Fair Value Measurements (Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs) (Level 3) (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		$ 438		$ 568		$ 380		$ 484
Included in earnings		13		29		103		119
Purchases						(1)
Sales				(1)				(1)
Settlements		(43)		(24)		(76)		(53)
Transfers Into Level 3	[1]	4		61		6		84
Ending Balance		412		633		412		633
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]	3		25		53		81
Residential Mortgage
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		160		126		167		108
Included in earnings		1		(1)		3		1
Settlements		(11)		(8)		(22)		(15)
Transfers Into Level 3	[1]	4		61		6		84
Ending Balance		154		178		154		178
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		(1)		3		1
Interest Rate Contract
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		25	[3]	17	[4]	12	[3]	10	[4]
Included in earnings		43	[3]	17	[4]	84	[3]	52	[4]
Purchases	[3]					(1)
Sales	[4]			(1)				(1)
Settlements		(38)	[3]	(23)	[4]	(65)	[3]	(51)	[4]
Ending Balance		30	[3]	10	[4]	30	[3]	10	[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]	33	[3]	13	[4]	34	[3]	14	[4]
Equity Contract
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance		253	[3]	425	[4]	201	[3]	366	[4]
Included in earnings		(31)	[3]	13	[4]	16	[3]	66	[4]
Settlements		6	[3]	7	[4]	11	[3]	13	[4]
Ending Balance		228	[3]	445	[4]	228	[3]	445	[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]	$ (31)	[3]	$ 13	[4]	$ 16	[3]	$ 66	[4]

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

[2] Includes interest income and expense.

[3] Net interest rate derivatives include derivative assets and liabilities of $ 34 and $ 4 , respectively , as of June 30, 2016 . Net equity derivatives include derivative assets and liabilities of $ 327 and $ 99 , respectively, as of June 30, 2016 .

[4] Net interest rate derivatives include derivative assets and liabilities of $ 14 and $4 , respectively, as of June 30, 2015 . Net equity derivatives include derivative assets and liabilities of $500 and $ 55 , respectively, as of June 30, 2015 .