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, unless otherwise specified	3 Months Ended								3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014 Trading Securities	Dec. 31, 2013 Trading Securities	Mar. 31, 2013 Trading Securities	Dec. 31, 2012 Trading Securities	Mar. 31, 2014 Residential Mortgage		Mar. 31, 2013 Residential Mortgage		Mar. 31, 2014 Interest Rate Contract		Mar. 31, 2013 Interest Rate Contract		Mar. 31, 2014 Equity Contract		Mar. 31, 2013 Equity Contract
FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollforward
Beginning Balance	$ 437		$ 278		$ 1	$ 1	$ 1	$ 1	$ 92		$ 76		$ 8	[1]	$ 57	[1]	$ 336	[1]	$ 144	[1]
Included in earnings	3		84						1		1		37	[1]	56	[1]	(35)	[1]	27	[1]
Settlements	(30)		(66)						(2)		(4)		(32)	[1]	(65)	[1]	4	[1]	3	[1]
Transfers Into Level 3	12	[2]	8	[2]					12	[2]	8	[2]
Ending Balance	422		304		1	1	1	1	103		81		13	[1]	48	[1]	305	[1]	174	[1]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Change In Unrealized Gains Losses Relating To Assets	$ (18)	[3]	$ 79	[3]					$ 1	[3]	$ 1	[3]	$ 16	[1],[3]	$ 51	[1],[3]	$ (35)	[1],[3]	$ 27	[1],[3]

[1] Net interest rate derivatives include derivative assets and liabilities of $16 and $3, respectively, as of March 31, 2014 and $51 and $3, respectively, as of March 31, 2013. Net equity derivatives include derivative assets and liabilities of $348 and $43, respectively, as of March 31, 2014, and $211 and $37, respectively, as of March 31, 2013.

[2] Includes residential mortgage loans held for sale that were transferred to held for investment.

[3] Includes interest income and expense.