Derivatives and Hedging Activities - Pre-Tax Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	$ 27	$ 23
Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	11	9
Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	19	18
Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	2	3
Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	(5)	(7)
Corporate Services Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	35	30
Corporate Services Income [Member] | Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	13	9
Corporate Services Income [Member] | Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	19	18
Corporate Services Income [Member] | Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	2	3
Corporate Services Income [Member] | Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	1
Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	(8)	(7)
Other Income [Member] | Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	(2)
Other Income [Member] | Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gains (Losses), Net	$ (6)	$ (7)