Bbva Usa Bancshares 10-Q 13 May 15 2015 Q1 Quarterly report Financial data

DEI_Document

DEI Document	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Entity [Abstract]
Entity Registrant Name	BBVA Compass Bancshares, Inc.
Entity Central Index Key	1409775
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		222,950,751

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets:
Cash and due from banks	$3,664,182	$2,764,345
Federal funds sold, securities purchased under agreements to resell and interest bearing deposits	300,175	624,060
Cash and cash equivalents	3,964,357	3,388,405
Trading account assets	3,680,427	2,834,397
Investment securities available for sale	10,101,828	10,237,275
Investment securities held to maturity (fair value of $1,297,565 and $1,275,963 at March 31, 2015 and December 31, 2014, respectively)	1,373,542	1,348,354
Loans held for sale (includes $198,488 and $154,816 measured at fair value at March 31, 2015 and December 31, 2014, respectively)	198,488	154,816
Loans	58,558,463	57,371,784
Allowance for loan losses	-701,864	-685,041
Net loans	57,856,599	56,686,743
Premises and equipment, net	1,332,539	1,351,479
Bank owned life insurance	694,370	694,335
Goodwill	5,046,847	5,046,847
Other intangible assets	60,097	70,784
Other real estate owned	17,764	20,600
Other assets	1,148,883	1,318,392
Total assets	85,475,741	83,152,427
Deposits:
Noninterest bearing	18,599,702	17,169,412
Interest bearing	44,300,979	44,020,304
Total deposits	62,900,681	61,189,716
FHLB and other borrowings	4,919,141	4,809,843
Federal funds purchased and securities sold under agreements to repurchase	909,683	1,129,503
Other short-term borrowings	3,377,694	2,545,724
Accrued expenses and other liabilities	1,206,612	1,474,067
Total liabilities	73,313,811	71,148,853
Shareholder’s Equity:
Common stock - $0.01 par value; Authorized - 300,000,000 shares, Issued - 222,950,721 shares at both March 31, 2015 and December 31, 2014	2,230	2,230
Surplus	15,278,877	15,285,991
Accumulated deficit	-3,121,071	-3,262,181
Accumulated other comprehensive loss	-27,654	-51,357
Total BBVA Compass Bancshares, Inc. shareholder’s equity	12,132,382	11,974,683
Noncontrolling interests	29,548	28,891
Total shareholder’s equity	12,161,930	12,003,574
Total liabilities and shareholder’s equity	$85,475,741	$83,152,427

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Unaudited) Parenthetical (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Investment Securities - Fair Value	$1,297,565	$1,275,963
Loans Held for Sale - Fair Value	$198,488	$154,816
Common stock, par value	$0.01	$0.01
Common stock, number of shares authorized	300,000,000	300,000,000
Common stock, number of shares issued	222,950,751	222,950,751

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income:
Interest and fees on loans	$543,842	$508,506
Interest on investment securities available for sale	48,208	49,090
Interest on investment securities held to maturity	6,702	7,246
Interest on federal funds sold, securities purchased under agreements to resell and interest bearing deposits	996	47
Interest on trading account assets	9,614	516
Total interest income	609,362	565,405
Interest expense:
Interest on deposits	69,653	53,216
Interest on FHLB and other borrowings	19,106	16,364
Interest on federal funds purchased and securities sold under agreements to repurchase	1,326	500
Interest on other short-term borrowings	10,248	26
Total interest expense	100,333	70,106
Net interest income	509,029	495,299
Provision for loan losses	42,031	37,266
Net interest income after provision for loan losses	466,998	458,033
Noninterest income:
Service charges on deposit accounts	53,284	53,391
Card and merchant processing fees	26,183	24,304
Retail investment sales	25,146	26,564
Investment banking and advisory fees	30,334	22,196
Asset management fees	8,096	10,758
Corporate and correspondent investment sales	6,259	8,656
Mortgage banking income	8,159	4,276
Bank owned life insurance	4,788	3,967
Investment securities gains, net	32,832	16,434
Loss on prepayment of FHLB and other borrowings	-2,549	-458
Other	56,738	49,240
Total noninterest income	249,270	219,328
Noninterest expense:
Salaries, benefits and commissions	259,262	262,569
Equipment	58,141	53,738
Professional services	46,559	46,399
Net occupancy	39,280	38,957
FDIC indemnification expense	28,789	31,618
Amortization of intangibles	10,687	12,534
Securities impairment:
Other-than-temporary impairment	372	381
Less: non-credit portion recognized in other comprehensive income	87	235
Total securities impairment	285	146
Other	79,716	72,906
Total noninterest expense	522,719	518,867
Net income before income tax expense	193,549	158,494
Income tax expense	51,782	43,567
Net income	141,767	114,927
Less: net income attributable to noncontrolling interests	657	453
Net income attributable to shareholder	$141,110	$114,474

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$141,767	$114,927
Other comprehensive income, net of tax:
Unrealized holding gains arising during period from securities available for sale	36,588	26,240
Less: reclassification adjustment for net gains on sale of securities available for sale in net income	18,540	10,526
Net change in unrealized holding gains on securities available for sale	18,048	15,714
Change in unamortized net holding losses on investment securities held to maturity	1,774	3,058
Less: non-credit related impairment on investment securities held to maturity	49	151
Change in unamortized non-credit related impairment on investment securities held to maturity	156	246
Net change in unamortized holding losses on securities held to maturity	1,881	3,153
Unrealized holding gains (losses) arising during period from cash flow hedge instruments	2,059	-807
Change in defined benefit plans	1,715	-1,671
Other comprehensive income, net of tax	23,703	16,389
Comprehensive income	165,470	131,316
Less: comprehensive income attributable to noncontrolling interests	657	453
Comprehensive income attributable to shareholder	$164,813	$130,863

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Shareholder's Equity (Unaudited) (USD $)	Total	Common Stock	Surplus	Accumulated Deficit	Accumulated Other Comprehensive Loss	Non-controlling Interests
In Thousands, unless otherwise specified
Balance, beginning of period at Dec. 31, 2013	$11,487,759	$2,207	$15,273,218	($3,728,737)	($87,936)	$29,007
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	114,927			114,474		453
Other comprehensive income, net of tax	16,389				16,389
Issuance of common stock	117,000	23	116,977
Vesting of restricted stock	-4,525		-4,525
Restricted stock retained to cover taxes	-2,266		-2,266
Amortization of stock-based deferred compensation	550		550
Balance, end of period at Mar. 31, 2014	11,729,834	2,230	15,383,954	-3,614,263	-71,547	29,460
Balance, beginning of period at Dec. 31, 2014	12,003,574	2,230	15,285,991	-3,262,181	-51,357	28,891
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	141,767			141,110		657
Other comprehensive income, net of tax	23,703				23,703
Vesting of restricted stock	-7,662		-7,662
Amortization of stock-based deferred compensation	548		548
Balance, end of period at Mar. 31, 2015	$12,161,930	$2,230	$15,278,877	($3,121,071)	($27,654)	$29,548

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Activities:
Net income	$141,767	$114,927
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	69,595	65,110
Securities impairment	285	146
Amortization of intangibles	10,687	12,534
Accretion of discount, loan fees and purchase market adjustments, net	-53,747	-50,201
Net change in FDIC indemnification asset/liability	28,789	31,618
Provision for loan losses	42,031	37,266
Amortization of stock based compensation	548	550
Net change in trading account assets	-191,826	-23,033
Net change in trading account liabilities	76,217	-10,444
Net change in loans held for sale	-43,672	45,494
Deferred tax expense	32,676	32,252
Investment securities gains, net	-32,832	-16,434
Loss on prepayment of FHLB and other borrowings	2,549	458
Loss on sale of premises and equipment	1,627	1,452
Loss on sale of student loans	2	75
Net (gain) loss on sale of other real estate and other assets	-134	1,701
Loss on disposition	0	981
(Increase) decrease in other assets	132,983	-123,144
Increase (decrease) in other liabilities	-372,520	4,830
Net cash (used in) provided by operating activities	-154,975	126,138
Investing Activities:
Proceeds from sales of investment securities available for sale	1,147,705	430,715
Proceeds from prepayments, maturities and calls of investment securities available for sale	349,624	315,980
Purchases of investment securities available for sale	-1,316,531	-947,146
Proceeds from prepayments, maturities and calls of investment securities held to maturity	28,700	30,787
Purchases of investment securities held to maturity	-50,632	0
Proceeds from sales of trading securities	1,292,110	0
Purchases of trading securities	-1,946,314	0
Net change in loan portfolio	-1,160,570	-2,070,125
Purchase of premises and equipment	-28,831	-15,941
Proceeds from sale of premises and equipment	778	4,156
Net cash paid in acquisition	0	-96,651
Proceeds from sales of loans	6	54,310
Reimbursements from (payments to) FDIC for covered assets	908	-6,478
Proceeds from sales of other real estate owned	5,688	4,630
Net cash used in investing activities	-1,677,359	-2,295,763
Financing Activities:
Net increase in demand deposits, NOW accounts and savings accounts	1,793,161	1,962,805
Net increase (decrease) in time deposits	-86,419	684,694
Net increase (decrease) in federal funds purchased and securities sold under agreements to repurchase	-219,820	104,808
Net increase in other short-term borrowings	831,970	23,231
Proceeds from FHLB and other borrowings	500,000	0
Repayment of FHLB and other borrowings	-402,944	-40,910
Vesting of restricted stock	-7,662	-4,525
Restricted stock grants retained to cover taxes	0	-2,266
Issuance of common stock	0	117,000
Net cash provided by financing activities	2,408,286	2,844,837
Net increase in cash and cash equivalents	575,952	675,212
Cash and cash equivalents at beginning of year	3,388,405	3,598,460
Cash and cash equivalents at end of period	$3,964,357	$4,273,672

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	General
	The accounting and reporting policies of the Company and the methods of applying those policies that materially affect the consolidated financial statements conform with U.S. GAAP and with general financial services industry practices. The accompanying interim financial statements have been prepared in accordance with the rules and regulations of the SEC and, therefore, do not include all information and notes to the consolidated financial statements necessary for a complete presentation of financial position, results of operations, comprehensive income and cash flows in conformity with U.S. GAAP. In the opinion of management, all adjustments, consisting of normal and recurring items, necessary for the fair presentation of the consolidated financial statements have been included. Operating results for the three months ended March 31, 2015, are not necessarily indicative of the results that may be expected for the year ended December 31, 2015. These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
	The Company has evaluated subsequent events for potential recognition and disclosure through the filing date of this Quarterly Report on Form 10-Q to determine if either recognition or disclosure of significant events or transactions is required. See Note 13, Subsequent Events.
	Use of Estimates in the Preparation of Financial Statements
	The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period, the most significant of which relate to the allowance for loan losses, goodwill impairment, fair value measurements and income taxes. Actual results could differ from those estimates.
	Recently Issued Accounting Standards
	Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure
	In January 2014, the FASB released ASU 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. The amendments in this ASU clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additionally, the amendments require interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure according to local requirements of the applicable jurisdiction. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The Company elected to adopt the amendments in this ASU using the prospective transition method. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company. See Note 3, Loans and Allowance for Loan Losses.
	Revenue from Contracts with Customers
	In May 2014, the FASB released ASU 2014-09, Revenue from Contracts with Customers. The core principle of this codified guidance requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides five steps to be analyzed to accomplish the core principle. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. Early application is not permitted. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.
	Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures
	In June 2014, the FASB issued ASU 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. The amendments in this ASU change the accounting for repurchase-to-maturity transactions to secured borrowing accounting. In addition, for repurchase financing arrangements, the amendments require separate accounting for a transfer of a financial asset executed contemporaneously with a repurchase agreement with the same counterparty, which will result in secured borrowing accounting for the repurchase agreement. The amendments in this ASU also require disclosures on transfers accounted for as sales in transactions that are economically similar to repurchase agreements, and provide increased transparency about the types of collateral pledged in repurchase agreements and similar transactions accounted for as secured borrowings. The accounting changes in this ASU and disclosures for certain transactions accounted for as a sale are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The disclosures for repurchase agreements, securities lending transactions, and repurchase-to-maturity transactions accounted for as secured borrowings is required to be presented for annual periods beginning after December 15, 2014 and for interim periods beginning after March 15, 2015. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company.
	Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure
	In August 2014, the FASB issued ASU 2014-14, Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure. The amendments in this ASU address the classification and measurement of foreclosed loans which were part of a government-sponsored loan guarantee program. If certain criteria are met, the loan should be derecognized and a separate other receivable should be recorded upon foreclosure at the amount of the loan balance expected to be recovered from the guarantor. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company.
	Consolidation
	In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis. The amendments in this ASU modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities, eliminate the presumption that a general partner should consolidate a limited partnership, affect the consolidation analysis of reporting entities that are involved with variable interest entities and provide a scope exception from consolidation guidance for reporting entities with interest in certain investment funds. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.
	Simplifying the Presentation of Debt Issuance Costs
	In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. To simplify presentation of debt issuance costs, the amendments in this ASU require debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.
	Customer's Accounting for Fees Paid in a Cloud Computing Arrangement
	In April 2015, the FASB issued ASU 2015-05, Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. The amendments in this ASU provide guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.

Investment_Securities_Availabl

Investment Securities Available for Sale and Investment Securities Held to Maturity	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities Available for Sale and Investment Securities Held to Maturity	Investment Securities Available for Sale and Investment Securities Held to Maturity
	The following table presents the adjusted cost and approximate fair value of investment securities available for sale and investment securities held to maturity.
		31-Mar-15
					Gross Unrealized
		Amortized Cost			Gains			Losses		Fair Value
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	2,521,508		$	25,318		$	10,056	$	2,536,770
	Mortgage-backed securities	4,155,135			53,876			21,524		4,187,487
	Collateralized mortgage obligations	2,423,466			25,813			4,210		2,445,069
	States and political subdivisions	408,115			8,124			197		416,042
	Other	17,430			356			19		17,767
	Equity securities	498,650			43			—		498,693
	Total	$	10,024,304		$	113,530		$	36,006	$	10,101,828
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	119,253		$	6,320		$	4,748	$	120,825
	Asset-backed securities	35,618			3,240			2,299		36,559
	States and political subdivisions	1,148,747			1,586			82,032		1,068,301
	Other	69,924			4,120			2,164		71,880
	Total	$	1,373,542		$	15,266		$	91,243	$	1,297,565
		31-Dec-14
					Gross Unrealized
		Amortized Cost			Gains			Losses		Fair Value
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	2,312,572		$	10,360		$	9,390	$	2,313,542
	Mortgage-backed securities	4,399,706			64,371			40,242		4,423,835
	Collateralized mortgage obligations	2,475,115			19,385			5,921		2,488,579
	States and political subdivisions	460,569			8,008			1,262		467,315
	Other	44,225			238			22		44,441
	Equity securities	499,522			41			—		499,563
	Total	$	10,191,709		$	102,403		$	56,837	$	10,237,275
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	124,051		$	5,878		$	5,452	$	124,477
	Asset-backed securities	39,187			3,568			2,011		40,744
	States and political subdivisions	1,112,415			2,143			79,246		1,035,312
	Other	72,701			4,920			2,191		75,430
	Total	$	1,348,354		$	16,509		$	88,900	$	1,275,963
	In the above table, equity securities include $499 million and $500 million at March 31, 2015 and December 31, 2014, respectively, of FHLB and Federal Reserve stock carried at par.
	The investments held within the states and political subdivision caption of investment securities held to maturity relate to private placement transactions underwritten as loans by the Company but that meet the definition of a security within ASC Topic 320, Investments – Debt and Equity Securities.
	The following table discloses the fair value and the gross unrealized losses of the Company’s available for sale securities and held to maturity securities that were in a loss position at March 31, 2015 and December 31, 2014. This information is aggregated by investment category and the length of time the individual securities have been in an unrealized loss position.
		March 31, 2015
		Securities in a loss position for less than 12 months						Securities in a loss position for 12 months or longer				Total
		Fair Value			Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	752,519		$	8,600		$	91,136	$	1,456	$	843,655	$	10,056
	Mortgage-backed securities	380,594			1,042			1,701,752		20,482		2,082,346		21,524
	Collateralized mortgage obligations	633,205			3,513			91,229		697		724,434		4,210
	States and political subdivisions	43,797			197			—		—		43,797		197
	Other	—			—			1,103		19		1,103		19
	Total	$	1,810,115		$	13,352		$	1,885,220	$	22,654	$	3,695,335	$	36,006
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	23,045		$	349		$	46,293	$	4,399	$	69,338	$	4,748
	Asset-backed securities	—			—			21,297		2,299		21,297		2,299
	States and political subdivisions	75,204			4,903			812,731		77,129		887,935		82,032
	Other	3,953			2,164			—		—		3,953		2,164
	Total	$	102,202		$	7,416		$	880,321	$	83,827	$	982,523	$	91,243
		December 31, 2014
		Securities in a loss position for less than 12 months						Securities in a loss position for 12 months or longer				Total
		Fair Value			Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In Thousands)
Investment securities available for sale:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	620,794		$	8,220		$	37,220	$	1,170	$	658,014	$	9,390
Mortgage-backed securities	308,734			862			1,915,494		39,380		2,224,228		40,242
Collateralized mortgage obligations	714,173			3,829			146,806		2,092		860,979		5,921
States and political subdivisions	—			—			135,825		1,262		135,825		1,262
Other	—			—			1,099		22		1,099		22
Total	$	1,643,701		$	12,911		$	2,236,444	$	43,926	$	3,880,145	$	56,837
Investment securities held to maturity:
Collateralized mortgage obligations	$	34,400		$	1,099		$	27,389	$	4,353	$	61,789	$	5,452
Asset-backed securities	—			—			23,374		2,011		23,374		2,011
States and political subdivisions	21,688			768			817,570		78,478		839,258		79,246
Other	4,061			2,191			—		—		4,061		2,191
Total	$	60,149		$	4,058		$	868,333	$	84,842	$	928,482	$	88,900
As indicated in the previous tables, at March 31, 2015, the Company held certain investment securities in unrealized loss positions. The Company does not have the intent to sell these securities and believes it is not more likely than not that it will be required to sell these securities before their anticipated recovery.
The Company regularly evaluates each available for sale and held to maturity security in a loss position for OTTI. In its evaluation, the Company considers such factors as the length of time and the extent to which the fair value has been below cost, the financial condition of the issuer, the Company’s intent to hold the security to an expected recovery in market value and whether it is more likely than not that the Company will have to sell the security before its fair value recovers. Activity related to the credit loss component of the OTTI is recognized in earnings. The portion of OTTI related to all other factors is recognized in other comprehensive income.
Management does not believe that any individual unrealized loss in the Company’s investment securities available for sale or held to maturity portfolios, presented in the preceding tables, represents an OTTI at either March 31, 2015 or December 31, 2014, other than those noted below.
The following table discloses activity related to credit losses for debt securities where a portion of the OTTI was recognized in other comprehensive income.
	Three Months Ended
	March 31,
	2015			2014
	(In Thousands)
Balance at beginning of period	$	21,123		$	20,943
Reductions for securities paid off during the period (realized)	—			—
Additions for the credit component on debt securities in which OTTI was not previously recognized	—			—
Additions for the credit component on debt securities in which OTTI was previously recognized	285			146
Balance at end of period	$	21,408		$	21,089
For the three months ended March 31, 2015, there was $285 thousand OTTI recognized on held to maturity securities, and for the three months ended March 31, 2014, the Company recognized $146 thousand. The investment securities primarily impacted by credit impairment are held to maturity non-agency collateralized mortgage obligations and asset-backed securities.
The maturities of the securities portfolios are presented in the following table.
March 31, 2015		Amortized Cost			Fair Value
		(In Thousands)
Investment securities available for sale:
Maturing within one year		$	48,475		$	48,860
Maturing after one but within five years		688,061			701,812
Maturing after five but within ten years		983,328			997,119
Maturing after ten years		1,227,189			1,222,788
		2,947,053			2,970,579
Mortgage-backed securities and collateralized mortgage obligations		6,578,601			6,632,556
Equity securities		498,650			498,693
Total		$	10,024,304		$	10,101,828
Investment securities held to maturity:
Maturing within one year		$	9,079		$	9,092
Maturing after one but within five years		300,029			286,940
Maturing after five but within ten years		182,574			176,641
Maturing after ten years		762,607			704,067
		1,254,289			1,176,740
Collateralized mortgage obligations		119,253			120,825
Total		$	1,373,542		$	1,297,565
The gross realized gains and losses recognized on sales of investment securities available for sale are shown in the table below.
	Three Months Ended March 31,
	2015			2014
	(In Thousands)
Gross gains	$	32,832		$	16,434
Gross losses	—			—
Net realized gains	$	32,832		$	16,434

