Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - Quarter to date - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		$ 380		$ 484
Included in earnings		91		90
Purchases		(1)
Settlements		(35)		(29)
Transfers Into Level 3	[1]	3		23
Ending Balance		438		568
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	[2]	78		74
Residential Mortgage
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		167		108
Included in earnings		1		2
Settlements		(11)		(7)
Transfers Into Level 3	[1]	3		23
Ending Balance		160		126
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	[2]	1		2
Interest Rate Contract
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		12	[3]	10	[4]
Included in earnings		42	[3]	35	[4]
Purchases	[3]	(1)
Settlements		(28)	[3]	(28)	[4]
Ending Balance		25	[3]	17	[4]
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	[2]	29	[3]	19	[4]
Equity Contract
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		201	[3]	366	[4]
Included in earnings		48	[3]	53	[4]
Settlements		4	[3]	6	[4]
Ending Balance		253	[3]	425	[4]
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held	[2]	$ 48	[3]	$ 53	[4]

[1] Includes certain residential mortgage loans originated as held for sale that were transferred to held for investment.

[2] Includes interest income and expense.

[3] Net interest rate derivatives include derivative assets and liabilities of $29 and $4, respectively, as of March 31, 2016. Net equity derivatives include derivative assets and liabilities of $308 and $55, respectively, as of March 31, 2016.

[4] Net interest rate derivatives include derivative assets and liabilities of $10 and $3, respectively, as of ##D. Net equity derivatives include derivative assets and liabilities of $358 and $53, respectively, as of ##D.