Significant Restructuring Costs - Additional Information (Detail) $ in Millions	3 Months Ended		36 Months Ended
	Dec. 31, 2018 USD ($) Employees Plant	Dec. 31, 2017 USD ($)	Sep. 30, 2018 Employees Plant
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs | $	$ 0	$ 154
Number of employees to be severed			11,300
Number of employees severed	5,000
Number of plants to be closed | Plant			12
Plants closed | Plant	8
Building Technologies & Solutions
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed			9,100
Number of plants to be closed | Plant			12
Corporate Segment
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed			2,200