Securities with Unrealized Losses, Aggregated by Category and Period of Continuous Unrealized Loss (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	$ 11,094		$ 2,129
Securities available for sale Less than 12 months Unrealized Losses	57		6
Securities available for sale 12 months or longer Fair Value	898		1,207
Securities available for sale 12 months or longer Unrealized Losses	216		234
Total Securities available for sale with unrealized losses Total Fair Value	11,992		3,336
Total Securities available for sale with unrealized losses Total Unrealized Losses	273		240
Securities held to maturity Less than 12 months Fair Value	384		6,880
Securities held to maturity Less than 12 months Unrealized Losses	2		137
Securities held to maturity 12 months or longer Fair Value
Securities held to maturity 12 months or longer Unrealized Losses
Total Securities held to maturity with unrealized losses Total Fair Value	384		6,880
Total Securities held to maturity with unrealized losses Total Unrealized Losses	2		137
Securities Less than 12 months Fair Value	11,478	[1]	9,009	[2]
Securities Less than 12 months Unrealized Losses	59	[1]	143	[2]
Securities 12 months or longer Fair Value	898	[1]	1,207	[2]
Securities 12 months or longer Unrealized Losses	216	[1]	234	[2]
Total securities with unrealized losses Total Fair Value	12,376	[1]	10,216	[2]
Total securities with unrealized losses Total Unrealized Losses	275	[1]	377	[2]
U.S. agency residential mortgage-backed securities
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	5,551		707
Securities available for sale Less than 12 months Unrealized Losses	14		3
Total Securities available for sale with unrealized losses Total Fair Value	5,551		707
Total Securities available for sale with unrealized losses Total Unrealized Losses	14		3
Securities held to maturity Less than 12 months Fair Value	384		6,880
Securities held to maturity Less than 12 months Unrealized Losses	2		137
Securities held to maturity 12 months or longer Fair Value
Securities held to maturity 12 months or longer Unrealized Losses
Total Securities held to maturity with unrealized losses Total Fair Value	384		6,880
Total Securities held to maturity with unrealized losses Total Unrealized Losses	2		137
Non-agency residential mortgage-backed securities
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	121
Securities available for sale Less than 12 months Unrealized Losses	8
Securities available for sale 12 months or longer Fair Value	746		1,207
Securities available for sale 12 months or longer Unrealized Losses	215		234
Total Securities available for sale with unrealized losses Total Fair Value	867		1,207
Total Securities available for sale with unrealized losses Total Unrealized Losses	223		234
Certificates of deposit
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	2,158
Securities available for sale Less than 12 months Unrealized Losses	3
Total Securities available for sale with unrealized losses Total Fair Value	2,158
Total Securities available for sale with unrealized losses Total Unrealized Losses	3
Corporate debt securities
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	1,888		549
Securities available for sale Less than 12 months Unrealized Losses	26		1
Total Securities available for sale with unrealized losses Total Fair Value	1,888		549
Total Securities available for sale with unrealized losses Total Unrealized Losses	26		1
Asset-backed and other securities
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value	1,376
Securities available for sale Less than 12 months Unrealized Losses	6
Securities available for sale 12 months or longer Fair Value	152
Securities available for sale 12 months or longer Unrealized Losses	1
Total Securities available for sale with unrealized losses Total Fair Value	1,528
Total Securities available for sale with unrealized losses Total Unrealized Losses	7
Asset-backed securities
Investment [Line Items]
Securities available for sale Less than 12 months Fair Value			873
Securities available for sale Less than 12 months Unrealized Losses			2
Total Securities available for sale with unrealized losses Total Fair Value			873
Total Securities available for sale with unrealized losses Total Unrealized Losses			$ 2

[1] The number of investment positions with unrealized losses totaled 296 for securities available for sale and 3 for securities held to maturity.

[2] The number of investment positions with unrealized losses totaled 178 for securities available for sale and 37 for securities held to maturity.