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	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Other Liabilities [Member]
Transfers to other balance sheet line items	$ 0		$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0		23		$ 27
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0		6	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(23)		(10)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liabilities Transfers Into Level 3	0		0
Fair Value Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liabilities Transfers Out Of Level 3	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		6	[1],[2]
Derivative contracts, net [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	6		15		20
Included in earnings	198	[3]	153	[4]
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2		0
Sales	0		0
Settlements	2		3
Transfers to other balance sheet line items	(211)		(161)
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	7	[3],[5]	20	[2],[4]
Trading Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	6		104		20
Included in earnings	197		140
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2		123
Sales	(88)		(21)
Settlements	2		3
Transfers to other balance sheet line items	211		(161)
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	7	[5]	7	[2]
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	4		5		12
Included in earnings	0		0
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0
Sales	0		0
Settlements	1		7
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
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	74		94		123
Included in earnings	0		(1)	[6]
OCI	1	[7]	1	[8]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0
Sales	0		0
Settlements	21		29
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		(1)	[2],[6]
Asset-backed Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	10		12		21
Included in earnings	0		0
OCI	1	[7]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0
Sales	0		0
Settlements	3		9
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 Debt Obligations [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0		89		0
Included in earnings	(1)	[9]	(13)	[10]
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		123
Sales	(88)		(21)
Settlements	0		0
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		(13)	[2],[10]
Corporate Debt Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	5		5		5
Included in earnings	0		0
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		5
Sales	0		0
Settlements	0		5
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
Equity Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	540		440		785
Included in earnings	0		0
OCI	0		(2)	[8]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	308		104
Sales	0		0
Settlements	208		447
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
Available-for-sale Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	633		556		946
Included in earnings	0		(1)	[6]
OCI	2	[7]	(1)	[8]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	308		109
Sales	0		0
Settlements	233		497
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		(1)	[2],[6]
Residential Mortgage, Loans Held For Sale [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	12		5		1
Included in earnings	(1)	[11]	0
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0
Sales	(35)		(20)
Settlements	0		1
Transfers to other balance sheet line items	(5)		(1)
Transfers into Level 3	52		26
Transferred Out of Level 3 in The Fair Value Hierarchy	(4)		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Other Income	(1)	[5],[11]	0
Loans Held For Investment [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	222		257		$ 272
Included in earnings	(2)	[11]	6	[12]
OCI	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0
Sales	0		0
Settlements	44		41
Transfers to other balance sheet line items	(1)		1
Transfers into Level 3	10		21
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	$ (2)	[5]	$ 4	[2],[12]

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

[2] Change in unrealized (losses)/gains included in earnings during the period related to financial assets/liabilities still held at December 31, 2015.

[3] Includes issuances, fair value changes, and expirations. Amount related to IRLCs is recognized in mortgage production related income and amount related to Visa derivative liability is recognized in other noninterest expense.

[4] Includes issuances, fair value changes, and expirations. Amount related to IRLCs is recognized in mortgage production related income and amount related to Visa derivative liability is recognized in other noninterest expense.

[5] Change in unrealized gains/(losses) included in earnings during the period related to financial assets still held at December 31, 2016.

[6] Amount included in earnings is recognized in net securities gains/(losses).

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

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

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

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

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

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