Restructuring - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2014
Restructuring Cost And Reserve [Line Items]
Restructuring charges		$ 86
Restructuring costs	17	24
Restructuring cost incurred to date		46
Employee-related Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges		78
Restructuring costs	15	22
Real Estate Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges		7
Restructuring costs	1	1
Other Costs
Restructuring Cost And Reserve [Line Items]
Restructuring charges		1
Restructuring costs	1	1
Cash Payments
Restructuring Cost And Reserve [Line Items]
Restructuring cost incurred to date		$ 31