Loans_and_Allowance_for_Loan_L

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Loans and Allowance for Loan Losses	Loans and Allowance for Loan Losses
	The following table presents the composition of the loan portfolio.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Commercial loans:
	Commercial, financial and agricultural	$	24,448,964			$	23,828,537
	Real estate – construction	2,325,495				2,154,652
	Commercial real estate – mortgage	9,920,583				9,877,206
	Total commercial loans	36,695,042				35,860,395
	Consumer loans:
	Residential real estate – mortgage	14,000,868				13,922,656
	Equity lines of credit	2,325,884				2,304,784
	Equity loans	635,295				634,968
	Credit card	600,030				630,456
	Consumer direct	707,251				652,927
	Consumer indirect	3,105,533				2,870,408
	Total consumer loans	21,374,861				21,016,199
	Covered loans	488,560				495,190
	Total loans	$	58,558,463			$	57,371,784
	Purchased Impaired Loans
	Purchased Impaired Loans are recognized on the Company's Unaudited Condensed Consolidated Balance Sheets within loans, net of recorded discount. The following table presents the unpaid principal balance, discount, allowance for loan losses and carrying value of the Purchased Impaired Loans.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Unpaid principal balance	$	367,704			$	378,913
	Discount	(12,287		)		(17,341		)
	Allowance for loan losses	(727		)		(2,066		)
	Carrying value	$	354,690			$	359,506
	An analysis of the accretable yield related to the Purchased Impaired Loans follows.
		Three Months Ended March 31,
		2015				2014
		(In Thousands)
	Balance at beginning of period	$	68,785			$	105,698
	Transfer to nonaccretable difference	(3,417		)		(8,162		)
	Accretion	(8,057		)		(16,172		)
	Other	—				—
	Balance at end of period	$	57,311			$	81,364
	The Company had allowance for loan losses of $727 thousand and $2.1 million related to Purchased Impaired Loans at March 31, 2015 and December 31, 2014, respectively. During the three months ended March 31, 2015 and 2014, the Company recognized $(907) thousand and $(10.8) million, respectively, of reduction in provision for loan losses attributable to credit improvements subsequent to acquisition of these loans.
	Purchased Nonimpaired Loans
	At acquisition, Purchased Nonimpaired Loans were determined to have fair value discounts, some of which were related to credit. The portion of the fair value discount not related to credit is being accreted to interest income over the expected remaining life of the loans based on expected cash flows. For the three months ended March 31, 2015 and 2014 approximately $36.6 million and $37.8 million, respectively, of interest income was recognized on these loans. The discount related to credit on the Purchased Nonimpaired Loans is reviewed for adequacy quarterly. If the expected losses exceed the credit discount, an allowance for loan losses is provided. If the expected losses are reduced, the related credit discount is accreted to interest income over the expected remaining life of the loans.
	The following table presents the unpaid principal balance, discount, allowance for loan losses, and carrying value of the Purchased Nonimpaired Loans.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Unpaid principal balance	$	274,581			$	294,202
	Discount	(57,280		)		(88,962		)
	Allowance for loan losses	(2,115		)		(2,283		)
	Carrying value	$	215,186			$	202,957
	FDIC Indemnification Asset (Liability)
	The Company has entered into loss sharing agreements with the FDIC that require the FDIC to reimburse the Bank for losses with respect to covered loans and covered OREO. In addition, the provisions of the loss sharing agreements may also require a payment by the Bank to the FDIC on October 15, 2019 if the acquired portfolio's credit improves beyond original expectations. Activity associated with the Company's estimate of the potential amount of this payment is included in the table below. The Company has chosen to net the amounts due from the FDIC and due to the FDIC into the FDIC indemnification asset (liability), which is recorded in accrued expenses and other liabilities in the Company's Unaudited Condensed Consolidated Balance Sheets. See Note 7, Commitments, Contingencies and Guarantees, for additional information related to the loss sharing agreements. A summary of the activity in the FDIC indemnification asset (liability) is presented in the following table.
		Three Months Ended March 31,
		2015				2014
		(In Thousands)
	Balance at beginning of period	$	(78,025	)		$	24,315
	Increase (decrease) due to credit loss provision (benefit) recorded on FDIC covered loans	(631		)		5,061
	Amortization and accretion, net	(27,898		)		(36,823		)
	Payments to (reimbursements from) FDIC for covered assets	(908		)		6,478
	Other	(260		)		144
	Balance at end of period	$	(107,722	)		$	(825	)
	Other adjustments include those resulting from the change in loss estimates related to OREO as a result of changes in expected cash flows as well as adjustments resulting from amounts owed to the FDIC for unexpected recoveries of amounts previously charged off and loan expenses incurred and claimed.
	Allowance for Loan Losses and Credit Quality
	The following table, which excludes loans held for sale, presents a summary of the activity in the allowance for loan losses. The portion of the allowance that has not been identified by the Company as related to specific loan categories has been allocated to the individual loan categories on a pro rata basis for purposes of the table below:
		Commercial, Financial and Agricultural				Commercial Real Estate (1)				Residential Real Estate (2)				Consumer (3)			Covered			Total Loans
		(In Thousands)
	Three months ended March 31, 2015
	Allowance for loan losses:
Beginning balance	$	299,482			$	138,233			$	154,627			$	89,891		$	2,808		$	685,041
Provision (credit) for loan losses	28,352				(185		)		(6,439		)		20,770			(467		)	42,031
Loans charged off	(6,619		)		(635		)		(6,754		)		(24,545		)	(873		)	(39,426		)
Loan recoveries	2,182				1,858				3,513				6,665			—			14,218
Net (charge-offs) recoveries	(4,437		)		1,223				(3,241		)		(17,880		)	(873		)	(25,208		)
Ending balance	$	323,397			$	139,271			$	144,947			$	92,781		$	1,468		$	701,864
Three months ended March 31, 2014
Allowance for loan losses:
Beginning balance	$	292,327			$	158,960			$	155,575			$	90,903		$	2,954		$	700,719
Provision (credit) for loan losses	7,501				(4,722		)		12,673				16,829			4,985			37,266
Loans charged off	(4,934		)		(2,646		)		(15,708		)		(21,704		)	(216		)	(45,208		)
Loan recoveries	4,985				1,538				2,694				5,329			342			14,888
Net (charge-offs) recoveries	51				(1,108		)		(13,014		)		(16,375		)	126			(30,320		)
Ending balance	$	299,879			$	153,130			$	155,234			$	91,357		$	8,065		$	707,665
-1	Includes commercial real estate – mortgage and real estate – construction loans.
-2	Includes residential real estate – mortgage, equity lines of credit and equity loans.
-3	Includes credit card, consumer direct and consumer indirect loans.
The table below provides a summary of the allowance for loan losses and related loan balances by portfolio.
	Commercial, Financial and Agricultural				Commercial Real Estate (1)				Residential Real Estate (2)				Consumer (3)			Covered			Total Loans
	(In Thousands)
March 31, 2015
Ending balance of allowance attributable to loans:
Individually evaluated for impairment	$	13,510			$	6,742			$	39,023			$	1,596		$	—		$	60,871
Collectively evaluated for impairment	308,826				132,529				105,924				90,872			—			638,151
Purchased impaired	—				—				—				—			727			727
Purchased nonimpaired	1,061				—				—				313			741			2,115
Total allowance for loan losses	$	323,397			$	139,271			$	144,947			$	92,781		$	1,468		$	701,864
Loans:
Ending balance of loans:
Individually evaluated for impairment	$	81,606			$	92,480			$	190,447			$	3,004		$	—		$	367,537
Collectively evaluated for impairment	24,328,772				12,114,814				16,770,610				4,404,012			—			57,618,208
Purchased impaired	—				—				—				—			355,417			355,417
Purchased nonimpaired	38,586				38,784				990				5,798			133,143			217,301
Total loans	$	24,448,964			$	12,246,078			$	16,962,047			$	4,412,814		$	488,560		$	58,558,463
December 31, 2014
Ending balance of allowance attributable to loans:
Individually evaluated for impairment	$	11,158			$	8,466			$	42,277			$	1,532		$	—		$	63,433
Collectively evaluated for impairment	287,105				129,767				112,350				88,037			—			617,259
Purchased impaired	—				—				—				—			2,066			2,066
Purchased nonimpaired	1,219				—				—				322			742			2,283
Total allowance for loan losses	$	299,482			$	138,233			$	154,627			$	89,891		$	2,808		$	685,041
Loans:
Ending balance of loans:
Individually evaluated for impairment	$	48,173			$	105,608			$	195,462			$	1,827		$	—		$	351,070
Collectively evaluated for impairment	23,745,149				11,896,943				16,665,930				4,145,880			—			56,453,902
Purchased impaired	—				—				—				—			361,572			361,572
Purchased nonimpaired	35,215				29,307				1,016				6,084			133,618			205,240
Total loans	$	23,828,537			$	12,031,858			$	16,862,408			$	4,153,791		$	495,190		$	57,371,784
-1	Includes commercial real estate – mortgage and real estate – construction loans.
-2	Includes residential real estate – mortgage, equity lines of credit and equity loans.
-3	Includes credit card, consumer direct and consumer indirect loans.
The following table presents information on individually evaluated impaired loans, by loan class.
	March 31, 2015
	Individually Evaluated Impaired Loans With No Recorded Allowance												Individually Evaluated Impaired Loans With a Recorded Allowance
	Recorded Investment				Unpaid Principal Balance				Allowance				Recorded Investment			Unpaid Principal Balance			Allowance
	(In Thousands)
Commercial, financial and agricultural	$	6,377			$	13,575			$	—			$	75,229		$	79,360		$	13,510
Real estate – construction	3,492				4,006				—				2,580			2,625			793
Commercial real estate – mortgage	22,240				23,210				—				64,168			68,690			5,949
Residential real estate – mortgage	6,886				6,886				—				105,079			105,162			7,188
Equity lines of credit	—				—				—				26,718			27,124			23,675
Equity loans	—				—				—				51,764			52,225			8,160
Credit card	—				—				—				—			—			—
Consumer direct	—				—				—				1,383			1,383			77
Consumer indirect	—				—				—				1,621			1,621			1,519
Total loans	$	38,995			$	47,677			$	—			$	328,542		$	338,190		$	60,871
	December 31, 2014
	Individually Evaluated Impaired Loans With No Recorded Allowance												Individually Evaluated Impaired Loans With a Recorded Allowance
	Recorded Investment				Unpaid Principal Balance				Allowance				Recorded Investment			Unpaid Principal Balance			Allowance
	(In Thousands)
Commercial, financial and agricultural	$	—			$	—			$	—			$	48,173		$	61,552		$	11,158
Real estate – construction	3,492				4,006				—				2,686			2,731			872
Commercial real estate – mortgage	22,822				23,781				—				76,608			82,005			7,594
Residential real estate – mortgage	8,795				8,795				—				107,223			107,306			9,236
Equity lines of credit	—				—				—				25,743			26,124			23,394
Equity loans	—				—				—				53,701			54,038			9,647
Credit card	—				—				—				—			—			—
Consumer direct	—				—				—				337			337			42
Consumer indirect	—				—				—				1,490			1,490			1,490
Total loans	$	35,109			$	36,582			$	—			$	315,961		$	335,583		$	63,433
The following table presents information on individually evaluated impaired loans, by loan class.
	Three Months Ended March 31, 2015								Three Months Ended March 31, 2014
	Average Recorded Investment				Interest Income Recognized				Average Recorded Investment				Interest Income Recognized
	(In Thousands)
Commercial, financial and agricultural	$	64,881			$	339			$	126,821			$	245
Real estate – construction	6,115				39				10,120				63
Commercial real estate – mortgage	88,178				580				141,347				942
Residential real estate – mortgage	113,926				695				114,965				719
Equity lines of credit	26,658				283				23,403				250
Equity loans	52,435				404				55,027				425
Credit card	—				—				—				—
Consumer direct	680				6				158				1
Consumer indirect	1,544				—				1,265				1
Total loans	$	354,417			$	2,346			$	473,106			$	2,646
The tables above do not include Purchased Impaired Loans, Purchased Nonimpaired Loans or loans held for sale. At March 31, 2015, there were $1.9 million and $4.7 million of recorded investment and unpaid principal balance, respectively, on Purchased Impaired Loans with credit deterioration subsequent to acquisition that were individually evaluated for impairment. There was no allowance for loan losses recorded on these loans. At December 31, 2014, there were $1.3 million and $4.7 million of recorded investment and unpaid principal balance, respectively, on Purchased Impaired Loans with credit deterioration subsequent to acquisition that were individually evaluated for impairment. There was no allowance for loan losses recorded on these loans. Purchased Nonimpaired Loans are not included in the tables above as they are evaluated collectively on a pool basis and not on an individual basis.
Detailed information on the Company's allowance for loan losses methodology and the Company's impaired loan policy are included in the Company's Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2014.
The Company monitors the credit quality of its commercial portfolio using an internal dual risk rating, which considers both the obligor and the facility. The obligor risk ratings are defined by ranges of default probabilities of the borrowers (AAA through D) and the facility risk ratings are defined by ranges of the loss given default. The combination of those two approaches results in the assessment of the likelihood of loss and it is mapped to the regulatory classifications. The Company assigns internal risk ratings at loan origination and at regular intervals subsequent to origination. Loan review intervals are dependent on the size and risk grade of the loan, and are generally conducted at least annually. Additional reviews are conducted when information affecting the loan’s risk grade becomes available. The general characteristics of the risk grades are as follows:
•	The Company’s internally assigned letter grades “AAA” through “B-” correspond to the regulatory classification “Pass.” These loans do not have any identified potential or well-defined weaknesses and have a high likelihood of orderly repayment. Exceptions exist when either the facility is fully secured by a CD and held at the Company or the facility is secured by properly margined and controlled marketable securities.
•	Internally assigned letter grades “CCC+” through “CCC” correspond to the regulatory classification “Special Mention.” Loans within this classification have potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or in the institution’s credit position at some future date. Special mention loans are not adversely classified and do not expose an institution to sufficient risk to warrant adverse classification.
•	Internally assigned letter grades “CCC-” through “D1” correspond to the regulatory classification “Substandard.” A loan classified as substandard is inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the loan. They are characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected.
•	The internally assigned letter grade “D2” corresponds to the regulatory classification “Doubtful.” Loans classified as doubtful have all the weaknesses inherent in one classified as substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable or improbable.
The Company considers payment history as the best indicator of credit quality for the consumer portfolio. Nonperforming loans in the tables below include loans classified as nonaccrual, loans 90 days or more past due and loans modified in a TDR 90 days or more past due.
The following tables, which exclude loans held for sale and covered loans, illustrate the credit quality indicators associated with the Company’s loans, by loan class.
	Commercial
	March 31, 2015
	Commercial, Financial and Agricultural				Real Estate - Construction				Commercial Real Estate - Mortgage
	(In Thousands)
Noncovered loans:
Pass	$	23,899,964			$	2,250,178			$	9,578,494
Special Mention	285,158				62,033				194,696
Substandard	222,535				13,261				130,061
Doubtful	41,307				23				17,332
	$	24,448,964			$	2,325,495			$	9,920,583
	December 31, 2014
	Commercial, Financial and Agricultural				Real Estate - Construction				Commercial Real Estate - Mortgage
	(In Thousands)
Noncovered loans:
Pass	$	23,380,541			$	2,098,994			$	9,514,917
Special Mention	280,934				42,176				210,337
Substandard	128,251				13,458				129,435
Doubtful	38,811				24				22,517
	$	23,828,537			$	2,154,652			$	9,877,206
	Consumer
	31-Mar-15
	Residential Real Estate – Mortgage				Equity Lines of Credit				Equity Loans				Credit Card			Consumer Direct			Consumer Indirect
	(In Thousands)
Noncovered loans:
Performing	$	13,890,173			$	2,289,292			$	616,266			$	591,412		$	702,815		$	3,098,855
Nonperforming	110,695				36,592				19,029				8,618			4,436			6,678
	$	14,000,868			$	2,325,884			$	635,295			$	600,030		$	707,251		$	3,105,533
	December 31, 2014
	Residential Real Estate -Mortgage				Equity Lines of Credit				Equity Loans				Credit Card			Consumer Direct			Consumer Indirect
	(In Thousands)
Noncovered loans:
Performing	$	13,810,857			$	2,269,231			$	614,064			$	621,015		$	649,832		$	2,865,013
Nonperforming	111,799				35,553				20,904				9,441			3,095			5,395
	$	13,922,656			$	2,304,784			$	634,968			$	630,456		$	652,927		$	2,870,408
The following tables present an aging analysis of the Company’s past due loans, excluding loans classified as held for sale.
	March 31, 2015
	30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Accruing TDRs			Total Past Due and Impaired			Not Past Due or Impaired		Total
	(In Thousands)
Commercial, financial and agricultural	$	7,940			$	3,981			$	2,901			$	95,318		$	9,632		$	119,772		$	24,329,192	$	24,448,964
Real estate – construction	5,275				450				392				7,781			2,237			16,135			2,309,360		2,325,495
Commercial real estate – mortgage	6,346				3,629				2,542				87,931			35,292			135,740			9,784,843		9,920,583
Residential real estate – mortgage	45,893				17,007				3,195				107,051			70,299			243,445			13,757,423		14,000,868
Equity lines of credit	10,615				4,602				1,995				34,597			—			51,809			2,274,075		2,325,884
Equity loans	5,387				1,728				703				18,313			40,432			66,563			568,732		635,295
Credit card	5,004				3,441				8,618				—			—			17,063			582,967		600,030
Consumer direct	7,545				2,406				2,426				2,010			180			14,567			692,684		707,251
Consumer indirect	34,444				6,726				2,576				4,102			—			47,848			3,057,685		3,105,533
Covered loans	6,582				3,872				45,402				179			—			56,035			432,525		488,560
Total loans	$	135,031			$	47,842			$	70,750			$	357,282		$	158,072		$	768,977		$	57,789,486	$	58,558,463
	December 31, 2014
	30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Accruing TDRs			Total Past Due and Impaired			Not Past Due or Impaired		Total
	(In Thousands)
Commercial, financial and agricultural	$	10,829			$	5,765			$	1,610			$	61,157		$	10,127		$	89,488		$	23,739,049	$	23,828,537
Real estate – construction	1,954				994				477				7,964			2,112			13,501			2,141,151		2,154,652
Commercial real estate – mortgage	9,813				4,808				628				89,736			39,841			144,826			9,732,380		9,877,206
Residential real estate – mortgage	45,279				16,510				2,598				108,357			69,408			242,152			13,680,504		13,922,656
Equity lines of credit	9,929				4,395				2,679				32,874			—			49,877			2,254,907		2,304,784
Equity loans	6,357				3,268				997				19,029			41,197			70,848			564,120		634,968
Credit card	5,692				3,921				9,441				—			—			19,054			611,402		630,456
Consumer direct	9,542				1,826				2,296				799			298			14,761			638,166		652,927
Consumer indirect	35,366				7,935				2,771				2,624			—			48,696			2,821,712		2,870,408
Covered loans	6,678				4,618				47,957				114			—			59,367			435,823		495,190
Total loans	$	141,439			$	54,040			$	71,454			$	322,654		$	162,983		$	752,570		$	56,619,214	$	57,371,784
Policies related to the Company's nonaccrual and past due loans are included in the Company's Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2014.
It is the Company’s policy to classify TDRs that are not accruing interest as nonaccrual loans. It is also the Company’s policy to classify TDR past due loans that are accruing interest as TDRs and not according to their past due status. The tables above reflect this policy.
The following table provides a breakout of TDRs, including nonaccrual loans and covered loans and excluding loans classified as held for sale.
	March 31, 2015
	30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Total Past Due and Nonaccrual			Not Past Due or Nonaccrual			Total
	(In Thousands)
Commercial, financial and agricultural	$	20			$	35			$	—			$	1,620		$	1,675		$	9,577		$	11,252
Real estate – construction	—				—				—				142			142			2,237			2,379
Commercial real estate – mortgage	—				—				358				6,226			6,584			34,934			41,518
Residential real estate – mortgage	1,366				658				449				29,087			31,560			67,826			99,386
Equity lines of credit	—				—				—				25,518			25,518			—			25,518
Equity loans	1,662				975				13				11,328			13,978			37,782			51,760
Credit card	—				—				—				—			—			—			—
Consumer direct	—				—				—				34			34			180			214
Consumer indirect	—				—				—				1,621			1,621			—			1,621
Covered loans	—				—				—				8			8			—			8
Total loans	$	3,048			$	1,668			$	820			$	75,584		$	81,120		$	152,536		$	233,656
	December 31, 2014
	30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Total Past Due and Nonaccrual			Not Past Due or Nonaccrual			Total
	(In Thousands)
Commercial, financial and agricultural	$	11			$	—			$	—			$	2,052		$	2,063		$	10,116		$	12,179
Real estate – construction	—				—				—				200			200			2,112			2,312
Commercial real estate – mortgage	371				536				—				7,068			7,975			38,934			46,909
Residential real estate – mortgage	2,440				2,688				844				32,518			38,490			63,436			101,926
Equity lines of credit	—				—				—				24,519			24,519			—			24,519
Equity loans	2,182				1,124				878				12,504			16,688			37,013			53,701
Credit card	—				—				—				—			—			—			—
Consumer direct	105				—				—				40			145			193			338
Consumer indirect	—				—				—				1,490			1,490			—			1,490
Covered loans	—				—				—				17			17			—			17
Total loans	$	5,109			$	4,348			$	1,722			$	80,408		$	91,587		$	151,804		$	243,391
At March 31, 2015 and December 31, 2014, there were no loans held for sale classified as TDRs.
Modifications to a borrower’s loan agreement are considered TDRs if a concession is granted for economic or legal reasons related to a borrower’s financial difficulties that otherwise would not be considered. Within each of the Company’s loan classes, TDRs typically involve modification of the loan interest rate to a below market rate or an extension or deferment of the loan. During the three months ended March 31, 2015, $300 thousand of TDR modifications included an interest rate concession and $4.5 million of TDR modifications resulted from modifications to the loan’s structure. During the three months ended March 31, 2014, $2.4 million of TDR modifications included an interest rate concession and $7.0 million of TDR modifications resulted from modifications to the loan’s structure.
The following table presents an analysis of the types of loans that were restructured and classified as TDRs, excluding loans classified as held for sale.
	Three Months Ended March 31, 2015							Three Months Ended March 31, 2014
	Number of Contracts			Post-Modification Outstanding Recorded Investment				Number of Contracts			Post-Modification Outstanding Recorded Investment
	(Dollars in Thousands)
Commercial, financial and agricultural	1			$	75			—			$	—
Real estate – construction	—			—				—			—
Commercial real estate – mortgage	—			—				6			3,930
Residential real estate – mortgage	11			1,740				10			994
Equity lines of credit	31			1,913				49			2,302
Equity loans	14			718				18			1,987
Credit card	—			—				—			—
Consumer direct	—			—				—			—
Consumer indirect	22			379				18			202
Covered loans	1			5				—			—
For the three months ended March 31, 2015 and 2014, charge-offs and changes to the allowance related to modifications classified as TDRs were not material.
The Company considers TDRs aged 90 days or more past due, charged off or classified as nonaccrual subsequent to modification, where the loan was not classified as a nonperforming loan at the time of modification, as subsequently defaulted.
The following tables provide a summary of initial subsequent defaults that occurred within one year of the restructure date. The table excludes loans classified as held for sale as of period-end and includes loans no longer in default as of period-end.
	Three Months Ended March 31, 2015							Three Months Ended March 31, 2014
	Number of Contracts			Recorded Investment at Default				Number of Contracts			Recorded Investment at Default
	(Dollars in Thousands)
Commercial, financial and agricultural	—			$	—			—			$	—
Real estate – construction	—			—				—			—
Commercial real estate – mortgage	1			178				—			—
Residential real estate – mortgage	4			647				—			—
Equity lines of credit	—			—				3			275
Equity loans	2			161				1			63
Credit card	—			—				—			—
Consumer direct	—			—				—			—
Consumer indirect	1			18				—			—
Covered loans	—			—				—			—
The Company’s allowance for loan losses is largely driven by updated risk ratings assigned to commercial loans, updated borrower credit scores on consumer loans, and borrower delinquency history in both commercial and consumer portfolios.  As such, the provision for loan losses is impacted primarily by changes in borrower payment performance rather than TDR classification.  In addition, all commercial and consumer loans modified in a TDR are considered to be impaired, even if they maintain their accrual status.
At March 31, 2015 and December 31, 2014, there were $1.0 million and $1.1 million, respectively, of commitments to lend additional funds to borrowers whose terms have been modified in a TDR.
Foreclosure Proceedings
Other real estate owned totaled $18 million and $21 million at March 31, 2015 and December 31, 2014, respectively. Other real estate owned included $11 million of foreclosed residential real estate properties at both March 31, 2015 and December 31, 2014. As of March 31, 2015 and December 31, 2014, there were $34 million and $26 million of residential real estate loans secured by residential real estate properties for which formal foreclosure proceedings were in process.

Loan_Sales_and_Servicing

Loan Sales and Servicing	3 Months Ended
	Mar. 31, 2015
Transfers and Servicing [Abstract]
Loan Sales and Servicing	Loan Sales and Servicing
	Loans held for sale were $198 million and $155 million at March 31, 2015 and December 31, 2014, respectively, and were comprised entirely of residential real estate - mortgage loans.
	There were no loans transferred from the held for investment portfolio to the loans held for sale portfolio during the three months ended March 31, 2015 and 2014. There were no material sales of loans and loans held for sale, excluding loans originated for sale in the secondary market, during the three months ended March 31, 2015. The Company sold loans and loans held for sale with a recorded balance of $62 million, excluding loans originated for sale in the secondary market, during the three months ended March 31, 2014.
	Sales of residential real estate – mortgage loans originated for sale in the secondary market, including loans originated for sale where the Company retained servicing responsibilities, were $245 million and $188 million for the three months ended March 31, 2015 and 2014, respectively. The Company recognized net gains of $10.6 million and $4.1 million on the sale of residential real estate mortgage loans originated for sale during the three months ended March 31, 2015 and 2014, respectively. These gains were recorded in mortgage banking income in the Company’s Unaudited Condensed Consolidated Statements of Income.
	Residential Real Estate Mortgage Loans Sold with Retained Servicing
	During the three months ended March 31, 2015 and 2014, the Company sold $245 million and $188 million, respectively, of residential real estate mortgage loans originated for sale where the Company retained servicing responsibilities. For these sold loans, there is no recourse to the Company for the failures of borrowers to pay when due. Residential real estate mortgage loans sold where the Company retained servicing totaled $3.5 billion and $3.3 billion, respectively, at March 31, 2015 and December 31, 2014. These loans are not included in loans on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	In connection with residential real estate mortgage loans sold with retained servicing, the Company receives servicing fees based on a percentage of the outstanding balance. The Company recognized servicing fees of $4.8 million and $3.6 million during the three months ended March 31, 2015 and 2014, respectively, as a component of other noninterest income in the Company’s Unaudited Condensed Consolidated Statements of Income. At both March 31, 2015 and December 31, 2014, the Company had recorded $35 million of MSRs, under the fair value method in other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	The fair value of MSRs is significantly affected by mortgage interest rates available in the marketplace, which influence mortgage loan prepayment speeds. In general, during periods of declining rates, the fair value of MSRs declines due to increasing prepayments attributable to increased mortgage-refinance activity. During periods of rising interest rates, the fair value of MSRs generally increases due to reduced refinance activity. The Company maintains a non-qualifying hedging strategy to manage a portion of the risk associated with changes in the fair value of the MSR portfolio.  This strategy includes the purchase of various trading securities.  The interest income, mark-to-market adjustments and gain or loss from sale activities associated with these securities are expected to economically hedge a portion of the change in the fair value of the MSR portfolio.
	The following table is an analysis of the activity in the Company’s MSRs.
		Three Months Ended
		March 31,
		2015			2014
		(In Thousands)
	Carrying value, at beginning of period	$	35,488		$	30,065
	Additions	2,759			2,083
	Increase (decrease) in fair value:
	Due to changes in valuation inputs or assumptions	(2,592		)	291
	Due to other changes in fair value (1)	(442		)	(611		)
	Carrying value, at end of period	$	35,213		$	31,828
	-1	Represents the realization of expected net servicing cash flows, expected borrower repayments and the passage of time.
	See Note 8, Fair Value of Financial Instruments, for additional disclosures related to the assumptions and estimates used in determining fair value of MSRs.
	At March 31, 2015 and December 31, 2014, the sensitivity of the current fair value of the residential MSRs to immediate 10% and 20% adverse changes in key economic assumptions are included in the following table:
		March 31, 2015			December 31, 2014
		(Dollars in Thousands)
	Fair value of MSRs	$	35,213		$	35,488
	Composition of residential loans serviced for others:
	Fixed rate mortgage loans	96		%	96.1		%
	Adjustable rate mortgage loans	4			3.9
	Total	100		%	100		%
	Weighted average life (in years)	6			6.2
	Prepayment speed:	11.2		%	10.6		%
	Effect on fair value of a 10% increase	$	(1,407	)	$	(1,220	)
	Effect on fair value of a 20% increase	(2,712		)	(2,375		)
	Weighted average discount rate:	10.1		%	10.1		%
	Effect on fair value of a 10% increase	$	(1,298	)	$	(1,291	)
	Effect on fair value of a 20% increase	(2,508		)	(2,492		)
	The sensitivity calculations above are hypothetical and should not be considered to be predictive of future performance. As indicated, changes in fair value based on adverse changes in assumptions generally cannot be extrapolated because the relationship of the change in assumption to the change in fair value may not be linear. Also, in this table, the effect of an adverse variation in a particular assumption on the fair value of the MSRs is calculated without changing any other assumption; while in reality, changes in one assumption may result in changes in another, which may magnify or counteract the effect of the change.

Derivatives_and_Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	Derivatives and Hedging
	The Company is a party to derivative instruments in the normal course of business for trading purposes and for purposes other than trading to meet the financing needs of its customers and to reduce its own exposure to fluctuations in interest rates and foreign currency exchange rates. The Company has made an accounting policy decision to not offset derivative fair value amounts under master netting agreements. See Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2014 for additional information on the Company's accounting policies related to derivative instruments and hedging activities. The following table reflects the notional amount and fair value of derivative instruments included on the Company’s Unaudited Condensed Consolidated Balance Sheets on a gross basis.
		March 31, 2015										December 31, 2014
						Fair Value								Fair Value
		Notional Amount				Derivative Assets (1)				Derivative Liabilities (2)		Notional Amount		Derivative Assets (1)		Derivative Liabilities (2)
		(In Thousands)
	Derivatives designated as hedging instruments:
	Fair value hedges:
	Interest rate swaps related to long-term debt	$	1,423,950			$	79,818			$	—	$	1,423,950	$	69,700	$	—
	Total fair value hedges					79,818				—				69,700		—
	Cash flow hedges:
	Interest rate contracts:
	Swaps related to commercial loans	1,800,000				5,807				—		1,100,000		1,793		1,023
	Swaps related to FHLB advances	320,000				—				14,871		320,000		—		13,474
	Total cash flow hedges					5,807				14,871				1,793		14,497
	Total derivatives designated as hedging instruments					$	85,625			$	14,871			$	71,493	$	14,497
	Free-standing derivatives not designated as hedging instruments:
	Interest rate contracts:
	Forward and option contracts related to held for sale mortgages	$	321,000			$	73			$	2,031	$	189,000	$	18	$	1,576
	Equity contracts:
	Purchased equity option related to equity-linked CDs	846,272				70,199				—		821,849		76,487		—
	Swap associated with sale of Visa, Inc. Class B shares	57,267				—				1,432		57,393		—		1,435
	Foreign exchange contracts:
	Forwards related to commercial loans	562,373				8,826				870		602,066		5,529		612
	Spots related to commercial loans	57,968				131				59		74,940		41		80
	Futures contracts (3)	683,000				—				—		342,000		—		—
	Interest rate lock commitments	294,685				4,988				1		180,822		2,319		1
	Written equity option related to equity-linked CDs	815,904				—				67,959		795,467		—		74,319
	Trading account assets and liabilities:
	Interest rate contracts for customers	20,758,720				369,042				310,602		18,678,390		296,239		236,763
	Commodity contracts for customers	235,099				21,568				21,471		264,491		25,569		25,448
	Foreign exchange contracts for customers	508,321				14,607				13,883		425,123		8,268		7,527
	Total trading account assets and liabilities					405,217				345,956				330,076		269,738
	Total free-standing derivative instruments not designated as hedging instruments					$	489,434			$	418,308			$	414,470	$	347,761
	-1	Derivative assets, except for trading account assets that are recorded as a component of trading account assets on the Company's Unaudited Condensed Consolidated Balance Sheets, are recorded in other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	-2	Derivative liabilities are recorded in accrued expenses and other liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	-3	Changes in fair value are cash settled daily; therefore, there is no ending balance at any given reporting period.
	Hedging Derivatives
	The Company uses derivative instruments to manage the risk of earnings fluctuations caused by interest rate volatility. For those financial instruments that qualify and are designated as a hedging relationship, either a fair value hedge or cash flow hedge, the effect of interest rate movements on the hedged assets or liabilities will generally be offset by the derivative instrument.
	Fair Value Hedges
	The Company enters into fair value hedging relationships using interest rate swaps to mitigate the Company’s exposure to losses in value as interest rates change. Derivative instruments that are used as part of the Company’s interest rate risk management strategy include interest rate swaps that relate to the pricing of specific balance sheet assets and liabilities. Interest rate swaps generally involve the exchange of fixed and variable rate interest payments between two parties, based on a common notional principal amount and maturity date.
	Interest rate swaps are used to convert the Company’s fixed rate long-term debt to a variable rate. The critical terms of the interest rate swaps match the terms of the corresponding hedged items. All components of each derivative instrument’s gain or loss are included in the assessment of hedge effectiveness.
	The Company recognized no gains or losses for the three months ended March 31, 2015 and 2014 related to hedged firm commitments no longer qualifying as a fair value hedge. At March 31, 2015, the fair value hedges had a weighted average expected remaining term of 3.8 years.
	The following table reflects the change in fair value for interest rate contracts and the related hedged items as well as other gains and losses related to fair value hedges including gains and losses recognized because of hedge ineffectiveness.
				Gain (Loss) for the
		Condensed Consolidated		Three Months Ended March 31,
		Statements of Income Caption		2015				2014
				(In Thousands)
	Change in fair value of interest rate contracts:
	Interest rate swaps hedging long term debt	Interest on FHLB and other borrowings		$	10,118			$	(935	)
	Hedged long term debt	Interest on FHLB and other borrowings		(9,413		)		1,809
	Other gains on interest rate contracts:
	Interest and amortization related to interest rate swaps on hedged long term debt	Interest on FHLB and other borrowings		9,566				5,265
	There were no material fair value hedging gains and losses recognized because of hedge ineffectiveness for the three months ended March 31, 2015 and 2014.
	Cash Flow Hedges
	The Company enters into cash flow hedging relationships using interest rate swaps and options, such as caps and floors, to mitigate exposure to the variability in future cash flows or other forecasted transactions associated with its floating rate assets and liabilities. The Company uses interest rate swaps and options to hedge the repricing characteristics of its floating rate commercial loans and FHLB advances. All components of each derivative instrument’s gain or loss are included in the assessment of hedge effectiveness. The initial assessment of expected hedge effectiveness is based on regression analysis. The ongoing periodic measures of hedge ineffectiveness are based on the expected change in cash flows of the hedged item caused by changes in the benchmark interest rate. There were no material cash flow hedging gains or losses recognized because of hedge ineffectiveness for the three months ended March 31, 2015 and 2014. There were no gains or losses reclassified from other comprehensive income because of the discontinuance of cash flow hedges related to certain forecasted transactions that are probable of not occurring for the three months ended March 31, 2015 and 2014.
	At March 31, 2015, cash flow hedges not terminated had a net fair value of $(9.1) million and a weighted average life of 2.2 years. Based on the current interest rate environment, $835 thousand of gains are expected to be reclassified to net interest income over the next 12 months as net settlements occur. The maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions is 6.3 years.
	The following table presents the effect of derivative instruments designated and qualifying as cash flow hedges on the Company’s Unaudited Condensed Consolidated Balance Sheets and the Company’s Unaudited Condensed Consolidated Statements of Income.
		Gain (Loss) for the
		Three Months Ended
		March 31,
		2015				2014
		(In Thousands)
	Interest rate contracts:
Net change in amount recognized in other comprehensive income	$	2,059			$	807
Amount reclassified from accumulated other comprehensive income into net interest income	1,047				(1,163		)
Amount of ineffectiveness recognized in net interest income	—				—
Derivatives Not Designated As Hedges
Derivatives not designated as hedges include those that are entered into as either economic hedges as part of the Company’s overall risk management strategy or to facilitate client needs. Economic hedges are those that do not qualify to be treated as a fair value hedge, cash flow hedge or foreign currency hedge for accounting purposes, but are necessary to economically manage the risk exposure associated with the assets and liabilities of the Company.
The Company also enters into a variety of interest rate contracts, commodity contracts and foreign exchange contracts in its trading activities. The primary purpose for using these derivative instruments in the trading account is to facilitate customer transactions. The trading interest rate contract portfolio is actively managed and hedged with similar products to limit market value risk of the portfolio. Changes in the estimated fair value of contracts in the trading account along with the related interest settlements on the contracts are recorded in noninterest income as corporate and correspondent investment sales in the Company's Unaudited Condensed Consolidated Statements of Income.
The Company enters into forward contracts to economically hedge the change in fair value of certain residential mortgage loans held for sale due to changes in interest rates. Revaluation gains and losses from free-standing derivatives related to mortgage banking activity are recorded as a component of mortgage banking income in the Company’s Unaudited Condensed Consolidated Statements of Income.
Interest rate lock commitments issued on residential mortgage loan commitments to be held for resale are also considered free-standing derivative instruments, and the interest rate exposure on these commitments is economically hedged primarily with forward contracts. Revaluation gains and losses from free-standing derivatives related to mortgage banking activity are recorded as a component of mortgage banking income in the Company's Unaudited Condensed Consolidated Statements of Income.
In conjunction with the sale of its Visa, Inc. Class B shares in 2009, the Company entered into a total return swap in which the Company will make or receive payments based on subsequent changes in the conversion rate of the Class B shares into Class A shares. This total return swap is accounted for as a free-standing derivative.
The Company offers its customers equity-linked CDs that have a return linked to individual equities and equity indices. Under appropriate accounting guidance, a CD that pays interest based on changes in an equity index is a hybrid instrument that requires separation into a host contract (the CD) and an embedded derivative contract (written equity call option). The Company has entered into an offsetting derivative contract in order to economically hedge the exposure related to the issuance of equity-linked CDs. Both the embedded derivative and derivative contract entered into by the Company are classified as free-standing derivative instruments that are recorded at fair value with offsetting gains and losses recognized within noninterest expense in the Company's Unaudited Condensed Consolidated Statements of Income.
The Company also enters into foreign currency contracts to hedge its exposure to fluctuations in foreign currency exchange rates due to its funding of commercial loans in foreign currencies.
The net gains and losses recorded in the Company's Unaudited Condensed Consolidated Statements of Income from free-standing derivative instruments not designated as hedging instruments are summarized in the following table.
			Gain (Loss) for the
	Condensed Consolidated		Three Months Ended March 31,
	Statements of Income Caption		2015			2014
			(In Thousands)
Futures contracts	Mortgage banking income		47			(76	)
	and corporate and correspondent investment sales
Option contracts related to mortgage servicing rights	Mortgage banking income		(195	)		—
Interest rate contracts:
Forward and option contracts related to residential mortgage loans held for sale	Mortgage banking income		(400	)		(1,554	)
Interest rate lock commitments	Mortgage banking income		2,669			792
Interest rate contracts for customers	Corporate and correspondent investment sales		4,639			5,118
Commodity contracts:
Commodity contracts for customers	Corporate and correspondent investment sales		14			8
Equity contracts:
Purchased equity option related to equity-linked CDs	Other expense		(6,288	)		3,778
Written equity option related to equity-linked CDs	Other expense		6,360			(3,679	)
Foreign currency contracts:
Forward contracts related to commercial loans	Other income		46,567			(5,487	)
Spot contracts related to commercial loans	Other income		(6,895	)		880
Foreign currency exchange contracts for customers	Corporate and correspondent investment sales		380			193
Derivatives Credit and Market Risks
By using derivative instruments, the Company is exposed to credit and market risk. If the counterparty fails to perform, credit risk is equal to the extent of the Company’s fair value gain in a derivative. When the fair value of a derivative instrument contract is positive, this generally indicates that the counterparty owes the Company and, therefore, creates a credit risk for the Company. When the fair value of a derivative instrument contract is negative, the Company owes the counterparty and, therefore, it has no credit risk. The Company minimizes the credit risk in derivative instruments by entering into transactions with high-quality counterparties that are reviewed periodically. Credit losses are also mitigated through collateral agreements and other contract provisions with derivative counterparties.
Market risk is the adverse effect that a change in interest rates or implied volatility rates has on the value of a financial instrument. The Company manages the market risk associated with interest rate contracts by establishing and monitoring limits as to the types and degree of risk that may be undertaken.
The Company’s derivatives activities are monitored by its Asset/Liability Committee as part of its risk-management oversight. The Company’s Asset/Liability Committee is responsible for mandating various hedging strategies that are developed through its analysis of data from financial simulation models and other internal and industry sources. The resulting hedging strategies are then incorporated into the Company’s overall interest rate risk management and trading strategies.
Entering into interest rate swap agreements and options involves not only the risk of dealing with counterparties and their ability to meet the terms of the contracts but also interest rate risk associated with unmatched positions. At March 31, 2015, interest rate swap agreements and options classified as trading were substantially matched. The Company had credit risk of $405 million related to derivative instruments in the trading account portfolio, which does not take into consideration master netting arrangements or the value of the collateral. There were $2 thousand and $1 thousand in credit losses associated with derivative instruments classified as trading for the three months ended March 31, 2015 and 2014, respectively. At March 31, 2015 and December 31, 2014, there were no material nonperforming derivative positions classified as trading.
The Company’s derivative positions held for hedging purposes are primarily executed in the over-the-counter market. These positions at March 31, 2015 have credit risk of $95 million, which does not take into consideration master netting arrangements or the value of the collateral.
There were no credit losses associated with derivative instruments classified as nontrading for the three months ended March 31, 2015 and 2014. At March 31, 2015 and December 31, 2014, there were no nonperforming derivative positions classified as nontrading.
As of March 31, 2015 and December 31, 2014, the Company had recorded the right to reclaim cash collateral of $54 million and $46 million, respectively, within other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets and had recorded the obligation to return cash collateral of $56 million and $62 million, respectively, within deposits on the Company’s Unaudited Condensed Consolidated Balance Sheets.
Contingent Features
Certain of the Company’s derivative instruments contain provisions that require the Company’s debt to maintain a certain credit rating from each of the major credit rating agencies. If the Company’s debt were to fall below this rating, it would be in violation of these provisions, and the counterparties to the derivative instruments could demand immediate and ongoing full overnight collateralization on derivative instruments in net liability positions. The aggregate fair value of all derivative instruments with credit-risk-related contingent features that were in a liability position on March 31, 2015 was $71 million for which the Company has collateral requirements of $67 million in the normal course of business. If the credit risk-related contingent features underlying these agreements had been triggered on March 31, 2015, the Company’s collateral requirements to its counterparties would have increased by $4 million. The aggregate fair value of all derivative instruments with credit risk-related contingent features that were in a liability position on December 31, 2014 was $65 million for which the Company had collateral requirements of $62 million in the normal course of business. If the credit risk-related contingent features underlying these agreements had been triggered on December 31, 2014, the Company’s collateral requirements to its counterparties would have increased by $4 million.

