Derivative Financial Instruments (Schedule fair value of derivative instruments) (Detail) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	$ 8,554,093,000	$ 8,539,724,000
Asset Derivatives, Fair Value, before netting	375,961,000	222,906,000
Asset Derivatives, Fair Value, Less: Master netting agreements	52,273,000	16,129,000
Asset Derivatives, Fair Value, Less: Cash collateral posted	311,774,000	184,095,000
Total derivative instruments, after netting	11,914,000	22,682,000
Liability Derivatives, Notional Amount	12,762,905,000	9,379,322,000
Liability Derivatives, Fair Value	433,696,000	414,499,000
Liability Derivatives, Fair Value, Less: Master netting agreements	52,273,000	16,129,000
Liability Derivatives, Fair Value, Less: Cash collateral posted	0	0
Total derivative instruments, after netting	381,423,000	398,370,000
CME
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value, Less: Cash collateral posted	4,600,000
Total derivative instruments, after netting	0
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	370,140,000	217,246,000
Asset Derivatives, Fair Value, Less: Master netting agreements	52,273,000	16,129,000
Total derivative instruments, after netting	311,774,000	184,095,000
Liability Derivatives, Fair Value	52,273,000	16,129,000
Liability Derivatives, Fair Value, Less: Master netting agreements	52,273,000	16,129,000
Total derivative instruments, after netting	0	0
Designated as Hedging Instrument | Interest rate derivatives
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	1,000,000,000	1,350,000,000
Asset Derivatives, Fair Value	453,000	1,515,000
Liability Derivatives, Notional Amount	4,750,000,000	1,750,000,000
Liability Derivatives, Fair Value	46,087,000	9,632,000
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	7,554,093,000	7,189,724,000
Asset Derivatives, Fair Value, Total	375,508,000	221,391,000
Liability Derivatives, Notional Amount	8,012,905,000	7,629,322,000
Liability Derivatives, Fair Value, Positions not subject to master netting agreement	387,609,000	404,867,000
Not Designated as Hedging Instrument | Interest rate derivatives
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	7,322,980,000	7,024,507,000
Asset Derivatives, Fair Value	375,350,000	221,225,000
Liability Derivatives, Notional Amount	7,329,236,000	7,022,844,000
Liability Derivatives, Fair Value	387,261,000	403,952,000
Not Designated as Hedging Instrument | Mortgage Banking Derivatives | RPA-Out
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	798,000	3,283,000
Asset Derivatives, Fair Value	5,000	32,000
Not Designated as Hedging Instrument | Mortgage Banking Derivatives | RPA-In
Derivatives, Fair Value [Line Items]
Liability Derivatives, Notional Amount	0	0
Liability Derivatives, Fair Value	0	0
Not Designated as Hedging Instrument | Other
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	230,315,000	161,934,000
Asset Derivatives, Fair Value	153,000	134,000
Liability Derivatives, Notional Amount	683,669,000	606,478,000
Liability Derivatives, Fair Value	348,000	915,000
Not Designated as Hedging Instrument | Interest Rate Swap, CME
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	600,000,000	2,700,000,000
Liability Derivatives, Notional Amount	100,000,000	0
Not Designated as Hedging Instrument | Credit Risk Contract | RPA-Out
Derivatives, Fair Value [Line Items]
Asset Derivatives, Notional Amounts	201,700,000	125,600,000
Not Designated as Hedging Instrument | Credit Risk Contract | RPA-In
Derivatives, Fair Value [Line Items]
Liability Derivatives, Notional Amount	648,200,000	559,200,000
Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Other commitment	$ 4,100,000	$ 2,400,000