Note 2. Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain	$ (151)	$ 0	$ 0
Payments to Acquire Businesses, Net of Cash Acquired	247	$ 0	18
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net			9
GAAS [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain	(151)
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value	(354)
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain	170
Noncash or Part Noncash Acquisition, Other Liabilities Assumed	(91)
Noncash or Part Noncash Acquisition, Payables Assumed	(83)
Noncash or Part Noncash Acquisition, Intangible Assets Acquired	$ 276
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	20 years
Fair Value Inputs, Comparability Adjustments	14.70%
Goodwill, Purchase Accounting Adjustments	$ 82
Noncash or Part Noncash Acquisition, Other Assets Acquired	3
Property, Plant and Equipment, Additions	17
Noncash or Part Noncash Acquisition, Inventory Acquired	2
Noncash or Part Noncash Acquisition, Accounts Receivable Acquired	46
Cash Acquired from Acquisition	102
Noncontrolling Interest, Change in Redemption Value	184
Futuris [Member]
Business Acquisition [Line Items]
Noncash or Part Noncash Acquisition, Debt Assumed	4
Payments to Acquire Businesses, Net of Cash Acquired	349
Business Acquisitions, Purchase Price Allocation, Year of Acquisition, Net Effect on Income	383
Noncash or Part Noncash Acquisition, Other Liabilities Assumed	(134)
Noncash or Part Noncash Acquisition, Payables Assumed	(85)
Noncash or Part Noncash Acquisition, Intangible Assets Acquired	$ 165
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Fair Value Inputs, Comparability Adjustments	16.50%
Goodwill, Purchase Accounting Adjustments	$ 202
Noncash or Part Noncash Acquisition, Other Assets Acquired	17
Property, Plant and Equipment, Additions	49
Noncash or Part Noncash Acquisition, Inventory Acquired	42
Noncash or Part Noncash Acquisition, Accounts Receivable Acquired	93
Cash Acquired from Acquisition	34
Business Combination, Consideration Transferred	353
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed	3
Interiors Segment [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain			(127)
Extraordinary Item, Gain (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest			20
Increase (Decrease) in Assets Held-for-sale			43
Seating Segment [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain			10
Payments to Acquire Businesses, Net of Cash Acquired			18
Goodwill, Period Increase (Decrease)			$ 4
Short-term Debt [Member] | Futuris [Member]
Business Acquisition [Line Items]
Noncash or Part Noncash Acquisition, Debt Assumed	2
Debt [Member] | Futuris [Member]
Business Acquisition [Line Items]
Noncash or Part Noncash Acquisition, Debt Assumed	$ 2