Assets_and_Liabilities_Subject

Assets and Liabilities Subject to Enforceable Master Netting Arrangements	3 Months Ended
	Mar. 31, 2015
Offsetting [Abstract]
Assets and Liabilities Subject to Enforceable Master Netting Arrangements	Assets and Liabilities Subject to Enforceable Master Netting Arrangements
	Derivatives
	In conjunction with the derivative and hedging activity discussed in Note 5, Derivatives and Hedging, the Company is party to master netting arrangements with its financial institution counterparties for some of its derivative and hedging activities. The Company does not offset assets and liabilities under these master netting arrangements for financial statement presentation purposes. The master netting arrangements provide for single net settlement of all derivative instrument arrangements, as well as collateral, in the event of default, or termination of, any one contract with the respective counterparties. Cash collateral is usually posted by the counterparty with a net liability position in accordance with contract thresholds.
	Securities Purchased Under Agreements to Resell and Securities Sold Under Agreements to Repurchase
	The Company enters into agreements under which it purchases or sells securities subject to an obligation to resell or repurchase the same or similar securities. Securities purchased under agreements to resell and securities sold under agreements to repurchase are generally accounted for as collateralized financing transactions and recorded at the amounts at which the securities were purchased or sold plus accrued interest. The securities pledged as collateral are generally U.S. government and federal agency securities.
	At March 31, 2015, the fair value of collateral received related to securities purchased under agreements to resell was $3.4 billion and the fair value of collateral pledged for securities sold under agreements to repurchase was $3.2 billion. At December 31, 2014, the fair value of collateral received related to securities purchased under agreements to resell was $2.6 billion and the fair value of collateral pledged for securities sold under agreements to repurchase was $2.5 billion.
	Securities purchased under agreements to resell and securities sold under agreements to repurchase are governed by a MRA. Under the terms of the MRA, all transactions between the Company and the counterparty constitute a single business relationship such that in the event of default, the nondefaulting party is entitled to set off claims and apply property held by that party in respect of any transaction against obligations owed. Any payments, deliveries, or other transfers may be applied against each other and netted. These amounts are limited to the contract asset/liability balance, and accordingly, do not include excess collateral received or pledged. The Company offsets the assets and liabilities under netting arrangements for the balance sheet presentation of securities purchased under agreements to resell and securities sold under agreements to repurchase provided certain criteria are met that permit balance sheet netting.
	The following represents the Company’s assets/liabilities subject to an enforceable master netting arrangement. The derivative instruments the Company has with its customers are not subject to an enforceable master netting arrangement.
								Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
		Gross Amounts Recognized		Gross Amounts Offset in the Condensed Consolidated Balance Sheets		Net Amount Presented in the Condensed Consolidated Balance Sheets		Financial Instruments (1)		Cash Collateral Received/ Pledged (1)		Net Amount
		(In Thousands)
	March 31, 2015
	Securities purchased under agreements to resell:
	Subject to a master netting arrangement	$	3,497,408	$	3,223,019	$	274,389	$	274,389	$	—	$	—
	Derivative financial assets:
	Subject to a master netting arrangement	$	245,285	$	—	$	245,285	$	—	$	49,064	$	196,221
	Not subject to a master netting arrangement	329,774		—		329,774		—		—		329,774
	Total derivative financial assets	$	575,059	$	—	$	575,059	$	—	$	49,064	$	525,995
	Securities sold under agreements to repurchase:
	Subject to a master netting arrangement	$	3,250,397	$	3,223,019	$	27,378	$	27,378	$	—	$	—
	Derivative financial liabilities:
	Subject to a master netting arrangement	$	335,349	$	—	$	335,349	$	27,453	$	55,574	$	252,322
	Not subject to a master netting arrangement	97,830		—		97,830		—		—		97,830
	Total derivative financial liabilities	$	433,179	$	—	$	433,179	$	27,453	$	55,574	$	350,152
	December 31, 2014
	Securities purchased under agreements to resell:
	Subject to a master netting arrangement	$	3,100,200	$	2,533,661	$	566,539	$	566,539	$	—	$	—
	Derivative financial assets:
	Subject to a master netting arrangement	$	225,227	$	—	$	225,227	$	—	$	58,309	$	166,918
	Not subject to a master netting arrangement	260,736		—		260,736		—		—		260,736
	Total derivative financial assets	$	485,963	$	—	$	485,963	$	—	$	58,309	$	427,654
	Securities sold under agreements to repurchase:
	Subject to a master netting arrangement	$	2,969,345	$	2,533,661	$	435,684	$	435,684	$	—	$	—
	Derivative financial liabilities:
	Subject to a master netting arrangement	$	259,018	$	—	$	259,018	$	29,677	$	44,163	$	185,178
	Not subject to a master netting arrangement	103,240		—		103,240		—		—		103,240
	Total derivative financial liabilities	$	362,258	$	—	$	362,258	$	29,677	$	44,163	$	288,418
	-1	The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists, the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.

Commitments_Contingencies_and_

Commitments, Contingencies and Guarantees	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees
	Commitments to Extend Credit & Standby and Commercial Letters of Credit
	The following represents the Company’s commitments to extend credit, standby letters of credit and commercial letters of credit:
		March 31, 2015		December 31, 2014
		(In Thousands)
	Commitments to extend credit	$	28,348,272	$	28,369,666
	Standby and commercial letters of credit	1,695,974		1,871,323
	Commitments to extend credit are agreements to lend to customers as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements.
	Standby and commercial letters of credit are commitments issued by the Company to guarantee the performance of a customer to a third party. These guarantees are primarily issued to support public and private borrowing arrangements, including commercial paper, bond financing and similar transactions, and expire in decreasing amounts with terms ranging from one to four years.
	The credit risk involved in issuing letters of credit and commitments is essentially the same as that involved in extending loan facilities to customers. The fair value of the letters of credit and commitments typically approximates the fee received from the customer for issuing such commitments. These fees are deferred and are recognized over the commitment period. At March 31, 2015 and December 31, 2014, the recorded amount of these deferred fees was $6.5 million and $5.2 million, respectively. The Company holds various assets as collateral supporting those commitments for which collateral is deemed necessary. At March 31, 2015, the maximum potential amount of future undiscounted payments the Company could be required to make under outstanding standby letters of credit was $1.7 billion. At March 31, 2015 and December 31, 2014, the Company had reserves related to letters of credit and unfunded commitments recorded in accrued expenses and other liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheet of $93 million and $94 million, respectively.
	Loan Sale Recourse
	The Company has potential recourse related to FNMA securitizations. At both March 31, 2015 and December 31, 2014, the amount of potential recourse was $20 million, of which the Company had reserved $716 thousand and $655 thousand, respectively, which is recorded in accrued expenses and other liabilities on the Company's Unaudited Condensed Consolidated Balance Sheets for the respective periods.
	The Company also issues standard representations and warranties related to mortgage loan sales to government-sponsored agencies. Although these agreements often do not specify limitations, the Company does not believe that any payments related to these representations and warranties would materially change the financial condition or results of operations of the Company. At March 31, 2015 and December 31, 2014, the Company recorded $1 million of reserves in accrued expenses and other liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheets related to potential losses from loans sold.
	Loss Sharing Agreement
	In connection with the Guaranty Bank acquisition, the Bank entered into loss sharing agreements with the FDIC that covered approximately $9.7 billion of loans and OREO, excluding the impact of purchase accounting adjustments. In accordance with the terms of the loss sharing agreements, the FDIC’s obligation to reimburse the Bank for losses with respect to the acquired loans and acquired OREO begins with the first dollar of incurred losses, as defined in the loss sharing agreements. The terms of the loss sharing agreements provide that the FDIC will reimburse the Bank for 80% of incurred losses up to $2.3 billion and 95% of incurred losses in excess of $2.3 billion. Gains and recoveries on covered assets offset incurred losses, or are paid to the FDIC, at the applicable loss share percentage at the time of recovery. The loss sharing agreements provide for FDIC loss sharing for five years for commercial loans and 10 years for single family residential loans. The loss sharing agreement for commercial loans expired in the fourth quarter of 2014.
	The provisions of the loss sharing agreements may also require a payment by the Bank to the FDIC on October 15, 2019. On that date, the Bank is required to pay the FDIC 60% of the excess, if any, of (i) $457 million over (ii) the sum of (a) 25% of the total net amounts paid to the Bank under both of the loss share agreements plus (b) 20% of the deemed total cost to the Bank of administering the covered assets under the loss sharing agreements. The deemed total cost to the Bank of administering the covered assets is the sum of 2% of the average of the principal amount of covered assets based on the beginning and end of year balances for each of the 10 years during which the loss sharing agreements are in effect. At both March 31, 2015 and December 31, 2014, the Company estimated the potential amount of payment due to the FDIC in 2019, at the end of the loss sharing agreements, to be $145 million. The ultimate settlement amount of this payment due to the FDIC is dependent upon the performance of the underlying covered assets, the passage of time and actual claims submitted to the FDIC. See Note 3, Loans and Allowance for Loan Losses, for additional information.
	Legal and Regulatory Proceedings
	In the ordinary course of business, the Company is subject to legal proceedings, including claims, litigation, investigations and administrative proceedings, all of which are considered incidental to the normal conduct of business. The Company believes it has substantial defenses to the claims asserted against it in its currently outstanding legal proceedings and, with respect to such legal proceedings, intends to continue to defend itself vigorously against such claims.
	Set forth below are descriptions of certain of the Company’s legal proceedings:
	In May 2013, the Company was named as a counterclaim defendant in a lawsuit filed in the United States District Court for the Southern District of California, BBVA Compass v. Morris Cerullo World Evangelism, wherein the counterclaim plaintiff alleges the Company wrongfully failed to honor a standby letter of credit in the amount of $5.2 million. The counterclaim plaintiff seeks $5.2 million, plus other, unspecified monetary relief. The Company believes there are substantial defenses to these claims and intends to defend them vigorously.
	In February 2015, the Company was named as a defendant in a lawsuit filed in the Superior Court for the State of California, Count of San Diego, Morris Cerullo World Evangelism v. BBVA Compass and Jack Wilkinson, wherein the plaintiff alleges the Company wrongfully failed to honor a standby letter of credit in the amount of $5.2 million. The plaintiff's allegations in this lawsuit are virtually identical to its allegations in the earlier filed federal court lawsuit. As in that lawsuit, the plaintiff seeks $5.2 million, plus other, unspecified monetary relief. The Company believes there are substantial defenses to these claims and intends to defend them vigorously.
	In June 2013, the Company was named as a defendant in a lawsuit filed in the United States District Court for the Northern District of Alabama, Intellectual Ventures II, LLC v. BBVA Compass Bancshares, Inc. and BBVA Compass, wherein the plaintiff alleges the Company is infringing five patents owned by the plaintiff and related to the security infrastructure for the Company's online banking services. The plaintiff seeks unspecified monetary relief. The Company believes there are substantial defenses to these claims and intends to defend them vigorously.
	In March 2014, the Company was named as a defendant in a lawsuit filed in the Circuit Court of the Fourth Judicial Circuit in Duval County, Florida, Jack C. Demetree, et al. v. BBVA Compass, wherein the plaintiffs allege that their accountant stole approximately $17.1 million through unauthorized transactions on their accounts from 2009 to 2013, and that BBVA Compass enabled the theft. The plaintiffs seek unspecified monetary relief. The Company believes there are substantial defenses to these claims and intends to defend them vigorously.
	In November 2014, the Company was named as a defendant in a lawsuit filed in the United States District Court for the Western District of Texas, Maxim Integrated Products v. Compass Bank, wherein the plaintiff alleges the Company is infringing three patents owned by the plaintiff and related to data encryption for the Company’s mobile banking applications. The plaintiff seeks unspecified monetary relief. The Company believes there are substantial defenses to these claims and intends to defend them vigorously.
	The Company (including the Bank) is or may become involved from time to time in information-gathering requests, reviews, investigations and proceedings (both formal and informal) by various governmental regulatory agencies, law enforcement authorities and self-regulatory bodies regarding the Company’s business. Such matters could develop into administrative, civil, or criminal proceeding or enforcement actions and may result in material adverse consequences, including without limitation adverse judgments, settlements, fines, penalties, orders, injunctions, alterations in the Company’s business practices or other actions, and could result in additional expenses and collateral costs, including reputational damage, which could have a material adverse impact on the Company’s business, consolidated financial position, results of operations or cash flows.
	The Company owns all of the outstanding stock of BSI, a registered broker-dealer. Applicable law limits BSI from deriving more than 25 percent of its gross revenues from underwriting or dealing in bank-ineligible securities (“ineligible revenue”). Prior to the contribution of BSI to the Company in April 2013, BSI’s ineligible revenues in certain periods exceeded the 25 percent limit. It is possible that the Federal Reserve Board may take either formal or informal enforcement action against BSI and the Company and civil money penalties cannot be excluded. At this time, the Company does not know the amount of a potential civil money penalty, if any.
	There are other litigation matters that arise in the normal course of business. The Company assesses its liabilities and contingencies in connection with outstanding legal proceedings utilizing the latest information available. Where it is probable that the Company will incur a loss and the amount of the loss can be reasonably estimated, the Company records a liability in its consolidated financial statements. These legal reserves may be increased or decreased to reflect any relevant developments. Where a loss is not probable or the amount of loss is not estimable, the Company does not accrue legal reserves. At March 31, 2015, the Company had accrued legal reserves in the amount of $15 million. Additionally, for those matters where a loss is both estimable and reasonably possible, the Company estimates losses that it could incur beyond the accrued legal reserves. Under U.S. GAAP, an event is “reasonably possible” if “the chance of the future event or events occurring is more than remote but less than likely” and an event is “remote” if “the chance of the future event or events occurring is slight.” At March 31, 2015, there were no such matters where a loss was both estimable and reasonably possible beyond the accrued legal reserve.
	While the outcome of legal proceedings and the timing of the ultimate resolution are inherently difficult to predict, based on information currently available, advice of counsel and available insurance coverage, the Company believes that it has established adequate legal reserves. Further, based upon available information, the Company is of the opinion that these legal proceedings, individually or in the aggregate, will not have a material adverse effect on the Company’s financial condition or results of operations. However, in the event of unexpected future developments, it is possible that the ultimate resolution of those matters, if unfavorable, may be material to the Company’s results of operations for any particular period, depending, in part, upon the size of the loss or liability imposed and the operating results for the applicable period.
	Income Tax Review
	The Company is subject to review and examination from various tax authorities. The Company is currently under examination by the IRS and a number of states, and has received notices of proposed adjustments related to federal and state income taxes due for prior years. Management believes that adequate provisions for income taxes have been recorded.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The Company applies the fair value accounting guidance required under ASC Topic 820 which establishes a framework for measuring fair value. This guidance defines fair value as the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. This guidance also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within this fair value hierarchy is based upon the lowest level of input that is significant to the instrument’s fair value measurement. The three levels within the fair value hierarchy are described as follows.
	•	Level 1 – Fair value is based on quoted prices in an active market for identical assets or liabilities.
	•	Level 2 – Fair value is based on quoted market prices for similar instruments traded in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market.
	•	Level 3 – Fair value is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities would include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar pricing techniques based on the Company’s own assumptions about what market participants would use to price the asset or liability.
	A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments under the fair value hierarchy, is set forth below. These valuation methodologies were applied to the Company’s financial assets and financial liabilities carried at fair value. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use observable market based parameters as inputs. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and the Company’s creditworthiness, among other things, as well as other unobservable parameters. Any such valuation adjustments are applied consistently over time. While management believes the Company’s valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. The Company’s valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and, therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein.
	Financial Instruments Measured at Fair Value on a Recurring Basis
	Trading account assets and liabilities, securities available for sale, certain mortgage loans held for sale, derivative assets and liabilities, and mortgage servicing rights are recorded at fair value on a recurring basis. The following is a description of the valuation methodologies for these assets and liabilities.
	Trading account assets and liabilities and investment securities available for sale – Trading account assets and liabilities and investment securities available for sale consist of U.S. Treasury and other U.S. government agencies securities, mortgage-backed securities, collateralized mortgage obligations, debt obligations of state and political subdivisions, other debt and equity securities, and derivative contracts.
	•	U.S. Treasury and other U.S. government agencies securities are valued based on quoted market prices of identical assets on active exchanges (Level 1 measurements) or are valued based on a market approach using observable inputs such as benchmark yields, reported trades, broker/dealer quotes, benchmark securities, and bids/offers of government-sponsored enterprise securities (Level 2 measurements).
	•	Mortgage-backed securities are primarily valued using market-based pricing matrices that are based on observable inputs including benchmark To Be Announced security prices, U.S. Treasury yields, U.S. dollar swap yields, and benchmark floating-rate indices. Mortgage-backed securities pricing may also give consideration to pool-specific data such as prepayment history and collateral characteristics. Valuations for mortgage-backed securities are therefore classified as Level 2 measurements.
	•	Collateralized mortgage obligations are valued using market-based pricing matrices that are based on observable inputs including reported trades, bids, offers, dealer quotes, U.S. Treasury yields, U.S. dollar swap yields, market convention prepayment speeds, tranche-specific characteristics, prepayment history, and collateral characteristics. Fair value measurements for collateralized mortgage obligations are classified as Level 2.
	•	Debt obligations of states and political subdivisions are primarily valued using market-based pricing matrices that are based on observable inputs including Municipal Securities Rulemaking Board reported trades, issuer spreads, material event notices, and benchmark yield curves. These valuations are Level 2 measurements.
	•	Other debt and equity securities consist of mutual funds, foreign and corporate debt, and U.S. government agencies equity securities. Mutual funds are valued based on quoted market prices of identical assets trading on active exchanges. These valuations are Level 1 measurements. Foreign and corporate debt valuations are based on information and assumptions that are observable in the market place. The valuations for these securities are therefore classified as Level 2. U.S. government agency equity securities are valued based on quoted market prices of identical assets trading on active exchanges. These valuations thus qualify as Level 1 measurements.
	•	Other derivative assets and liabilities consist primarily of interest rate and commodity contracts. The Company’s interest rate contracts are valued utilizing Level 2 observable inputs (yield curves and volatilities) to determine a current market price for each interest rate contract. Commodity contracts are priced using raw market data, primarily in the form of quotes for fixed and basis swaps with monthly, quarterly, seasonal or calendar-year terms. Proprietary models provided by a third party are used to generate forward curves and volatility surfaces. As a result of the valuation process and observable inputs used, commodity contracts are classified as Level 2 measurements. To validate the reasonableness of these calculations, management compares the assumptions with market information.
	•	Other trading assets primarily consist of interest-only strips which are valued by an independent third-party. The independent third-party values the assets on a loan-by-loan basis using a discounted cash flow analysis that employs prepayment assumptions, discount rate assumptions, and default curves. The prepayment assumptions are created from actual SBA pool prepayment history. The discount rates are derived from actual SBA loan secondary market transactions. The default curves are created using historical observable and unobservable inputs. As such, interest-only strips are classified as Level 3 measurements. The Company’s SBA department is responsible for ensuring the appropriate application of the valuation, capitalization, and amortization policies of the Company’s interest-only strips. The department performs independent, internal valuations of the interest-only strips on a quarterly basis, which are then reconciled to the third-party valuations to ensure their validity.
	Loans held for sale – The Company has elected to apply the fair value option for single family real estate mortgage loans originated for resale in the secondary market. The election allows for a more effective offset of the changes in fair values of the loans and the derivative instruments used to economically hedge them without the burden of complying with the requirements for hedge accounting. The Company has not elected the fair value option for other loans held for sale primarily because they are not economically hedged using derivative instruments.
	The fair value of loans held for sale is based on what secondary markets are currently offering for portfolios with similar characteristics. The changes in fair value of these assets are largely driven by changes in interest rates subsequent to loan funding and changes in the fair value of servicing associated with the mortgage loan held for sale. Both the mortgage loans held for sale and the related forward contracts are classified as Level 2.
	At both March 31, 2015 and December 31, 2014, no material loans held for sale for which the fair value option was elected were 90 days or more past due or were in nonaccrual. Interest income on mortgage loans held for sale is recognized based on contractual rates and is reflected in interest and fees on loans in the Company's Unaudited Condensed Consolidated Statements of Income. Net gains of $548 thousand and $690 thousand resulting from changes in fair value of these loans were recorded in noninterest income during the three months ended March 31, 2015 and 2014, respectively.
	The Company also had fair value changes on forward contracts related to residential mortgage loans held for sale of approximately $(400) thousand and $(1.6) million for the three months ended March 31, 2015 and 2014, respectively. An immaterial portion of these amounts was attributable to changes in instrument-specific credit risk.
	The following tables summarize the difference between the aggregate fair value and the aggregate unpaid principal balance for residential mortgage loans measured at fair value.
		Aggregate Fair Value			Aggregate Unpaid Principal Balance			Difference
		(In Thousands)
	March 31, 2015
	Residential mortgage loans held for sale	$	198,488		$	191,687		$	6,801
	December 31, 2014
	Residential mortgage loans held for sale	$	154,816		$	148,564		$	6,252
	Derivative assets and liabilities – Derivative assets and liabilities are measured using models that primarily use market observable inputs, such as quoted security prices, and are accordingly classified as Level 2. The derivative assets and liabilities classified within Level 3 of the fair value hierarchy were comprised of interest rate lock commitments that are valued using third-party software that calculates fair market value considering current quoted TBA and other market based prices and then applies closing ratio assumptions based on software-produced pull through ratios that are generated using the Company’s historical fallout activity. Based upon this process, the fair value measurement obtained for these financial instruments is deemed a Level 3 classification. The Company's Secondary Marketing Committee is responsible for the appropriate application of the valuation policies and procedures surrounding the Company’s interest rate lock commitments. Policies established to govern mortgage pipeline risk management activities must be approved by the Company’s Asset/Liability Committee on an annual basis.
	Other assets – Other assets measured at fair value on a recurring basis and classified within Level 3 of the fair value hierarchy were comprised of MSRs that are valued through a discounted cash flow analysis using a third-party commercial valuation system. The valuation takes into consideration the objective characteristics of the MSR portfolio, such as loan amount, note rate, service fee, loan term, and common industry assumptions, such as servicing costs, ancillary income, prepayment estimates, earning rates, cost of fund rates, discount rates, etc. The Company’s portfolio-specific factors are also considered in calculating the fair value of MSRs to the extent one can reasonably assume a buyer would also incorporate these factors. Examples of such factors are geographical concentrations of the portfolio, liquidity considerations such as housing authority loans which have a limited number of approved servicers, or additional views of risk not inherently accounted for in prepayment assumptions. Product liquidity and these other risks are generally incorporated through adjustment of discount factors applied to forecasted cash flows. Based on this method of pricing MSRs, the fair value measurement obtained for these financial instruments is deemed a Level 3 classification. The value of the MSR is calculated by a third-party firm that specializes in the MSR market and valuation services. Additionally, the Company obtains a valuation from an independent party to compare for reasonableness. The Company’s Secondary Marketing Committee is responsible for ensuring the appropriate application of valuation, capitalization, and fair value decay policies for the MSR portfolio. The Committee meets at least monthly to review the MSR portfolio.
	The following tables summarize the financial assets and liabilities measured at fair value on a recurring basis.
					Fair Value Measurements at the End of the Reporting Period Using
		Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs
		March 31, 2015			(Level 1)			(Level 2)		(Level 3)
		(In Thousands)
	Recurring fair value measurements
	Assets:
	Trading account assets:
	U.S. Treasury and other U.S. government agencies	$	3,267,024		$	3,267,024		$	—	$	—
	State and political subdivisions	1,030			—			1,030		—
	Other debt securities	3,972			—			3,972		—
	Other equity securities	166			—			166		—
	Interest rate contracts	369,042			—			369,042		—
	Commodity contracts	21,568			—			21,568		—
	Foreign exchange contracts	14,607			—			14,607		—
	Other trading assets	3,018			—			1,582		1,436
	Total trading account assets	3,680,427			3,267,024			411,967		1,436
	Loans held for sale	198,488			—			198,488		—
	Investment securities available for sale:
	U.S. Treasury and other U.S. government agencies	2,536,770			1,367,699			1,169,071		—
	Mortgage-backed securities	4,187,487			—			4,187,487		—
	Collateralized mortgage obligations	2,445,069			—			2,445,069		—
	States and political subdivisions	416,042			—			416,042		—
	Other debt securities	17,767			17,767			—		—
	Equity securities (1)	126			46			—		80
	Total investment securities available for sale	9,603,261			1,385,512			8,217,669		80
	Derivative assets:
	Interest rate contracts	90,686			—			85,698		4,988
	Equity contracts	70,199			—			70,199		—
	Foreign exchange contracts	8,957			—			8,957		—
	Total derivative assets	169,842			—			164,854		4,988
	Other assets	35,213			—			—		35,213
	Liabilities:
	Trading account liabilities:
	U.S. Treasury and other U.S. government agencies	$	3,368,354		$	3,368,354		$	—	$	—
Interest rate contracts	310,602			—			310,602		—
Commodity contracts	21,471			—			21,471		—
Foreign exchange contracts	13,883			—			13,883		—
Other debt securities	7,756			—			7,756		—
Other trading liabilities	1,584			—			1,584		—
Total trading account liabilities	3,723,650			3,368,354			355,296		—
Derivative liabilities:
Interest rate contracts	16,903			—			16,902		1
Equity contracts	67,959			—			67,959		—
Foreign exchange contracts	929			—			929		—
Total derivative liabilities	85,791			—			85,790		1
-1	Excludes $499 million of FHLB and Federal Reserve stock required to be owned by the Company at March 31, 2015. These securities are carried at par.
				Fair Value Measurements at the End of the Reporting Period Using
	Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs
	December 31, 2014			(Level 1)			(Level 2)		(Level 3)
	(In Thousands)
Recurring fair value measurements
Assets:
Trading account assets:
U.S. Treasury and other U.S. government agencies	$	2,502,308		$	2,502,308		$	—	$	—
Interest rate contracts	296,239			—			296,239		—
Commodity contracts	25,569			—			25,569		—
Foreign exchange contracts	8,268			—			8,268		—
Other trading assets	2,013			—			423		1,590
Total trading account assets	2,834,397			2,502,308			330,499		1,590
Loans held for sale	154,816			—			154,816		—
Investment securities available for sale:
U.S. Treasury and other U.S. government agencies	2,313,542			1,298,040			1,015,502		—
Mortgage-backed securities	4,423,835			—			4,423,835		—
Collateralized mortgage obligations	2,488,579			—			2,488,579		—
States and political subdivisions	467,315			—			467,315		—
Other debt securities	44,441			44,441			—		—
Equity securities (1)	48			44			—		4
Total investment securities available for sale	9,737,760			1,342,525			8,395,231		4
Derivative assets:
Interest rate contracts	73,830			—			71,511		2,319
Equity contracts	76,487			—			76,487		—
Foreign exchange contracts	5,570			—			5,570		—
Total derivative assets	155,887			—			153,568		2,319
Other assets	35,488			—			—		35,488
Liabilities:
Trading account liabilities:
U.S. Treasury and other U.S. government agencies	$	2,545,299		$	2,545,299		$	—	$	—
Interest rate contracts	236,763			—			236,763		—
Commodity contracts	25,448			—			25,448		—
Foreign exchange contracts	7,527			—			7,527		—
Other trading liabilities	425			—			425		—
Total trading account liabilities	2,815,462			2,545,299			270,163		—
Derivative liabilities:
Interest rate contracts	16,074			—			16,073		1
Equity contracts	74,319			—			74,319		—
Foreign exchange contracts	692			—			692		—
Total derivative liabilities	91,085			—			91,084		1
-1	Excludes $500 million of FHLB and Federal Reserve stock required to be owned by the Company at December 31, 2014. These securities are carried at par.
There were no transfers between Levels 1 or 2 of the fair value hierarchy for the three months ended March 31, 2015 and 2014. It is the Company’s policy to value any transfers between levels of the fair value hierarchy based on end of period fair values.
The following table reconciles the assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3).
	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Three Months Ended March 31,	Other Trading Assets			Equity Securities			Interest Rate Contracts, net		Other Assets
	(In Thousands)
Balance, January 1, 2014	$	1,645		$	6		$	890	$	30,065
Transfers into Level 3	—			—			—		—
Transfers out of Level 3	—			—			—		—
Total gains or losses (realized/unrealized):
Included in earnings (1)	47			—			792		(320		)
Included in other comprehensive income	—			—			—		—
Purchases, issuances, sales and settlements:
Purchases	—			—			—		—
Issuances	—			—			—		2,083
Sales	—			—			—		—
Settlements	—			—			—		—
Balance, March 31, 2014	$	1,692		$	6		$	1,682	$	31,828
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at March 31, 2014	$	47		$	—		$	792	$	(320	)
Balance, January 1, 2015	$	1,590		$	4		$	2,318	$	35,488
Transfers into Level 3	—			—			—		—
Transfers out of Level 3	—			—			—		—
Total gains or losses (realized/unrealized):
Included in earnings (1)	(154		)	—			2,669		(3,034		)
Included in other comprehensive income	—			—			—		—
Purchases, issuances, sales and settlements:
Purchases	—			76			—		—
Issuances	—			—			—		2,759
Sales	—			—			—		—
Settlements	—			—			—		—
Balance, March 31, 2015	$	1,436		$	80		$	4,987	$	35,213
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at March 31, 2015	$	(154	)	$	—		$	2,669	$	(3,034	)
-1	Included in noninterest income in the Unaudited Condensed Consolidated Statements of Income.
Assets Measured at Fair Value on a Nonrecurring Basis
Periodically, certain assets may be recorded at fair value on a non-recurring basis. These adjustments to fair value usually result from the application of lower of cost or fair value accounting or write-downs of individual assets due to impairment. The following table represents those assets that were subject to fair value adjustments during the three months ended March 31, 2015 and 2014 and still held as of the end of the period, and the related gains and losses from fair value adjustments on assets sold during the period as well as assets still held as of the end of the period.
				Fair Value Measurements at the End of the Reporting Period Using
	Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs			Total Gains (Losses)
	March 31, 2015			(Level 1)			(Level 2)		(Level 3)			Three Months Ended March 31, 2015
	(In Thousands)
Nonrecurring fair value measurements
Assets:
Investment securities held to maturity	$	3,205		$	—		$	—	$	3,205		$	(285	)
Impaired loans (1)	132,336			—			—		132,336			(3,304		)
OREO	17,764			—			—		17,764			(1,259		)
				Fair Value Measurements at the End of the Reporting Period Using
	Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs			Total Gains (Losses)
	March 31, 2014			(Level 1)			(Level 2)		(Level 3)			Three Months Ended March 31, 2014
	(In Thousands)
Nonrecurring fair value measurements
Assets:
Investment securities held to maturity	$	3,462		$	—		$	—	$	3,462		$	(146	)
Impaired loans (1)	169,546			—			—		169,546			(4,344		)
OREO	25,817			—			—		25,817			577
-1	Total gains (losses) represent charge-offs on impaired loans for which adjustments are based on the appraised value of the collateral.
The following is a description of the methodologies applied for valuing these assets:
Investment securities held to maturity – Nonrecurring fair value adjustments on investment securities held to maturity reflect impairment write-downs which the Company believes are other than temporary. For analyzing these securities, the Company has retained a third party valuation firm. Impairment is determined through the use of cash flow models that estimate cash flows on the underlying mortgages using security-specific collateral and the transaction structure. The cash flow models incorporate the remaining cash flows which are adjusted for future expected credit losses. Future expected credit losses are determined by using various assumptions such as current default rates, prepayment rates, and loss severities. The Company develops these assumptions through the use of market data published by third party sources in addition to historical analysis which includes actual delinquency and default information through the current period. The expected cash flows are then discounted at the interest rate used to recognize interest income on the security to arrive at a present value amount. As the fair value measurements are derived using a discounted cash flow modeling approach, the nonrecurring fair value measurements are classified as Level 3.
Impaired Loans – Impaired loans measured at fair value on a non-recurring basis represent the carrying value of impaired loans for which adjustments are based on the appraised value of the collateral. Nonrecurring fair value adjustments to impaired loans reflect full or partial write-downs that are generally based on the fair value of the underlying collateral supporting the loan. Loans subjected to nonrecurring fair value measurements based on the current estimated fair value of the collateral are classified as Level 3.
OREO – OREO is recorded on the Company's Unaudited Condensed Consolidated Balance Sheets at the lower of recorded balance or fair value, which is based on appraisals and third-party price opinions, less estimated costs to sell. The fair value is classified as Level 3.
The table below presents quantitative information about the significant unobservable inputs for material assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring and nonrecurring basis.
				Quantitative Information about Level 3 Fair Value Measurements
	Fair Value at						Range of Unobservable Inputs
	March 31, 2015			Valuation Technique		Unobservable Input(s)	(Weighted Average)
	(In Thousands)
Recurring fair value measurements:
Other trading assets	$	1,436		Discounted cash flow		Default rate	8.90%
						Prepayment rate	5.4% - 9.8% (7.3%)
Interest rate contracts	4,987			Discounted cash flow		Closing ratios (pull-through)	6.4% - 98.7% (59.6%)
						Cap grids	0.3% - 2.5% (1.1%)
Other assets - MSRs	35,213			Discounted cash flow		Discount rate	10.0% - 11.0% (10.1%)
						Constant prepayment rate or life speed	6.1% - 49.5% (11.2%)
						Cost to service	$57 - $566 ($67)
Nonrecurring fair value measurements:
Investment securities held to maturity	$	3,205		Discounted cash flow		Prepayment rate	9.60%
						Default rate	7.50%
						Loss severity	61.20%
Impaired loans	132,336			Appraised value		Appraised value	0.0% - 100.0% (26.8%)
OREO	17,764			Appraised value		Appraised value	8.00%
The following provides a description of the sensitivity of the valuation technique to changes in unobservable inputs for recurring fair value measurements.
Recurring Fair Value Measurements Using Significant Unobservable Inputs
Other Trading Assets – Interest-Only Strips
Significant unobservable inputs used in the valuation of the Company’s interest-only strips include default rates and prepayment assumptions. Significant increases in either of these inputs in isolation would result in significantly lower fair value measurements. Generally, a change in the assumption used for the probability of default is accompanied by a directionally opposite change in the assumption used for prepayment rates.
Interest Rate Contracts - Interest Rate Lock Commitments
Significant unobservable inputs used in the valuation of interest rate lock commitments are pull-through and cap grids. Increases or decreases in the pull-through or cap grids will have a corresponding impact in the value of interest rate contracts.
Other Assets - MSRs
The significant unobservable inputs used in the fair value measurement of MSRs are discount rates, constant prepayment rate or life speed, and cost to service assumptions. The impact of prepayments and changes in the discount rate are based on a variety of underlying inputs. Increases or decreases to the underlying cash flow inputs will have a corresponding impact on the value of the MSR asset. The impact of the costs to service assumption will have a directionally opposite change in the fair value of the MSR asset.
Fair Value of Financial Instruments
The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments, excluding financial instruments measured at fair value on a recurring basis, are as follows:
	March 31, 2015
	Carrying Amount			Estimated Fair Value			Level 1		Level 2			Level 3
	(In Thousands)
Financial Instruments:
Assets:
Cash and cash equivalents	$	3,964,357		$	3,964,357		$	3,964,357	$	—		$	—
Investment securities held to maturity	1,373,542			1,297,565			—		—			1,297,565
Loans, net	57,856,599			55,263,025			—		—			55,263,025
Liabilities:
Deposits	$	62,900,681		$	63,012,674		$	—	$	63,012,674		$	—
FHLB and other borrowings	4,919,141			4,925,458			—		4,925,458			—
Federal funds purchased and securities sold under agreements to repurchase	909,683			909,683			—		909,683			—
	December 31, 2014
	Carrying Amount			Estimated Fair Value			Level 1		Level 2			Level 3
	(In Thousands)
Financial Instruments:
Assets:
Cash and cash equivalents	$	3,388,405		$	3,388,405		$	3,388,405	$	—		$	—
Investment securities held to maturity	1,348,354			1,275,963			—		—			1,275,963
Loans, net	56,686,743			54,551,442			—		—			54,551,442
Liabilities:
Deposits	$	61,189,716		$	61,263,812		$	—	$	61,263,812		$	—
FHLB and other borrowings	4,809,843			4,786,152			—		4,786,152			—
Federal funds purchased and securities sold under agreements to repurchase	1,129,503			1,129,503			—		1,129,503			—
The following methods and assumptions were used by the Company in estimating the fair value of its financial instruments not carried at fair value:
Cash and cash equivalents: Cash and cash equivalents have maturities of three months or less. Accordingly, the carrying amount approximates fair value. Because these amounts generally relate to either currency or highly liquid assets, these are considered a Level 1 measurement.
Investment securities held to maturity: The fair values of securities held to maturity are estimated using a discounted cash flow approach. The discounted cash flow model uses inputs such as estimated prepayment speed, loss rates, and default rates. They are considered a Level 3 measurement as the valuation employs significant unobservable inputs.
Loans: Loans are presented net of the allowance for loan losses and are valued using discounted cash flows. The discount rates used to determine the present value of these loans are based on current market interest rates for loans with similar credit risk and term. They are considered a Level 3 measurement as the valuation employs significant unobservable inputs.
Deposits: The fair values of demand deposits are equal to the carrying amounts. Demand deposits include noninterest bearing demand deposits, savings accounts, NOW accounts and money market demand accounts. Discounted cash flows have been used to value fixed rate term deposits. The discount rate used is based on interest rates currently being offered by the Company on comparable deposits as to amount and term. They are considered a Level 2 measurement as the valuation primarily employs observable inputs for similar instruments.
Federal funds purchased and securities sold under agreements to repurchase: The carrying amounts of federal funds purchased and securities sold under agreements to repurchase approximate fair value. They are therefore considered a Level 2 measurement.
FHLB and other borrowings: The fair value of the Company’s fixed rate borrowings, which includes the Company’s Capital Securities, are estimated using discounted cash flows, based on the Company’s current incremental borrowing rates for similar types of borrowing arrangements. The carrying amount of the Company’s variable rate borrowings approximates fair value. As such, these borrowings are considered a Level 2 measurement as the valuation primarily employs observable inputs for similar instruments.

