LHFI Considered Impaired (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		$ 3,434,000,000		$ 3,165,000,000
Impaired Financing Receivable, Recorded Investment	[1]	3,068,000,000		2,876,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		255,000,000		287,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		3,045,000,000		2,916,000,000	$ 2,847,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	128,000,000		132,000,000	139,000,000
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		266,000,000		55,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	214,000,000		42,000,000
Impaired Financing Receivable, Unpaid Principal Balance		225,000,000		173,000,000
Impaired Financing Receivable, Recorded Investment	[1]	151,000,000		167,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		31,000,000		28,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		169,000,000		58,000,000	84,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	3,000,000		2,000,000	1,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		170,000,000		147,000,000	16,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	1,000,000		5,000,000	1,000,000
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0		11,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	0		9,000,000
Impaired Financing Receivable, Unpaid Principal Balance		26,000,000		0
Impaired Financing Receivable, Recorded Investment	[1]	17,000,000		0
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		2,000,000		0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0		10,000,000	11,000,000
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		25,000,000		0	5,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		1,000,000	[2]	0	0
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		266,000,000		66,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	214,000,000		51,000,000
Impaired Financing Receivable, Unpaid Principal Balance		251,000,000		173,000,000
Impaired Financing Receivable, Recorded Investment	[1]	168,000,000		167,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		33,000,000		28,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		169,000,000		68,000,000	95,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	3,000,000		2,000,000	2,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		195,000,000		147,000,000	21,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	2,000,000		5,000,000	1,000,000
Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		466,000,000		500,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	360,000,000		380,000,000
Impaired Financing Receivable, Unpaid Principal Balance		1,277,000,000		1,381,000,000
Impaired Financing Receivable, Recorded Investment	[1]	1,248,000,000		1,344,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		150,000,000		178,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		370,000,000		390,000,000	437,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	16,000,000		17,000,000	17,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		1,251,000,000		1,349,000,000	1,357,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	64,000,000		65,000,000	78,000,000
Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		863,000,000		740,000,000
Impaired Financing Receivable, Recorded Investment	[1]	795,000,000		670,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		54,000,000		60,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		812,000,000		682,000,000	644,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	29,000,000		28,000,000	27,000,000
Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		16,000,000		29,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	8,000,000		8,000,000
Impaired Financing Receivable, Unpaid Principal Balance		109,000,000		127,000,000
Impaired Financing Receivable, Recorded Investment	[1]	107,000,000		125,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		11,000,000		14,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		8,000,000		11,000,000	12,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0		0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		110,000,000		125,000,000	144,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	6,000,000		8,000,000	8,000,000
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		482,000,000		529,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	368,000,000		388,000,000
Impaired Financing Receivable, Unpaid Principal Balance		2,249,000,000		2,248,000,000
Impaired Financing Receivable, Recorded Investment	[1]	2,150,000,000		2,139,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		215,000,000		252,000,000
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		378,000,000		401,000,000	449,000,000
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	16,000,000		17,000,000	17,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		2,173,000,000		2,156,000,000	2,145,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	99,000,000		101,000,000	113,000,000
Consumer Other Direct [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		59,000,000	[3]	11,000,000
Impaired Financing Receivable, Recorded Investment	[1]	59,000,000	[3]	11,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		1,000,000		1,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		10,000,000		12,000,000	14,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		1,000,000	[2]	0	0
Consumer Indirect [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		103,000,000		114,000,000
Impaired Financing Receivable, Recorded Investment	[1]	103,000,000		114,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		5,000,000		5,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		114,000,000		125,000,000	113,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	6,000,000		6,000,000	5,000,000
Credit Card Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		24,000,000		24,000,000
Impaired Financing Receivable, Recorded Investment	[1]	6,000,000		6,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		1,000,000		1,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		6,000,000		7,000,000	10,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	1,000,000		1,000,000	1,000,000
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance		186,000,000		149,000,000
Impaired Financing Receivable, Recorded Investment	[1]	168,000,000		131,000,000
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7,000,000		7,000,000
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		130,000,000		144,000,000	137,000,000
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	$ 8,000,000		$ 7,000,000	$ 6,000,000

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

[2] Of the interest income recognized during the years ended December 31, 2016, 2015, and 2014, cash basis interest income was $4 million, $7 million, and $4 million respectively.

[3] Includes $41 million of TDRs that were modified prior to 2016 and reclassified as TDRs in the fourth quarter of 2016.