Derivatives and Hedging - Derivatives by Balance Sheet Location (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative assets		$ 191,061	$ 225,227
Derivative liabilities		269,255	259,018
Derivatives designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	61,549	71,493
Derivative liabilities	[2]	21,045	14,497
Derivatives designated as hedging instrument | Fair value hedges
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	59,975	69,700
Derivative liabilities	[2]	9,405
Derivatives designated as hedging instrument | Fair value hedges | Interest rate swaps related to long-term debt
Derivatives, Fair Value [Line Items]
Derivative notional amount		2,123,950	1,423,950
Derivative assets	[1]	59,975	69,700
Derivative liabilities	[2]	9,405
Derivatives designated as hedging instrument | Cash flow hedges
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	1,574	1,793
Derivative liabilities	[2]	11,640	14,497
Derivatives designated as hedging instrument | Cash flow hedges | Swaps related to commercial loans
Derivatives, Fair Value [Line Items]
Derivative notional amount		1,900,000	1,100,000
Derivative assets	[1]	1,574	1,793
Derivative liabilities	[2]	782	1,023
Derivatives designated as hedging instrument | Cash flow hedges | Swaps related to FHLB advances
Derivatives, Fair Value [Line Items]
Derivative notional amount		320,000	320,000
Derivative liabilities	[2]	10,858	13,474
Derivatives not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	394,554	414,470
Derivative liabilities	[2]	320,902	347,761
Derivatives not designated as hedging instrument | Forward contracts related to held for sale mortgages
Derivatives, Fair Value [Line Items]
Derivative notional amount		216,500	189,000
Derivative assets	[1]	502	18
Derivative liabilities	[2]	217	1,576
Derivatives not designated as hedging instrument | Purchased equity option related to equity-linked CDs
Derivatives, Fair Value [Line Items]
Derivative notional amount		876,649	821,849
Derivative assets	[1]	59,375	76,487
Derivatives not designated as hedging instrument | Swap associated with sale of Visa, Inc. Class B shares
Derivatives, Fair Value [Line Items]
Derivative notional amount		67,896	57,393
Derivative liabilities	[2]	1,697	1,435
Derivatives not designated as hedging instrument | Forwards related to commercial loans
Derivatives, Fair Value [Line Items]
Derivative notional amount		479,072	602,066
Derivative assets	[1]	3,821	5,529
Derivative liabilities	[2]	752	612
Derivatives not designated as hedging instrument | Spots related to commercial loans
Derivatives, Fair Value [Line Items]
Derivative notional amount		54,511	74,940
Derivative assets	[1]	6	41
Derivative liabilities	[2]	372	80
Derivatives not designated as hedging instrument | Futures contracts
Derivatives, Fair Value [Line Items]
Derivative notional amount	[3]	390,000	342,000
Derivatives not designated as hedging instrument | Interest rate lock commitments
Derivatives, Fair Value [Line Items]
Derivative notional amount		175,002	180,822
Derivative assets	[1]	2,880	2,319
Derivative liabilities	[2]	6	1
Derivatives not designated as hedging instrument | Written equity option related to equity-linked CDs
Derivatives, Fair Value [Line Items]
Derivative notional amount		831,480	795,467
Derivative liabilities	[2]	56,559	74,319
Derivatives not designated as hedging instrument | Interest rate contracts for customers
Derivatives, Fair Value [Line Items]
Derivative notional amount		23,370,927	18,678,390
Derivative assets	[1]	303,944	296,239
Derivative liabilities	[2]	238,611	236,763
Derivatives not designated as hedging instrument | Commodity contracts for customers
Derivatives, Fair Value [Line Items]
Derivative notional amount		114,336	264,491
Derivative assets	[1]	14,127	25,569
Derivative liabilities	[2]	14,110	25,448
Derivatives not designated as hedging instrument | Foreign exchange contracts for customers
Derivatives, Fair Value [Line Items]
Derivative notional amount		425,946	425,123
Derivative assets	[1]	9,899	8,268
Derivative liabilities	[2]	8,578	7,527
Derivatives not designated as hedging instrument | Trading account assets and liabilities
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	327,970	330,076
Derivative liabilities	[2]	$ 261,299	$ 269,738

[1] Derivative assets, except for trading account assets that are recorded as a component of trading account assets on the Consolidated Balance Sheets, are recorded in other assets on the Company’s Consolidated Balance Sheets.

[2] Derivative liabilities are recorded in accrued expenses and other liabilities on the Company’s Consolidated Balance Sheets.

[3] Changes in fair value are cash settled daily; therefore, there is no ending balance at any given reporting period.