Comprehensive_Income

Comprehensive Income	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Comprehensive Income	Comprehensive Income
	Comprehensive income is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances arising from nonowner sources. The following summarizes the change in the components of other comprehensive income (loss).
		Three Months Ended March 31,
		2015											2014
		Pretax				Tax Expense/ (Benefit)				After-tax			Pretax			Tax Expense/ (Benefit)			After-tax
		(In Thousands)
	Other comprehensive income:
	Unrealized holding gains arising during period from securities available for sale	$	64,790			$	28,202			$	36,588		$	40,962		$	14,722		$	26,240
	Less: reclassification adjustment for net gains on sale of securities in net income	32,832				14,292				18,540			16,434			5,908			10,526
	Net change in unrealized gains on securities available for sale	31,958				13,910				18,048			24,528			8,814			15,714
	Change in unamortized net holding losses on investment securities held to maturity	3,142				1,368				1,774			4,774			1,716			3,058
	Less: non-credit related impairment on investment securities held to maturity	87				38				49			235			84			151
	Change in unamortized non-credit related impairment on investment securities held to maturity	276				120				156			385			139			246
	Net change in unamortized holding losses on securities held to maturity	3,331				1,450				1,881			4,924			1,771			3,153
	Unrealized holding gains (losses) arising during period from cash flow hedge instruments	3,646				1,587				2,059			(1,261		)	(454		)	(807		)
	Change in defined benefit plans	2,716				1,001				1,715			(2,672		)	(1,001		)	(1,671		)
	Other comprehensive income	$	41,651			$	17,948			$	23,703		$	25,519		$	9,130		$	16,389
	Activity in accumulated other comprehensive income (loss), net of tax was as follows:
		Unrealized Gains (Losses) on Securities Available for Sale and Transferred to Held to Maturity				Accumulated Gains (Losses) on Cash Flow Hedging Instruments				Defined Benefit Plan Adjustment			Unamortized Impairment Losses on Investment Securities Held to Maturity			Total
		(In Thousands)
	Balance, January 1, 2014	$	(31,490	)		$	(5,289	)		$	(41,921	)	$	(9,236	)	$	(87,936	)
	Other comprehensive income (loss) before reclassifications	26,240				(1,553		)		—			(151		)	24,536
	Amounts reclassified from accumulated other comprehensive income (loss)	(7,468		)		746				(1,671		)	246			(8,147		)
	Net current period other comprehensive income (loss)	18,772				(807		)		(1,671		)	95			16,389
	Balance, March 31, 2014	$	(12,718	)		$	(6,096	)		$	(43,592	)	$	(9,141	)	$	(71,547	)
	Balance, January 1, 2015	$	4,469			$	(7,189	)		$	(41,121	)	$	(7,516	)	$	(51,357	)
	Other comprehensive income (loss) before reclassifications	36,588				2,650				—			(49		)	39,189
	Amounts reclassified from accumulated other comprehensive income (loss)	(16,766		)		(591		)		1,715			156			(15,486		)
	Net current period other comprehensive income	19,822				2,059				1,715			107			23,703
	Balance, March 31, 2015	$	24,291			$	(5,130	)		$	(39,406	)	$	(7,409	)	$	(27,654	)
	The following table presents information on reclassifications out of accumulated other comprehensive income.
	Details About Accumulated Other Comprehensive Income Components		Amounts Reclassified From Accumulated Other Comprehensive Income (1)								Condensed Consolidated Statement of Income Caption
			Three Months Ended March 31,
			2015				2014
			(In Thousands)
	Unrealized Gains on Securities Available for Sale and Transferred to Held to Maturity		$	32,832			$	16,434			Investment securities gains, net
			(3,142		)		(4,774		)		Interest on investment securities held to maturity
			29,690				11,660
			(12,924		)		(4,192		)		Income tax expense
			$	16,766			$	7,468			Net of tax
	Accumulated (Gains) Losses on Cash Flow Hedging Instruments		$	2,813			$	612			Interest and fees on loans
			(1,766		)		(1,775		)		Interest and fees on FHLB advances
			1,047				(1,163		)
			(456		)		417				Income tax (expense) benefit
			$	591			$	(746	)		Net of tax
	Defined Benefit Plan Adjustment		$	(2,716	)		$	2,672			-2
			1,001				(1,001		)		Income tax (expense) benefit
			$	(1,715	)		$	1,671			Net of tax
	Unamortized Impairment Losses on Investment Securities Held to Maturity		$	(276	)		$	(385	)		Interest on investment securities held to maturity
			120				139				Income tax benefit
			$	(156	)		$	(246	)		Net of tax
	-1	Amounts in parentheses indicate debits to the consolidated statement of income.
	-2	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 18, Benefit Plans, in the Notes to the December 31, 2014, Consolidated Financial Statements for additional details).

Supplemental_Disclosure_for_St

Supplemental Disclosure for Statement of Cash Flows	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosure for Statement of Cash Flows	Supplemental Disclosure for Statement of Cash Flows
	The following table presents the Company’s supplemental disclosures for statement of cash flows.
		Three Months Ended March 31,
		2015		2014
		(In Thousands)
	Supplemental disclosures of cash flow information:
	Interest paid	$	90,984	$	55,675
	Net income taxes paid (refunded)	2,212		(708		)
	Supplemental schedule of noncash investing and financing activities:
	Transfer of loans and loans held for sale to OREO	$	2,718	$	8,920
	Change in unrealized gain (loss) on available for sale securities	31,958		24,528
	Issuance of restricted stock, net of cancellations	458		(547		)
	Business combinations:
	Assets acquired	—		116,152
	Liabilities assumed	—		18,329

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information
	The Company’s operating segments are based on the Company’s organizational structure. Each segment reflects the manner in which financial information is evaluated by management. The operating segment results include certain overhead allocations and intercompany transactions. All intercompany transactions have been eliminated to determine the consolidated balances. The Company operates primarily in the United States, and, accordingly, revenue and assets outside the United States are not material. There are no individual customers whose revenues exceeded 10% of consolidated revenue.
	During the first quarter of 2015, the Company reorganized its internal management structure and, accordingly, its segment reporting structure. As a result of this reorganization, the Wealth and Retail and Commercial operating segments were combined into one operating segment, Consumer and Commercial Banking. Prior periods' information has been restated to conform to the current periods' presentation. The Company's operating segments now consist of Consumer and Commercial Banking, Corporate and Investment Banking, and Treasury.
	The Consumer and Commercial Banking segment serves both the Company’s consumer customers through its full-service banking centers, private client offices throughout the U.S., and through the use of alternative delivery channels such as the internet, mobile devices and telephone banking. It also serves its commercial customers through its full array of banking and investment services to businesses in the Company’s markets. The Consumer and Commercial Banking segment provides individuals with comprehensive products and services including home mortgages, credit and debit cards, deposit accounts, insurance products, mutual funds and brokerage services. The segment also provides private banking and wealth management services to high net worth individuals, including specialized investment portfolio management, traditional credit products, traditional trust and estate services, investment advisory services, financial counseling and customized services to companies and their employees. In addition to traditional credit and deposit products, the Consumer and Commercial Banking segment also supports its commercial customers with capabilities in treasury management, leasing, accounts receivable purchasing, asset-based lending, international services, and insurance and interest rate protection and investment products. The Consumer and Commercial Banking segment is additionally responsible for the Company's small business customers and indirect automobile portfolio.
	The Corporate and Investment Banking segment is responsible for providing a full array of banking and investment services to corporate and institutional clients. In addition to traditional credit and deposit products, the Corporate and Investment Banking segment also supports its customers with capabilities in treasury management, leasing, accounts receivable purchasing, asset-based lending, foreign-exchange and international services, and interest rate protection and investment products.
	The Treasury segment’s primary function is to manage the liquidity and funding positions of the Company, the interest rate sensitivity of the Company's balance sheet, and to manage the investment securities portfolio.
	Corporate Support and Other includes activities that are not directly attributable to the operating segments, such as, the activities of the Parent and corporate support functions that are not directly attributable to a strategic business segment, as well as the elimination of intercompany transactions. Corporate Support and Other also includes activities associated with assets and liabilities of Guaranty Bank acquired by the Company in 2009 and the related FDIC indemnification asset as well as the activities associated with Simple acquired by the Company in 2014.
	The following tables present the segment information for the Company’s segments.
		Three Months Ended March 31, 2015
		Consumer and Commercial Banking		Corporate and Investment Banking		Treasury		Corporate Support and Other			Consolidated
		(In Thousands)
	Net interest income (expense)	$	482,365	$	39,932	$	18,382	$	(31,650	)	$	509,029
	Allocated provision for loan losses	30,294		11,025		—		712			42,031
	Noninterest income	176,317		49,487		33,856		(10,390		)	249,270
	Noninterest expense	424,608		40,186		5,097		52,828			522,719
	Net income (loss) before income tax expense (benefit)	203,780		38,208		47,141		(95,580		)	193,549
	Income tax expense (benefit)	71,323		13,373		16,500		(49,414		)	51,782
	Net income (loss)	132,457		24,835		30,641		(46,166		)	141,767
	Less: net income attributable to noncontrolling interests	228		—		429		—			657
	Net income (loss) attributable to shareholder	$	132,229	$	24,835	$	30,212	$	(46,166	)	$	141,110
	Average assets	$	52,605,892	$	11,833,948	$	13,572,927	$	7,074,388		$	85,087,155
		Three Months Ended March 31, 2014
		Consumer and Commercial Banking		Corporate and Investment Banking		Treasury		Corporate Support and Other			Consolidated
		(In Thousands)
	Net interest income	$	453,867	$	32,077	$	4,625	$	4,730		$	495,299
	Allocated provision for loan losses	36,621		1,010		—		(365		)	37,266
	Noninterest income	174,257		47,235		22,013		(24,177		)	219,328
	Noninterest expense	429,925		31,214		3,640		54,088			518,867
	Net income (loss) before income tax expense (benefit)	161,578		47,088		22,998		(73,170		)	158,494
	Income tax expense (benefit)	60,188		17,540		8,567		(42,728		)	43,567
	Net income (loss)	101,390		29,548		14,431		(30,442		)	114,927
	Less: net income attributable to noncontrolling interests	17		—		436		—			453
	Net income (loss) attributable to shareholder	$	101,373	$	29,548	$	13,995	$	(30,442	)	$	114,474
	Average assets	$	47,781,589	$	6,418,599	$	12,334,277	$	6,824,679		$	73,359,144
	The financial information presented was derived from the internal profitability reporting system used by management to monitor and manage the financial performance of the Company. This information is based on internal management accounting policies that have been developed to reflect the underlying economics of the businesses. These policies address the methodologies applied and include policies related to funds transfer pricing, cost allocations and capital allocations.
	Funds transfer pricing was used in the determination of net interest income earned primarily on loans and deposits. The method employed for funds transfer pricing is a matched funding concept whereby lines of business which are fund providers are credited and those that are fund users are charged based on maturity, prepayment and/or repricing characteristics applied on an instrument level. Costs for centrally managed operations are generally allocated to the lines of business based on the utilization of services provided or other appropriate indicators. Capital is allocated to the lines of business based upon the underlying risks in each business taking into account economic and regulatory capital standards.
	The development and application of these methodologies is a dynamic process. Accordingly, prior period financials have been revised to reflect management accounting enhancements and changes in the Company's organizational structure. The 2014 segment information has been revised to conform to the 2015 presentation. In addition, unlike financial accounting, there is no authoritative literature for management accounting similar to U.S. GAAP. Consequently, reported results are not necessarily comparable to those presented by other financial institutions.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	The Company enters into various contracts with BBVA that affect the Company’s business and operations. The following discloses the significant transactions between the Company and BBVA during 2015 and 2014.
	The Company believes all of the transactions entered into between the Company and BBVA were transacted on terms that were no more or less beneficial to the Company than similar transactions entered into with unrelated market participants, including interest rates and transaction costs. The Company foresees executing similar transactions with BBVA in the future.
	Derivatives
	The Company has entered into various derivative contracts as noted below with BBVA as the upstream counterparty. The net fair value of outstanding derivative contracts between the Company and BBVA are detailed below.
		March 31, 2015			December 31, 2014
		(In Thousands)
	Derivative contracts:
	Cash flow hedges	$	1,164		$	1,693
	Free-standing derivatives not designated as hedging instruments	(10,055		)	9,512
	Securities Purchased Under Agreements to Resell/ Securities Sold Under Agreements to Repurchase
	The Company enters into agreements with BBVA as the counterparty under which it purchases/sells securities subject to an obligation to resell/repurchase the same or similar securities. The following represents the amount of securities purchased under agreement to resell and securities sold under agreement to repurchase where BBVA is the counterparty.
		March 31, 2015			December 31, 2014
		(In Thousands)
	Securities purchased under agreements to resell	$	—		$	97,970
	Securities sold under agreements to repurchase	212			435,684
	Borrowings
	BSI, a wholly owned subsidiary of the Company, has a $420 million revolving note and cash subordination agreement with BBVA that was executed on March 16, 2012 with a maturity date of March 16, 2018. BSI also has a $150 million line of credit with BBVA that was initiated on August 1, 2014. At March 31, 2015 and December 31, 2014, there were no amounts outstanding under either of these agreements.

Subsequent_Event

Subsequent Event	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events
	On April 10, 2015, the Bank closed the sale of $700 million aggregate principal amount of its 3.875% unsecured subordinated notes due 2025. The notes were offered in connection with a Global Bank Note Program under which the Bank may from time to time issue senior notes due seven days or more from the date of issue and subordinated notes due five years or more from the date of issue.

