Retirement and Post-Retirement Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total net pension and other post-retirement benefit expense		$ 45	$ 19
Defined benefit plan remeasurement benefit		(1)
Parent Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Funding payments from parent	$ 1,900	1,900
The Transaction [Member]
Defined Benefit Plan Disclosure [Line Items]
Total net pension and other post-retirement benefit expense		33
Defined benefit plan remeasurement benefit		1
Net pension liability transfer threshold		570
Total estimated funding amount in excess of threshold		$ 0