LHFI Considered Impaired (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 298,000,000				$ 319,000,000
Impaired Financing Receivable, Unpaid Principal Balance	3,074,000,000				3,091,000,000
Impaired Financing Receivable, Recorded Investment	2,767,000,000	[1]			2,781,000,000	[1]
Impaired Financing Receivable, Interest Income, Cash Basis Method	1,000,000		1,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,790,000,000		3,116,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	32,000,000	[2]	36,000,000	[2]
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	65,000,000				82,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	49,000,000	[1]			62,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	6,000,000				11,000,000
Impaired Financing Receivable, Unpaid Principal Balance	37,000,000				31,000,000
Impaired Financing Receivable, Recorded Investment	31,000,000	[1]			30,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	51,000,000		68,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		1,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	41,000,000		79,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	0
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	587,000,000				623,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	418,000,000	[1]			434,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	285,000,000				300,000,000
Impaired Financing Receivable, Unpaid Principal Balance	2,258,000,000				2,229,000,000
Impaired Financing Receivable, Recorded Investment	2,143,000,000	[1]			2,129,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	422,000,000		458,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	4,000,000	[2]	4,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,147,000,000		2,392,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	26,000,000	[2]	30,000,000	[2]
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	7,000,000				8,000,000
Impaired Financing Receivable, Unpaid Principal Balance	127,000,000				126,000,000
Impaired Financing Receivable, Recorded Investment	126,000,000	[1]			126,000,000	[1]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	129,000,000		119,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	54,000,000				70,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	39,000,000	[1]			51,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	5,000,000				7,000,000
Impaired Financing Receivable, Unpaid Principal Balance	34,000,000				27,000,000
Impaired Financing Receivable, Recorded Investment	28,000,000	[1]			26,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	41,000,000		52,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		1,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	38,000,000		63,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	0
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	11,000,000				12,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	10,000,000	[1]			11,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	1,000,000				4,000,000
Impaired Financing Receivable, Unpaid Principal Balance	3,000,000				4,000,000
Impaired Financing Receivable, Recorded Investment	3,000,000	[1]			4,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	10,000,000		11,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	3,000,000		12,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0
Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	0		5,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0		4,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0
Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	557,000,000				592,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	410,000,000	[1]			425,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	196,000,000				215,000,000
Impaired Financing Receivable, Unpaid Principal Balance	1,413,000,000				1,381,000,000
Impaired Financing Receivable, Recorded Investment	1,373,000,000	[1]			1,354,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	413,000,000		440,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	4,000,000	[2]	4,000,000	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,374,000,000		1,591,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	17,000,000	[2]	21,000,000	[2]
Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	73,000,000				66,000,000
Impaired Financing Receivable, Unpaid Principal Balance	708,000,000				703,000,000
Impaired Financing Receivable, Recorded Investment	633,000,000	[1]			630,000,000	[1]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	636,000,000		637,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	7,000,000	[2]	7,000,000	[2]
Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	30,000,000				31,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	8,000,000	[1]			9,000,000	[1]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	16,000,000				19,000,000
Impaired Financing Receivable, Unpaid Principal Balance	137,000,000				145,000,000
Impaired Financing Receivable, Recorded Investment	137,000,000	[1]			145,000,000	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	9,000,000		18,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	137,000,000		164,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	2,000,000	[2]	2,000,000	[2]
Consumer Other Direct [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				1,000,000
Impaired Financing Receivable, Unpaid Principal Balance	12,000,000				13,000,000
Impaired Financing Receivable, Recorded Investment	12,000,000	[1]			13,000,000	[1]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	13,000,000		14,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0
Consumer Indirect [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	5,000,000				5,000,000
Impaired Financing Receivable, Unpaid Principal Balance	107,000,000				105,000,000
Impaired Financing Receivable, Recorded Investment	106,000,000	[1]			105,000,000	[1]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	108,000,000		93,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	1,000,000	[2]	1,000,000	[2]
Consumer Credit Card Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	2,000,000				2,000,000
Impaired Financing Receivable, Unpaid Principal Balance	8,000,000				8,000,000
Impaired Financing Receivable, Recorded Investment	8,000,000	[1]			8,000,000	[1]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	8,000,000		12,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0		0
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				0
Impaired Financing Receivables With No Related Allowance [Member] | Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				0
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0				0
Impaired Financing Receivables With No Related Allowance [Member] | Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 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 both the three months ended March 31, 2015 and 2014, cash basis interest income was $1 million.