Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011
Assets:
Available For Sale Securities	$ 15,251	[1]	$ 14,520		$ 14,267
Trading securities	195		177		216
Residential mortgage loans held for sale	1,429		2,751		1,017
Residential mortgage loans	67	[2]	65	[2]	54
Derivative assets	2,101		2,356		1,826
Total assets	19,043		19,869		17,380
Liabilities:
Derivative liabilities	1,046		1,344		1,183
Short positions	6		6		10
Total liabilities	1,052		1,350		1,193
US Treasury and Government
Assets:
Available For Sale Securities	51		171		228
US Government Agencies Debt Securities
Assets:
Available For Sale Securities	1,954		1,962		1,739
US States and Political Subdivisions Debt Securities
Assets:
Available For Sale Securities	214		101		153
Trading securities	20		9		21
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets:
Available For Sale Securities	10,358		10,284		10,785
Trading securities	19		11		35
Other Debt Securities
Assets:
Available For Sale Securities	2,365		1,812		1,183
Trading securities	11		13		11
Equity Securities, Other
Assets:
Available For Sale Securities	309	[1]	190		179
Trading securities	145		144		149
Interest Rate Contract
Assets:
Derivative assets	1,595		1,815		1,310
Liabilities:
Derivative liabilities	693		858		722
Foreign Exchange Contract
Assets:
Derivative assets	191		294		315
Liabilities:
Derivative liabilities	178		275		307
Equity Contract
Assets:
Derivative assets	159		113		78
Liabilities:
Derivative liabilities	24		81		38
Commodity Contract
Assets:
Derivative assets	156		134		123
Liabilities:
Derivative liabilities	151		130		116
Fair Value, Inputs, Level 1
Assets:
Available For Sale Securities	355	[1]	356		402
Trading securities	145		144		50
Derivative assets	22		8		3
Total assets	522		508		455
Liabilities:
Derivative liabilities	11		54		10
Short positions	5		2		8
Total liabilities	16		56		18
Fair Value, Inputs, Level 1 | US Treasury and Government
Assets:
Available For Sale Securities	51		171		228
Fair Value, Inputs, Level 1 | Equity Securities, Other
Assets:
Available For Sale Securities	304	[1]	185		174
Trading securities	145		144		50
Fair Value, Inputs, Level 1 | Interest Rate Contract
Assets:
Derivative assets	22		8		3
Liabilities:
Derivative liabilities	11		54		10
Fair Value, Inputs, Level 2
Assets:
Available For Sale Securities	14,896		14,164		13,865
Trading securities	49		32		165
Residential mortgage loans held for sale	1,429		2,751		1,017
Derivative assets	1,899		2,201		1,733
Total assets	18,273		19,148		16,780
Liabilities:
Derivative liabilities	1,007		1,207		1,133
Short positions	1		4		2
Total liabilities	1,008		1,211		1,135
Fair Value, Inputs, Level 2 | US Government Agencies Debt Securities
Assets:
Available For Sale Securities	1,954		1,962		1,739
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities
Assets:
Available For Sale Securities	214		101		153
Trading securities	19		8		20
Fair Value, Inputs, Level 2 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets:
Available For Sale Securities	10,358		10,284		10,785
Trading securities	19		11		35
Fair Value, Inputs, Level 2 | Other Debt Securities
Assets:
Available For Sale Securities	2,365		1,812		1,183
Trading securities	11		13		11
Fair Value, Inputs, Level 2 | Equity Securities, Other
Assets:
Available For Sale Securities	5		5		5
Trading securities					99
Fair Value, Inputs, Level 2 | Interest Rate Contract
Assets:
Derivative assets	1,552		1,773		1,295
Liabilities:
Derivative liabilities	678		802		710
Fair Value, Inputs, Level 2 | Foreign Exchange Contract
Assets:
Derivative assets	191		294		315
Liabilities:
Derivative liabilities	178		275		307
Fair Value, Inputs, Level 2 | Commodity Contract
Assets:
Derivative assets	156		134		123
Liabilities:
Derivative liabilities	151		130		116
Fair Value, Inputs, Level 3
Assets:
Trading securities	1		1		1
Residential mortgage loans	67	[2]	65	[2]	54
Derivative assets	180		147		90
Total assets	248		213		145
Liabilities:
Derivative liabilities	28		83		40
Total liabilities	28		83		40
Fair Value, Inputs, Level 3 | US States and Political Subdivisions Debt Securities
Assets:
Trading securities			1		1
Fair Value, Inputs, Level 3 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets:
Trading securities	1
Fair Value, Inputs, Level 3 | Interest Rate Contract
Assets:
Derivative assets	21		34		12
Liabilities:
Derivative liabilities	4		2		2
Fair Value, Inputs, Level 3 | Equity Contract
Assets:
Derivative assets	159		113		78
Liabilities:
Derivative liabilities	$ 24		$ 81		$ 38

[1] Excludes FHLB and FRB restricted stock totaling $497 and $345, respectively, at March 31, 2012 and December 31, 2011, and $524 and $344, respectively at March 31, 2011.

[2] Includes residential mortgage loans originated as held for sale and subsequently transferred to held for investment. (c) During the three months ended March 31, 2012, no assets or liabilities were transferred between Level 1 and Level 2