Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional values of derivative contracts	$ 1,765	$ 1,765
Fair value of collateral agreements with affiliate counterparties	274	317
Decrease in debt carrying value due to fair value hedge	14	15
Losses on current derivative instruments designated as cash flow hedges are reported in OCI net of tax (less than $1 million at March 31, 2017 and December 31, 2016)	1	1
Unrealized net losses on cash flow hedges (less than $1 million)	1
HSBC Bank USA [Member]
Derivative [Line Items]
Notional values of derivative contracts	$ 1,800	$ 1,800