Restructuring and Relocation Activities - Additional Information (Detail) $ in Millions		9 Months Ended
	Dec. 31, 2017 USD ($) Jobs	Sep. 30, 2016 USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring expected accrual to pay		$ 41
Restructuring expected accrual remaining to pay		$ 5
FUSION [Member]
Restructuring Cost And Reserve [Line Items]
Jobs relocation completion date		Dec. 31, 2017
Scenario, Forecast [Member] | FUSION [Member]
Restructuring Cost And Reserve [Line Items]
Number of Jobs relocated from Elmwood park to Charlotte | Jobs	1,300
Scenario, Forecast [Member] | FUSION [Member] | Building Cost Of Charlotte Campus
Restructuring Cost And Reserve [Line Items]
Total estimated net cash cost	$ 120