Reinsurance Arrangements and Guarantees - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	6 Months Ended		12 Months Ended				102 Months Ended			102 Months Ended	6 Months Ended	12 Months Ended			102 Months Ended			3 Months Ended		6 Months Ended									6 Months Ended					1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jun. 30, 2013	Mar. 31, 2013	Mar. 31, 2012	Jun. 30, 2013 Ginnie Mae	Jun. 30, 2013 Non Government Sponsored Agency [Member]	Dec. 31, 2012 Non Government Sponsored Agency [Member]	Dec. 31, 2011 Non Government Sponsored Agency [Member]	Dec. 31, 2010 Non Government Sponsored Agency [Member]	Jun. 30, 2013 Non Government Sponsored Agency [Member]	Jun. 30, 2013 US Government Sponsored Agency [Member]	Dec. 31, 2012 US Government Sponsored Agency [Member]	Jun. 30, 2013 Mortgage Reinsurance Contracts	Jun. 30, 2012 Mortgage Reinsurance Contracts	Jun. 30, 2013 Mortgage Reinsurance Contracts	Jun. 30, 2012 Mortgage Reinsurance Contracts	Dec. 31, 2012 Mortgage Reinsurance Contracts	Jun. 30, 2013 Mortgage Reinsurance Contracts Upper Limit	Dec. 31, 2012 Mortgage Reinsurance Contracts Upper Limit	Jun. 30, 2013 Standby Letters of Credit	Dec. 31, 2012 Standby Letters of Credit	Jun. 30, 2013 Mortgage Servicing Rights [Member]	Dec. 31, 2012 Mortgage Servicing Rights [Member]	Jun. 30, 2013 Visa Interest [Member]	Jun. 30, 2012 Visa Interest [Member]	May 31, 2009 Visa Interest [Member]	Jun. 30, 2013 Tax Credit Sales [Member]	Dec. 31, 2012 Tax Credit Sales [Member]	May 31, 2009 Not Designated as Hedging Instrument [Member] Derivative Financial Instruments, Liabilities [Member] Visa Interest [Member]	Jun. 30, 2013 Loans Held For Investment [Member]	Dec. 31, 2012 Loans Held For Investment [Member]	Jun. 30, 2013 Loans Held For Investment [Member] Nonperforming Financing Receivable [Member]	Dec. 31, 2012 Loans Held For Investment [Member] Nonperforming Financing Receivable [Member]	Jun. 30, 2013 Residential Mortgage, Loans Held For Sale [Member]	Dec. 31, 2012 Residential Mortgage, Loans Held For Sale [Member]	Jun. 30, 2013 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]	Dec. 31, 2012 Residential Mortgage, Loans Held For Sale [Member] Nonperforming Financing Receivable [Member]
Mortgage loans were covered by such mortgage reinsurance contracts																		$ 800,000,000		$ 800,000,000		$ 5,200,000,000
Total loss exposure ceded to the Company																		34,000,000		34,000,000		179,000,000
Maximum amount of loss exposure based on funds held in each seperate trust account, including net premiums due to the trust accounts																		4,000,000		4,000,000		6,000,000
Valuation Allowances and Reserves, Balance																		1,000,000		1,000,000		3,000,000
Future reported losses																							3,000,000	3,000,000
Future cash losses																							3,000,000
Premium income, mortgage reinsurance																		1,000,000	3,000,000	1,000,000	8,000,000
Provision For Losses, Mortgage Reinsurance																		1,000,000	3,000,000	1,000,000	9,000,000
Maximum potential amount obligation																									3,600,000,000	4,000,000,000						37,000,000
Loans sold from January 1, 2005 to September 30, 2011							285,000,000,000			33,000,000,000					30,300,000,000	221,700,000,000
Loans Sold Repurchased Request Amount	929,000,000		1,700,000,000	1,700,000,000	1,100,000,000		8,000,000,000				9,000,000	22,000,000	50,000,000	55,000,000
Unpaid principal balance of loans related to unresolved requests previously received from investors	419,000,000		655,000,000				419,000,000				7,000,000	16,000,000			7,000,000	412,000,000	639,000,000
Reserve For Mortgage Loan Repurchase Losses	363,000,000	434,000,000	632,000,000	320,000,000			363,000,000	513,000,000	383,000,000
Repurchased or otherwise settled mortgages	571,000,000	368,000,000
Repurchased mortgage loans	358,000,000		240,000,000				358,000,000																												314,000,000	209,000,000	50,000,000	70,000,000	44,000,000	31,000,000	44,000,000	31,000,000
Loss Contingency Accrual, at Carrying Value																											12,000,000	12,000,000
Business Acquisition, Contingent Consideration, Potential Cash Payment	29,000,000		30,000,000				29,000,000
Third Party Escrow, Gross Funded Since Inception																													8,500,000,000
Third Party Escrow, Amount Paid From Escrow																													4,100,000,000
Third Party litigation claims paid from escrow																													4,400,000,000
Number Of Shares Sold To Selected Financial Institutions																																		3.2
Shares of Class B Visa Inc Common Stock Sold to Another FinancialIinstitution, Value						112,000,000
Gain (Loss) on Sale of Other Investments						112,000,000
Common stock conversion rate																													0.4206		0.6296
Payments to derivative counterparty																													0	22,000,000
Visa Share of Claims in Settlement Agreement Amount																													4,400,000,000
Tax Credits To Be Delivered																																$ 2,000,000	$ 3,000,000