SUBSEQUENT EVENTS Additional Information (Detail) - 2.108% senior notes due October 2047 - Subsequent events ¥ in Billions	1 Months Ended
	Oct. 31, 2017 JPY (¥)
Subsequent Event [Line Items]
Debt instrument, principal amount	¥ 60.0
Debt instrument, interest rate terms	The debentures bear interest at an initial rate of 2.108% per annum through October 22, 2027, or earlier redemption. Thereafter, the rate of the interest of the debentures will be reset every five years at a rate of interest equal to the then-current JPY 5-year Swap Offered Rate plus 205 basis points.
Debt instrument, term	30 years
Debt instrument, redemption, description	The debentures are redeemable (i) at any time, in whole but not in part, upon the occurrence of certain tax events or certain rating agency events, as specified in the indenture governing the terms of the debentures or (ii) in 10 years, in whole or in part, at a redemption price equal to their principal amount plus accrued and unpaid interest to, but excluding, the date of redemption.