Long-Term Debt - Additional Information (Detail) (USD $)										12 Months Ended				12 Months Ended					12 Months Ended					12 Months Ended									12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended	3 Months Ended		12 Months Ended						12 Months Ended				12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013 Parent company	Dec. 31, 2012 Parent company	Dec. 31, 2012 Parent company Senior Debt Obligations Fixed Rate 6.25 Percent Notes Due 2013	Dec. 31, 2011 Parent company Senior Debt Obligations Fixed Rate 3.625 Percent Notes Due 2016	Dec. 31, 2012 Parent company Senior Debt Obligations Fixed Rate 3.50 Percent Notes Due 2022	Dec. 31, 2013 Parent company Subordinated debt Floating Rate 0.67 Percent Notes Due 2016		Dec. 31, 2012 Parent company Subordinated debt Floating Rate 0.67 Percent Notes Due 2016		Dec. 31, 2013 Parent company Subordinated debt Floating Rate 0.67 Percent Notes Due 2016 Three Month LIBOR	Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 5.45 Percent Notes Due 2017		Dec. 31, 2012 Parent company Subordinated debt Fixed Rate 5.45 Percent Notes Due 2017		Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 5.45 Percent Notes Due 2017 Three Month LIBOR	Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 4.50 Percent Notes Due 2018		Dec. 31, 2012 Parent company Subordinated debt Fixed Rate 4.50 Percent Notes Due 2018		Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 4.50 Percent Notes Due 2018 Three Month LIBOR	Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 4.30 Notes Due 2024		Dec. 31, 2013 Parent company Subordinated debt Fixed Rate 8.25 Percent Notes Due 2038		Dec. 31, 2012 Parent company Subordinated debt Fixed Rate 8.25 Percent Notes Due 2038		Dec. 31, 2012 Parent company Junior subordinated debt Fixed Rate 6.50 Percent Notes Due 2067		Dec. 31, 2013 Parent company Junior subordinated debt Trust Preferred Securities	Dec. 31, 2013 Subsidiaries	Dec. 31, 2012 Subsidiaries	Dec. 31, 2013 Subsidiaries Federal Home Loan Bank Advances 0.05 To 6.87 Percent Due 2014 Through 2037	Dec. 31, 2013 Subsidiaries Senior Debt Obligations	Mar. 31, 2013 Subsidiaries Senior Debt Obligations	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Floating Rate 0.67 Percent Notes Due 2016	Mar. 31, 2013 Subsidiaries Senior Debt Obligations Floating Rate 0.67 Percent Notes Due 2016	Dec. 31, 2012 Subsidiaries Senior Debt Obligations Floating Rate Bank Notes Due 2013	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Fixed Rate 1.15 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Fixed Rate 0.90 Percent Notes Due 2016	Mar. 31, 2013 Subsidiaries Senior Debt Obligations Fixed Rate 0.90 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Floating Rate 0.75 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Floating Rate 0.75 Percent Notes Due 2016 Three Month LIBOR	Mar. 31, 2013 Subsidiaries Senior Debt Obligations Floating Rate 0.75 Percent Notes Due 2016 Three Month LIBOR	Dec. 31, 2013 Subsidiaries Senior Debt Obligations Fixed Rate 1.45 Percent Notes Due 2018	Mar. 31, 2013 Subsidiaries Senior Debt Obligations Fixed Rate 1.45 Percent Notes Due 2018	Dec. 31, 2013 Subsidiaries Subordinated debt Floating Rate 0.67 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Subordinated debt Fixed Rate 0.90 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Subordinated debt Floating Rate 0.75 Percent Notes Due 2016	Dec. 31, 2013 Subsidiaries Subordinated debt Fixed Rate 1.45 Percent Notes Due 2018	Dec. 31, 2013 Subsidiaries Subordinated debt Fixed Rate 4.75 Percent Bank Notes Due 2015		Dec. 31, 2012 Subsidiaries Subordinated debt Fixed Rate 4.75 Percent Bank Notes Due 2015		Dec. 31, 2013 Subsidiaries Junior subordinated debt Floating Rate 2.24 Percent Debentures Due 2035 Three Month LIBOR Group 1	Dec. 31, 2013 Subsidiaries Junior subordinated debt Floating Rate 2.24 Percent Debentures Due 2035 Three Month LIBOR Group 2	Dec. 31, 2013 Subsidiaries Junior subordinated debt Trust Preferred Securities	Dec. 31, 2013 Subsidiaries Variable Interest Entity, Primary Beneficiary Automobile Securitization Notes Due 2014-2020
