Derivative Financial Instruments (Detail) (Nondesignated, USD $) In Thousands	Sep. 30, 2011
Derivatives, Fair Value [Line Items]
Notional Amount	$ 7,720,483
Treasury Options
Derivatives, Fair Value [Line Items]
Notional Amount	990,000
Treasury Options | Other Liability
Derivatives, Fair Value [Line Items]
Unrealized Loss	5,141	[1]
Eurodollar Futures
Derivatives, Fair Value [Line Items]
Notional Amount	1,100,000
Eurodollar Futures | Other Liability
Derivatives, Fair Value [Line Items]
Unrealized Loss	592	[1]
Forward commitments to sell loans/mortgage-backed securities
Derivatives, Fair Value [Line Items]
Notional Amount	2,699,766
Forward commitments to sell loans/mortgage-backed securities | Other Liability
Derivatives, Fair Value [Line Items]
Unrealized Loss	28,767	[1]
Forward commitments to buy loans/mortgage-backed securities
Derivatives, Fair Value [Line Items]
Notional Amount	710,000
Forward commitments to buy loans/mortgage-backed securities | Other Asset
Derivatives, Fair Value [Line Items]
Unrealized Gain	8,440	[1]
Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Notional Amount	2,220,717
Interest Rate Lock Commitments | Other Asset
Derivatives, Fair Value [Line Items]
Unrealized Gain	29,146	[1]
Other Asset
Derivatives, Fair Value [Line Items]
Unrealized Gain	37,586	[1]
Other Liability
Derivatives, Fair Value [Line Items]
Unrealized Loss	$ 34,500	[1]

[1] Derivatives in a net gain position are recorded as "other assets" and derivatives in a net loss position are recorded as "other liabilities" in the Consolidated Statements of Condition.