LHFI Considered Impaired (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 3,556				$ 3,523
Impaired Financing Receivable, Recorded Investment	3,071	[1]			3,078	[1]
Impaired Financing Receivable, Related Allowance	361				364
Impaired Financing Receivable, Average Recorded Investment	3,097		3,439
Impaired Financing Receivable, Interest Income, Accrual Method	31	[2]	30	[2]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	134				110
Impaired Financing Receivable, Recorded Investment	91	[1]			90	[1]
Impaired Financing Receivable, Related Allowance	0				0
Impaired Financing Receivable, Average Recorded Investment	103		87
Impaired Financing Receivable, Interest Income, Accrual Method	1	[2]	0	[2]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	80				59
Impaired Financing Receivable, Recorded Investment	37	[1]			40	[1]
Impaired Financing Receivable, Related Allowance	0				0
Impaired Financing Receivable, Average Recorded Investment	49		28
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	0	[2]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	9				6
Impaired Financing Receivable, Recorded Investment	9	[1]			5	[1]
Impaired Financing Receivable, Related Allowance	0				0
Impaired Financing Receivable, Average Recorded Investment	9		42
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	0	[2]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	45				45
Impaired Financing Receivable, Recorded Investment	45	[1]			45	[1]
Impaired Financing Receivable, Related Allowance	0				0
Impaired Financing Receivable, Average Recorded Investment	45		17
Impaired Financing Receivable, Interest Income, Accrual Method	1	[2]	0	[2]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	50				66
Impaired Financing Receivable, Recorded Investment	42	[1]			48	[1]
Impaired Financing Receivable, Related Allowance	3				7
Impaired Financing Receivable, Average Recorded Investment	44		249
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	1	[2]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	30				46
Impaired Financing Receivable, Recorded Investment	28	[1]			38	[1]
Impaired Financing Receivable, Related Allowance	3				6
Impaired Financing Receivable, Average Recorded Investment	29		75
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	0	[2]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	14				15
Impaired Financing Receivable, Recorded Investment	9	[1]			7	[1]
Impaired Financing Receivable, Related Allowance	0				1
Impaired Financing Receivable, Average Recorded Investment	10		90
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	0	[2]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	6				5
Impaired Financing Receivable, Recorded Investment	5	[1]			3	[1]
Impaired Financing Receivable, Related Allowance	0				0
Impaired Financing Receivable, Average Recorded Investment	5		84
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	1	[2]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	3,279				3,266
Impaired Financing Receivable, Recorded Investment	2,845	[1]			2,859	[1]
Impaired Financing Receivable, Related Allowance	349				348
Impaired Financing Receivable, Average Recorded Investment	2,855		3,064
Impaired Financing Receivable, Interest Income, Accrual Method	29	[2]	28	[2]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	2,305				2,346
Impaired Financing Receivable, Recorded Investment	2,013	[1]			2,046	[1]
Impaired Financing Receivable, Related Allowance	229				234
Impaired Financing Receivable, Average Recorded Investment	2,020		2,319
Impaired Financing Receivable, Interest Income, Accrual Method	22	[2]	22	[2]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Home Equity
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	705				661
Impaired Financing Receivable, Recorded Investment	626	[1]			612	[1]
Impaired Financing Receivable, Related Allowance	93				88
Impaired Financing Receivable, Average Recorded Investment	629		521
Impaired Financing Receivable, Interest Income, Accrual Method	5	[2]	4	[2]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Residential Construction
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	269				259
Impaired Financing Receivable, Recorded Investment	206	[1]			201	[1]
Impaired Financing Receivable, Related Allowance	27				26
Impaired Financing Receivable, Average Recorded Investment	206		224
Impaired Financing Receivable, Interest Income, Accrual Method	2	[2]	2	[2]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	93				81
Impaired Financing Receivable, Recorded Investment	93	[1]			81	[1]
Impaired Financing Receivable, Related Allowance	9				9
Impaired Financing Receivable, Average Recorded Investment	95		39
Impaired Financing Receivable, Interest Income, Accrual Method	1	[2]	1	[2]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Other Direct
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	15				14
Impaired Financing Receivable, Recorded Investment	15	[1]			14	[1]
Impaired Financing Receivable, Related Allowance	2				2
Impaired Financing Receivable, Average Recorded Investment	15		12
Impaired Financing Receivable, Interest Income, Accrual Method	0	[2]	0	[2]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Indirect
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	59				46
Impaired Financing Receivable, Recorded Investment	59	[1]			46	[1]
Impaired Financing Receivable, Related Allowance	3				2
Impaired Financing Receivable, Average Recorded Investment	60		0
Impaired Financing Receivable, Interest Income, Accrual Method	1	[2]	0	[2]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Credit Card
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	19				21
Impaired Financing Receivable, Recorded Investment	19	[1]			21	[1]
Impaired Financing Receivable, Related Allowance	4				5
Impaired Financing Receivable, Average Recorded Investment	20		27
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	[2]	$ 1	[2]

[1] Amortized cost reflects charge-offs that have been recognized plus other amounts that have been applied to reduce the net book balance.

[2] 1Of the interest income recognized during the three months ended March 31, 2013 and 2012, cash basis interest income was $4 million and $2 million, respectively.