Debt Instrument [Line Items]
Long-term debt	$ 9,633,000,000	[1]	$ 7,085,000,000	[1]	$ 4,757,000,000	$ 5,751,000,000	$ 758,000,000			$ 250,000,000	[2]	$ 250,000,000	[2]		$ 558,000,000	[2]	$ 583,000,000	[2]		$ 555,000,000	[2]	$ 584,000,000	[2]		$ 748,000,000	[2]	$ 1,150,000,000	[2]	$ 1,330,000,000	[2]	$ 750,000,000	[3]									$ 500,000,000	$ 1,000,000,000								$ 300,000,000	$ 400,000,000	$ 750,000,000	$ 587,000,000	$ 524,000,000	[2]	$ 546,000,000	[2]				$ 1,048,000,000
Debt, outstanding principal balance	9,400,000,000		6,500,000,000
Debt, discounts and premiums	21,000,000		20,000,000
Additions for mark-to-market adjustments on hedged debt	278,000,000		555,000,000
Issue of senior notes to third party investors								1,000,000,000	500,000,000																750,000,000		1,000,000,000										1,800,000,000	1,300,000,000		300,000,000		1,000,000,000		400,000,000	750,000,000				600,000,000
Debt Instrument Maturity Date Range Start										Dec. 13, 2006	[2]				Dec. 20, 2006	[2]				May 23, 2003	[2]				Nov. 20, 2013	[2]	Mar. 04, 2008	[2]											Feb. 28, 2013			Nov. 20, 2013	Feb. 28, 2013		Nov. 20, 2013			Feb. 28, 2013						Jan. 31, 2005							Jan. 01, 2014
Debt Instrument Maturity Date Range End										Dec. 20, 2016	[2]				Jan. 15, 2017	[2]				Jun. 01, 2018	[2]				Jan. 16, 2024	[2]	Mar. 01, 2038	[2]											Feb. 26, 2016			Nov. 18, 2016	Feb. 26, 2016		Nov. 18, 2016			Feb. 28, 2018						Feb. 01, 2015							Feb. 18, 2020
Amount of debt converted to floating rate																											705,000,000
Redemption price, per share																																																												$ 1,000
Unpaid Distributions Amount																																	10,000,000
Extinguishment of Debt, Amount																																	750,000,000
Payments of Debt Extinguishment Costs																																	8,000,000
Debt, available for future issuance																																		21,500,000,000
Interest rate paid															0.66%					0.49%							3.29%																0.65%					0.77%						0.34%
Interest Rate Minimum																																				0.05%
Interest Rate Maximum																																				6.87%
Global Bank Note Program																																		25,000,000,000	20,000,000,000
Basis points														42					42					25																						51	41											169	142
Residential mortgage loans and securities serving as FHLB collateral																																				17,200,000,000
FHLB advance																																				44,000,000
FHLB advances maturing 2015																																				2,000,000
FHLB advances maturing 2016																																				3,000,000
FHLB advances maturing 2017																																				1,000,000
FHLB advances maturing 2018																																				5,000,000
FHLB advances maturing thereafter																																				$ 33,000,000

[1] At December 31, 2013 and 2012, includes $49 and $0 of cash and due from banks, $48 and $50 of commercial mortgage loans, $ 1,010 and $0 of automobile loans, $(15) and $(5) of ALLL, $13 and $3 of other assets, $1 and $0 of other liabilities, $ 1,048 and $0 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 10.

[2] Qualify as Tier II capital for regulatory capital purposes.

[3] Qualify as Tier I capital for regulatory capital purposes. See Note 28 for further information.