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Use of estimates	Use of Estimates in the Preparation of Financial Statements
	The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period, the most significant of which relate to the allowance for loan losses, goodwill impairment, fair value measurements and income taxes. Actual results could differ from those estimates.
Recently issued accounting standards	Recently Issued Accounting Standards
	Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure
	In January 2014, the FASB released ASU 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. The amendments in this ASU clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additionally, the amendments require interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure according to local requirements of the applicable jurisdiction. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The Company elected to adopt the amendments in this ASU using the prospective transition method. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company. See Note 3, Loans and Allowance for Loan Losses.
	Revenue from Contracts with Customers
	In May 2014, the FASB released ASU 2014-09, Revenue from Contracts with Customers. The core principle of this codified guidance requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides five steps to be analyzed to accomplish the core principle. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. Early application is not permitted. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.
	Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures
	In June 2014, the FASB issued ASU 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. The amendments in this ASU change the accounting for repurchase-to-maturity transactions to secured borrowing accounting. In addition, for repurchase financing arrangements, the amendments require separate accounting for a transfer of a financial asset executed contemporaneously with a repurchase agreement with the same counterparty, which will result in secured borrowing accounting for the repurchase agreement. The amendments in this ASU also require disclosures on transfers accounted for as sales in transactions that are economically similar to repurchase agreements, and provide increased transparency about the types of collateral pledged in repurchase agreements and similar transactions accounted for as secured borrowings. The accounting changes in this ASU and disclosures for certain transactions accounted for as a sale are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The disclosures for repurchase agreements, securities lending transactions, and repurchase-to-maturity transactions accounted for as secured borrowings is required to be presented for annual periods beginning after December 15, 2014 and for interim periods beginning after March 15, 2015. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company.
	Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure
	In August 2014, the FASB issued ASU 2014-14, Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure. The amendments in this ASU address the classification and measurement of foreclosed loans which were part of a government-sponsored loan guarantee program. If certain criteria are met, the loan should be derecognized and a separate other receivable should be recorded upon foreclosure at the amount of the loan balance expected to be recovered from the guarantor. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2014. The adoption of this standard did not have a material impact on the financial condition or results of operations of the Company.
	Consolidation
	In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis. The amendments in this ASU modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities, eliminate the presumption that a general partner should consolidate a limited partnership, affect the consolidation analysis of reporting entities that are involved with variable interest entities and provide a scope exception from consolidation guidance for reporting entities with interest in certain investment funds. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.
	Simplifying the Presentation of Debt Issuance Costs
	In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. To simplify presentation of debt issuance costs, the amendments in this ASU require debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.
	Customer's Accounting for Fees Paid in a Cloud Computing Arrangement
	In April 2015, the FASB issued ASU 2015-05, Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. The amendments in this ASU provide guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.
Derivatives	The Company has made an accounting policy decision to not offset derivative fair value amounts under master netting agreements.
Securities for repurchase and resale	Securities purchased under agreements to resell and securities sold under agreements to repurchase are governed by a MRA. Under the terms of the MRA, all transactions between the Company and the counterparty constitute a single business relationship such that in the event of default, the nondefaulting party is entitled to set off claims and apply property held by that party in respect of any transaction against obligations owed. Any payments, deliveries, or other transfers may be applied against each other and netted. These amounts are limited to the contract asset/liability balance, and accordingly, do not include excess collateral received or pledged. The Company offsets the assets and liabilities under netting arrangements for the balance sheet presentation of securities purchased under agreements to resell and securities sold under agreements to repurchase provided certain criteria are met that permit balance sheet netting.

Investment_Securities_Availabl1

Investment Securities Available for Sale and Investment Securities Held to Maturity (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Schedule of adjusted cost and approximate fair value of investment securities available for sale and investments held to maturity	The following table presents the adjusted cost and approximate fair value of investment securities available for sale and investment securities held to maturity.
		31-Mar-15
					Gross Unrealized
		Amortized Cost			Gains			Losses		Fair Value
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	2,521,508		$	25,318		$	10,056	$	2,536,770
	Mortgage-backed securities	4,155,135			53,876			21,524		4,187,487
	Collateralized mortgage obligations	2,423,466			25,813			4,210		2,445,069
	States and political subdivisions	408,115			8,124			197		416,042
	Other	17,430			356			19		17,767
	Equity securities	498,650			43			—		498,693
	Total	$	10,024,304		$	113,530		$	36,006	$	10,101,828
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	119,253		$	6,320		$	4,748	$	120,825
	Asset-backed securities	35,618			3,240			2,299		36,559
	States and political subdivisions	1,148,747			1,586			82,032		1,068,301
	Other	69,924			4,120			2,164		71,880
	Total	$	1,373,542		$	15,266		$	91,243	$	1,297,565
		31-Dec-14
					Gross Unrealized
		Amortized Cost			Gains			Losses		Fair Value
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	2,312,572		$	10,360		$	9,390	$	2,313,542
	Mortgage-backed securities	4,399,706			64,371			40,242		4,423,835
	Collateralized mortgage obligations	2,475,115			19,385			5,921		2,488,579
	States and political subdivisions	460,569			8,008			1,262		467,315
	Other	44,225			238			22		44,441
	Equity securities	499,522			41			—		499,563
	Total	$	10,191,709		$	102,403		$	56,837	$	10,237,275
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	124,051		$	5,878		$	5,452	$	124,477
	Asset-backed securities	39,187			3,568			2,011		40,744
	States and political subdivisions	1,112,415			2,143			79,246		1,035,312
	Other	72,701			4,920			2,191		75,430
	Total	$	1,348,354		$	16,509		$	88,900	$	1,275,963
Schedule of fair value and gross unrealized losses of available for sale and held to maturity securities that were in a loss position	The following table discloses the fair value and the gross unrealized losses of the Company’s available for sale securities and held to maturity securities that were in a loss position at March 31, 2015 and December 31, 2014. This information is aggregated by investment category and the length of time the individual securities have been in an unrealized loss position.
		March 31, 2015
		Securities in a loss position for less than 12 months						Securities in a loss position for 12 months or longer				Total
		Fair Value			Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	752,519		$	8,600		$	91,136	$	1,456	$	843,655	$	10,056
	Mortgage-backed securities	380,594			1,042			1,701,752		20,482		2,082,346		21,524
	Collateralized mortgage obligations	633,205			3,513			91,229		697		724,434		4,210
	States and political subdivisions	43,797			197			—		—		43,797		197
	Other	—			—			1,103		19		1,103		19
	Total	$	1,810,115		$	13,352		$	1,885,220	$	22,654	$	3,695,335	$	36,006
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	23,045		$	349		$	46,293	$	4,399	$	69,338	$	4,748
	Asset-backed securities	—			—			21,297		2,299		21,297		2,299
	States and political subdivisions	75,204			4,903			812,731		77,129		887,935		82,032
	Other	3,953			2,164			—		—		3,953		2,164
	Total	$	102,202		$	7,416		$	880,321	$	83,827	$	982,523	$	91,243
		December 31, 2014
		Securities in a loss position for less than 12 months						Securities in a loss position for 12 months or longer				Total
		Fair Value			Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
		(In Thousands)
	Investment securities available for sale:
	Debt securities:
	U.S. Treasury and other U.S. government agencies	$	620,794		$	8,220		$	37,220	$	1,170	$	658,014	$	9,390
	Mortgage-backed securities	308,734			862			1,915,494		39,380		2,224,228		40,242
	Collateralized mortgage obligations	714,173			3,829			146,806		2,092		860,979		5,921
	States and political subdivisions	—			—			135,825		1,262		135,825		1,262
	Other	—			—			1,099		22		1,099		22
	Total	$	1,643,701		$	12,911		$	2,236,444	$	43,926	$	3,880,145	$	56,837
	Investment securities held to maturity:
	Collateralized mortgage obligations	$	34,400		$	1,099		$	27,389	$	4,353	$	61,789	$	5,452
	Asset-backed securities	—			—			23,374		2,011		23,374		2,011
	States and political subdivisions	21,688			768			817,570		78,478		839,258		79,246
	Other	4,061			2,191			—		—		4,061		2,191
	Total	$	60,149		$	4,058		$	868,333	$	84,842	$	928,482	$	88,900
Schedule of activity related to credit losses for debt securities where other than temporary impairments was recognized in other comprehensive income	The following table discloses activity related to credit losses for debt securities where a portion of the OTTI was recognized in other comprehensive income.
		Three Months Ended
		March 31,
		2015			2014
		(In Thousands)
	Balance at beginning of period	$	21,123		$	20,943
	Reductions for securities paid off during the period (realized)	—			—
	Additions for the credit component on debt securities in which OTTI was not previously recognized	—			—
	Additions for the credit component on debt securities in which OTTI was previously recognized	285			146
	Balance at end of period	$	21,408		$	21,089
Schedule of investments classified by contractual maturity date	The maturities of the securities portfolios are presented in the following table.
	March 31, 2015		Amortized Cost			Fair Value
			(In Thousands)
	Investment securities available for sale:
	Maturing within one year		$	48,475		$	48,860
	Maturing after one but within five years		688,061			701,812
	Maturing after five but within ten years		983,328			997,119
	Maturing after ten years		1,227,189			1,222,788
			2,947,053			2,970,579
	Mortgage-backed securities and collateralized mortgage obligations		6,578,601			6,632,556
	Equity securities		498,650			498,693
	Total		$	10,024,304		$	10,101,828
	Investment securities held to maturity:
	Maturing within one year		$	9,079		$	9,092
	Maturing after one but within five years		300,029			286,940
	Maturing after five but within ten years		182,574			176,641
	Maturing after ten years		762,607			704,067
			1,254,289			1,176,740
	Collateralized mortgage obligations		119,253			120,825
	Total		$	1,373,542		$	1,297,565
Schedule of realized gain (loss) on investments	The gross realized gains and losses recognized on sales of investment securities available for sale are shown in the table below.
		Three Months Ended March 31,
		2015			2014
		(In Thousands)
	Gross gains	$	32,832		$	16,434
	Gross losses	—			—
	Net realized gains	$	32,832		$	16,434

Loans_and_Allowance_for_Loan_L1

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Schedule of composition of loan portfolio	The following table presents the composition of the loan portfolio.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Commercial loans:
	Commercial, financial and agricultural	$	24,448,964			$	23,828,537
	Real estate – construction	2,325,495				2,154,652
	Commercial real estate – mortgage	9,920,583				9,877,206
	Total commercial loans	36,695,042				35,860,395
	Consumer loans:
	Residential real estate – mortgage	14,000,868				13,922,656
	Equity lines of credit	2,325,884				2,304,784
	Equity loans	635,295				634,968
	Credit card	600,030				630,456
	Consumer direct	707,251				652,927
	Consumer indirect	3,105,533				2,870,408
	Total consumer loans	21,374,861				21,016,199
	Covered loans	488,560				495,190
	Total loans	$	58,558,463			$	57,371,784
Schedule of purchased impaired loans	The following table presents the unpaid principal balance, discount, allowance for loan losses and carrying value of the Purchased Impaired Loans.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Unpaid principal balance	$	367,704			$	378,913
	Discount	(12,287		)		(17,341		)
	Allowance for loan losses	(727		)		(2,066		)
	Carrying value	$	354,690			$	359,506
Schedule of accretable yield on purchased impaired loans	An analysis of the accretable yield related to the Purchased Impaired Loans follows.
		Three Months Ended March 31,
		2015				2014
		(In Thousands)
	Balance at beginning of period	$	68,785			$	105,698
	Transfer to nonaccretable difference	(3,417		)		(8,162		)
	Accretion	(8,057		)		(16,172		)
	Other	—				—
	Balance at end of period	$	57,311			$	81,364
Schedule of purchased nonimpaired loans	The following table presents the unpaid principal balance, discount, allowance for loan losses, and carrying value of the Purchased Nonimpaired Loans.
		March 31, 2015				December 31, 2014
		(In Thousands)
	Unpaid principal balance	$	274,581			$	294,202
	Discount	(57,280		)		(88,962		)
	Allowance for loan losses	(2,115		)		(2,283		)
	Carrying value	$	215,186			$	202,957
Schedule of FDIC indemnification asset (liability)	A summary of the activity in the FDIC indemnification asset (liability) is presented in the following table.
		Three Months Ended March 31,
		2015				2014
		(In Thousands)
	Balance at beginning of period	$	(78,025	)		$	24,315
	Increase (decrease) due to credit loss provision (benefit) recorded on FDIC covered loans	(631		)		5,061
	Amortization and accretion, net	(27,898		)		(36,823		)
	Payments to (reimbursements from) FDIC for covered assets	(908		)		6,478
	Other	(260		)		144
	Balance at end of period	$	(107,722	)		$	(825	)
Disclosure of activity in allowance for loan losses during year	The following table, which excludes loans held for sale, presents a summary of the activity in the allowance for loan losses. The portion of the allowance that has not been identified by the Company as related to specific loan categories has been allocated to the individual loan categories on a pro rata basis for purposes of the table below:
		Commercial, Financial and Agricultural				Commercial Real Estate (1)				Residential Real Estate (2)				Consumer (3)			Covered			Total Loans
		(In Thousands)
	Three months ended March 31, 2015
	Allowance for loan losses:
	Beginning balance	$	299,482			$	138,233			$	154,627			$	89,891		$	2,808		$	685,041
	Provision (credit) for loan losses	28,352				(185		)		(6,439		)		20,770			(467		)	42,031
	Loans charged off	(6,619		)		(635		)		(6,754		)		(24,545		)	(873		)	(39,426		)
	Loan recoveries	2,182				1,858				3,513				6,665			—			14,218
	Net (charge-offs) recoveries	(4,437		)		1,223				(3,241		)		(17,880		)	(873		)	(25,208		)
	Ending balance	$	323,397			$	139,271			$	144,947			$	92,781		$	1,468		$	701,864
	Three months ended March 31, 2014
	Allowance for loan losses:
	Beginning balance	$	292,327			$	158,960			$	155,575			$	90,903		$	2,954		$	700,719
	Provision (credit) for loan losses	7,501				(4,722		)		12,673				16,829			4,985			37,266
	Loans charged off	(4,934		)		(2,646		)		(15,708		)		(21,704		)	(216		)	(45,208		)
	Loan recoveries	4,985				1,538				2,694				5,329			342			14,888
	Net (charge-offs) recoveries	51				(1,108		)		(13,014		)		(16,375		)	126			(30,320		)
	Ending balance	$	299,879			$	153,130			$	155,234			$	91,357		$	8,065		$	707,665
	-1	Includes commercial real estate – mortgage and real estate – construction loans.
	-2	Includes residential real estate – mortgage, equity lines of credit and equity loans.
	-3	Includes credit card, consumer direct and consumer indirect loans.
	The table below provides a summary of the allowance for loan losses and related loan balances by portfolio.
		Commercial, Financial and Agricultural				Commercial Real Estate (1)				Residential Real Estate (2)				Consumer (3)			Covered			Total Loans
		(In Thousands)
	March 31, 2015
	Ending balance of allowance attributable to loans:
	Individually evaluated for impairment	$	13,510			$	6,742			$	39,023			$	1,596		$	—		$	60,871
	Collectively evaluated for impairment	308,826				132,529				105,924				90,872			—			638,151
	Purchased impaired	—				—				—				—			727			727
	Purchased nonimpaired	1,061				—				—				313			741			2,115
	Total allowance for loan losses	$	323,397			$	139,271			$	144,947			$	92,781		$	1,468		$	701,864
	Loans:
	Ending balance of loans:
	Individually evaluated for impairment	$	81,606			$	92,480			$	190,447			$	3,004		$	—		$	367,537
	Collectively evaluated for impairment	24,328,772				12,114,814				16,770,610				4,404,012			—			57,618,208
	Purchased impaired	—				—				—				—			355,417			355,417
	Purchased nonimpaired	38,586				38,784				990				5,798			133,143			217,301
	Total loans	$	24,448,964			$	12,246,078			$	16,962,047			$	4,412,814		$	488,560		$	58,558,463
	December 31, 2014
	Ending balance of allowance attributable to loans:
	Individually evaluated for impairment	$	11,158			$	8,466			$	42,277			$	1,532		$	—		$	63,433
	Collectively evaluated for impairment	287,105				129,767				112,350				88,037			—			617,259
	Purchased impaired	—				—				—				—			2,066			2,066
	Purchased nonimpaired	1,219				—				—				322			742			2,283
	Total allowance for loan losses	$	299,482			$	138,233			$	154,627			$	89,891		$	2,808		$	685,041
	Loans:
	Ending balance of loans:
	Individually evaluated for impairment	$	48,173			$	105,608			$	195,462			$	1,827		$	—		$	351,070
	Collectively evaluated for impairment	23,745,149				11,896,943				16,665,930				4,145,880			—			56,453,902
	Purchased impaired	—				—				—				—			361,572			361,572
	Purchased nonimpaired	35,215				29,307				1,016				6,084			133,618			205,240
	Total loans	$	23,828,537			$	12,031,858			$	16,862,408			$	4,153,791		$	495,190		$	57,371,784
	-1	Includes commercial real estate – mortgage and real estate – construction loans.
	-2	Includes residential real estate – mortgage, equity lines of credit and equity loans.
	-3	Includes credit card, consumer direct and consumer indirect loans.
Schedule of impaired financing receivables	The following table presents information on individually evaluated impaired loans, by loan class.
		March 31, 2015
		Individually Evaluated Impaired Loans With No Recorded Allowance												Individually Evaluated Impaired Loans With a Recorded Allowance
		Recorded Investment				Unpaid Principal Balance				Allowance				Recorded Investment			Unpaid Principal Balance			Allowance
		(In Thousands)
	Commercial, financial and agricultural	$	6,377			$	13,575			$	—			$	75,229		$	79,360		$	13,510
	Real estate – construction	3,492				4,006				—				2,580			2,625			793
	Commercial real estate – mortgage	22,240				23,210				—				64,168			68,690			5,949
	Residential real estate – mortgage	6,886				6,886				—				105,079			105,162			7,188
	Equity lines of credit	—				—				—				26,718			27,124			23,675
	Equity loans	—				—				—				51,764			52,225			8,160
	Credit card	—				—				—				—			—			—
	Consumer direct	—				—				—				1,383			1,383			77
	Consumer indirect	—				—				—				1,621			1,621			1,519
	Total loans	$	38,995			$	47,677			$	—			$	328,542		$	338,190		$	60,871
		December 31, 2014
		Individually Evaluated Impaired Loans With No Recorded Allowance												Individually Evaluated Impaired Loans With a Recorded Allowance
		Recorded Investment				Unpaid Principal Balance				Allowance				Recorded Investment			Unpaid Principal Balance			Allowance
		(In Thousands)
	Commercial, financial and agricultural	$	—			$	—			$	—			$	48,173		$	61,552		$	11,158
	Real estate – construction	3,492				4,006				—				2,686			2,731			872
	Commercial real estate – mortgage	22,822				23,781				—				76,608			82,005			7,594
	Residential real estate – mortgage	8,795				8,795				—				107,223			107,306			9,236
	Equity lines of credit	—				—				—				25,743			26,124			23,394
	Equity loans	—				—				—				53,701			54,038			9,647
	Credit card	—				—				—				—			—			—
	Consumer direct	—				—				—				337			337			42
	Consumer indirect	—				—				—				1,490			1,490			1,490
	Total loans	$	35,109			$	36,582			$	—			$	315,961		$	335,583		$	63,433
	The following table presents information on individually evaluated impaired loans, by loan class.
		Three Months Ended March 31, 2015								Three Months Ended March 31, 2014
		Average Recorded Investment				Interest Income Recognized				Average Recorded Investment				Interest Income Recognized
		(In Thousands)
	Commercial, financial and agricultural	$	64,881			$	339			$	126,821			$	245
	Real estate – construction	6,115				39				10,120				63
	Commercial real estate – mortgage	88,178				580				141,347				942
	Residential real estate – mortgage	113,926				695				114,965				719
	Equity lines of credit	26,658				283				23,403				250
	Equity loans	52,435				404				55,027				425
	Credit card	—				—				—				—
	Consumer direct	680				6				158				1
	Consumer indirect	1,544				—				1,265				1
	Total loans	$	354,417			$	2,346			$	473,106			$	2,646
Schedule of credit quality indicators associated with the Company's loans	The following tables, which exclude loans held for sale and covered loans, illustrate the credit quality indicators associated with the Company’s loans, by loan class.
		Commercial
		March 31, 2015
		Commercial, Financial and Agricultural				Real Estate - Construction				Commercial Real Estate - Mortgage
		(In Thousands)
	Noncovered loans:
	Pass	$	23,899,964			$	2,250,178			$	9,578,494
	Special Mention	285,158				62,033				194,696
	Substandard	222,535				13,261				130,061
	Doubtful	41,307				23				17,332
		$	24,448,964			$	2,325,495			$	9,920,583
		December 31, 2014
		Commercial, Financial and Agricultural				Real Estate - Construction				Commercial Real Estate - Mortgage
		(In Thousands)
	Noncovered loans:
	Pass	$	23,380,541			$	2,098,994			$	9,514,917
	Special Mention	280,934				42,176				210,337
	Substandard	128,251				13,458				129,435
	Doubtful	38,811				24				22,517
		$	23,828,537			$	2,154,652			$	9,877,206
		Consumer
		31-Mar-15
		Residential Real Estate – Mortgage				Equity Lines of Credit				Equity Loans				Credit Card			Consumer Direct			Consumer Indirect
		(In Thousands)
	Noncovered loans:
	Performing	$	13,890,173			$	2,289,292			$	616,266			$	591,412		$	702,815		$	3,098,855
	Nonperforming	110,695				36,592				19,029				8,618			4,436			6,678
		$	14,000,868			$	2,325,884			$	635,295			$	600,030		$	707,251		$	3,105,533
		December 31, 2014
		Residential Real Estate -Mortgage				Equity Lines of Credit				Equity Loans				Credit Card			Consumer Direct			Consumer Indirect
		(In Thousands)
	Noncovered loans:
	Performing	$	13,810,857			$	2,269,231			$	614,064			$	621,015		$	649,832		$	2,865,013
	Nonperforming	111,799				35,553				20,904				9,441			3,095			5,395
		$	13,922,656			$	2,304,784			$	634,968			$	630,456		$	652,927		$	2,870,408
Schedule of past due loans	The following tables present an aging analysis of the Company’s past due loans, excluding loans classified as held for sale.
		March 31, 2015
		30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Accruing TDRs			Total Past Due and Impaired			Not Past Due or Impaired		Total
		(In Thousands)
	Commercial, financial and agricultural	$	7,940			$	3,981			$	2,901			$	95,318		$	9,632		$	119,772		$	24,329,192	$	24,448,964
	Real estate – construction	5,275				450				392				7,781			2,237			16,135			2,309,360		2,325,495
	Commercial real estate – mortgage	6,346				3,629				2,542				87,931			35,292			135,740			9,784,843		9,920,583
	Residential real estate – mortgage	45,893				17,007				3,195				107,051			70,299			243,445			13,757,423		14,000,868
	Equity lines of credit	10,615				4,602				1,995				34,597			—			51,809			2,274,075		2,325,884
	Equity loans	5,387				1,728				703				18,313			40,432			66,563			568,732		635,295
	Credit card	5,004				3,441				8,618				—			—			17,063			582,967		600,030
	Consumer direct	7,545				2,406				2,426				2,010			180			14,567			692,684		707,251
	Consumer indirect	34,444				6,726				2,576				4,102			—			47,848			3,057,685		3,105,533
	Covered loans	6,582				3,872				45,402				179			—			56,035			432,525		488,560
	Total loans	$	135,031			$	47,842			$	70,750			$	357,282		$	158,072		$	768,977		$	57,789,486	$	58,558,463
		December 31, 2014
		30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Accruing TDRs			Total Past Due and Impaired			Not Past Due or Impaired		Total
		(In Thousands)
	Commercial, financial and agricultural	$	10,829			$	5,765			$	1,610			$	61,157		$	10,127		$	89,488		$	23,739,049	$	23,828,537
	Real estate – construction	1,954				994				477				7,964			2,112			13,501			2,141,151		2,154,652
	Commercial real estate – mortgage	9,813				4,808				628				89,736			39,841			144,826			9,732,380		9,877,206
	Residential real estate – mortgage	45,279				16,510				2,598				108,357			69,408			242,152			13,680,504		13,922,656
	Equity lines of credit	9,929				4,395				2,679				32,874			—			49,877			2,254,907		2,304,784
	Equity loans	6,357				3,268				997				19,029			41,197			70,848			564,120		634,968
	Credit card	5,692				3,921				9,441				—			—			19,054			611,402		630,456
	Consumer direct	9,542				1,826				2,296				799			298			14,761			638,166		652,927
	Consumer indirect	35,366				7,935				2,771				2,624			—			48,696			2,821,712		2,870,408
	Covered loans	6,678				4,618				47,957				114			—			59,367			435,823		495,190
	Total loans	$	141,439			$	54,040			$	71,454			$	322,654		$	162,983		$	752,570		$	56,619,214	$	57,371,784
Schedule of troubled debt restructuring loans	The following table provides a breakout of TDRs, including nonaccrual loans and covered loans and excluding loans classified as held for sale.
		March 31, 2015
		30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Total Past Due and Nonaccrual			Not Past Due or Nonaccrual			Total
		(In Thousands)
	Commercial, financial and agricultural	$	20			$	35			$	—			$	1,620		$	1,675		$	9,577		$	11,252
	Real estate – construction	—				—				—				142			142			2,237			2,379
	Commercial real estate – mortgage	—				—				358				6,226			6,584			34,934			41,518
	Residential real estate – mortgage	1,366				658				449				29,087			31,560			67,826			99,386
	Equity lines of credit	—				—				—				25,518			25,518			—			25,518
	Equity loans	1,662				975				13				11,328			13,978			37,782			51,760
	Credit card	—				—				—				—			—			—			—
	Consumer direct	—				—				—				34			34			180			214
	Consumer indirect	—				—				—				1,621			1,621			—			1,621
	Covered loans	—				—				—				8			8			—			8
	Total loans	$	3,048			$	1,668			$	820			$	75,584		$	81,120		$	152,536		$	233,656
		December 31, 2014
		30-59 Days Past Due				60-89 Days Past Due				90 Days or More Past Due				Nonaccrual			Total Past Due and Nonaccrual			Not Past Due or Nonaccrual			Total
		(In Thousands)
	Commercial, financial and agricultural	$	11			$	—			$	—			$	2,052		$	2,063		$	10,116		$	12,179
	Real estate – construction	—				—				—				200			200			2,112			2,312
	Commercial real estate – mortgage	371				536				—				7,068			7,975			38,934			46,909
	Residential real estate – mortgage	2,440				2,688				844				32,518			38,490			63,436			101,926
	Equity lines of credit	—				—				—				24,519			24,519			—			24,519
	Equity loans	2,182				1,124				878				12,504			16,688			37,013			53,701
	Credit card	—				—				—				—			—			—			—
	Consumer direct	105				—				—				40			145			193			338
	Consumer indirect	—				—				—				1,490			1,490			—			1,490
	Covered loans	—				—				—				17			17			—			17
	Total loans	$	5,109			$	4,348			$	1,722			$	80,408		$	91,587		$	151,804		$	243,391
	The following table presents an analysis of the types of loans that were restructured and classified as TDRs, excluding loans classified as held for sale.
		Three Months Ended March 31, 2015							Three Months Ended March 31, 2014
		Number of Contracts			Post-Modification Outstanding Recorded Investment				Number of Contracts			Post-Modification Outstanding Recorded Investment
		(Dollars in Thousands)
	Commercial, financial and agricultural	1			$	75			—			$	—
	Real estate – construction	—			—				—			—
	Commercial real estate – mortgage	—			—				6			3,930
	Residential real estate – mortgage	11			1,740				10			994
	Equity lines of credit	31			1,913				49			2,302
	Equity loans	14			718				18			1,987
	Credit card	—			—				—			—
	Consumer direct	—			—				—			—
	Consumer indirect	22			379				18			202
	Covered loans	1			5				—			—
Schedule of subsequent default on restructured loans	The following tables provide a summary of initial subsequent defaults that occurred within one year of the restructure date. The table excludes loans classified as held for sale as of period-end and includes loans no longer in default as of period-end.
		Three Months Ended March 31, 2015							Three Months Ended March 31, 2014
		Number of Contracts			Recorded Investment at Default				Number of Contracts			Recorded Investment at Default
		(Dollars in Thousands)
	Commercial, financial and agricultural	—			$	—			—			$	—
	Real estate – construction	—			—				—			—
	Commercial real estate – mortgage	1			178				—			—
	Residential real estate – mortgage	4			647				—			—
	Equity lines of credit	—			—				3			275
	Equity loans	2			161				1			63
	Credit card	—			—				—			—
	Consumer direct	—			—				—			—
	Consumer indirect	1			18				—			—
	Covered loans	—			—				—			—

