Borrowings (Schedule of Borrowings 1) (Detail)	Mar. 31, 2017
4.2% Senior Notes, due December 2021
Debt Instrument [Line Items]
Stated interest rate	4.20%
4.5% Senior Notes, due December 2020
Debt Instrument [Line Items]
Stated interest rate	4.50%
3.2% Senior Notes, due June 2023
Debt Instrument [Line Items]
Stated interest rate	3.20%
3.37% Senior Notes, due June 2025
Debt Instrument [Line Items]
Stated interest rate	3.37%