Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Beginning balance	$ 278		$ 130		$ 107
Included in earnings	233		440		166
Purchases	(2)				2
Sales					(5)
Settlements	(106)		(318)		(164)
Transfers into Level 3	34	[1]	26	[1]	24	[1]
Ending balance	437		278		130
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Change In Unrealized Gains Losses Relating To Assets	185	[2]	255	[2]	(7)	[2]
Trading Securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Beginning balance					6
Sales					(5)
Ending balance	1		1		1
Residential mortgage loans
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Beginning balance	76		65		46
Included in earnings	(1)				4
Settlements	(17)		(15)		(9)
Transfers into Level 3	34	[1]	26	[1]	24	[1]
Ending balance	92		76		65
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Change In Unrealized Gains Losses Relating To Assets	(1)	[2]			4	[2]
Interest Rate Contract
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Beginning balance	57	[3]	32	[3]	2	[3]
Included in earnings	59	[3]	418	[3]	205	[3]
Purchases	(2)	[3]
Settlements	(106)	[3]	(393)	[3]	(175)	[3]
Ending balance	8	[3]	57	[3]	32	[3]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Change In Unrealized Gains Losses Relating To Assets	11	[2],[3]	233	[2],[3]	32	[2],[3]
Equity Contract
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Beginning balance	144	[3]	32	[3]	53	[3]
Included in earnings	175	[3]	22	[3]	(43)	[3]
Purchases					2	[3]
Settlements	17	[3]	90	[3]	20	[3]
Ending balance	336	[3]	144	[3]	32	[3]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Change In Unrealized Gains Losses Relating To Assets	$ 175	[2],[3]	$ 22	[2],[3]	$ (43)	[2],[3]

[1] Includes residential mortgage loans 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 $12 and $4, respectively, as of December 31, 2013, $60 and $3, respectively as of December 31, 2012 and $34 and $2, respectively, as of December 31, 2011. Net equity derivatives include derivative assets and liabilities of $384 and $48, respectively, as of December 31, 2013, $177 and $33, respectively, as of December 31, 2012, and $113 and $81, respectively, as of December 31, 2011.