Long-Term Debt - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Debt Instrument [Line Items]
Contractually obligated payments for long-term debt due in 2012	$ 8,000,000
Contractually obligated payments for long-term debt due in 2013	1,700,000,000
Contractually obligated payments for long-term debt due in 2014	18,000,000
Contractually obligated payments for long-term debt due in 2015	738,000,000
Contractually obligated payments for long-term debt due in 2016	2,300,000,000
Contractually obligated payments for long-term debt due after 2016	5,000,000,000
Debt, discounts and premiums	18,000,000		15,000,000
Additions for mark-to-market adjustments on hedged debt	662,000,000		439,000,000
Long-term debt	9,682,000,000	[1]	9,558,000,000	[1]
Debt, outstanding principal balance	9,000,000,000		9,100,000,000
Parent company
Debt Instrument [Line Items]
Long-term debt	6,784,000,000		5,960,000,000
Parent company | Senior Debt Obligations | Fixed Rate 3.625 Percent Notes Due 2016
Debt Instrument [Line Items]
Maturity date	January 25, 2016
Issuance date	January 25, 2011
Issue of senior notes to third party investors	1,000,000,000
Amount of debt converted to floating rate	500,000,000
Interest rate paid	0.26%
Parent company | Senior Debt Obligations | Fixed Rate 6.25 Percent Notes Due 2013
Debt Instrument [Line Items]
Interest rate	6.25%
Maturity date	May 1, 2013
Issuance date	April 2008
Issue of senior notes to third party investors	750,000,000
Amount of debt converted to floating rate	675,000,000
Interest rate paid	2.84%		2.70%
Long-term debt	779,000,000		797,000,000
Parent company | Subordinated debt | Floating Rate 0.98 Percent Notes Due 2016
Debt Instrument [Line Items]
Long-term debt	250,000,000		250,000,000
Parent company | Subordinated debt | Floating Rate 0.98 Percent Notes Due 2016 | Three Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	42
Parent company | Subordinated debt | Fixed Rate 5.45 Percent Notes Due 2017
Debt Instrument [Line Items]
Interest rate	5.45%
Interest rate paid	0.82%
Long-term debt	589,000,000		613,000,000
Parent company | Subordinated debt | Fixed Rate 5.45 Percent Notes Due 2017 | Three Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	42
Parent company | Subordinated debt | Fixed Rate 4.50 Percent Notes Due 2018
Debt Instrument [Line Items]
Interest rate	4.50%
Interest rate paid	0.78%
Long-term debt	581,000,000		584,000,000
Parent company | Subordinated debt | Fixed Rate 4.50 Percent Notes Due 2018 | Three Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	25
Parent company | Subordinated debt | Fixed Rate 8.25 Percent Notes Due 2038
Debt Instrument [Line Items]
Issue of senior notes to third party investors	1,000,000,000
Interest rate	8.25%
Amount of debt converted to floating rate	705,000,000
Interest rate paid	3.58%
Long-term debt	1,348,000,000		1,034,000,000
Parent company | Junior subordinated debt
Debt Instrument [Line Items]
Gain on the extinguishment	6,000,000
Parent company | Junior subordinated debt | Fixed Rate 7.25 Percent Notes Due 2067 | Group 1 [Member]
Debt Instrument [Line Items]
Interest rate	7.25%
Debt, carry amount	594,000,000
Amount of debt converted to floating rate	500,000,000
Interest rate paid	1.18%
Long-term debt	594,000,000		613,000,000
Debt, outstanding principal balance	575,000,000
Parent company | Junior subordinated debt | Fixed Rate 7.25 Percent Notes Due 2067 | Group 2 [Member]
Debt Instrument [Line Items]
Interest rate	7.25%
Debt, carry amount	894,000,000
Amount of debt converted to floating rate	700,000,000
Interest rate paid	1.61%
Long-term debt	894,000,000		907,000,000
Parent company | Junior subordinated debt | Fixed Rate 7.25 Percent Notes Due 2067 | Three Month L I B O R [Member] | Group 1 [Member]
