ (51)	(31)	(24)	(24)
Income tax provision				$ 2,238	$ 600	$ 407