Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, before accumulated amortization, of debt issuance costs related to line of credit arrangements. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

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Amount of long-term debt and capital lease obligations including current maturities.

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Amount of long-term debt classified as other.

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Debt and Financing Arrangements Long-Term Debt (Details)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 EUR (€)	Sep. 30, 2019 JPY (¥)	Sep. 30, 2018 USD ($)	Sep. 30, 2016 USD ($)
Debt Instrument [Line Items]
Other Long-term Debt	$ 3,000,000			$ 3,000,000
Long-term Debt and Capital Lease Obligations, Including Current Maturities	7,240,000,000			9,668,000,000
Less: current portion	501,000,000			1,000,000
Debt Issuance Costs, Line of Credit Arrangements, Gross	31,000,000			44,000,000
Net long-term debt	$ 6,708,000,000			9,623,000,000
Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Long-term Debt				4,000,000,000.0	$ 4,000,000,000.0
Four Point Six Two Five Percent Due in Two Thousand Twenty Three [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%	4.625%	4.625%
Debt instrument, face amount	$ 25,000,000
Long-term Debt	$ 26,000,000			37,000,000
Four Point Six Two Five Percent Due in Two Thousand Twenty Three [Member] \| Tyco International Finance S.A. (TIFSA) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%	4.625%	4.625%
Debt instrument, face amount	$ 7,000,000
Long-term Debt	$ 7,000,000			8,000,000
5.0 % Due in 2020 \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.00%	5.00%	5.00%
Debt instrument, face amount	$ 47,000,000
Long-term Debt	$ 47,000,000			47,000,000
5.0 % Due in 2020 \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.00%	5.00%	5.00%
Debt instrument, face amount	$ 453,000,000
Long-term Debt	$ 453,000,000			452,000,000
Zero Point Zero Percent Due Two Thousand Twenty-One [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.00%	0.00%	0.00%
Debt instrument, face amount \| €		€ 750,000,000
Long-term Debt	$ 818,000,000			868,000,000
4.25% Due in 2021 \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%	4.25%	4.25%
Debt instrument, face amount	$ 53,000,000
Long-term Debt	$ 53,000,000			53,000,000
4.25% Due in 2021 \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%	4.25%	4.25%
Debt instrument, face amount	$ 204,000,000
Long-term Debt	$ 204,000,000			446,000,000
3.75 % Due in 2022 \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%	3.75%	3.75%
Debt instrument, face amount	$ 22,000,000
Long-term Debt	$ 22,000,000			22,000,000
3.75 % Due in 2022 \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%	3.75%	3.75%
Debt instrument, face amount	$ 171,000,000
Long-term Debt	$ 171,000,000			427,000,000
One Point Zero Percent Due Two Thousand Twenty Three \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.00%	1.00%	1.00%
Debt instrument, face amount \| €		€ 888,000,000
Long-term Debt	$ 967,000,000			1,154,000,000
Three Point Six Two Five Percent Due Two Thousand Twenty Four [Member] \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.625%	3.625%	3.625%
Debt instrument, face amount	$ 31,000,000
Long-term Debt	$ 31,000,000			31,000,000
Three Point Six Two Five Percent Due Two Thousand Twenty Four [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.625%	3.625%	3.625%
Debt instrument, face amount	$ 453,000,000
Long-term Debt	$ 453,000,000			468,000,000
One Point Three Seven Five Percent Due in Two Thousand Twenty Five [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.375%	1.375%	1.375%
Debt instrument, face amount \| €		€ 423,000,000
Long-term Debt	$ 471,000,000			501,000,000
One Point Three Seven Five Percent Due in Two Thousand Twenty Five [Member] \| Tyco International Finance S.A. (TIFSA) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.375%	1.375%	1.375%
Debt instrument, face amount \| €		€ 54,000,000
Long-term Debt	$ 60,000,000			69,000,000
One Point Three Seven Five Percent Due in Two Thousand Twenty Five [Member] \| Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Debt instrument, face amount \| €		€ 215,000,000
Three Point Ninety Percent Due in Two Thousand Twenty Six [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.90%	3.90%	3.90%
Debt instrument, face amount	$ 487,000,000
Long-term Debt	$ 521,000,000			755,000,000