Debt Instrument [Line Items]
Basis points	257
Parent company | Junior subordinated debt | Fixed Rate 7.25 Percent Notes Due 2067 | Three Month L I B O R [Member] | Group 2 [Member]
Debt Instrument [Line Items]
Basis points	303
Parent company | Junior subordinated debt | Fixed Rate 6.50 Percent Notes Due 2067
Debt Instrument [Line Items]
Interest rate	6.50%
Long-term debt	750,000,000		750,000,000
Parent company | Junior subordinated debt | Fixed Rate 6.50 Percent Notes Due 2067 | Three Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	137
Parent company | Junior subordinated debt | Fixed Rate 6.50 Percent Notes Due 2067 | One Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	237
Parent company | Junior subordinated debt | Fixed Rate 8.88 Percent Notes Due 2068
Debt Instrument [Line Items]
Long-term debt			400,000,000
Parent company | Structured Repurchase Agreements
Debt Instrument [Line Items]
Long-term debt	375,000,000
Subsidiaries
Debt Instrument [Line Items]
Debt, available for future issuance	19,000,000,000
Debt, outstanding principal balance	1,000,000,000		1,000,000,000
Subsidiaries | Federal Home Loan Bank Advances 0.05 To 8.34 Percent Due 2011 Through 2037
Debt Instrument [Line Items]
Payments of Debt Extinguishment Costs	2,000,000
Amount of debt converted to fixed rate			500,000,000
Interest rate paid			2.63%
Interest Rate Minimum	0.05%
Interest Rate Maximum	8.34%
Advances secured by certain residential mortgage loans and securities	17,500,000,000
Floating rate FHLB advances			500,000,000
Repayment of floating rate advance due in 2012			1,000,000,000
Gain on extinguishment of debt			1,000,000
FHLB advance	1,100,000,000
FHLB advances maturing 2014	3,000,000
FHLB advances maturing 2015	5,000,000
FHLB advances maturing 2016	1,000,000,000
FHLB advances maturing thereafter	43,000,000
Subsidiaries | Senior Debt Obligations | Floating Rate 0.58 Percent Bank Notes Due 2013
Debt Instrument [Line Items]
Long-term debt	500,000,000		499,000,000
Subsidiaries | Senior Debt Obligations | Floating Rate 0.58 Percent Bank Notes Due 2013 | Three Month L I B O R [Member]
Debt Instrument [Line Items]
Basis points	11
Subsidiaries | Subordinated debt
Debt Instrument [Line Items]
Debt Instrument Principal Amount Redeemed	65,000,000
Gain on the extinguishment	1,000,000
Subsidiaries | Subordinated debt | Fixed Rate 4.75 Percent Bank Notes Due 2015
Debt Instrument [Line Items]
Interest rate	4.75%
Interest rate paid	0.53%
Long-term debt	561,000,000		561,000,000
Subsidiaries | Junior subordinated debt
Debt Instrument [Line Items]
Debt Instrument Principal Amount Redeemed	452,000,000
Subsidiaries | Junior subordinated debt | Floating Rate 5.29 Percent Debentures Due 2034 Member
Debt Instrument [Line Items]
Long-term debt			67,000,000
Subsidiaries | Junior subordinated debt | Floating Rate 2.24 Percent Debentures Due 2035
Debt Instrument [Line Items]
Basis points	169
Subsidiaries | Junior subordinated debt | Floating Rate 2.24 Percent Debentures Due 2035 | Three Month L I B O R [Member] | Group 2 [Member]
Debt Instrument [Line Items]
Basis points	142
Subsidiaries | Variable Interest Entity, Primary Beneficiary | Automobile Loan
Debt Instrument [Line Items]
Long-term debt	171,000,000
Subsidiaries | Variable Interest Entity, Primary Beneficiary | Home Equity
Debt Instrument [Line Items]
Long-term debt	$ 22,000,000

[1] At December 31, 2011 and 2010, includes $30 and $52 of cash, $7 of other short-term investments, $50 and $29 of commercial mortgage loans, $223 and $241 of home equity loans, $259 and $648 of automobile loans, ($10) and ($14) of ALLL, $4 and $7 of other assets, $4 and $12 of other liabilities, $191 and $692 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 11.