LHFI Considered Impaired (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 3,523		$ 4,150
Amortized Cost	3,078	[1]	3,592	[2]
Related Allowance	364		448
Average Amortized Cost	3,154		3,751
Interest Income Recognized	127	[3]	132	[4]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	110		196
Amortized Cost	90	[1]	163	[2]
Related Allowance	0		0
Average Amortized Cost	102		212
Interest Income Recognized	2	[3]	5	[4]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	59		93
Amortized Cost	40	[1]	73	[2]
Related Allowance	0		0
Average Amortized Cost	48		109
Interest Income Recognized	1	[3]	3	[4]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	6		58
Amortized Cost	5	[1]	50	[2]
Related Allowance	0		0
Average Amortized Cost	9		56
Interest Income Recognized	0	[3]	1	[4]
Impaired Financing Receivables With No Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	45		45
Amortized Cost	45	[1]	40	[2]
Related Allowance	0		0
Average Amortized Cost	45		47
Interest Income Recognized	1	[3]	1	[4]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	66		319
Amortized Cost	48	[1]	249	[2]
Related Allowance	7		34
Average Amortized Cost	64		292
Interest Income Recognized	1	[3]	5	[4]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	46		76
Amortized Cost	38	[1]	67	[2]
Related Allowance	6		9
Average Amortized Cost	51		68
Interest Income Recognized	1	[3]	1	[4]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	15		111
Amortized Cost	7	[1]	82	[2]
Related Allowance	1		15
Average Amortized Cost	9		103
Interest Income Recognized	0	[3]	2	[4]
Impaired Financing Receivables with Related Allowance [Member] | Commercial Portfolio Segment [Member] | Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	5		132
Amortized Cost	3	[1]	100	[2]
Related Allowance	0		10
Average Amortized Cost	4		121
Interest Income Recognized	0	[3]	2	[4]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	3,266		3,596
Amortized Cost	2,859	[1]	3,141	[2]
Related Allowance	348		405
Average Amortized Cost	2,899		3,208
Interest Income Recognized	119	[3]	119	[4]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Residential Nonguaranteed [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,346		2,797
Amortized Cost	2,046	[1]	2,405	[2]
Related Allowance	234		293
Average Amortized Cost	2,063		2,451
Interest Income Recognized	83	[3]	88	[4]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Home Equity
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	661		553
Amortized Cost	612	[1]	515	[2]
Related Allowance	88		86
Average Amortized Cost	627		528
Interest Income Recognized	26	[3]	23	[4]
Impaired Financing Receivables with Related Allowance [Member] | Residential Portfolio Segment [Member] | Residential Construction
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	259		246
Amortized Cost	201	[1]	221	[2]
Related Allowance	26		26
Average Amortized Cost	209		229
Interest Income Recognized	10	[3]	8	[4]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	81		39
Amortized Cost	81	[1]	39	[2]
Related Allowance	9		9
Average Amortized Cost	89		39
Interest Income Recognized	5	[3]	3	[4]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Other Direct
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	14		12
Amortized Cost	14	[1]	12	[2]
Related Allowance	2		1
Average Amortized Cost	15		13
Interest Income Recognized	1	[3]	1	[4]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Indirect
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	46
Amortized Cost	46	[1]
Related Allowance	2
Average Amortized Cost	50
Interest Income Recognized	2	[3]
Impaired Financing Receivables with Related Allowance [Member] | Consumer Portfolio Segment [Member] | Consumer Credit Card
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	21		27
Amortized Cost	21	[1]	27	[2]
Related Allowance	5		8
Average Amortized Cost	24		26
Interest Income Recognized	$ 2	[3]	$ 2	[4]

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

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

[3] Of the interest income recognized for the year ended December 31, 2012, cash basis interest income was $18 million. As of December 31, 2011 Year Ended December 31, 2011(Dollars in millions)UnpaidPrincipalBalance Amortized Cost1 RelatedAllowance AverageAmortized Cost InterestIncomeRecognized2Impaired loans with no related allowance recorded: Commercial loans: Commercial & industrial$93 $73 $— $109 $3Commercial real estate58 50 — 56 1Commercial construction45 40 — 47 1Total commercial loans196 163 — 212 5Impaired loans with an allowance recorded: Commercial loans: Commercial & industrial76 67 9 68 1Commercial real estate111 82 15 103 2Commercial construction132 100 10 121 2Total commercial loans319 249 34 292 5Residential loans: Residential mortgages - nonguaranteed2,797 2,405 293 2,451 88Home equity products553 515 86 528 23Residential construction246 221 26 229 8Total residential loans3,596 3,141 405 3,208 119Consumer loans: Other direct12 12 1 13 1Credit cards27 27 8 26 2Total consumer loans39 39 9 39 3Total impaired loans$4,150 $3,592 $448 $3,751 $132

[4] Of the interest income recognized for the year ended December 31, 2011, cash basis interest income was $25 million.