Litigation and Regulatory Matters - Additional Information (Detail) (USD $)	12 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended	93 Months Ended	11 Months Ended	1 Months Ended		6 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
	Feb. 28, 2013 servicers	Jun. 30, 2013 Obligations to Repurchase Mortage Loans [Member]	Dec. 31, 2011 Securities Litigation [Member] claim	Jun. 30, 2013 Securities Litigation [Member]	Aug. 31, 2002 Securities Litigation [Member] state	Jun. 30, 2013 Securities Litigation [Member] Minimum [Member]	Mar. 31, 2010 Securities Litigation [Member] Minimum [Member]	Jun. 30, 2013 Securities Litigation [Member] Maximum [Member]	Mar. 31, 2010 Securities Litigation [Member] Maximum [Member]	Jun. 30, 2013 Pending Supplemental Notices [Member]	Mar. 31, 2013 Cards Litigation [Member] class_action	May 31, 2011 Debt Cancellation Litigation [Member] class_action	Apr. 30, 2012 Debt Cancellation Litigation [Member] Hawaii Attorney General [Member] company	Jan. 31, 2013 Telephone Consumer Protection Act Litigation [Member] claim	Jun. 30, 2013 Telephone Consumer Protection Act Litigation [Member] TCPA [Member]	Jun. 30, 2013 Foreclosure Litigation [Member] state	Dec. 31, 2012 Foreclosure Litigation [Member]	Jun. 30, 2013 Foreclosure Litigation [Member] servicer state	Dec. 31, 2012 Foreclosure Litigation [Member]	Feb. 28, 2013 Foreclosure Litigation [Member] HSBC North America [Member]	Dec. 31, 2012 Foreclosure Litigation [Member] HSBC North America [Member]
Loss Contingencies [Line Items]
Number of states in 2002 settlement					46
Estimated damage							$ 2,400,000,000		$ 3,200,000,000
Total claims of loss			45,921
Aggregate amount of claims		650,000,000	2,200,000,000							179,000,000
Claims still open to special court				510,000,000
Litigation judgment claims						1,500,000,000		2,200,000,000
Number of days to appeal verdict to Seventh Circuit Court of Appeals				30 days
Possible amount of damages				2,700,000,000
Possible future expenses related to amount of damages				3,500,000,000
Class actions filed											4	8
Number of credit card companies have lawsuits	12												7
Loss Contingency, Pending Claims, Number														2
Statutory damages for each violation (usd per violation)															500
Statutory damages for each willful violation (usd per violation)															1,500
Cash payments mortgage servicers would pay in excess	9,300,000,000
Cash payment into a fund hat will be used to make payments to borrowers																				96,000,000
Recorded expenses in period																			85,000,000		104,000,000
Number of states in settlement with U.S. mortgage servicers																49		49
Number of U.S. mortgage servicers																		5
Accrual																	157,000,000
Decrease in accrual																$ (14,000,000)