Key economic assumptions used in measuring the servicing rights retained at the date of the residential mortgage loan securitizations and whole loan sales by the banking subsidiaries (Detail) (Residential Mortgage)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Residential Mortgage
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed	6.20%	8.20%
Weighted average life (in years)	0 years 0 months 5877 days	0 years 0 months 4453 days
Discount rate (annual rate)	10.70%	11.10%