Restructuring and Impairment Costs (Details) $ in Millions	12 Months Ended				36 Months Ended
	Sep. 30, 2019 USD ($) plant employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2019 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	$ 176	$ 1,181	$ 46
Restructuring reserves	(108)	(135)	(179)
Restructuring charges recovered	$ 6
Number of positions eliminated to date | employee	8,600				8,600
Number of positions eliminated | employee	5,800
Number of plants expected to close | plant	17
Number of plants closed | plant	15
2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	$ 105
Noncash adjustment - underspend	16
Restructuring reserves	9
2019 Restructuring Plan | EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	81
2019 Restructuring Plan | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	16
2019 Restructuring Plan | Asia
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	8
2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs		71
Noncash adjustment - underspend	10
2018 Restructuring Plan | Employee Severance and Termination Benefits
Restructuring Cost and Reserve [Line Items]
Noncash adjustment - underspend	10
2018 Restructuring Plan | EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs		52
2018 Restructuring Plan | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs		9
2018 Restructuring Plan | Asia
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs		10
2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs			46
Noncash adjustment - underspend	4
2017 Restructuring Plan | Employee Severance and Termination Benefits
Restructuring Cost and Reserve [Line Items]
Noncash adjustment - underspend	4
2017 Restructuring Plan | EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs			34
2017 Restructuring Plan | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs			7
2017 Restructuring Plan | Asia
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs			$ 5
2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs				$ 332
Noncash adjustment - underspend	1	20
Severance costs					$ 20
2016 Restructuring Plan | Employee Severance and Termination Benefits
Restructuring Cost and Reserve [Line Items]
Noncash adjustment - underspend	$ 1	20
2016 Restructuring Plan | EMEA
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs				298
2016 Restructuring Plan | Americas
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs				32
2016 Restructuring Plan | Asia
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs				$ 2
Other Plan Years
Restructuring Cost and Reserve [Line Items]
Noncash adjustment - underspend		$ 5