Loan_Sales_and_Servicing_Table

Loan Sales and Servicing (Tables)	3 Months Ended
	Mar. 31, 2015
Transfers and Servicing [Abstract]
Schedule of residential real estate mortgage servicing rights	The following table is an analysis of the activity in the Company’s MSRs.
		Three Months Ended
		March 31,
		2015			2014
		(In Thousands)
	Carrying value, at beginning of period	$	35,488		$	30,065
	Additions	2,759			2,083
	Increase (decrease) in fair value:
	Due to changes in valuation inputs or assumptions	(2,592		)	291
	Due to other changes in fair value (1)	(442		)	(611		)
	Carrying value, at end of period	$	35,213		$	31,828
	-1	Represents the realization of expected net servicing cash flows, expected borrower repayments and the passage of time.
Schedule of sensitivity of current fair value of residential real estate mortgage servicing rights	At March 31, 2015 and December 31, 2014, the sensitivity of the current fair value of the residential MSRs to immediate 10% and 20% adverse changes in key economic assumptions are included in the following table:
		March 31, 2015			December 31, 2014
		(Dollars in Thousands)
	Fair value of MSRs	$	35,213		$	35,488
	Composition of residential loans serviced for others:
	Fixed rate mortgage loans	96		%	96.1		%
	Adjustable rate mortgage loans	4			3.9
	Total	100		%	100		%
	Weighted average life (in years)	6			6.2
	Prepayment speed:	11.2		%	10.6		%
	Effect on fair value of a 10% increase	$	(1,407	)	$	(1,220	)
	Effect on fair value of a 20% increase	(2,712		)	(2,375		)
	Weighted average discount rate:	10.1		%	10.1		%
	Effect on fair value of a 10% increase	$	(1,298	)	$	(1,291	)
	Effect on fair value of a 20% increase	(2,508		)	(2,492		)

Derivatives_and_Hedging_Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table reflects the notional amount and fair value of derivative instruments included on the Company’s Unaudited Condensed Consolidated Balance Sheets on a gross basis.
		March 31, 2015										December 31, 2014
						Fair Value								Fair Value
		Notional Amount				Derivative Assets (1)				Derivative Liabilities (2)		Notional Amount		Derivative Assets (1)		Derivative Liabilities (2)
		(In Thousands)
	Derivatives designated as hedging instruments:
	Fair value hedges:
	Interest rate swaps related to long-term debt	$	1,423,950			$	79,818			$	—	$	1,423,950	$	69,700	$	—
	Total fair value hedges					79,818				—				69,700		—
	Cash flow hedges:
	Interest rate contracts:
	Swaps related to commercial loans	1,800,000				5,807				—		1,100,000		1,793		1,023
	Swaps related to FHLB advances	320,000				—				14,871		320,000		—		13,474
	Total cash flow hedges					5,807				14,871				1,793		14,497
	Total derivatives designated as hedging instruments					$	85,625			$	14,871			$	71,493	$	14,497
	Free-standing derivatives not designated as hedging instruments:
	Interest rate contracts:
	Forward and option contracts related to held for sale mortgages	$	321,000			$	73			$	2,031	$	189,000	$	18	$	1,576
	Equity contracts:
	Purchased equity option related to equity-linked CDs	846,272				70,199				—		821,849		76,487		—
	Swap associated with sale of Visa, Inc. Class B shares	57,267				—				1,432		57,393		—		1,435
	Foreign exchange contracts:
	Forwards related to commercial loans	562,373				8,826				870		602,066		5,529		612
	Spots related to commercial loans	57,968				131				59		74,940		41		80
	Futures contracts (3)	683,000				—				—		342,000		—		—
	Interest rate lock commitments	294,685				4,988				1		180,822		2,319		1
	Written equity option related to equity-linked CDs	815,904				—				67,959		795,467		—		74,319
	Trading account assets and liabilities:
	Interest rate contracts for customers	20,758,720				369,042				310,602		18,678,390		296,239		236,763
	Commodity contracts for customers	235,099				21,568				21,471		264,491		25,569		25,448
	Foreign exchange contracts for customers	508,321				14,607				13,883		425,123		8,268		7,527
	Total trading account assets and liabilities					405,217				345,956				330,076		269,738
	Total free-standing derivative instruments not designated as hedging instruments					$	489,434			$	418,308			$	414,470	$	347,761
	-1	Derivative assets, except for trading account assets that are recorded as a component of trading account assets on the Company's Unaudited Condensed Consolidated Balance Sheets, are recorded in other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	-2	Derivative liabilities are recorded in accrued expenses and other liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheets.
	-3	Changes in fair value are cash settled daily; therefore, there is no ending balance at any given reporting period.
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following table reflects the change in fair value for interest rate contracts and the related hedged items as well as other gains and losses related to fair value hedges including gains and losses recognized because of hedge ineffectiveness.
				Gain (Loss) for the
		Condensed Consolidated		Three Months Ended March 31,
		Statements of Income Caption		2015				2014
				(In Thousands)
	Change in fair value of interest rate contracts:
	Interest rate swaps hedging long term debt	Interest on FHLB and other borrowings		$	10,118			$	(935	)
	Hedged long term debt	Interest on FHLB and other borrowings		(9,413		)		1,809
	Other gains on interest rate contracts:
	Interest and amortization related to interest rate swaps on hedged long term debt	Interest on FHLB and other borrowings		9,566				5,265
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The following table presents the effect of derivative instruments designated and qualifying as cash flow hedges on the Company’s Unaudited Condensed Consolidated Balance Sheets and the Company’s Unaudited Condensed Consolidated Statements of Income.
		Gain (Loss) for the
		Three Months Ended
		March 31,
		2015				2014
		(In Thousands)
	Interest rate contracts:
	Net change in amount recognized in other comprehensive income	$	2,059			$	807
	Amount reclassified from accumulated other comprehensive income into net interest income	1,047				(1,163		)
	Amount of ineffectiveness recognized in net interest income	—				—
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position	The net gains and losses recorded in the Company's Unaudited Condensed Consolidated Statements of Income from free-standing derivative instruments not designated as hedging instruments are summarized in the following table.
				Gain (Loss) for the
		Condensed Consolidated		Three Months Ended March 31,
		Statements of Income Caption		2015			2014
				(In Thousands)
	Futures contracts	Mortgage banking income		47			(76	)
		and corporate and correspondent investment sales
	Option contracts related to mortgage servicing rights	Mortgage banking income		(195	)		—
	Interest rate contracts:
	Forward and option contracts related to residential mortgage loans held for sale	Mortgage banking income		(400	)		(1,554	)
	Interest rate lock commitments	Mortgage banking income		2,669			792
	Interest rate contracts for customers	Corporate and correspondent investment sales		4,639			5,118
	Commodity contracts:
	Commodity contracts for customers	Corporate and correspondent investment sales		14			8
	Equity contracts:
	Purchased equity option related to equity-linked CDs	Other expense		(6,288	)		3,778
	Written equity option related to equity-linked CDs	Other expense		6,360			(3,679	)
	Foreign currency contracts:
	Forward contracts related to commercial loans	Other income		46,567			(5,487	)
	Spot contracts related to commercial loans	Other income		(6,895	)		880
	Foreign currency exchange contracts for customers	Corporate and correspondent investment sales		380			193

Assets_and_Liabilities_Subject1

Assets and Liabilities Subject to Enforceable Master Netting Arrangements (Tables)	3 Months Ended
	Mar. 31, 2015
Offsetting [Abstract]
Schedule of assets and liabilities subject to enforceable master netting arrangements	The following represents the Company’s assets/liabilities subject to an enforceable master netting arrangement. The derivative instruments the Company has with its customers are not subject to an enforceable master netting arrangement.
								Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets
		Gross Amounts Recognized		Gross Amounts Offset in the Condensed Consolidated Balance Sheets		Net Amount Presented in the Condensed Consolidated Balance Sheets		Financial Instruments (1)		Cash Collateral Received/ Pledged (1)		Net Amount
		(In Thousands)
	March 31, 2015
	Securities purchased under agreements to resell:
	Subject to a master netting arrangement	$	3,497,408	$	3,223,019	$	274,389	$	274,389	$	—	$	—
	Derivative financial assets:
	Subject to a master netting arrangement	$	245,285	$	—	$	245,285	$	—	$	49,064	$	196,221
	Not subject to a master netting arrangement	329,774		—		329,774		—		—		329,774
	Total derivative financial assets	$	575,059	$	—	$	575,059	$	—	$	49,064	$	525,995
	Securities sold under agreements to repurchase:
	Subject to a master netting arrangement	$	3,250,397	$	3,223,019	$	27,378	$	27,378	$	—	$	—
	Derivative financial liabilities:
	Subject to a master netting arrangement	$	335,349	$	—	$	335,349	$	27,453	$	55,574	$	252,322
	Not subject to a master netting arrangement	97,830		—		97,830		—		—		97,830
	Total derivative financial liabilities	$	433,179	$	—	$	433,179	$	27,453	$	55,574	$	350,152
	December 31, 2014
	Securities purchased under agreements to resell:
	Subject to a master netting arrangement	$	3,100,200	$	2,533,661	$	566,539	$	566,539	$	—	$	—
	Derivative financial assets:
	Subject to a master netting arrangement	$	225,227	$	—	$	225,227	$	—	$	58,309	$	166,918
	Not subject to a master netting arrangement	260,736		—		260,736		—		—		260,736
	Total derivative financial assets	$	485,963	$	—	$	485,963	$	—	$	58,309	$	427,654
	Securities sold under agreements to repurchase:
	Subject to a master netting arrangement	$	2,969,345	$	2,533,661	$	435,684	$	435,684	$	—	$	—
	Derivative financial liabilities:
	Subject to a master netting arrangement	$	259,018	$	—	$	259,018	$	29,677	$	44,163	$	185,178
	Not subject to a master netting arrangement	103,240		—		103,240		—		—		103,240
	Total derivative financial liabilities	$	362,258	$	—	$	362,258	$	29,677	$	44,163	$	288,418
	-1	The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists, the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.

Commitment_Contingencies_and_G

Commitment, Contingencies and Guarantees (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of commitments to extend credit, standby letters of credit and commercial letters of credit	The following represents the Company’s commitments to extend credit, standby letters of credit and commercial letters of credit:
		March 31, 2015		December 31, 2014
		(In Thousands)
	Commitments to extend credit	$	28,348,272	$	28,369,666
	Standby and commercial letters of credit	1,695,974		1,871,323

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of differences between aggregate fair value and aggregate unpaid principle balance	The following tables summarize the difference between the aggregate fair value and the aggregate unpaid principal balance for residential mortgage loans measured at fair value.
		Aggregate Fair Value			Aggregate Unpaid Principal Balance			Difference
		(In Thousands)
	March 31, 2015
	Residential mortgage loans held for sale	$	198,488		$	191,687		$	6,801
	December 31, 2014
	Residential mortgage loans held for sale	$	154,816		$	148,564		$	6,252
Summary of asset and liabilities measure at fair value on a recurring basis	The following tables summarize the financial assets and liabilities measured at fair value on a recurring basis.
					Fair Value Measurements at the End of the Reporting Period Using
		Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs
		March 31, 2015			(Level 1)			(Level 2)		(Level 3)
		(In Thousands)
	Recurring fair value measurements
	Assets:
	Trading account assets:
	U.S. Treasury and other U.S. government agencies	$	3,267,024		$	3,267,024		$	—	$	—
	State and political subdivisions	1,030			—			1,030		—
	Other debt securities	3,972			—			3,972		—
	Other equity securities	166			—			166		—
	Interest rate contracts	369,042			—			369,042		—
	Commodity contracts	21,568			—			21,568		—
	Foreign exchange contracts	14,607			—			14,607		—
	Other trading assets	3,018			—			1,582		1,436
	Total trading account assets	3,680,427			3,267,024			411,967		1,436
	Loans held for sale	198,488			—			198,488		—
	Investment securities available for sale:
	U.S. Treasury and other U.S. government agencies	2,536,770			1,367,699			1,169,071		—
	Mortgage-backed securities	4,187,487			—			4,187,487		—
	Collateralized mortgage obligations	2,445,069			—			2,445,069		—
	States and political subdivisions	416,042			—			416,042		—
	Other debt securities	17,767			17,767			—		—
	Equity securities (1)	126			46			—		80
	Total investment securities available for sale	9,603,261			1,385,512			8,217,669		80
	Derivative assets:
	Interest rate contracts	90,686			—			85,698		4,988
	Equity contracts	70,199			—			70,199		—
	Foreign exchange contracts	8,957			—			8,957		—
	Total derivative assets	169,842			—			164,854		4,988
	Other assets	35,213			—			—		35,213
	Liabilities:
	Trading account liabilities:
	U.S. Treasury and other U.S. government agencies	$	3,368,354		$	3,368,354		$	—	$	—
	Interest rate contracts	310,602			—			310,602		—
	Commodity contracts	21,471			—			21,471		—
	Foreign exchange contracts	13,883			—			13,883		—
	Other debt securities	7,756			—			7,756		—
	Other trading liabilities	1,584			—			1,584		—
	Total trading account liabilities	3,723,650			3,368,354			355,296		—
	Derivative liabilities:
	Interest rate contracts	16,903			—			16,902		1
	Equity contracts	67,959			—			67,959		—
	Foreign exchange contracts	929			—			929		—
	Total derivative liabilities	85,791			—			85,790		1
	-1	Excludes $499 million of FHLB and Federal Reserve stock required to be owned by the Company at March 31, 2015. These securities are carried at par.
					Fair Value Measurements at the End of the Reporting Period Using
		Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs
		December 31, 2014			(Level 1)			(Level 2)		(Level 3)
		(In Thousands)
	Recurring fair value measurements
	Assets:
	Trading account assets:
	U.S. Treasury and other U.S. government agencies	$	2,502,308		$	2,502,308		$	—	$	—
	Interest rate contracts	296,239			—			296,239		—
	Commodity contracts	25,569			—			25,569		—
	Foreign exchange contracts	8,268			—			8,268		—
	Other trading assets	2,013			—			423		1,590
	Total trading account assets	2,834,397			2,502,308			330,499		1,590
	Loans held for sale	154,816			—			154,816		—
	Investment securities available for sale:
	U.S. Treasury and other U.S. government agencies	2,313,542			1,298,040			1,015,502		—
	Mortgage-backed securities	4,423,835			—			4,423,835		—
Collateralized mortgage obligations	2,488,579			—			2,488,579		—
States and political subdivisions	467,315			—			467,315		—
Other debt securities	44,441			44,441			—		—
Equity securities (1)	48			44			—		4
Total investment securities available for sale	9,737,760			1,342,525			8,395,231		4
Derivative assets:
Interest rate contracts	73,830			—			71,511		2,319
Equity contracts	76,487			—			76,487		—
Foreign exchange contracts	5,570			—			5,570		—
Total derivative assets	155,887			—			153,568		2,319
Other assets	35,488			—			—		35,488
Liabilities:
Trading account liabilities:
U.S. Treasury and other U.S. government agencies	$	2,545,299		$	2,545,299		$	—	$	—
Interest rate contracts	236,763			—			236,763		—
Commodity contracts	25,448			—			25,448		—
Foreign exchange contracts	7,527			—			7,527		—
Other trading liabilities	425			—			425		—
Total trading account liabilities	2,815,462			2,545,299			270,163		—
Derivative liabilities:
Interest rate contracts	16,074			—			16,073		1
Equity contracts	74,319			—			74,319		—
Foreign exchange contracts	692			—			692		—
Total derivative liabilities	91,085			—			91,084		1
-1	Excludes $500 million of FHLB and Federal Reserve stock required to be owned by the Company at December 31, 2014. These securities are carried at par.
Reconciliation of assets measured on a recurring basis using significant unobservable inputs	The following table reconciles the assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3).
		Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Three Months Ended March 31,	Other Trading Assets			Equity Securities			Interest Rate Contracts, net		Other Assets
		(In Thousands)
	Balance, January 1, 2014	$	1,645		$	6		$	890	$	30,065
	Transfers into Level 3	—			—			—		—
	Transfers out of Level 3	—			—			—		—
	Total gains or losses (realized/unrealized):
	Included in earnings (1)	47			—			792		(320		)
	Included in other comprehensive income	—			—			—		—
	Purchases, issuances, sales and settlements:
	Purchases	—			—			—		—
	Issuances	—			—			—		2,083
	Sales	—			—			—		—
	Settlements	—			—			—		—
	Balance, March 31, 2014	$	1,692		$	6		$	1,682	$	31,828
	Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at March 31, 2014	$	47		$	—		$	792	$	(320	)
	Balance, January 1, 2015	$	1,590		$	4		$	2,318	$	35,488
	Transfers into Level 3	—			—			—		—
	Transfers out of Level 3	—			—			—		—
	Total gains or losses (realized/unrealized):
	Included in earnings (1)	(154		)	—			2,669		(3,034		)
	Included in other comprehensive income	—			—			—		—
	Purchases, issuances, sales and settlements:
	Purchases	—			76			—		—
	Issuances	—			—			—		2,759
	Sales	—			—			—		—
	Settlements	—			—			—		—
	Balance, March 31, 2015	$	1,436		$	80		$	4,987	$	35,213
	Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at March 31, 2015	$	(154	)	$	—		$	2,669	$	(3,034	)
	-1	Included in noninterest income in the Unaudited Condensed Consolidated Statements of Income.
Schedule of carrying amounts and estimated fair values within the fair value hierarchy	The following table represents those assets that were subject to fair value adjustments during the three months ended March 31, 2015 and 2014 and still held as of the end of the period, and the related gains and losses from fair value adjustments on assets sold during the period as well as assets still held as of the end of the period.
					Fair Value Measurements at the End of the Reporting Period Using
		Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs			Total Gains (Losses)
		March 31, 2015			(Level 1)			(Level 2)		(Level 3)			Three Months Ended March 31, 2015
		(In Thousands)
	Nonrecurring fair value measurements
	Assets:
	Investment securities held to maturity	$	3,205		$	—		$	—	$	3,205		$	(285	)
	Impaired loans (1)	132,336			—			—		132,336			(3,304		)
	OREO	17,764			—			—		17,764			(1,259		)
					Fair Value Measurements at the End of the Reporting Period Using
		Fair Value			Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs		Significant Unobservable Inputs			Total Gains (Losses)
		March 31, 2014			(Level 1)			(Level 2)		(Level 3)			Three Months Ended March 31, 2014
		(In Thousands)
	Nonrecurring fair value measurements
	Assets:
	Investment securities held to maturity	$	3,462		$	—		$	—	$	3,462		$	(146	)
	Impaired loans (1)	169,546			—			—		169,546			(4,344		)
	OREO	25,817			—			—		25,817			577
	-1	Total gains (losses) represent charge-offs on impaired loans for which adjustments are based on the appraised value of the collateral.
Schedule of fair value measurement inputs	The table below presents quantitative information about the significant unobservable inputs for material assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring and nonrecurring basis.
					Quantitative Information about Level 3 Fair Value Measurements
		Fair Value at						Range of Unobservable Inputs
		March 31, 2015			Valuation Technique		Unobservable Input(s)	(Weighted Average)
		(In Thousands)
	Recurring fair value measurements:
	Other trading assets	$	1,436		Discounted cash flow		Default rate	8.90%
							Prepayment rate	5.4% - 9.8% (7.3%)
	Interest rate contracts	4,987			Discounted cash flow		Closing ratios (pull-through)	6.4% - 98.7% (59.6%)
							Cap grids	0.3% - 2.5% (1.1%)
	Other assets - MSRs	35,213			Discounted cash flow		Discount rate	10.0% - 11.0% (10.1%)
							Constant prepayment rate or life speed	6.1% - 49.5% (11.2%)
							Cost to service	$57 - $566 ($67)
	Nonrecurring fair value measurements:
	Investment securities held to maturity	$	3,205		Discounted cash flow		Prepayment rate	9.60%
							Default rate	7.50%
							Loss severity	61.20%
	Impaired loans	132,336			Appraised value		Appraised value	0.0% - 100.0% (26.8%)
	OREO	17,764			Appraised value		Appraised value	8.00%
Schedule of fair value by balance sheet location	The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments, excluding financial instruments measured at fair value on a recurring basis, are as follows:
		March 31, 2015
		Carrying Amount			Estimated Fair Value			Level 1		Level 2			Level 3
		(In Thousands)
	Financial Instruments:
	Assets:
	Cash and cash equivalents	$	3,964,357		$	3,964,357		$	3,964,357	$	—		$	—
	Investment securities held to maturity	1,373,542			1,297,565			—		—			1,297,565
	Loans, net	57,856,599			55,263,025			—		—			55,263,025
	Liabilities:
	Deposits	$	62,900,681		$	63,012,674		$	—	$	63,012,674		$	—
	FHLB and other borrowings	4,919,141			4,925,458			—		4,925,458			—
	Federal funds purchased and securities sold under agreements to repurchase	909,683			909,683			—		909,683			—
		December 31, 2014
		Carrying Amount			Estimated Fair Value			Level 1		Level 2			Level 3
		(In Thousands)
	Financial Instruments:
	Assets:
	Cash and cash equivalents	$	3,388,405		$	3,388,405		$	3,388,405	$	—		$	—
	Investment securities held to maturity	1,348,354			1,275,963			—		—			1,275,963
	Loans, net	56,686,743			54,551,442			—		—			54,551,442
	Liabilities:
	Deposits	$	61,189,716		$	61,263,812		$	—	$	61,263,812		$	—
	FHLB and other borrowings	4,809,843			4,786,152			—		4,786,152			—
	Federal funds purchased and securities sold under agreements to repurchase	1,129,503			1,129,503			—		1,129,503			—

Comprehensive_Income_Tables

Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Change in components of other comprehensive income (loss)	The following summarizes the change in the components of other comprehensive income (loss).
		Three Months Ended March 31,
		2015											2014
		Pretax				Tax Expense/ (Benefit)				After-tax			Pretax			Tax Expense/ (Benefit)			After-tax
		(In Thousands)
	Other comprehensive income:
	Unrealized holding gains arising during period from securities available for sale	$	64,790			$	28,202			$	36,588		$	40,962		$	14,722		$	26,240
	Less: reclassification adjustment for net gains on sale of securities in net income	32,832				14,292				18,540			16,434			5,908			10,526
	Net change in unrealized gains on securities available for sale	31,958				13,910				18,048			24,528			8,814			15,714
	Change in unamortized net holding losses on investment securities held to maturity	3,142				1,368				1,774			4,774			1,716			3,058
	Less: non-credit related impairment on investment securities held to maturity	87				38				49			235			84			151
	Change in unamortized non-credit related impairment on investment securities held to maturity	276				120				156			385			139			246
	Net change in unamortized holding losses on securities held to maturity	3,331				1,450				1,881			4,924			1,771			3,153
	Unrealized holding gains (losses) arising during period from cash flow hedge instruments	3,646				1,587				2,059			(1,261		)	(454		)	(807		)
	Change in defined benefit plans	2,716				1,001				1,715			(2,672		)	(1,001		)	(1,671		)
	Other comprehensive income	$	41,651			$	17,948			$	23,703		$	25,519		$	9,130		$	16,389
Schedule of accumulated other comprehensive income (loss)	Activity in accumulated other comprehensive income (loss), net of tax was as follows:
		Unrealized Gains (Losses) on Securities Available for Sale and Transferred to Held to Maturity				Accumulated Gains (Losses) on Cash Flow Hedging Instruments				Defined Benefit Plan Adjustment			Unamortized Impairment Losses on Investment Securities Held to Maturity			Total
		(In Thousands)
	Balance, January 1, 2014	$	(31,490	)		$	(5,289	)		$	(41,921	)	$	(9,236	)	$	(87,936	)
	Other comprehensive income (loss) before reclassifications	26,240				(1,553		)		—			(151		)	24,536
	Amounts reclassified from accumulated other comprehensive income (loss)	(7,468		)		746				(1,671		)	246			(8,147		)
	Net current period other comprehensive income (loss)	18,772				(807		)		(1,671		)	95			16,389
	Balance, March 31, 2014	$	(12,718	)		$	(6,096	)		$	(43,592	)	$	(9,141	)	$	(71,547	)
	Balance, January 1, 2015	$	4,469			$	(7,189	)		$	(41,121	)	$	(7,516	)	$	(51,357	)
	Other comprehensive income (loss) before reclassifications	36,588				2,650				—			(49		)	39,189
	Amounts reclassified from accumulated other comprehensive income (loss)	(16,766		)		(591		)		1,715			156			(15,486		)
	Net current period other comprehensive income	19,822				2,059				1,715			107			23,703
	Balance, March 31, 2015	$	24,291			$	(5,130	)		$	(39,406	)	$	(7,409	)	$	(27,654	)
Schedule of reclassifications out of accumulated other comprehensive income	The following table presents information on reclassifications out of accumulated other comprehensive income.
	Details About Accumulated Other Comprehensive Income Components		Amounts Reclassified From Accumulated Other Comprehensive Income (1)								Condensed Consolidated Statement of Income Caption
			Three Months Ended March 31,
			2015				2014
			(In Thousands)
	Unrealized Gains on Securities Available for Sale and Transferred to Held to Maturity		$	32,832			$	16,434			Investment securities gains, net
			(3,142		)		(4,774		)		Interest on investment securities held to maturity
			29,690				11,660
			(12,924		)		(4,192		)		Income tax expense
			$	16,766			$	7,468			Net of tax
	Accumulated (Gains) Losses on Cash Flow Hedging Instruments		$	2,813			$	612			Interest and fees on loans
			(1,766		)		(1,775		)		Interest and fees on FHLB advances
			1,047				(1,163		)
			(456		)		417				Income tax (expense) benefit
			$	591			$	(746	)		Net of tax
	Defined Benefit Plan Adjustment		$	(2,716	)		$	2,672			-2
			1,001				(1,001		)		Income tax (expense) benefit
			$	(1,715	)		$	1,671			Net of tax
	Unamortized Impairment Losses on Investment Securities Held to Maturity		$	(276	)		$	(385	)		Interest on investment securities held to maturity
			120				139				Income tax benefit
			$	(156	)		$	(246	)		Net of tax
	-1	Amounts in parentheses indicate debits to the consolidated statement of income.
	-2	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 18, Benefit Plans, in the Notes to the December 31, 2014, Consolidated Financial Statements for additional details).

Supplemental_Disclosure_for_St1

Supplemental Disclosure for Statement of Cash Flows (Tables)	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Schedule of supplemental cash flow disclosures	The following table presents the Company’s supplemental disclosures for statement of cash flows.
		Three Months Ended March 31,
		2015		2014
		(In Thousands)
	Supplemental disclosures of cash flow information:
	Interest paid	$	90,984	$	55,675
	Net income taxes paid (refunded)	2,212		(708		)
	Supplemental schedule of noncash investing and financing activities:
	Transfer of loans and loans held for sale to OREO	$	2,718	$	8,920
	Change in unrealized gain (loss) on available for sale securities	31,958		24,528
	Issuance of restricted stock, net of cancellations	458		(547		)
	Business combinations:
	Assets acquired	—		116,152
	Liabilities assumed	—		18,329

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Schedule of segment reporting information	The following tables present the segment information for the Company’s segments.
		Three Months Ended March 31, 2015
		Consumer and Commercial Banking		Corporate and Investment Banking		Treasury		Corporate Support and Other			Consolidated
		(In Thousands)
	Net interest income (expense)	$	482,365	$	39,932	$	18,382	$	(31,650	)	$	509,029
	Allocated provision for loan losses	30,294		11,025		—		712			42,031
	Noninterest income	176,317		49,487		33,856		(10,390		)	249,270
	Noninterest expense	424,608		40,186		5,097		52,828			522,719
	Net income (loss) before income tax expense (benefit)	203,780		38,208		47,141		(95,580		)	193,549
	Income tax expense (benefit)	71,323		13,373		16,500		(49,414		)	51,782
	Net income (loss)	132,457		24,835		30,641		(46,166		)	141,767
	Less: net income attributable to noncontrolling interests	228		—		429		—			657
	Net income (loss) attributable to shareholder	$	132,229	$	24,835	$	30,212	$	(46,166	)	$	141,110
	Average assets	$	52,605,892	$	11,833,948	$	13,572,927	$	7,074,388		$	85,087,155
		Three Months Ended March 31, 2014
		Consumer and Commercial Banking		Corporate and Investment Banking		Treasury		Corporate Support and Other			Consolidated
		(In Thousands)
	Net interest income	$	453,867	$	32,077	$	4,625	$	4,730		$	495,299
	Allocated provision for loan losses	36,621		1,010		—		(365		)	37,266
	Noninterest income	174,257		47,235		22,013		(24,177		)	219,328
	Noninterest expense	429,925		31,214		3,640		54,088			518,867
	Net income (loss) before income tax expense (benefit)	161,578		47,088		22,998		(73,170		)	158,494
	Income tax expense (benefit)	60,188		17,540		8,567		(42,728		)	43,567
	Net income (loss)	101,390		29,548		14,431		(30,442		)	114,927
	Less: net income attributable to noncontrolling interests	17		—		436		—			453
	Net income (loss) attributable to shareholder	$	101,373	$	29,548	$	13,995	$	(30,442	)	$	114,474
	Average assets	$	47,781,589	$	6,418,599	$	12,334,277	$	6,824,679		$	73,359,144

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Schedule of derivative contracts between the Company and BBVA	The net fair value of outstanding derivative contracts between the Company and BBVA are detailed below.
		March 31, 2015			December 31, 2014
		(In Thousands)
	Derivative contracts:
	Cash flow hedges	$	1,164		$	1,693
	Free-standing derivatives not designated as hedging instruments	(10,055		)	9,512
	Securities Purchased Under Agreements to Resell/ Securities Sold Under Agreements to Repurchase
	The Company enters into agreements with BBVA as the counterparty under which it purchases/sells securities subject to an obligation to resell/repurchase the same or similar securities. The following represents the amount of securities purchased under agreement to resell and securities sold under agreement to repurchase where BBVA is the counterparty.
		March 31, 2015			December 31, 2014
		(In Thousands)
	Securities purchased under agreements to resell	$	—		$	97,970
	Securities sold under agreements to repurchase	212			435,684
	Borrowings
	BSI, a wholly owned subsidiary of the Company, has a $420 million revolving note and cash subordination agreement with BBVA that was executed on March 16, 2012 with a maturity date of March 16, 2018. BSI also has a $150 million line of credit with BBVA that was initiated on August 1, 2014. At March 31, 2015 and December 31, 2014, there were no amounts outstanding under either of these agreements.

