LHFI Considered Impaired (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 3,091,000,000		$ 3,625,000,000
Impaired Financing Receivable, Recorded Investment	2,781,000,000	[1]	3,159,000,000	[1]
Impaired Financing Receivable, Related Allowance	319,000,000		363,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	4,000,000		10,000,000		18,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,847,000,000		3,175,000,000		3,154,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	139,000,000	[2]	138,000,000	[2]	127,000,000	[2]
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	82,000,000		142,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	62,000,000	[1]	116,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	31,000,000		65,000,000
Impaired Financing Receivable, Recorded Investment	30,000,000	[1]	55,000,000	[1]
Impaired Financing Receivable, Related Allowance	11,000,000		10,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	95,000,000		135,000,000		102,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	2,000,000	[2]	3,000,000	[2]	2,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	21,000,000		53,000,000		64,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]	1,000,000	[2]
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	623,000,000		740,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	434,000,000	[1]	442,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	2,229,000,000		2,568,000,000
Impaired Financing Receivable, Recorded Investment	2,129,000,000	[1]	2,436,000,000	[1]
Impaired Financing Receivable, Related Allowance	300,000,000		345,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	449,000,000		470,000,000		565,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	17,000,000	[2]	19,000,000	[2]	16,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,145,000,000		2,397,000,000		2,334,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	113,000,000	[2]	109,000,000	[2]	103,000,000	[2]
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	126,000,000		110,000,000
Impaired Financing Receivable, Recorded Investment	126,000,000	[1]	110,000,000	[1]
Impaired Financing Receivable, Related Allowance	8,000,000		8,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	137,000,000		120,000,000		89,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	6,000,000	[2]	6,000,000	[2]	5,000,000	[2]
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	70,000,000		81,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	51,000,000	[1]	56,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	27,000,000		51,000,000
Impaired Financing Receivable, Recorded Investment	26,000,000	[1]	49,000,000	[1]
Impaired Financing Receivable, Related Allowance	7,000,000		10,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	84,000,000		75,000,000		48,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]	1,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	16,000,000		45,000,000		51,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]	1,000,000	[2]
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	12,000,000		61,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	11,000,000	[1]	60,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	4,000,000		8,000,000
Impaired Financing Receivable, Recorded Investment	4,000,000	[1]	3,000,000	[1]
Impaired Financing Receivable, Related Allowance	4,000,000		0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	11,000,000		60,000,000		9,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	2,000,000	[2]	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	5,000,000		3,000,000		9,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0		0
Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0		6,000,000
Impaired Financing Receivable, Recorded Investment	0		3,000,000	[1]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	0		0		45,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		0		1,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		5,000,000		4,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0		0
Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	592,000,000		672,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	425,000,000	[1]	425,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	1,381,000,000		1,685,000,000
Impaired Financing Receivable, Recorded Investment	1,354,000,000	[1]	1,626,000,000	[1]
Impaired Financing Receivable, Related Allowance	215,000,000		226,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	437,000,000		449,000,000		512,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	17,000,000	[2]	18,000,000	[2]	15,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,357,000,000		1,576,000,000		1,551,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	78,000,000	[2]	76,000,000	[2]	68,000,000	[2]
Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	703,000,000		710,000,000
Impaired Financing Receivable, Recorded Investment	630,000,000	[1]	638,000,000	[1]
Impaired Financing Receivable, Related Allowance	66,000,000		96,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	644,000,000		649,000,000		627,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	27,000,000	[2]	23,000,000	[2]	26,000,000	[2]
Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	31,000,000		68,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	9,000,000	[1]	17,000,000	[1]
Impaired Financing Receivable, Unpaid Principal Balance	145,000,000		173,000,000
Impaired Financing Receivable, Recorded Investment	145,000,000	[1]	172,000,000	[1]
Impaired Financing Receivable, Related Allowance	19,000,000		23,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	12,000,000		21,000,000		53,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		1,000,000	[2]	1,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	144,000,000		172,000,000		156,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	8,000,000	[2]	10,000,000	[2]	9,000,000	[2]
Consumer Other Direct [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	13,000,000		14,000,000
Impaired Financing Receivable, Recorded Investment	13,000,000	[1]	14,000,000	[1]
Impaired Financing Receivable, Related Allowance	1,000,000		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	14,000,000		15,000,000		15,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		1,000,000	[2]	1,000,000	[2]
Consumer Indirect [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	105,000,000		83,000,000
Impaired Financing Receivable, Recorded Investment	105,000,000	[1]	83,000,000	[1]
Impaired Financing Receivable, Related Allowance	5,000,000		5,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	113,000,000		89,000,000		50,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	5,000,000	[2]	4,000,000	[2]	2,000,000	[2]
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	8,000,000		13,000,000
Impaired Financing Receivable, Recorded Investment	8,000,000	[1]	13,000,000	[1]
Impaired Financing Receivable, Related Allowance	2,000,000		3,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	10,000,000		16,000,000		24,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]	2,000,000	[2]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance	$ 0		$ 0

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

[2] Of the interest income recognized during the year ended December 31, 2014, 2013, and 2012, cash basis interest income was $4 million, $10 million, and $18 million, respectively.