Certain Transfers of Financial Assets and Variable Interest Entities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Total assets	$ 172,435,000,000			$ 173,442,000,000
Loans Receivable Held-for-sale, Net	3,193,000,000	[1]		3,399,000,000
Long-term Debt	9,331,000,000	[2]		9,357,000,000	[2]
Total liabilities	151,241,000,000			152,457,000,000
Derivative asset positions	7,568,000,000			8,656,000,000
Derivative Liability, Fair Value, Gross Liability	6,795,000,000			7,514,000,000
Other assets	5,345,000,000			5,335,000,000
Variable Interest Entity, Primary Beneficiary
Loans Receivable Held-for-sale, Net	315,000,000			319,000,000
Long-term Debt	656,000,000			666,000,000
Residential Mortgage | Variable Interest Entity, Not Primary Beneficiary [Member]
Loans and Leases Receivable, Gain (Loss) on Sales, Net	157,000,000		224,000,000
Transferor's Interests in Transferred Financial Assets, Fair Value	95,000,000			98,000,000
Total assets	422,000,000			445,000,000
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets	1,700,000,000			1,800,000,000
Total liabilities	1,700,000,000			1,700,000,000
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Preference Shares
Total assets	3,000,000			3,000,000
Commercial and Corporate Loans [Member] | Variable Interest Entity, Primary Beneficiary
Long-term Debt	286,000,000			286,000,000
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary
Long-term Debt	370,000,000			380,000,000
Loans Receivable, Net	374,000,000			384,000,000
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary | Upper Limit
Government guaranteed percent	97.00%			97.00%
Collateralized Debt Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets	1,100,000,000			1,200,000,000
Declines in fair values for the total retained interests due to 20% adverse changes in the discount rate	21,000,000
Collateralized Debt Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Trading Assets [Member]
Transferor's Interests in Transferred Financial Assets, Fair Value	61,000,000			52,000,000
CDO Securities Weighted Average Expected Maturity in Years	21 years
Collateralized Debt Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Upper Limit | Trading Assets [Member]
Fair Value Inputs, Market Yield	11.00%
Collateralized Debt Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Lower Limit
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Other Assumption	5,000,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Other Assumption	11,000,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Expected Credit Losses	7,000,000
Collateralized Debt Obligations [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Lower Limit | Trading Assets [Member]
Fair Value Inputs, Market Yield	8.50%
Total Return Swap | Variable Interest Entity, Not Primary Beneficiary [Member]
Senior financing outstanding to VIEs	1,800,000,000			1,900,000,000
VIEs had entered into TRS contracts with the Company with outstanding notional amounts	1,800,000,000			1,900,000,000
Derivative asset positions	55,000,000			51,000,000
Derivative Liability, Fair Value, Gross Liability	52,000,000			46,000,000
Community Development Investments [Member] | General Partner [Member]
Total assets	3,000,000			3,000,000
Total liabilities	1,000,000			1,000,000
Community Development Investments [Member] | Partnership [Member]
Total assets	233,000,000			239,000,000
Total liabilities	98,000,000			100,000,000
Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets	1,200,000,000
Other assets	67,000,000			63,000,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	121,000,000			110,000,000
Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Limited Partner
Other assets	205,000,000			186,000,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	536,000,000			505,000,000
Loans issued by the Company to the limited partnerships	258,000,000			236,000,000
Ridgeworth Fund | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets	$ 354,000,000			$ 372,000,000

[1] 1 Includes loans held for sale, at fair value, of consolidated VIEs315 319

[2] 3 Includes debt of consolidated VIEs ($286 at fair value at March 31, 2013 and December 31, 2012)656 666