Investment_Securities_Availabl2

Investment Securities Available for Sale and Investment Securities Held to Maturity - Adjusted cost and fair value of securities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$10,024,304	$10,191,709
Available-for-sale Securities, Gross Unrealized Gain	113,530	102,403
Available-for-sale Securities, Gross Unrealized Losses	36,006	56,837
Investment securities available for sale	10,101,828	10,237,275
Held-to-maturity Securities, Amortized Cost Basis	1,373,542	1,348,354
Held-to-maturity Securities, Gross Unrealized Gain	15,266	16,509
Held-to-maturity Securities, Gross Unrealized Losses	91,243	88,900
Investment Securities - Fair Value	1,297,565	1,275,963
US Treasury and other US Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,521,508	2,312,572
Available-for-sale Securities, Gross Unrealized Gain	25,318	10,360
Available-for-sale Securities, Gross Unrealized Losses	10,056	9,390
Investment securities available for sale	2,536,770	2,313,542
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4,155,135	4,399,706
Available-for-sale Securities, Gross Unrealized Gain	53,876	64,371
Available-for-sale Securities, Gross Unrealized Losses	21,524	40,242
Investment securities available for sale	4,187,487	4,423,835
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,423,466	2,475,115
Available-for-sale Securities, Gross Unrealized Gain	25,813	19,385
Available-for-sale Securities, Gross Unrealized Losses	4,210	5,921
Investment securities available for sale	2,445,069	2,488,579
Held-to-maturity Securities, Amortized Cost Basis	119,253	124,051
Held-to-maturity Securities, Gross Unrealized Gain	6,320	5,878
Held-to-maturity Securities, Gross Unrealized Losses	4,748	5,452
Investment Securities - Fair Value	120,825	124,477
State and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	408,115	460,569
Available-for-sale Securities, Gross Unrealized Gain	8,124	8,008
Available-for-sale Securities, Gross Unrealized Losses	197	1,262
Investment securities available for sale	416,042	467,315
Held-to-maturity Securities, Amortized Cost Basis	1,148,747	1,112,415
Held-to-maturity Securities, Gross Unrealized Gain	1,586	2,143
Held-to-maturity Securities, Gross Unrealized Losses	82,032	79,246
Investment Securities - Fair Value	1,068,301	1,035,312
Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	17,430	44,225
Available-for-sale Securities, Gross Unrealized Gain	356	238
Available-for-sale Securities, Gross Unrealized Losses	19	22
Investment securities available for sale	17,767	44,441
Held-to-maturity Securities, Amortized Cost Basis	69,924	72,701
Held-to-maturity Securities, Gross Unrealized Gain	4,120	4,920
Held-to-maturity Securities, Gross Unrealized Losses	2,164	2,191
Investment Securities - Fair Value	71,880	75,430
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	498,650	499,522
Available-for-sale Securities, Gross Unrealized Gain	43	41
Available-for-sale Securities, Gross Unrealized Losses	0	0
Investment securities available for sale	498,693	499,563
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Amortized Cost Basis	35,618	39,187
Held-to-maturity Securities, Gross Unrealized Gain	3,240	3,568
Held-to-maturity Securities, Gross Unrealized Losses	2,299	2,011
Investment Securities - Fair Value	$36,559	$40,744

Investment_Securities_Availabl3

Investment Securities Available for Sale and Investment Securities Held to Maturity - Fair value and unrealized losses of available for sale securities and held to maturity securities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	$1,810,115	$1,643,701
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	13,352	12,911
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	1,885,220	2,236,444
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	22,654	43,926
Available-for-sale securities, fair value	3,695,335	3,880,145
Available-for-sale securities, unrealized losses	36,006	56,837
Held-to-maturity securities, securities in a loss position for less than 12 months, fair value	102,202	60,149
Held-to-maturity securities, securities in a loss position for less than 12 months, unrealized losses	7,416	4,058
Held-to-maturity securities, securities in a loss position for 12 months or longer, fair value	880,321	868,333
Held-to-maturity securities, securities in a loss position for 12 months or longer, unrealized losses	83,827	84,842
Held-to-maturity securities, fair value	982,523	928,482
Held-to-maturity securities unrealized losses	91,243	88,900
US Treasury and government agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	752,519	620,794
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	8,600	8,220
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	91,136	37,220
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	1,456	1,170
Available-for-sale securities, fair value	843,655	658,014
Available-for-sale securities, unrealized losses	10,056	9,390
Mortgage backed securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	380,594	308,734
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	1,042	862
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	1,701,752	1,915,494
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	20,482	39,380
Available-for-sale securities, fair value	2,082,346	2,224,228
Available-for-sale securities, unrealized losses	21,524	40,242
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity securities, securities in a loss position for less than 12 months, fair value	0	0
Held-to-maturity securities, securities in a loss position for less than 12 months, unrealized losses	0	0
Held-to-maturity securities, securities in a loss position for 12 months or longer, fair value	21,297	23,374
Held-to-maturity securities, securities in a loss position for 12 months or longer, unrealized losses	2,299	2,011
Held-to-maturity securities, fair value	21,297	23,374
Held-to-maturity securities unrealized losses	2,299	2,011
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	633,205	714,173
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	3,513	3,829
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	91,229	146,806
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	697	2,092
Available-for-sale securities, fair value	724,434	860,979
Available-for-sale securities, unrealized losses	4,210	5,921
Held-to-maturity securities, securities in a loss position for less than 12 months, fair value	23,045	34,400
Held-to-maturity securities, securities in a loss position for less than 12 months, unrealized losses	349	1,099
Held-to-maturity securities, securities in a loss position for 12 months or longer, fair value	46,293	27,389
Held-to-maturity securities, securities in a loss position for 12 months or longer, unrealized losses	4,399	4,353
Held-to-maturity securities, fair value	69,338	61,789
Held-to-maturity securities unrealized losses	4,748	5,452
State and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	43,797	0
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	197	0
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	0	135,825
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	0	1,262
Available-for-sale securities, fair value	43,797	135,825
Available-for-sale securities, unrealized losses	197	1,262
Held-to-maturity securities, securities in a loss position for less than 12 months, fair value	75,204	21,688
Held-to-maturity securities, securities in a loss position for less than 12 months, unrealized losses	4,903	768
Held-to-maturity securities, securities in a loss position for 12 months or longer, fair value	812,731	817,570
Held-to-maturity securities, securities in a loss position for 12 months or longer, unrealized losses	77,129	78,478
Held-to-maturity securities, fair value	887,935	839,258
Held-to-maturity securities unrealized losses	82,032	79,246
Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, securities in a loss position for less than 12 months, fair value	0	0
Available-for-sale securities, securities in a loss position for less than 12 months, unrealized losses	0	0
Available-for-sale securities, securities in a loss position for 12 months or longer, fair value	1,103	1,099
Available-for-sale securities, Securities in a loss position for 12 months or longer, unrealized losses	19	22
Available-for-sale securities, fair value	1,103	1,099
Available-for-sale securities, unrealized losses	19	22
Held-to-maturity securities, securities in a loss position for less than 12 months, fair value	3,953	4,061
Held-to-maturity securities, securities in a loss position for less than 12 months, unrealized losses	2,164	2,191
Held-to-maturity securities, securities in a loss position for 12 months or longer, fair value	0	0
Held-to-maturity securities, securities in a loss position for 12 months or longer, unrealized losses	0	0
Held-to-maturity securities, fair value	3,953	4,061
Held-to-maturity securities unrealized losses	$2,164	$2,191

Investment_Securities_Availabl4

Investment Securities Available for Sale and Investment Securities Held to Maturity - Other temporary impairments losses recognized in other comprehensive income (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Other than temporary impairment recognized in other comprehensive income, beginning of period	$21,123	$20,943
Reductions for securities paid off during the period (realized)	0	0
Additions for the credit component on debt securities in which OTTI was not previously recognized	0	0
Additions for the credit component on debt securities in which OTTI was previously recognized	285	146
Other than temporary impairment recognized in other comprehensive income, end of period	$21,408	$21,089

Investment_Securities_Availabl5

Investment Securities Available for Sale and Investment Securities Held to Maturity - Maturities of securities portfolios (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment securities available for sale, amortized cost [Abstract]
Maturing within one year	$48,475
Maturing after one but within five years	688,061
Maturing after five both within ten years	983,328
Maturing after ten years	1,227,189
Total single date maturities	2,947,053
Mortgage-backed securities and collateralized mortgage obligations	6,578,601
Available-for-sale Securities, Amortized Cost Basis	10,024,304	10,191,709
Investment securities available for sale, fair value [Abstract]
Maturing within one year	48,860
Maturing after one but within five years	701,812
Maturing after five but within ten years	997,119
Maturing after ten years	1,222,788
Total single date maturities	2,970,579
Mortgage-backed securities and collateralized mortgage obligations	6,632,556
Investment securities available for sale	10,101,828	10,237,275
Held-to-maturity securities, amortized cost [Abstract]
Maturing within one year	9,079
Maturing after one but within five years	300,029
Maturing after five but within ten years	182,574
Maturing after ten years	762,607
Total single date maturities	1,254,289
Collateralized mortgage obligations	119,253
Total	1,373,542	1,348,354
Held-to-maturity securities, fair value [Abstract]
Maturing within one year	9,092
Maturing after one but within five years	286,940
Maturing after five but within ten years	176,641
Maturing after ten years	704,067
Total single date maturities	1,176,740
Collateralized mortgage obligations	120,825
Total Investments Securities Held to Maturity	1,297,565	1,275,963
Equity securities
Investment securities available for sale, amortized cost [Abstract]
Available-for-sale Securities, Amortized Cost Basis	498,650	499,522
Investment securities available for sale, fair value [Abstract]
Investment securities available for sale	$498,693	$499,563

Investment_Securities_Availabl6

Investment Securities Available for Sale and Investment Securities Held to Maturity - Gross Realized Gains and Losses (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Gross gains	$32,832	$16,434
Gross losses	0	0
Net realized gains	$32,832	$16,434

Investment_Securities_Availabl7

Investment Securities Available for Sale and Investment Securities Held to Maturity - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Federal home loan bank and federal reserve stock carried at par value	$499,000,000		$500,000,000
Securities impairment	$285,000	$146,000

Loans_and_Allowance_for_Loan_L2

Loans and Allowance for Loan Losses - Composition of loan portfolio (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Commercial loans:
Commercial, financial and agricultural	$24,448,964	$23,828,537
Real estate – construction	2,325,495	2,154,652
Commercial real estate – mortgage	9,920,583	9,877,206
Total commercial loans	36,695,042	35,860,395
Consumer loans:
Residential real estate – mortgage	14,000,868	13,922,656
Equity lines of credit	2,325,884	2,304,784
Equity loans	635,295	634,968
Credit card	600,030	630,456
Consumer direct	707,251	652,927
Consumer indirect	3,105,533	2,870,408
Total consumer loans	21,374,861	21,016,199
Covered loans	488,560	495,190
Total loans	$58,558,463	$57,371,784

Loans_and_Allowance_for_Loan_L3

Loans and Allowance for Loan Losses - Purchased Impaired Loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
Unpaid principal balance	$367,704	$378,913
Discount	-12,287	-17,341
Allowance for loan losses	-727	-2,066
Carrying value	$354,690	$359,506

Loans_and_Allowance_for_Loan_L4

Loans and Allowance for Loan Losses - Accretable yields on purchased impaired loans (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	$68,785	$105,698
Transfer to nonaccretable difference	-3,417	-8,162
Accretion	-8,057	-16,172
Other	0	0
Balance, end of period	$57,311	$81,364

Loans_and_Allowances_for_Loan_

Loans and Allowances for Loan Losses - Purchased Nonimpaired Loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
Unpaid principal balance	$274,581	$294,202
Discount	-57,280	-88,962
Allowance for loan losses	-2,115	-2,283
Carrying value	$215,186	$202,957

Loans_and_Allowance_for_Loan_L5

Loans and Allowance for Loan Losses - FDIC Indemnification Asset (Liability) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
FDIC Indemnification Asset [Roll Forward]
Beginning balance	($78,025)	$24,315
Increase (decrease) due to credit loss provision (benefit) recorded on FDIC covered loans	-631	5,061
Amortization and accretion, net	-27,898	-36,823
Reimbursements from (payments to) FDIC for covered assets	-908	6,478
Other	-260	144
Ending balance	($107,722)	($825)

Loans_and_Allowance_for_Loan_L6

Loans and Allowance for Loan Losses - Allowances for loan losses activity (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, covered, beginning of period	$2,808		$2,954
Allowance for loan losses, total loans, beginning of period	685,041		700,719
Provision (credit) for loan losses, covered	-467		4,985
Provision charged to income, total loans	42,031		37,266
Loans charged off, covered	-873		-216
Loans charged off, total loans	-39,426		-45,208
Loan recoveries, covered	0		342
Loan recoveries, total loans	14,218		14,888
Net (charge offs) recoveries, covered	-873		126
Net (charge offs) recoveries, total loans	-25,208		-30,320
Allowance for loan losses, covered, end of period	1,468		8,065
Allowance for loan losses, total loans, end of period	701,864		707,665
Ending Balance of Allowance Attributable to Loans [Abstract]
Individually evaluated for impairment	60,871				63,433
Collectively evaluated for impairment	638,151				617,259
Purchased impaired	727				2,066
Purchased nonimpaired	2,115				2,283
Purchased nonimpaired, covered	741				742
Purchased nonimpaired, covered and not covered	2,115				2,283
Ending Balance of Loans [Abstract]
Individually evaluated for impairment	367,537				351,070
Collectively evaluated for impairment	57,618,208				56,453,902
Purchased Impaired Loans	355,417				361,572
Purchased nonimpaired loans, covered	133,143				133,618
Purchased nonimpaired loans, covered and not covered	217,301				205,240
Covered loans	488,560				495,190
Total loans	58,558,463				57,371,784
Commercial, financial and agricultural
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning of period	299,482		292,327
Provision (credit) for loan losses	28,352		7,501
Loans charged off	-6,619		-4,934
Loan recoveries	2,182		4,985
Net (charge offs) recoveries	-4,437		51
Allowance for loan losses, end of period	323,397		299,879
Ending Balance of Allowance Attributable to Loans [Abstract]
Individually evaluated for impairment	13,510				11,158
Collectively evaluated for impairment	308,826				287,105
Purchased nonimpaired	1,061				1,219
Ending Balance of Loans [Abstract]
Individually evaluated for impairment	81,606				48,173
Collectively evaluated for impairment	24,328,772				23,745,149
Purchased nonimpaired loans	38,586				35,215
Total loans, excluding covered loans	24,448,964				23,828,537
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning of period	138,233	[1]	158,960	[1]
Provision (credit) for loan losses	-185	[1]	-4,722	[1]
Loans charged off	-635	[1]	-2,646	[1]
Loan recoveries	1,858	[1]	1,538	[1]
Net (charge offs) recoveries	1,223	[1]	-1,108	[1]
Allowance for loan losses, end of period	139,271	[1]	153,130	[1]
Ending Balance of Allowance Attributable to Loans [Abstract]
Individually evaluated for impairment	6,742	[1]			8,466	[1]
Collectively evaluated for impairment	132,529	[1]			129,767	[1]
Ending Balance of Loans [Abstract]
Individually evaluated for impairment	92,480	[1]			105,608	[1]
Collectively evaluated for impairment	12,114,814	[1]			11,896,943	[1]
Purchased nonimpaired loans	38,784	[1]			29,307	[1]
Total loans, excluding covered loans	12,246,078	[1]			12,031,858	[1]
Residential real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning of period	154,627	[2]	155,575	[2]
Provision (credit) for loan losses	-6,439	[2]	12,673	[2]
Loans charged off	-6,754	[2]	-15,708	[2]
Loan recoveries	3,513	[2]	2,694	[2]
Net (charge offs) recoveries	-3,241	[2]	-13,014	[2]
Allowance for loan losses, end of period	144,947	[2]	155,234	[2]
Ending Balance of Allowance Attributable to Loans [Abstract]
Individually evaluated for impairment	39,023	[2]			42,277	[2]
Collectively evaluated for impairment	105,924	[2]			112,350	[2]
Ending Balance of Loans [Abstract]
Individually evaluated for impairment	190,447	[2]			195,462	[2]
Collectively evaluated for impairment	16,770,610	[2]			16,665,930	[2]
Purchased nonimpaired loans	990	[2]			1,016	[2]
Total loans, excluding covered loans	16,962,047	[2]			16,862,408	[2]
Consumer loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning of period	89,891	[3]	90,903	[3]
Provision (credit) for loan losses	20,770	[3]	16,829	[3]
Loans charged off	-24,545	[3]	-21,704	[3]
Loan recoveries	6,665	[3]	5,329	[3]
Net (charge offs) recoveries	-17,880	[3]	-16,375	[3]
Allowance for loan losses, end of period	92,781	[3]	91,357	[3]
Ending Balance of Allowance Attributable to Loans [Abstract]
Individually evaluated for impairment	1,596	[3]			1,532	[3]
Collectively evaluated for impairment	90,872	[3]			88,037	[3]
Purchased nonimpaired	313	[3]			322	[3]
Ending Balance of Loans [Abstract]
Individually evaluated for impairment	3,004	[3]			1,827	[3]
Collectively evaluated for impairment	4,404,012	[3]			4,145,880	[3]
Purchased nonimpaired loans	5,798	[3]			6,084	[3]
Total loans, excluding covered loans	$4,412,814	[3]			$4,153,791	[3]
[1]	Includes commercial real estate – mortgage and real estate – construction loans.
[2]	Includes residential real estate – mortgage, equity lines of credit and equity loans.
[3]	Includes credit card, consumer direct and consumer indirect loans.

Loans_and_Allowances_for_Loan_1

Loans and Allowances for Loan Losses - Impaired loans by loan class (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	$38,995		$35,109
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	47,677		36,582
Individually evaluated impaired loans with a recorded allowance, recorded investment	328,542		315,961
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	338,190		335,583
Individually evaluated impaired loans with a recorded allowance, allowance	60,871		63,433
Total individually evaluated impaired loans, average recorded investment	354,417	473,106
Total individually evaluated impaired loans, interest income recognized	2,346	2,646
Commercial, financial and agricultural
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	6,377		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	13,575		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	75,229		48,173
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	79,360		61,552
Individually evaluated impaired loans with a recorded allowance, allowance	13,510		11,158
Total individually evaluated impaired loans, average recorded investment	64,881	126,821
Total individually evaluated impaired loans, interest income recognized	339	245
Real estate - construction
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	3,492		3,492
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	4,006		4,006
Individually evaluated impaired loans with a recorded allowance, recorded investment	2,580		2,686
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	2,625		2,731
Individually evaluated impaired loans with a recorded allowance, allowance	793		872
Total individually evaluated impaired loans, average recorded investment	6,115	10,120
Total individually evaluated impaired loans, interest income recognized	39	63
Commercial real estate - mortgage
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	22,240		22,822
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	23,210		23,781
Individually evaluated impaired loans with a recorded allowance, recorded investment	64,168		76,608
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	68,690		82,005
Individually evaluated impaired loans with a recorded allowance, allowance	5,949		7,594
Total individually evaluated impaired loans, average recorded investment	88,178	141,347
Total individually evaluated impaired loans, interest income recognized	580	942
Residential real estate - mortgage
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	6,886		8,795
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	6,886		8,795
Individually evaluated impaired loans with a recorded allowance, recorded investment	105,079		107,223
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	105,162		107,306
Individually evaluated impaired loans with a recorded allowance, allowance	7,188		9,236
Total individually evaluated impaired loans, average recorded investment	113,926	114,965
Total individually evaluated impaired loans, interest income recognized	695	719
Equity lines of credit
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	26,718		25,743
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	27,124		26,124
Individually evaluated impaired loans with a recorded allowance, allowance	23,675		23,394
Total individually evaluated impaired loans, average recorded investment	26,658	23,403
Total individually evaluated impaired loans, interest income recognized	283	250
Equity loans
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	51,764		53,701
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	52,225		54,038
Individually evaluated impaired loans with a recorded allowance, allowance	8,160		9,647
Total individually evaluated impaired loans, average recorded investment	52,435	55,027
Total individually evaluated impaired loans, interest income recognized	404	425
Credit card
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, allowance	0		0
Total individually evaluated impaired loans, average recorded investment	0	0
Total individually evaluated impaired loans, interest income recognized	0	0
Consumer - direct
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	1,383		337
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	1,383		337
Individually evaluated impaired loans with a recorded allowance, allowance	77		42
Total individually evaluated impaired loans, average recorded investment	680	158
Total individually evaluated impaired loans, interest income recognized	6	1
Consumer - indirect
Financing Receivable, Impaired [Line Items]
Individually evaluated impaired loans with no recorded allowance, recorded investment	0		0
Individually evaluated impaired loans with no recorded allowance, unpaid principle balance	0		0
Individually evaluated impaired loans with a recorded allowance, recorded investment	1,621		1,490
Individually evaluated impaired loans with a recorded allowance, unpaid principle balance	1,621		1,490
Individually evaluated impaired loans with a recorded allowance, allowance	1,519		1,490
Total individually evaluated impaired loans, average recorded investment	1,544	1,265
Total individually evaluated impaired loans, interest income recognized	$0	$1

Loans_and_Allowance_for_Loan_L7

Loans and Allowance for Loan Losses - Credit quality indicators (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	$24,448,964	$23,828,537
Real estate - construction
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	2,325,495	2,154,652
Commercial real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	9,920,583	9,877,206
Residential real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	14,000,868	13,922,656
Equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	2,325,884	2,304,784
Equity loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	635,295	634,968
Credit card
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	600,030	630,456
Consumer - direct
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	707,251	652,927
Consumer - indirect
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	3,105,533	2,870,408
Pass | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	23,899,964	23,380,541
Pass | Real estate - construction
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	2,250,178	2,098,994
Pass | Commercial real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	9,578,494	9,514,917
Special Mention | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	285,158	280,934
Special Mention | Real estate - construction
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	62,033	42,176
Special Mention | Commercial real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	194,696	210,337
Substandard | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	222,535	128,251
Substandard | Real estate - construction
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	13,261	13,458
Substandard | Commercial real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	130,061	129,435
Doubtful | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	41,307	38,811
Doubtful | Real estate - construction
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	23	24
Doubtful | Commercial real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	17,332	22,517
Performing | Residential real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	13,890,173	13,810,857
Performing | Equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	2,289,292	2,269,231
Performing | Equity loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	616,266	614,064
Performing | Credit card
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	591,412	621,015
Performing | Consumer - direct
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	702,815	649,832
Performing | Consumer - indirect
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	3,098,855	2,865,013
Nonperforming | Residential real estate - mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	110,695	111,799
Nonperforming | Equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	36,592	35,553
Nonperforming | Equity loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	19,029	20,904
Nonperforming | Credit card
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	8,618	9,441
Nonperforming | Consumer - direct
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	4,436	3,095
Nonperforming | Consumer - indirect
Financing Receivable, Recorded Investment [Line Items]
Total loans, excluding covered loans	$6,678	$5,395

Loans_and_Allowance_for_Loan_L8

Loans and Allowance for Loan Losses - Past due loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due, Covered	$6,582	$6,678
60 - 89 Days Past Due, Covered	3,872	4,618
90 Days or More Past Due, Covered	45,402	47,957
Nonaccrual, Covered	179	114
Accruing TDRs, Covered	0	0
Total Past Due and Impaired, Covered	56,035	59,367
Not Past Due or Impaired, Covered	432,525	435,823
Total, Covered	488,560	495,190
30 - 59 Days Past Due, Total Loans	135,031	141,439
60 - 89 Days Past Due, Total Loans	47,842	54,040
90 Days or More Past Due, Total Loans	70,750	71,454
Nonaccrual, Total Loans	357,282	322,654
Accruing TDRs, Total Loans	158,072	162,983
Total Past Due and Impaired, Total Loans	768,977	752,570
Not Past Due or Impaired, Total Loans	57,789,486	56,619,214
Total Loans	58,558,463	57,371,784
Commercial, financial and agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	7,940	10,829
60 - 89 Days Past Due	3,981	5,765
90 Days or More Past Due	2,901	1,610
Nonaccrual	95,318	61,157
Accruing TDRs	9,632	10,127
Total Past Due and Impaired	119,772	89,488
Not Past Due or Impaired	24,329,192	23,739,049
Total	24,448,964	23,828,537
Real estate - construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	5,275	1,954
60 - 89 Days Past Due	450	994
90 Days or More Past Due	392	477
Nonaccrual	7,781	7,964
Accruing TDRs	2,237	2,112
Total Past Due and Impaired	16,135	13,501
Not Past Due or Impaired	2,309,360	2,141,151
Total	2,325,495	2,154,652
Commercial real estate - mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	6,346	9,813
60 - 89 Days Past Due	3,629	4,808
90 Days or More Past Due	2,542	628
Nonaccrual	87,931	89,736
Accruing TDRs	35,292	39,841
Total Past Due and Impaired	135,740	144,826
Not Past Due or Impaired	9,784,843	9,732,380
Total	9,920,583	9,877,206
Residential real estate - mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	45,893	45,279
60 - 89 Days Past Due	17,007	16,510
90 Days or More Past Due	3,195	2,598
Nonaccrual	107,051	108,357
Accruing TDRs	70,299	69,408
Total Past Due and Impaired	243,445	242,152
Not Past Due or Impaired	13,757,423	13,680,504
Total	14,000,868	13,922,656
Equity lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	10,615	9,929
60 - 89 Days Past Due	4,602	4,395
90 Days or More Past Due	1,995	2,679
Nonaccrual	34,597	32,874
Accruing TDRs	0	0
Total Past Due and Impaired	51,809	49,877
Not Past Due or Impaired	2,274,075	2,254,907
Total	2,325,884	2,304,784
Equity loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	5,387	6,357
60 - 89 Days Past Due	1,728	3,268
90 Days or More Past Due	703	997
Nonaccrual	18,313	19,029
Accruing TDRs	40,432	41,197
Total Past Due and Impaired	66,563	70,848
Not Past Due or Impaired	568,732	564,120
Total	635,295	634,968
Credit card
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	5,004	5,692
60 - 89 Days Past Due	3,441	3,921
90 Days or More Past Due	8,618	9,441
Nonaccrual	0	0
Accruing TDRs	0	0
Total Past Due and Impaired	17,063	19,054
Not Past Due or Impaired	582,967	611,402
Total	600,030	630,456
Consumer - direct
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	7,545	9,542
60 - 89 Days Past Due	2,406	1,826
90 Days or More Past Due	2,426	2,296
Nonaccrual	2,010	799
Accruing TDRs	180	298
Total Past Due and Impaired	14,567	14,761
Not Past Due or Impaired	692,684	638,166
Total	707,251	652,927
Consumer - indirect
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	34,444	35,366
60 - 89 Days Past Due	6,726	7,935
90 Days or More Past Due	2,576	2,771
Nonaccrual	4,102	2,624
Accruing TDRs	0	0
Total Past Due and Impaired	47,848	48,696
Not Past Due or Impaired	3,057,685	2,821,712
Total	$3,105,533	$2,870,408

