Long-Term Debt Additional Details (Details)	3 Months Ended				12 Months Ended
	Sep. 30, 2016 USD ($)	Mar. 31, 2016	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2016 EUR (€)	Sep. 30, 2015 EUR (€)
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 4,978,000,000				$ 4,978,000,000
Interest Paid, Net					319,000,000	$ 373,000,000	$ 314,000,000
Proceeds from Issuance of Unsecured Debt					2,000,000,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	628,000,000				628,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	310,000,000				310,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	0				0
Long-term Debt, Maturities, Repayments of Principal in Year Four	906,000,000				906,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	$ 1,999,000,000				$ 1,999,000,000
Foreign Currency Denominated Debt [Member]
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	1.30%				1.30%	1.10%		1.30%	1.10%
70 million euro floating rate credit facility [Member]
Debt Instrument [Line Items]
Long-term Debt			$ 70,000,000
Repayments of Debt			$ 32,000,000
Four Point Eight Seven Five Percent Due Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 900,000,000				$ 900,000,000
5.5 % Due in 2016
Debt Instrument [Line Items]
Interest rate on notes	5.50%				5.50%	5.50%		5.50%	5.50%
Debt instrument, face amount	$ 800,000,000				$ 800,000,000	$ 800,000,000
Long-term Debt	$ 0				$ 0	$ 800,000,000
7.125 % Due in 2017
Debt Instrument [Line Items]
Interest rate on notes	7.125%				7.125%	7.125%		7.125%	7.125%
Debt instrument, face amount	$ 150,000,000				$ 150,000,000	$ 150,000,000
Long-term Debt	$ 149,000,000				$ 149,000,000	$ 153,000,000
2.6 % Due in 2017
Debt Instrument [Line Items]
Interest rate on notes	2.60%				2.60%	2.60%		2.60%	2.60%
Debt instrument, face amount	$ 400,000,000				$ 400,000,000	$ 400,000,000
Long-term Debt	$ 404,000,000				$ 404,000,000	$ 404,000,000
2.355 % Due in 2017
Debt Instrument [Line Items]
Interest rate on notes	2.355%				2.355%	2.355%		2.355%	2.355%
Debt instrument, face amount	$ 46,000,000				$ 46,000,000	$ 46,000,000
Long-term Debt	$ 46,000,000				$ 46,000,000	$ 46,000,000
1.4% Due in 2018
Debt Instrument [Line Items]
Interest rate on notes	1.40%				1.40%	1.40%		1.40%	1.40%
Debt instrument, face amount	$ 300,000,000				$ 300,000,000	$ 300,000,000
Long-term Debt	$ 301,000,000				$ 301,000,000	$ 303,000,000
5.0 % Due in 2020
Debt Instrument [Line Items]
Interest rate on notes	5.00%				5.00%	5.00%		5.00%	5.00%
Debt instrument, face amount	$ 500,000,000				$ 500,000,000	$ 500,000,000
Long-term Debt	$ 499,000,000				$ 499,000,000	$ 499,000,000
4.25% Due in 2021
Debt Instrument [Line Items]
Interest rate on notes	4.25%				4.25%	4.25%		4.25%	4.25%
Debt instrument, face amount	$ 500,000,000				$ 500,000,000	$ 500,000,000
Long-term Debt	$ 498,000,000				$ 498,000,000	$ 498,000,000
3.75 % Due in 2022
Debt Instrument [Line Items]
Interest rate on notes	3.75%				3.75%	3.75%		3.75%	3.75%
Debt instrument, face amount	$ 450,000,000				$ 450,000,000	$ 450,000,000
Long-term Debt	$ 448,000,000				$ 448,000,000	$ 448,000,000
3.625% Due in 2024
Debt Instrument [Line Items]
Interest rate on notes	3.625%				3.625%	3.625%		3.625%	3.625%
Debt instrument, face amount	$ 500,000,000				$ 500,000,000	$ 500,000,000
Long-term Debt	$ 500,000,000				$ 500,000,000	$ 500,000,000
6.0 % Due in 2036
Debt Instrument [Line Items]
Interest rate on notes	6.00%				6.00%	6.00%		6.00%	6.00%
Debt instrument, face amount	$ 400,000,000				$ 400,000,000	$ 400,000,000
Long-term Debt	$ 396,000,000				$ 396,000,000	$ 395,000,000
5.7 % Due in 2041
