Certain Transfers of Financial Assets and Variable Interest Entities - Additional Information (Detail) (USD $)	3 Months Ended							3 Months Ended												3 Months Ended				3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended													3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011	Dec. 31, 2011		Mar. 31, 2012 Variable Interest Entity, Primary Beneficiary day	Dec. 31, 2011 Variable Interest Entity, Primary Beneficiary	Mar. 31, 2012 Residential Mortgage Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2011 Residential Mortgage Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Residential Mortgage Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Commercial and Corporate Loans [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Commercial and Corporate Loans [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Commercial and Corporate Loans [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Preference Shares	Dec. 31, 2011 Commercial and Corporate Loans [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Preference Shares	Mar. 31, 2012 Commercial and Corporate Loans [Member] Variable Interest Entity, Primary Beneficiary	Dec. 31, 2011 Commercial and Corporate Loans [Member] Variable Interest Entity, Primary Beneficiary	Mar. 31, 2012 Student Loans Variable Interest Entity, Primary Beneficiary	Dec. 31, 2011 Student Loans Variable Interest Entity, Primary Beneficiary	Mar. 31, 2012 Student Loans Variable Interest Entity, Primary Beneficiary Upper Limit	Mar. 31, 2012 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Trading Assets [Member]	Dec. 31, 2011 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Trading Assets [Member]	Mar. 31, 2012 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Upper Limit	Dec. 31, 2011 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Upper Limit	Mar. 31, 2012 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Lower Limit	Dec. 31, 2011 Collateralized Debt Obligations [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Lower Limit	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary years	Mar. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary	Dec. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary years	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Receivables	Dec. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Receivables	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Trade Accounts Receivable [Member]	Dec. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Trade Accounts Receivable [Member]	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Loans Receivable [Member]	Dec. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Loans Receivable [Member]	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Commercial Portfolio Segment	Dec. 31, 2011 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Commercial Portfolio Segment	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Upper Limit years	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary Lower Limit years	Mar. 31, 2012 Three Pillars [Member] Variable Interest Entity, Primary Beneficiary A And A2 Or Above Credit Rating	Mar. 31, 2012 Total Return Swap Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Total Return Swap Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Community Development Investments [Member] General Partner [Member]	Dec. 31, 2011 Community Development Investments [Member] General Partner [Member]	Mar. 31, 2012 Community Development Investments [Member] Partnership [Member]	Dec. 31, 2011 Community Development Investments [Member] Partnership [Member]	Mar. 31, 2012 Community Development Investments [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Community Development Investments [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Community Development Investments [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Limited Partner	Dec. 31, 2011 Community Development Investments [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Limited Partner	Mar. 31, 2012 Ridgeworth Fund Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2011 Ridgeworth Fund Variable Interest Entity, Not Primary Beneficiary [Member]	Mar. 31, 2012 Loans Held For Investment [Member] Commercial Portfolio Segment
Funding commitments extended by Three Pillars to its customers, almost all of which renew annually																												$ 1,800,000,000		$ 4,100,000,000	$ 972,000,000	$ 2,900,000,000
Loans and Leases Receivable, Gain (Loss) on Sales, Net								224,000,000	12,000,000
Transferor's Interests in Transferred Financial Assets, Fair Value								100,000,000		104,000,000												43,000,000	43,000,000
Total assets	178,226,000,000			176,859,000,000				508,000,000		529,000,000	2,000,000,000	2,000,000,000	2,000,000	2,000,000						1,200,000,000	1,200,000,000																972,000,000	2,900,000,000						5,000,000	5,000,000	351,000,000	360,000,000	1,200,000,000	1,200,000,000			1,000,000,000	1,100,000,000	2,000,000,000
Total liabilities	157,985,000,000			156,793,000,000							1,900,000,000	1,900,000,000																																1,000,000	1,000,000	104,000,000	107,000,000
Loans Receivable, Net															326,000,000	315,000,000	428,000,000	438,000,000
Long-term Debt	11,894,000,000	[1]		10,908,000,000	[1]	713,000,000	722,000,000								289,000,000	289,000,000	424,000,000	433,000,000
Government guaranteed percent																			97.00%
The weighted average remaining lives of the Company's retained interests, approximating (years)																				22
Assumed discount rate in valuing securities, over LIBOR																								11.00%	12.00%	8.00%	8.00%
Declines in fair values for the total retained interests due to 20% adverse changes in the discount rate																				8,000,000	5,000,000					16,000,000
Servicing fees received by the Company	81,000,000		72,000,000
Total Fee Revenue																												8,000,000	16,000,000
Assets supporting those commitments have a weighted average life (years)																												2.2		2.8
Initial terms																																							3	1
The majority of the commitments that have been originated by companies operating across a number of industries which collateralize, percent of the outstanding commitments																																	57.00%	40.00%	12.00%	20.00%
Transactions structured to minimum implied credit and underwriting risk																																									Each transaction added to Three Pillars is typically structured to a minimum implied A/A2 rating according to established credit and underwriting policies
Weighted average lives (days)						15
Minimum tangible net worth allowed for a period of 15 days																												5,000
Credit enhancement requirements as a percent of aggregate commitments of Three Pillars																												10.00%
Other assets	6,043,000,000			6,159,000,000																																												68,000,000	68,000,000	189,000,000	194,000,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount																												1,800,000,000		4,300,000,000																		105,000,000	108,000,000	460,000,000	472,000,000
Loans issued by the Company to the limited partnerships																																																		246,000,000	249,000,000
Senior financing outstanding to VIEs	6,316,000,000			6,279,000,000																																						1,800,000,000	1,700,000,000
VIEs had entered into TRS contracts with the Company with outstanding notional amounts																																										1,800,000,000	1,600,000,000
Derivative asset positions																																										40,000,000	20,000,000
Derivative liability positions																																										$ 36,000,000	$ 17,000,000

[1] Includes debt of consolidated VIEs ($289 at fair value as of both March 31, 2012 and December 31, 2011)713 722