Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Assets:
Available For Sale Securities	$ 15,342	[1]	$ 14,363	[1]
Trading securities	219		207
Residential mortgage loans held for sale	2,113		2,856
Residential mortgage loans	83	[2]	76	[2]
Derivative assets	1,818		1,972
Total assets	19,575		19,474
Liabilities:
Derivative liabilities	871		915
Short positions	21		10
Total liabilities	892		925
US Treasury and Government
Assets:
Available For Sale Securities	26		41
Trading securities			1
US Government Agencies Debt Securities
Assets:
Available For Sale Securities	1,758		1,911
Trading securities	18		6
US States and Political Subdivisions Debt Securities
Assets:
Available For Sale Securities	205		212
Trading securities	11		17
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets:
Available For Sale Securities	9,663		8,730
Trading securities	7		7
Other Debt Securities
Assets:
Available For Sale Securities	3,548		3,277
Trading securities	11		15
Equity Securities, Other
Assets:
Available For Sale Securities	142	[1]	192	[1]
Trading securities	172		161
Interest Rate Contract
Assets:
Derivative assets	1,176		1,507
Liabilities:
Derivative liabilities	520		617
Foreign Exchange Contract
Assets:
Derivative assets	257		201
Liabilities:
Derivative liabilities	215		183
Equity Contract
Assets:
Derivative assets	287		177
Liabilities:
Derivative liabilities	37		33
Commodity Contract
Assets:
Derivative assets	98		87
Liabilities:
Derivative liabilities	99		82
Fair Value, Inputs, Level 1
Assets:
Available For Sale Securities	112	[1],[3]	120	[1],[3]
Trading securities	172	[3]	162	[3]
Derivative assets	193	[3]	2	[3]
Total assets	477	[3]	284	[3]
Liabilities:
Derivative liabilities	44	[3]	14	[3]
Short positions	18	[3]	8	[3]
Total liabilities	62	[3]	22	[3]
Fair Value, Inputs, Level 1 | US Treasury and Government
Assets:
Available For Sale Securities	26	[3]	41	[3]
Trading securities			1	[3]
Fair Value, Inputs, Level 1 | Equity Securities, Other
Assets:
Available For Sale Securities	86	[1],[3]	79	[1],[3]
Trading securities	172	[3]	161	[3]
Fair Value, Inputs, Level 1 | Interest Rate Contract
Assets:
Derivative assets	185	[3]	2	[3]
Liabilities:
Derivative liabilities	26	[3]	14	[3]
Fair Value, Inputs, Level 1 | Commodity Contract
Assets:
Derivative assets	8	[3]
Liabilities:
Derivative liabilities	18	[3]
Fair Value, Inputs, Level 2
Assets:
Available For Sale Securities	15,230	[1],[3]	14,243	[1],[3]
Trading securities	46	[3]	44	[3]
Residential mortgage loans held for sale	2,113	[3]	2,856	[3]
Derivative assets	1,331	[3]	1,733	[3]
Total assets	18,720	[3]	18,876	[3]
Liabilities:
Derivative liabilities	753	[3]	865	[3]
Short positions	3	[3]	2	[3]
Total liabilities	756	[3]	867	[3]
Fair Value, Inputs, Level 2 | US Government Agencies Debt Securities
Assets:
Available For Sale Securities	1,758	[3]	1,911	[3]
Trading securities	18	[3]	6	[3]
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities
Assets:
Available For Sale Securities	205	[3]	212	[3]
Trading securities	10	[3]	16	[3]
Fair Value, Inputs, Level 2 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets:
Available For Sale Securities	9,663	[3]	8,730	[3]
Trading securities	7	[3]	7	[3]
Fair Value, Inputs, Level 2 | Other Debt Securities
Assets:
Available For Sale Securities	3,548	[3]	3,277	[3]
Trading securities	11	[3]	15	[3]
Fair Value, Inputs, Level 2 | Equity Securities, Other
Assets:
Available For Sale Securities	56	[1],[3]	113	[1],[3]
Fair Value, Inputs, Level 2 | Interest Rate Contract
Assets:
Derivative assets	984	[3]	1,445	[3]
Liabilities:
Derivative liabilities	457	[3]	600	[3]
Fair Value, Inputs, Level 2 | Foreign Exchange Contract
Assets:
Derivative assets	257	[3]	201	[3]
Liabilities:
Derivative liabilities	215	[3]	183	[3]
Fair Value, Inputs, Level 2 | Commodity Contract
Assets:
Derivative assets	90	[3]	87	[3]
Liabilities:
Derivative liabilities	81	[3]	82	[3]
Fair Value, Inputs, Level 3
Assets:
Trading securities	1		1
Residential mortgage loans	83	[2]	76	[2]
Derivative assets	294		237
Total assets	378		314
Liabilities:
Derivative liabilities	74		36
Total liabilities	74		36
Fair Value, Inputs, Level 3 | US States and Political Subdivisions Debt Securities
Assets:
Trading securities	1		1
Fair Value, Inputs, Level 3 | Interest Rate Contract
Assets:
Derivative assets	7		60
Liabilities:
Derivative liabilities	37		3
Fair Value, Inputs, Level 3 | Equity Contract
Assets:
Derivative assets	287		177
Liabilities:
Derivative liabilities	$ 37		$ 33

[1] Excludes FHLB and FRB restricted stock totaling $497 and $348, respectively, at June 30, 2013 and $497 and $347, respectively, at December 31, 2012.

[2] Includes residential mortgage loans originated as held for sale and subsequently transferred to held for investment

[3] During the three and six months ended June 30, 2013 and for the year ended December 31, 2012, no assets or liabilities were transferred between Level 1 and Level 2.