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				9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015		Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
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	$ 23	$ 27
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings				0		0		6	[1]
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				0		0		6	[1],[2]
Collateralized Debt Obligations [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		0				0					89
Included in earnings	[3]					(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		64		32		64		32		$ 60	15	14	20
Included in earnings		118	[4]	58	[5]	279	[4]	148	[5]
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		(2)		(1)		(2)		(2)
Transfers to other balance sheet line items		(116)		(41)		(232)		(138)
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		73	[4],[6]	(1)	[2],[5]	68	[4],[6]	(5)	[2],[5]
Trading Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		64				64					104
Included in earnings						278
OCI						0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases						0
Sales						(88)
Settlements						(2)
Transfers to other balance sheet line items						(232)
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						68
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		4		5		4		5		4	5	5	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		0		0		(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		76		102		76		102		83	94	112	123
Included in earnings		0		(1)		0		(1)
OCI		0		1	[7]	(1)	[8]	2	[7]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		(7)		(10)		(17)		(22)
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		(1)	[2]	0		(1)	[2]
Asset-backed Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		11		15		11		15		11	12	17	21
Included in earnings		0		0		0		0
OCI		1	[8]	0		1	[8]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		0		0
Sales		0		0		0		0
Settlements		(1)		(2)		(2)		(6)
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		5		5		5		5	5	3	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		5		0		5
Sales		0		0		0		0
Settlements		0		(3)		0		(5)
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		551		440		551		440		610	440	582	785
Included in earnings		0		0		0		0
OCI		0		(2)	[7]	(1)	[8]	(2)	[7]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0		276		104
Sales		0		0		0		0
Settlements		(59)		(140)		(166)		(447)
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		647		567		647		567		713	556	719	946
Included in earnings		0		(1)		0		(1)
OCI		1	[8]	(1)		1	[8]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		5		276		109
Sales		0		0		0		0
Settlements		(67)		(155)		(186)		(487)
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		(1)		0		(1)
Residential Mortgage, Loans Held For Sale [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		3		2		3		2		4	5	2	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		(13)		(7)		(27)		(16)
Settlements		0		0		0		0
Transfers to other balance sheet line items		(2)		(1)		(4)		(2)
Transfers into Level 3		14		8		31		19
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		234		262		234		262		$ 246	$ 257	$ 263	$ 272
Included in earnings		(2)	[9]	3	[10]	4	[9]	3	[10]
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		(10)		(8)		(32)		(32)
Transfers to other balance sheet line items		(2)		0		(1)		(1)
Transfers into Level 3		2		4		6		20
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		$ (2)	[6],[9]	$ 3	[2],[10]	$ 4	[6],[9]	$ 1	[2],[10]

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

[2] Change in unrealized gains/(losses) included in earnings during the period related to financial assets/liabilities still held at September 30, 2015.

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

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

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

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

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

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

[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