LHFI Considered Impaired (Detail) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014		Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		$ 269			$ 269				$ 319
Impaired Financing Receivable, Unpaid Principal Balance		2,975			2,975				3,108
Impaired Financing Receivable, Recorded Investment	[1]	2,690			2,690				2,781
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		2,708		$ 3,042	2,737		$ 3,023
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	31		33	96		106
Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		59			59				70
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	49			49				51
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7			7				7
Impaired Financing Receivable, Unpaid Principal Balance		14			14				27
Impaired Financing Receivable, Recorded Investment	[1]	12			12				26
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		51		65	53		68
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	[2]	0	1	[2]	1	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		20		45	23		46
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		0		0	1	[2]	1	[2]
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		70			70				82
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	58			58				62
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7			7				11
Impaired Financing Receivable, Unpaid Principal Balance		14			14				31
Impaired Financing Receivable, Recorded Investment	[1]	12			12				30
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		60		80	63		84
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	[2]	0	1	[2]	1	[2]
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		20		55	23		55
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		0		0	1	[2]	1	[2]
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		455			455				623
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	335			335				434
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		255			255				300
Impaired Financing Receivable, Unpaid Principal Balance		2,288			2,288				2,229
Impaired Financing Receivable, Recorded Investment	[1]	2,156			2,156				2,129
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		339		468	346		482
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	4		5	11		14
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		2,157		2,299	2,167		2,267
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	26		27	79		85
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7			7				8
Impaired Financing Receivable, Unpaid Principal Balance		148			148				143
Impaired Financing Receivable, Recorded Investment	[1]	129			129				126
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		132		140	138		135
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	1		1	4		5
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		11			11				12
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	9			9				11
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0			0				4
Impaired Financing Receivable, Unpaid Principal Balance		0			0				4
Impaired Financing Receivable, Recorded Investment		0			0				4	[1]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		9		15	10		16
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0		0	0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0		10	0		9
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		0		0	0		0
Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		431			431				592
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	326			326				425
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		181			181				215
Impaired Financing Receivable, Unpaid Principal Balance		1,451			1,451				1,381
Impaired Financing Receivable, Recorded Investment	[1]	1,395			1,395				1,354
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		330		454	335		467
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	[2]	4		5	11		14
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		1,393		1,467	1,396		1,443
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	17		18	52		59
Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		60			60				66
Impaired Financing Receivable, Unpaid Principal Balance		709			709				703
Impaired Financing Receivable, Recorded Investment	[1]	637			637				630
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		640		668	646		662
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	7		7	21		20
Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		24			24				31
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	9			9				9
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		14			14				19
Impaired Financing Receivable, Unpaid Principal Balance		128			128				145
Impaired Financing Receivable, Recorded Investment	[1]	124			124				145
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		9		14	11		15
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0		0	0		0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		124		164	125		162
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	2		2	6		6
Consumer Other Direct [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		1			1				1
Impaired Financing Receivable, Unpaid Principal Balance		11			11				13
Impaired Financing Receivable, Recorded Investment	[1]	11			11				13
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		12		14	12		14
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		0		0	0		0
Consumer Indirect [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		5			5				5
Impaired Financing Receivable, Unpaid Principal Balance		113			113				105
Impaired Financing Receivable, Recorded Investment	[1]	112			112				105
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		114		116	119		110
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	[2]	1		1	4		4
Credit Card Receivable [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		1			1				2
Impaired Financing Receivable, Unpaid Principal Balance		24			24				25
Impaired Financing Receivable, Recorded Investment	[1]	6			6				$ 8
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		6		10	7		11
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		$ 0		$ 0	$ 0		$ 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] Of the interest income recognized during the three and nine months ended September 30, 2015, cash basis interest income was $1 million and $3 million, respectively.Of the interest income recognized during the three and nine months ended September 30, 2014, cash basis interest income was less than $1 million and $2 million, respectively.