Debt Instrument [Line Items]
Interest rate on notes	5.70%				5.70%	5.70%		5.70%	5.70%
Debt instrument, face amount	$ 300,000,000				$ 300,000,000	$ 300,000,000
Long-term Debt	$ 299,000,000				$ 299,000,000	$ 299,000,000
5.25 % Due in 2042
Debt Instrument [Line Items]
Interest rate on notes	5.25%				5.25%	5.25%		5.25%	5.25%
Debt instrument, face amount	$ 250,000,000				$ 250,000,000	$ 250,000,000
Long-term Debt	$ 250,000,000				$ 250,000,000	$ 250,000,000
4.625% Due in 2044
Debt Instrument [Line Items]
Interest rate on notes	4.625%				4.625%	4.625%		4.625%	4.625%
Debt instrument, face amount	$ 450,000,000				$ 450,000,000	$ 450,000,000
Long-term Debt	$ 447,000,000				$ 447,000,000	$ 447,000,000
6.95 % Due in 2046
Debt Instrument [Line Items]
Interest rate on notes	6.95%				6.95%	6.95%		6.95%	6.95%
Debt instrument, face amount	$ 125,000,000				$ 125,000,000	$ 125,000,000
Long-term Debt	$ 125,000,000				$ 125,000,000	$ 125,000,000
4.95% Due in 2064
Debt Instrument [Line Items]
Interest rate on notes	4.95%				4.95%	4.95%		4.95%	4.95%
Debt instrument, face amount	$ 450,000,000				$ 450,000,000	$ 450,000,000
Long-term Debt	$ 449,000,000				$ 449,000,000	449,000,000
Three Point Five Percent Due Two Thousand Twenty Four [Member]
Debt Instrument [Line Items]
Interest rate on notes	3.50%				3.50%			3.50%
Debt instrument, face amount | €								€ 1,000,000,000
125 Million USD floating term loan maturing in October 2016 [Domain]
Debt Instrument [Line Items]
Short-term Bank Loans and Notes Payable	$ 125,000,000				$ 125,000,000
Debt Instrument, Term		10 months
7.7 % Due in 2015
Debt Instrument [Line Items]
Interest rate on notes				0.00%
Debt retired, amount				$ 125,000,000
Four Point Eight Seven Five Percent Due Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	10 years
500 million USD floating rate term loan maturing in September 2016 [Member]
Debt Instrument [Line Items]
Debt retired, amount	$ 500,000,000
150 million USD floating rate term loan maturing in September 2015 [Member]
Debt Instrument [Line Items]
Debt retired, amount						150,000,000
100 million USD floating rate term loan maturing in September 2015 [Member]
Debt Instrument [Line Items]
Debt retired, amount						100,000,000
Three Point Five Percent Due Two Thousand Twenty Four [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	8 years
Adient [Member]
Debt Instrument [Line Items]
Proceeds from Lines of Credit					0
Proceeds from Issuance of Unsecured Debt					500,000,000
Length of Credit Facility	5 years
Adient [Member] | Four Point Eight Seven Five Percent Due Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 900,000,000				$ 900,000,000	$ 0
Adient [Member] | 4.95% Due in 2064
Debt Instrument [Line Items]
Interest rate on notes	4.875%				4.875%	4.875%		4.875%	4.875%
Debt instrument, face amount	$ 900,000,000				$ 900,000,000	$ 900,000,000
Adient [Member] | Three Point Five Percent Due Two Thousand Twenty Four [Member]
Debt Instrument [Line Items]
Interest rate on notes	3.50%				3.50%	3.50%		3.50%	3.50%
Debt instrument, face amount | €								€ 1,000,000,000	€ 1,000,000,000
Long-term Debt	$ 1,119,000,000				$ 1,119,000,000	$ 0
Adient [Member] | LIBOR plus One Point Zero Zero Five Percent Due Two Thousand Twenty One [Member]
Debt Instrument [Line Items]
Interest rate on notes	1.005%				1.005%	1.005%		1.005%	1.005%
Long-term Debt	$ 1,500,000,000				$ 1,500,000,000	$ 0
Length of Credit Facility	5 years
Adient [Member] | LIBOR plus One Point Zero Zero Five Percent Due Two Thousand Twenty One [Member]
Debt Instrument [Line Items]
Proceeds from Lines of Credit	$ 1,500,000,000