Valuation and Qualifying Accounts Schedule II (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Acquisition of businesses	$ 2,400
Accounts Receivable - Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	82	$ 72	$ 68
Provision charged to costs and expenses	62	41	50
Reserve adjustments	(16)	(15)	(22)
Accounts charged off	(26)	(16)	(19)
Acquisition of businesses	92	1	1
Currency translation	0	(1)	(1)
Transfers to held for sale	0	0	5
Balance at end of period	194	82	72
Deferred Tax Assets - Valuation Allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	1,256	1,285	1,172
Acquisition of businesses	2,459	0	0
Allowance provision for new operating and other loss carryforwards	121	23	121
Allowance provision benefits	272	52	8
Balance at end of period	$ 3,564	$ 1,256	$ 1,285