Reconciliation of the Beginning and Ending Balances for Fair Valued Assets and Liabilities Measured on a Recurring Basis Using Significant Unobservable Inputs (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		$ 713		$ 719		$ 713		$ 719		$ 580		$ 767	$ 946
Included in earnings		0						0
OCI		1	[1]					1	[2]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		170						104
Sales		0						0
Settlements		(38)						(332)
Transfers to other balance sheet line items		0						0
Transfers into Level 3		0						0
Transferred Out of Level 3 in The Fair Value Hierarchy		0						0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0						0
Other Liabilities [Member]
Transfers to other balance sheet line items				0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value		0		23		0		23			$ 23	21	27
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings				2	[3]	0		6	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)				0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases				0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales				0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements				0		(23)		(10)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liabilities Transfers Into Level 3				0		0		0
Fair Value Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liabilities Transfers Out Of Level 3				0		0		0
Change in unrealized gains / (losses) included in earnings for the period related to financial assets still held at the end of period				2	[3],[4]	0		6	[3],[4]
Collateralized Debt Obligations [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		0				0					89
Included in earnings	[5]					(1)
OCI						0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases						0
Sales						(88)
Settlements						0
Transfers to other balance sheet line items						0
Transfers into Level 3						0
Transferred Out of Level 3 in The Fair Value Hierarchy						0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income						0
Derivative contracts, net [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		60		14		60		14		32	15	37	20
Included in earnings		116	[6]	12	[7]	161	[6]	89	[7]
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		1		(1)		0		(1)
Transfers to other balance sheet line items		(87)		(36)		(116)		(96)
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		64	[6],[8]	0		65	[6],[8]	(4)	[4],[7]
Trading Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		60				60					104
Included in earnings						160
OCI						0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases						0
Sales						(88)
Settlements						0
Transfers to other balance sheet line items						(116)
Transfers into Level 3						0
Transferred Out of Level 3 in The Fair Value Hierarchy						0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income						65
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		4		5		4		5		5	5	6	12
Included in earnings		0		0		0		0
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		1		(1)		(1)		(7)
Transfers to other balance sheet line items		0		0		0		0
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		83		112		83		112		88	94	119	123
Included in earnings		0		0		0		0
OCI		0		0		(1)	[1]	1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		5		(7)		(10)		(12)
Transfers to other balance sheet line items		0		0		0		0
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Asset-backed Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		11		17		11		17		11	12	21	21
Included in earnings		0		0		0		0
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		0		(4)		(1)		(4)
Transfers to other balance sheet line items		0		0		0		0
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Other Debt Obligations [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		5		3		5		3		5	5	5	5
Included in earnings		0		0		0		0
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		0		(2)		0		(2)
Transfers to other balance sheet line items		0		0		0		0
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Equity Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		610		582		610		582		471	440	616	785
Included in earnings		0		0		0		0
OCI		1	[1]	0		(1)	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		170		83		276		104
Sales		0		0		0		0
Settlements		32		(117)		(107)		(307)
Transfers to other balance sheet line items		0		0		0		0
Transfers into Level 3		0		0		0		0
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Available-for-sale Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		713		719		713		719			556
Included in earnings				0		0
OCI				0		0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases				83		276
Sales				0		0
Settlements				(131)		(119)
Transfers to other balance sheet line items				0		0
Transfers into Level 3				0		0
Transferred Out of Level 3 in The Fair Value Hierarchy				0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income				0		0
Residential Mortgage, Loans Held For Sale [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		4		2		4		2		4	5	4	1
Included in earnings		0		0		0		0
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		(7)		(6)		(14)		(9)
Settlements		0		0		0		0
Transfers to other balance sheet line items		(1)		(1)		(2)		(1)
Transfers into Level 3		8		5		17		11
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		(2)		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		0		0		0		0
Loans Held For Investment [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		246		263		246		263		$ 255	$ 257	$ 268	$ 272
Included in earnings		3	[9]	(3)	[10]	6	[9]	0
OCI		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		(12)		(15)		(22)		(24)
Transfers to other balance sheet line items		0		(1)		1		(1)
Transfers into Level 3		0		14		4		16
Transferred Out of Level 3 in The Fair Value Hierarchy		0		0		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income		$ 3	[8],[9]	$ (4)	[4],[10]	$ 6	[8],[9]	$ (2)	[4],[10]

[1] Amount recognized in OCI is included in change in net unrealized gains/(losses) on securities AFS, net of tax.

[2] Amounts recognized in OCI are included in change in net unrealized gains/(losses) on securities AFS, net of tax.

[3] Amounts included in earnings are recognized in other noninterest expense.

[4] Change in unrealized gains/(losses) included in earnings for the period related to financial assets still held at June 30, 2015.

[5] Amounts included in earnings are recognized in trading income.

[6] Includes issuances, fair value changes, and expirations and are recognized in mortgage production related income.

[7] Includes issuances, fair value changes, and expirations and are recognized in mortgage production related income.

[8] Change in unrealized gains/(losses) included in earnings during the period related to financial assets/liabilities still held at June 30, 2016

[9] Amounts are generally included in mortgage production related income; however, the mark on certain fair value loans is included in other noninterest income.

[10] Amounts are generally included in mortgage production related income; however, the mark on certain fair value loans is included in trading income.