Note 11. Stock Based Compensation (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 13.15	$ 15.53
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value			$ 18,000,000	$ 4,000,000	$ 30,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares			236,034
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 44.60	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Amount Per Share				$ 0
Share-based Compensation			$ 45,000,000	$ 28,000,000	16,000,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense			21,000,000	11,000,000	6,000,000
Adient Share Bifurcation		1
JCI Share Bifurcation		10
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options			$ 0
Former Parent Outstanding Remaining Contractual Life			4 years 9 months 18 days
Former Parent Outstanding Aggregate Intrinsic Value			$ 12,000,000
Adient Outstanding Remaining Contractual Life			4 years 1 month 6 days
Adient Outstanding Aggregate Intrinsic Value			$ 10,000,000
Former Parent Exercisable Remaining Contractual Life			4 years 1 month 6 days
Former Parent Exercisable Aggregate Intrinsic Value			$ 12,000,000
Adient Exercisable Remaining Contractual Life			3 years 7 months 6 days
Adient Exercisable Aggregate Intrinsic Value			$ 9,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value			$ 1,000,000	$ 4,000,000	$ 7,000,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price			$ 32.04	$ 32.42
Weighted Average Price Exercised Prior to 10.31.2016	$ 27.22
Weighted Average Options Forfeited prior to 10.31.2016	31.71
Weighted Average Options Converted Prior to 10.31.2016	33.28
Weighted Average Options Converted at Separation	$ 32.49
Options Forfeited prior to 10.31.2016	3,330
Options Converted Prior to 10.31.2016	169,125
optionsconvertedatseparation	2,495,543
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				2,336,028
Adient Weighted Average Exercisable			$ 31.34
Adient Weighted Average Outstanding			$ 33.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number			1,422,133
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price			$ 29.58
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price			4 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value			$ 22,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares			3,126
Share-based Compensation Arrangement by Share-based Payment Award, Options, Number of Shares, Period Increase (Decrease)			(1,070,284)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price			$ 26.32
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price			$ 27.58
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options			1,151,192
Options Exercised Prior to 10.31.2016	6,280
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 0.00
Former Parent Weighted Average Outstanding			$ 31.83
formerparentoptionsoutstanding			1,221,817
Adientoutstandingoptions			200,316
Former Parent Weighted Average Exercisable			$ 29.26
formerparentoptionsexercisable			975,505
adientoptionsexercisable			175,687
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term			4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value			$ 21,000,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 45.19
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number			2,252,438	1,320,448
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			(1,162,213)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Amount Per Share			$ 60,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 45.49	$ 46.42
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value			$ 50.29
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares			(281,539)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period			(83,710)
Adientoutstandingoptions			1,241,471
Weighted Average Options Converted Prior to 10.31.2016	$ 48.06
Options Converted Prior to 10.31.2016	135,026
Weighted Average Options Converted at Separation		$ 46.57
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value			$ 44.08
optionsconvertedatseparation		1,455,474
Former Parent Weighted Average Remaining Contractual Term			$ 45.57
formerparentoptionsoutstanding			1,010,967
Adient Weighted Average Remaining Contractual Term			$ 45.42
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price			2 years
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number			549,158	654,694
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 28.12	$ 31.26
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested			$ 549,158
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value			$ 32.35
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period			(6,309)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Exercisable			$ 27.10
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Exercisable			511,854
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Exercisble Remaining Contractual Term			3 years 7 months 6 days
Former Parent Weighted Average Exercisable			$ 26.78
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price			3 years 9 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding			$ 9,000,000
formerparentoptionsexercisable			461,841
Former Parent Exercisable Remaining Contractual Life			3 years 7 months 6 days
Former Parent Exercisable Aggregate Intrinsic Value			$ 6,000,000
Adient Weighted Average Exercisable			$ 30.12
adientoptionsexercisable			50,013
Adient Exercisable Remaining Contractual Life			3 years 6 months
Adient Exercisable Aggregate Intrinsic Value			$ 3,000,000
Adient Outstanding Remaining Contractual Life			3 years 9 months 18 days
Adient Outstanding Aggregate Intrinsic Value			$ 3,000,000
Weighted Average Price Exercised Prior to 10.31.2016	$ 29.68
Options Exercised Prior to 10.31.2016	(9,470)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Number of Shares, Period Increase (Decrease)			(131,470)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value			$ 45.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options			511,854
Former Parent Outstanding Remaining Contractual Life			3 years 9 months 18 days
Former Parent Outstanding Aggregate Intrinsic Value			$ 6,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value			9,000,000
SARS Weighted Average Options Converted Prior to 10.31.2016	$ 33.16
SARS Converted Prior to 10.31.2016	41,713
SARS Weighted Average Options Converted at Separation	$ 31.40
SARSconvertedatseparation	686,937
SARS Former Parent Weighted Average Outstanding			$ 27.79
SARS formerparentoptionsoutstanding			495,754
SARS Adient Weighted Average Outstanding			$ 31.19
SARS Adientoutstandingoptions			53,404
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 44.60
PSU Weighted Average Price Converted 10.31.2016	$ 0.00
PSU converted 10.31.2016	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			236,034
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value			$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares			0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period			0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value			$ 0.00
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options			$ 18,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price			2 years 1 month 6 days