Three Point Ninety Percent Due in Two Thousand Twenty Six [Member] \| Tyco International Finance S.A. (TIFSA) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.90%	3.90%	3.90%
Debt instrument, face amount	$ 51,000,000
Long-term Debt	$ 51,000,000			52,000,000
Six Point Zero Percent Due Two Thousand Thirty Six [Member] \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%	6.00%
Debt instrument, face amount	$ 8,000,000
Long-term Debt	$ 8,000,000			8,000,000
Six Point Zero Percent Due Two Thousand Thirty Six [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.00%	6.00%	6.00%
Debt instrument, face amount	$ 342,000,000
Long-term Debt	$ 339,000,000			388,000,000
Five Point Seven Percent Due Two Thousand Forty One \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%	5.70%	5.70%
Debt instrument, face amount	$ 30,000,000
Long-term Debt	$ 30,000,000			30,000,000
Five Point Seven Percent Due Two Thousand Forty One \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%	5.70%	5.70%
Debt instrument, face amount	$ 190,000,000
Long-term Debt	$ 189,000,000			269,000,000
Five Point Two Five Percent Due Two Thousand Forty Two \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.25%	5.25%	5.25%
Debt instrument, face amount	$ 6,000,000
Long-term Debt	$ 6,000,000			8,000,000
Five Point Two Five Percent Due Two Thousand Forty Two \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.25%	5.25%	5.25%
Debt instrument, face amount	$ 155,000,000
Long-term Debt	$ 155,000,000			242,000,000
Four Point Six Two Five Percent Due Two Thousand Forty Four \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%	4.625%	4.625%
Debt instrument, face amount	$ 6,000,000
Long-term Debt	$ 6,000,000			6,000,000
Four Point Six Two Five Percent Due Two Thousand Forty Four \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%	4.625%	4.625%
Debt instrument, face amount	$ 444,000,000
Long-term Debt	$ 441,000,000			441,000,000
Five Point One Two Five Percent Due in Two Thousand Forty Five [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.125%	5.125%	5.125%
Debt instrument, face amount	$ 477,000,000
Long-term Debt	$ 567,000,000			867,000,000
Five Point One Two Five Percent Due in Two Thousand Forty Five [Member] \| Tyco International Finance S.A. (TIFSA) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.125%	5.125%	5.125%
Debt instrument, face amount	$ 23,000,000
Long-term Debt	$ 22,000,000			23,000,000
Six Point Nine Five Percent Due Two Thousand Forty Six \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.95%	6.95%	6.95%
Debt instrument, face amount	$ 4,000,000
Long-term Debt	$ 4,000,000			4,000,000
Six Point Nine Five Percent Due Two Thousand Forty Six \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.95%	6.95%	6.95%
Debt instrument, face amount	$ 32,000,000
Long-term Debt	$ 32,000,000			121,000,000
Four point five percent maturing in fiscal 2047 [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.50%	4.50%	4.50%
Debt instrument, face amount	$ 500,000,000
Long-term Debt	$ 496,000,000			496,000,000
Four Point Nine Five Percent Due Two Thousand Sixty Four [Member] \| Johnson Controls Inc. [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.95%	4.95%	4.95%
Debt instrument, face amount	$ 15,000,000
Long-term Debt	$ 15,000,000			15,000,000
Four Point Nine Five Percent Due Two Thousand Sixty Four [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.95%	4.95%	4.95%
Debt instrument, face amount	$ 341,000,000
Long-term Debt	$ 340,000,000			434,000,000
LIBOR plus One Point Two Five Percent Due in Two Thousand Twenty [Member] \| Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.25%	1.25%	1.25%
Long-term Debt	$ 0
EURIBOR plus Zero Point Six Two Percent due in Two Thousand Twenty [Member] \| Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.62%	0.62%	0.62%
Long-term Debt	$ 0
LIBOR JPY Plus Zero Point Four Two Percent Due in Two Thousand Twenty Two [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.40%	0.40%	0.40%
Debt instrument, face amount \| ¥			¥ 25,000,000,000
Long-term Debt	$ 232,000,000
LIBOR JPY Plus Zero Point Four Two Percent Due in Two Thousand Twenty Two [Member] \| Johnson Controls International plc [Member]
Debt Instrument [Line Items]
Long-term Debt				309,000,000
EURIBOR plus Zero Point Six Two Percent due in Two Thousand Twenty [Member] \| Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Long-term Debt				250,000,000
LIBOR plus One Point Two Five Percent Due in Two Thousand Twenty [Member] \| Tyco International Holding S.a.r.L. (TSarL) [Member]
Debt Instrument [Line Items]
Long-term Debt				$ 364,000,000