Significant Restructuring Costs Change in Restructuring Reserve - 2020 Restructuring Plan (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	$ 111	$ 0
2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	111
Payments for Restructuring	(8)
Restructuring Reserve, Settled without Cash	(54)
Restructuring Reserve	49
Employee Severance | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	54
Payments for Restructuring	(8)
Restructuring Reserve, Settled without Cash	0
Restructuring Reserve	46
Fixed Asset Impairment | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	54
Payments for Restructuring	0
Restructuring Reserve, Settled without Cash	(54)
Restructuring Reserve	0
Other Restructuring | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	3
Payments for Restructuring	0
Restructuring Reserve, Settled without Cash	0
Restructuring Reserve	3
Global Products | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	87
Building Solutions Asia Pacific | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	10
Building Solutions EMEA/LA | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	6
Building Solutions North America | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	8
Continuing Operations | 2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	$ 111