Business Restructuring Charges - Summary of Restructuring Accrual Activity (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2016 USD ($)
Restructuring Reserve [Roll Forward]
Balance at September 30, 2016	$ 69
Charged to expense	35
Cash payments	(28)
Non-cash settlements	(4)
Other adjustments	5
Balance at December 31, 2016	67
Employee Termination
Restructuring Reserve [Roll Forward]
Balance at September 30, 2016	67
Charged to expense	9
Cash payments	(11)
Non-cash settlements	0
Other adjustments	0
Balance at December 31, 2016	65
Other
Restructuring Reserve [Roll Forward]
Balance at September 30, 2016	2
Charged to expense	26
Cash payments	(17)
Non-cash settlements	(4)
Other adjustments	5
Balance at December 31, 2016	$ 2