Loans_and_Allowance_for_Loans_

Loans and Allowance for Loans Losses - Troubled debt restructurings (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Modifications [Line Items]
30 - 59 Days Past Due, Covered	$0	$0
60 - 89 Days Past Due, Covered	0	0
90 Days or More Past Due, Covered	0	0
Nonaccrual, Covered	8	17
Total Past Due and Nonaccrual, Covered	8	17
Not Past Due or Nonaccrual, Covered	0	0
Total, Covered	8	17
30 - 59 Days Past Due, Total Loans	3,048	5,109
60 - 89 Days Past Due, Total Loans	1,668	4,348
90 Days or More Past Due, Total Loans	820	1,722
Nonaccrual, Total Loans	75,584	80,408
Total Past Due and Nonaccrual, Total Loans	81,120	91,587
Not Past Due or Nonaccrual, Total Loans	152,536	151,804
Total Loans	233,656	243,391
Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	20	11
60-89 Days Past Due	35	0
90 Days or More Past Due	0	0
Nonaccrual	1,620	2,052
Total Past Due and Nonaccrual	1,675	2,063
Not Past Due or Nonaccrual	9,577	10,116
Total	11,252	12,179
Real estate - construction
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
90 Days or More Past Due	0	0
Nonaccrual	142	200
Total Past Due and Nonaccrual	142	200
Not Past Due or Nonaccrual	2,237	2,112
Total	2,379	2,312
Commercial real estate - mortgage
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	371
60-89 Days Past Due	0	536
90 Days or More Past Due	358	0
Nonaccrual	6,226	7,068
Total Past Due and Nonaccrual	6,584	7,975
Not Past Due or Nonaccrual	34,934	38,934
Total	41,518	46,909
Residential real estate - mortgage
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	1,366	2,440
60-89 Days Past Due	658	2,688
90 Days or More Past Due	449	844
Nonaccrual	29,087	32,518
Total Past Due and Nonaccrual	31,560	38,490
Not Past Due or Nonaccrual	67,826	63,436
Total	99,386	101,926
Equity lines of credit
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
90 Days or More Past Due	0	0
Nonaccrual	25,518	24,519
Total Past Due and Nonaccrual	25,518	24,519
Not Past Due or Nonaccrual	0	0
Total	25,518	24,519
Equity loans
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	1,662	2,182
60-89 Days Past Due	975	1,124
90 Days or More Past Due	13	878
Nonaccrual	11,328	12,504
Total Past Due and Nonaccrual	13,978	16,688
Not Past Due or Nonaccrual	37,782	37,013
Total	51,760	53,701
Credit card
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
90 Days or More Past Due	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	0
Not Past Due or Nonaccrual	0	0
Total	0	0
Consumer - direct
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	105
60-89 Days Past Due	0	0
90 Days or More Past Due	0	0
Nonaccrual	34	40
Total Past Due and Nonaccrual	34	145
Not Past Due or Nonaccrual	180	193
Total	214	338
Consumer - indirect
Financing Receivable, Modifications [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
90 Days or More Past Due	0	0
Nonaccrual	1,621	1,490
Total Past Due and Nonaccrual	1,621	1,490
Not Past Due or Nonaccrual	0	0
Total	$1,621	$1,490

Loans_and_Allowance_for_Loan_L9

Loans and Allowance for Loan Losses - Classified as troubled debt restructurings (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
	Contract	Contract
Financing Receivable, Modifications [Line Items]
Number of contracts, covered	1	0
Post modification outstanding, recorded investment, covered	$5	$0
Number of subsequent default contracts, covered	0	0
Recorded investment at subsequent default, covered	0	0
Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Number of contracts	1	0
Post modification outstanding, recorded investment	75	0
Number of subsequent default contracts	0	0
Recorded investment at subsequent default	0	0
Real estate - construction
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Post modification outstanding, recorded investment	0	0
Number of subsequent default contracts	0	0
Recorded investment at subsequent default	0	0
Commercial real estate - mortgage
Financing Receivable, Modifications [Line Items]
Number of contracts	0	6
Post modification outstanding, recorded investment	0	3,930
Number of subsequent default contracts	1	0
Recorded investment at subsequent default	178	0
Residential real estate - mortgage
Financing Receivable, Modifications [Line Items]
Number of contracts	11	10
Post modification outstanding, recorded investment	1,740	994
Number of subsequent default contracts	4	0
Recorded investment at subsequent default	647	0
Equity lines of credit
Financing Receivable, Modifications [Line Items]
Number of contracts	31	49
Post modification outstanding, recorded investment	1,913	2,302
Number of subsequent default contracts	0	3
Recorded investment at subsequent default	0	275
Equity loans
Financing Receivable, Modifications [Line Items]
Number of contracts	14	18
Post modification outstanding, recorded investment	718	1,987
Number of subsequent default contracts	2	1
Recorded investment at subsequent default	161	63
Credit card
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Post modification outstanding, recorded investment	0	0
Number of subsequent default contracts	0	0
Recorded investment at subsequent default	0	0
Consumer - direct
Financing Receivable, Modifications [Line Items]
Number of contracts	0	0
Post modification outstanding, recorded investment	0	0
Number of subsequent default contracts	0	0
Recorded investment at subsequent default	0	0
Consumer - indirect
Financing Receivable, Modifications [Line Items]
Number of contracts	22	18
Post modification outstanding, recorded investment	379	202
Number of subsequent default contracts	1	0
Recorded investment at subsequent default	$18	$0

Recovered_Sheet1

Loans and Allowance for Loan Losses - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased impaired loans, allowance	$727,000		$2,066,000
Recognized provision for loan losses attributable to credit deterioration (improvements) subsequent to acquisition of loan	-907,000	-10,800,000
Interest income on purchased nonimpaired loans	36,600,000	37,800,000
Recorded investment of purchased impaired loans with credit deterioration subsequent to acquisition that were individually evaluated for impairment	1,900,000		1,300,000
Unpaid principle balance of purchased impaired loans with credit deterioration subsequent to acquisition that were individually evaluated for impairment	4,700,000		4,700,000
Certain loans and debt securities acquired in transfer, allowance recorded due to subsequent impairment	0
Loans held-for-sale, classified as TDR, nonaccrual	0
Commitment to lend additional funds to borrowers owing TDR loans	1,000,000		1,100,000
Other real estate owned	17,764,000		20,600,000
Residential real estate loans secured by loans in formal foreclosure proceedings that are in process	34,000,000		26,000,000
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other real estate owned	11,000,000		11,000,000
Interest rate concession
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs	300,000	2,400,000
Modification of loan structure
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs	$4,500,000	$7,000,000

Loan_Sales_and_Servicing_Narra

Loan Sales and Servicing - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$198,488,000		$154,816,000
Transfer of loans to loans held for sale	0	0
Balance of residential mortgage loans sold with retained servicing	3,500,000,000		3,300,000,000
Fair value of MSRs	35,213,000		35,488,000
Originated For Sale In The Secondary Market
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgage loans sold	245,000,000	188,000,000
Recognized net gains or losses on sale of residential mortgage loans	10,600,000	4,100,000
Residential real estate - mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Servicing fees	4,800,000	3,600,000
Residential Real Estate Mortgage Loans Sold with Retained Servicing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgage loans sold	245,000,000	188,000,000
Loans and Loans Held for Sale Excluding Loans Originated for Sale in Secondary Market | Loans and Loans Held for Sale Excluding Loans Originated for Sale in Secondary Market
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost of loans and leases sold		$62,000,000

Loan_Sales_and_Servicing_Resid

Loan Sales and Servicing - Residential MSRs (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance					$35,488
Ending balance	35,213				35,488
Residential mortgage
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	35,488		30,065
Additions	2,759		2,083
Due to changes in valuation inputs or assumptions	-2,592		291
Due to other changes in fair value	-442	[1]	-611	[1]
Ending balance	$35,213		$31,828
[1]	Represents the realization of expected net servicing cash flows, expected borrower repayments and the passage of time.

Loan_Sales_and_Servicing_Valua

Loan Sales and Servicing - Valuation Assumptions (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Servicing Assets at Fair Value [Line Items]
Fair value of MSRs	$35,213	$35,488
Mortgage loans sold and serviced, percentage	100.00%	100.00%
Weighted average life (in years)	6 years 0 months 0 days	6 years 2 months 12 days
Prepayment speed:	11.20%	10.60%
Effect on fair value of a 10% increase	-1,407	-1,220
Effect on fair value of a 20% increase	-2,712	-2,375
Weighted average discount rate:	10.10%	10.10%
Effect on fair value of a 10% increase	-1,298	-1,291
Effect on fair value of a 20% increase	($2,508)	($2,492)
Fixed rate mortgage loan
Servicing Assets at Fair Value [Line Items]
Mortgage loans sold and serviced, percentage	96.00%	96.10%
Adjustable rate mortgage loan
Servicing Assets at Fair Value [Line Items]
Mortgage loans sold and serviced, percentage	4.00%	3.90%

Derivatives_and_Hedging_Deriva

Derivatives and Hedging - Derivatives by Balance Sheet Location (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Derivative assets	$245,285		$225,227
Derivative liabilities	335,349		259,018
Derivatives designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative assets	85,625	[1]	71,493	[1]
Derivative liabilities	14,871	[2]	14,497	[2]
Derivatives designated as hedging instrument | Fair value hedges
Derivatives, Fair Value [Line Items]
Derivative assets	79,818	[1]	69,700	[1]
Derivative liabilities	0	[2]
Derivatives designated as hedging instrument | Fair value hedges | Interest rate swap long term debt
Derivatives, Fair Value [Line Items]
Derivative, notional amount	1,423,950		1,423,950
Derivative assets	79,818	[1]	69,700	[1]
Derivative liabilities	0	[2]
Derivatives designated as hedging instrument | Cash flow hedges
Derivatives, Fair Value [Line Items]
Derivative assets	5,807	[1]	1,793	[1]
Derivative liabilities	14,871	[2]	14,497	[2]
Derivatives designated as hedging instrument | Cash flow hedges | Interest rate swap commercial loan
Derivatives, Fair Value [Line Items]
Derivative, notional amount	1,800,000		1,100,000
Derivative assets	5,807	[1]	1,793	[1]
Derivative liabilities	0	[2]	1,023
Derivatives designated as hedging instrument | Cash flow hedges | Interest rate swap FHLB advances
Derivatives, Fair Value [Line Items]
Derivative, notional amount	320,000		320,000
Derivative liabilities	14,871	[2]	13,474	[2]
Free-standing derivatives not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative assets	489,434	[1]	414,470	[1]
Derivative liabilities	418,308	[2]	347,761	[2]
Free-standing derivatives not designated as hedging instrument | Forward and option contracts related to residential mortgage loans held for sale
Derivatives, Fair Value [Line Items]
Derivative, notional amount	321,000		189,000
Derivative assets	73	[1]	18	[1]
Derivative liabilities	2,031	[2]	1,576	[2]
Free-standing derivatives not designated as hedging instrument | Purchased equity option related to equity-linked CDs
Derivatives, Fair Value [Line Items]
Derivative, notional amount	846,272		821,849
Derivative assets	70,199	[1]	76,487	[1]
Free-standing derivatives not designated as hedging instrument | Equity contracts, swap associated with sale of Visa Inc. Class B shares
Derivatives, Fair Value [Line Items]
Derivative, notional amount	57,267		57,393
Derivative liabilities	1,432	[2]	1,435	[2]
Free-standing derivatives not designated as hedging instrument | Forward contracts related to commercial loans
Derivatives, Fair Value [Line Items]
Derivative, notional amount	562,373		602,066
Derivative assets	8,826	[1]	5,529	[1]
Derivative liabilities	870	[2]	612	[2]
Free-standing derivatives not designated as hedging instrument | Spot contracts related to commercial loans
Derivatives, Fair Value [Line Items]
Derivative, notional amount	57,968		74,940
Derivative assets	131	[1]	41	[1]
Derivative liabilities	59	[2]	80	[2]
Free-standing derivatives not designated as hedging instrument | Futures contracts
Derivatives, Fair Value [Line Items]
Derivative, notional amount	683,000	[3]	342,000	[3]
Free-standing derivatives not designated as hedging instrument | Interest rate lock commitments
Derivatives, Fair Value [Line Items]
Derivative, notional amount	294,685		180,822
Derivative assets	4,988	[1]	2,319	[1]
Derivative liabilities	1	[2]	1	[2]
Free-standing derivatives not designated as hedging instrument | Written equity option related to equity-linked CDs
Derivatives, Fair Value [Line Items]
Derivative, notional amount	815,904		795,467
Derivative liabilities	67,959	[2]	74,319	[2]
Free-standing derivatives not designated as hedging instrument | Interest rate contracts for customers
Derivatives, Fair Value [Line Items]
Derivative, notional amount	20,758,720		18,678,390
Derivative assets	369,042	[1]	296,239	[1]
Derivative liabilities	310,602	[2]	236,763	[2]
Free-standing derivatives not designated as hedging instrument | Commodity contracts for customers
Derivatives, Fair Value [Line Items]
Derivative, notional amount	235,099		264,491
Derivative assets	21,568	[1]	25,569	[1]
Derivative liabilities	21,471	[2]	25,448	[2]
Free-standing derivatives not designated as hedging instrument | Foreign exchange contracts for customers
Derivatives, Fair Value [Line Items]
Derivative, notional amount	508,321		425,123
Derivative assets	14,607	[1]	8,268	[1]
Derivative liabilities	13,883	[2]	7,527	[2]
Free-standing derivatives not designated as hedging instrument | Total trading account assets and liabilities
Derivatives, Fair Value [Line Items]
Derivative assets	405,217	[1]	330,076	[1]
Derivative liabilities	$345,956	[2]	$269,738	[2]
[1]	Derivative assets, except for trading account assets that are recorded as a component of trading account assets on the Company's Unaudited Condensed Consolidated Balance Sheets, are recorded in other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets.
[2]	Derivative liabilities are recorded in accrued expenses and other liabilities on the Company’s Unaudited Condensed Consolidated Balance Sheets.
[3]	Changes in fair value are cash settled daily; therefore, there is no ending balance at any given reporting period.

Derivatives_and_Hedging_Fair_V

Derivatives and Hedging - Fair Value Hedges (Details) (Derivatives designated as hedging instrument, Fair value hedges, Interest Rate Swap, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Fair value hedges weighted average expected remaining term	3 years 8 months 60 days
Interest on FHLB and other borrowings
Interest Rate Fair Value Hedges [Abstract]
Change in fair value of interest rate contract - interest rate swaps hedging long term debt	$10,118	($935)
Change in fair value of interest rate contract - hedged long term debt	-9,413	1,809
Interest and amortization related to interest rate swaps on hedged long term debt	$9,566	$5,265

Derivatives_and_Hedging_Cash_F

Derivatives and Hedging - Cash Flow Hedges (Details) (Derivatives designated as hedging instrument, Cash flow hedges, Interest Rate Swap, USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedges not terminated, net fair value	($9,100,000)
Fair value hedges weighted average expected remaining term	2 years 2 months 1 day
Maximum length of time hedged in interest rate cash flow hedge	6 years 3 months 3 days
Interest Rate Cash Flow Hedges [Abstract]
Net change in amount recognized in other comprehensive income	2,059,000	807,000
Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain to be reclassified within twelve months	835,000
Interest Rate Cash Flow Hedges [Abstract]
Amount reclassified from accumulated other comprehensive income into net interest income	1,047,000	-1,163,000
Amount of ineffectiveness recognized in net interest income	$0	$0

Derivatives_and_Hedging_Free_S

Derivatives and Hedging - Free Standing Derivative Instruments (Details) (Free-standing derivatives not designated as hedging instrument, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Futures contracts | Mortgage Banking Income and Corporate and Correspondent Investment Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$47	($76)
Option contracts related to mortgage servicing rights | Mortgage banking income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	-195	0
Forward and option contracts related to residential mortgage loans held for sale | Mortgage banking income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	-400	-1,554
Interest rate lock commitments | Mortgage banking income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	2,669	792
Interest rate contracts for customers | Corporate and correspondent investments sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	4,639	5,118
Commodity contracts for customers | Corporate and correspondent investments sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	14	8
Purchased equity option related to equity-linked CDs | Other expense
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	-6,288	3,778
Written equity option related to equity-linked CDs | Other expense
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	6,360	-3,679
Forward contracts related to commercial loans | Other income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	46,567	-5,487
Spot contracts related to commercial loans | Other income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	-6,895	880
Foreign currency exchange contracts for customers | Corporate and correspondent investments sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$380	$193

Derivatives_and_Hedging_Credit

Derivatives and Hedging - Credit and Market Risks (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Credit Derivatives [Line Items]
Derivative, collateral, right to reclaim cash	$55,574,000	[1]		$44,163,000	[1]
Derivative, collateral, obligation to return	49,064,000	[1]		58,309,000	[1]
Other assets
Credit Derivatives [Line Items]
Derivative, collateral, right to reclaim cash	54,000,000			46,000,000
Deposits
Credit Derivatives [Line Items]
Derivative, collateral, obligation to return	56,000,000			62,000,000
Free-standing derivatives not designated as hedging instrument | Interest Rate Swap
Credit Derivatives [Line Items]
Credit risk derivatives, at fair value, net	405,000,000
Gain (loss) on derivative instruments held for trading purposes, net	2,000		1,000
Derivatives designated as hedging instrument | Interest Rate Swap | Over the Counter
Credit Derivatives [Line Items]
Credit risk derivatives, at fair value, net	$95,000,000
[1]	The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists, the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.

Derivatives_and_Hedging_Contin

Derivatives and Hedging - Contingent Features (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, net liability position, aggregate fair value	$71	$65
Collateral already posted, aggregate fair value	67	62
Additional collateral, aggregate fair value	$4	$4

Assets_and_Liabilities_Subject2

Assets and Liabilities Subject to Enforceable Master Netting Arrangements (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Offsetting [Abstract]
Fair value of collateral received related to securities purchased under agreements to resell	$3,400,000,000		$2,600,000,000
Fair value of collateral pledged related to securities sold under agreements to repurchase	3,200,000,000		2,500,000,000
Securities purchased under agreements to resell
Securities purchased under agreements to resell, subject to master netting arrangement, gross amounts recognized	3,497,408,000		3,100,200,000
Securities purchased under agreements to resell, subject to a master netting arrangement, gross amounts offset in the condensed consolidated balance sheets	3,223,019,000		2,533,661,000
Securities purchased under agreements to resell, subject to a master netting arrangement, net amount presented in the condensed consolidated balance sheets	274,389,000		566,539,000
Securities purchased under agreements to resell, subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheets, financial instruments	274,389,000		566,539,000
Securities purchased under agreements to resell, net amount	0		0
Derivative financial assets:
Derivative assets, total derivatives subject to a master netting arrangement, gross amounts recognized	245,285,000		225,227,000
Derivative assets, total derivative subject to a master netting arrangement, gross amounts offset in the condensed consolidated balance sheet	0		0
Derivative assets, total derivatives subject to a master netting arrangement, net amount presented in the condensed consolidated balance sheets	245,285,000		225,227,000
Derivative assets, total derivatives subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheet, financial instruments	0	[1]	0	[1]
Derivate assets, total derivatives subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheets, cash collateral received/pledged	49,064,000	[1]	58,309,000	[1]
Derivative assets, total derivatives subject to a master netting arrangement, net amount	196,221,000		166,918,000
Derivative assets, total derivatives not subject to a master netting arrangement	329,774,000		260,736,000
Total derivative financial assets, gross amounts recognized	575,059,000		485,963,000
Total derivative financial assets, net amount presented in the condensed consolidated balance sheet	575,059,000		485,963,000
Total derivative financial assets, net amount	525,995,000		427,654,000
Securities sold under agreements to repurchase
Securities sold under agreements to repurchase, subject to a master netting arrangement, gross amounts recognized	3,250,397,000		2,969,345,000
Securities sold under agreements to repurchase, gross amounts offset in the condensed consolidated balance sheets	3,223,019,000		2,533,661,000
Securities sold under agreements to repurchase, subject to a master netting arrangement, net amount presented in the condensed consolidated balance sheet	27,378,000		435,684,000
Securities sold under agreements to repurchase, subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheet, financial instruments	27,378,000		435,684,000
Securities sold under agreements to repurchase, subject to a master netting arrangement, net amount	0		0
Derivative financial liabilities:
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts recognized	335,349,000		259,018,000
Derivative liabilities, total derivative subject to a master netting arrangement, gross amount offset in the condensed consolidated balance sheets	0		0
Derivative liabilities, total derivative subject to a master netting arrangement, net amount presented in the condensed consolidated balance sheets	335,349,000		259,018,000
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheets, financial instruments	27,453,000	[1]	29,677,000	[1]
Derivative liabilities, total derivative subject to a master netting arrangement, gross amounts not offset in the condensed consolidated balance sheets, cash collateral received/pledged	55,574,000	[1]	44,163,000	[1]
Derivative liabilities, total derivatives subject to a master netting arrangement, net amount	252,322,000		185,178,000
Derivative liabilities, total derivatives not subject to a master netting arrangement	97,830,000		103,240,000
Derivative liabilities, total derivative financial liabilities, gross amount recognized	433,179,000		362,258,000
Total derivative financial liabilities, net amount presented in the condensed consolidated balance sheets	433,179,000		362,258,000
Total derivative financial liabilities, net amount	$350,152,000		$288,418,000
[1]	The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists, the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.

Commitments_Contingencies_and_1

Commitments, Contingencies and Guarantees - Commitments (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Guarantor Obligations [Line Items]
Commitments to extend credit	$28,348,272	$28,369,666
Financial Standby Letter of Credit
Guarantor Obligations [Line Items]
Standby and commercial letters of credit	$1,695,974	$1,871,323

Commitments_Contingencies_and_2

Commitments, Contingencies and Guarantees - Narrative (Details) (USD $)	1 Months Ended			3 Months Ended
	31-May-13	Feb. 28, 2015	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014
Pending Litigation | BBVA Compass v. Morris Cerullo World Evangelism
Loss Contingencies And Guarantor Obligations [Line Items]
Damages sought	$5,200,000
Pending Litigation | Morris Cerullo World Evangelism v. BBVA Compass and Jack Wilkinson
Loss Contingencies And Guarantor Obligations [Line Items]
Damages sought		5,200,000
Pending Litigation | Jack Demetree Vs. BBVA Compass
Loss Contingencies And Guarantor Obligations [Line Items]
Damages sought			17,100,000
Pending Litigation | Other Litigation Matters
Loss Contingencies And Guarantor Obligations [Line Items]
Loss contingency accrual				15,000,000
Potential Recourse Related To FNMA Securitizations
Loss Contingencies And Guarantor Obligations [Line Items]
Potential recourse				20,000,000	20,000,000
Potential Recourse Related To FNMA Securitizations | Accrued expenses and other liabilities
Loss Contingencies And Guarantor Obligations [Line Items]
Loss contingency accrual				716,000	655,000
Standard Representations And Warranties Related To Loan Sales To Government-Sponsored Agencies | Accrued expenses and other liabilities
Loss Contingencies And Guarantor Obligations [Line Items]
Loss contingency accrual				1,000,000	1,000,000
FDIC Loss Sharing Agreement
Loss Contingencies And Guarantor Obligations [Line Items]
Covered loans				9,700,000,000
Loan losses reimbursable by FDIC, percentage of loss reimbursable				80.00%
FDIC indemnification asset, threshold loss amount				2,300,000,000
FDIC indemnification asset, percentage of incurred losses above threshold, amount reimbursed				95.00%
FDIC loss sharing agreement, term				10 years
Loss sharing agreement, percentage owed by company to FDIC if terms are met				60.00%
Loss sharing agreement, threshold amount				457,000,000
Loss sharing agreement, percentage of net amount paid to company, subject to repayment to FDIC				25.00%
Loss sharing agreement, administration costs for loans, percentage subject to repayment to FDIC				20.00%
Loss sharing agreement, average administration cost percentage				2.00%
Loss sharing agreement, amount owed to FDIC				145,000,000	145,000,000
FDIC Loss Sharing Agreement | Commercial Loan
Loss Contingencies And Guarantor Obligations [Line Items]
FDIC loss sharing agreement, term				5 years
FDIC Loss Sharing Agreement | Single Family Residential Loan
Loss Contingencies And Guarantor Obligations [Line Items]
FDIC loss sharing agreement, term				10 years
Financial Standby Letter of Credit
Loss Contingencies And Guarantor Obligations [Line Items]
Letters of credit, deferred fees				6,500,000	5,200,000
Maximum potential amount of future undiscounted payments Company could be required to make on outstanding standby letters of credit				1,700,000,000
Financial Standby Letter of Credit | Pending Litigation | BBVA Compass v. Morris Cerullo World Evangelism
Loss Contingencies And Guarantor Obligations [Line Items]
Line of credit	5,200,000
Financial Standby Letter of Credit | Pending Litigation | Morris Cerullo World Evangelism v. BBVA Compass and Jack Wilkinson
Loss Contingencies And Guarantor Obligations [Line Items]
Line of credit		5,200,000
Financial Standby Letter of Credit | Accrued expenses and other liabilities
Loss Contingencies And Guarantor Obligations [Line Items]
Loss contingency accrual				$93,000,000	$94,000,000
Financial Standby Letter of Credit | Minimum
Loss Contingencies And Guarantor Obligations [Line Items]
Standby and commercial letters of credit expiration term				1 year
Financial Standby Letter of Credit | Maximum
Loss Contingencies And Guarantor Obligations [Line Items]
Standby and commercial letters of credit expiration term				4 years

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Fair Value, Option, Quantitative Disclosures [Line Items]
Federal home loan bank and federal reserve stock required to be owned by company	$499,000,000		$500,000,000
Forward contracts
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains realized due to changes in fair value of loans	-400,000	-1,600,000
Noninterest income | Residential mortgage loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains realized due to changes in fair value of loans	$548,000	$690,000

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Unpaid Principle Balances (Details) (Residential mortgage loans held for sale, USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Residential mortgage loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Aggregate fair value	$198,488	$154,816
Aggregate unpaid principle balance	191,687	148,564
Difference	$6,801	$6,252

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Fair value of balance sheet items (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Assets:
Trading account assets	$3,680,427		$2,834,397
Loans held for sale, estimated fair value	198,488		154,816
Investment securities available for sale	10,101,828		10,237,275
Derivative asset	575,059		485,963
Other assets	1,148,883		1,318,392
Liabilities:
Derivative liabilities	433,179		362,258
US Treasury and government agency
Assets:
Investment securities available for sale	2,536,770		2,313,542
State and political subdivisions
Assets:
Investment securities available for sale	416,042		467,315
Other debt obligations
Assets:
Investment securities available for sale	17,767		44,441
Collateralized mortgage obligations
Assets:
Investment securities available for sale	2,445,069		2,488,579
Equity securities
Assets:
Investment securities available for sale	498,693		499,563
Fair Value, measurements, recurring
Assets:
Trading account assets	3,680,427		2,834,397
Loans held for sale, estimated fair value	198,488		154,816
Investment securities available for sale	9,603,261		9,737,760
Derivative asset	169,842		155,887
Other assets	35,213		35,488
Liabilities:
Trading account liabilities	3,723,650		2,815,462
Derivative liabilities	85,791		91,085
Fair Value, measurements, recurring | Interest rate contracts
Assets:
Derivative asset	90,686		73,830
Liabilities:
Derivative liabilities	16,903		16,074
Fair Value, measurements, recurring | Equity Contract
Assets:
Derivative asset	70,199		76,487
Liabilities:
Derivative liabilities	67,959		74,319
Fair Value, measurements, recurring | Foreign exchange contracts
Assets:
Derivative asset	8,957		5,570
Liabilities:
Derivative liabilities	929		692
Fair Value, measurements, recurring | US Treasury and government agency
Assets:
Trading account assets	3,267,024		2,502,308
Investment securities available for sale	2,536,770		2,313,542
Liabilities:
Trading account liabilities	3,368,354		2,545,299
Fair Value, measurements, recurring | State and political subdivisions
Assets:
Trading account assets	1,030
Investment securities available for sale	416,042		467,315
Fair Value, measurements, recurring | Other debt obligations
Assets:
Trading account assets	3,972
Investment securities available for sale	17,767		44,441
Liabilities:
Trading account liabilities	7,756
Fair Value, measurements, recurring | Other equity securities
Assets:
Trading account assets	166
Fair Value, measurements, recurring | Interest rate contracts
Assets:
Trading account assets	369,042		296,239
Liabilities:
Trading account liabilities	310,602		236,763
Fair Value, measurements, recurring | Commodity contracts for customers
Assets:
Trading account assets	21,568		25,569
Liabilities:
Trading account liabilities	21,471		25,448
Fair Value, measurements, recurring | Foreign exchange contracts
Assets:
Trading account assets	14,607		8,268
Liabilities:
Trading account liabilities	13,883		7,527
Fair Value, measurements, recurring | Other trading assets
Assets:
Trading account assets	3,018		2,013
Fair Value, measurements, recurring | Collateralized mortgage obligations
Assets:
Investment securities available for sale	4,187,487		4,423,835
Fair Value, measurements, recurring | Collateralized mortgage obligations
Assets:
Investment securities available for sale	2,445,069		2,488,579
Fair Value, measurements, recurring | Equity securities
Assets:
Investment securities available for sale	126	[1]	48	[2]
Fair Value, measurements, recurring | Other trading liabilities
Liabilities:
Trading account liabilities	1,584		425
Fair Value, measurements, recurring | Quoted Prices in Active Markets for Identical Assets, Level 1
Assets:
Trading account assets	3,267,024		2,502,308
Investment securities available for sale	1,385,512		1,342,525
Liabilities:
Trading account liabilities	3,368,354		2,545,299
Fair Value, measurements, recurring | Quoted Prices in Active Markets for Identical Assets, Level 1 | US Treasury and government agency
Assets:
Trading account assets	3,267,024		2,502,308
Investment securities available for sale	1,367,699		1,298,040
Liabilities:
Trading account liabilities	3,368,354		2,545,299
Fair Value, measurements, recurring | Quoted Prices in Active Markets for Identical Assets, Level 1 | Other debt obligations
Assets:
Investment securities available for sale	17,767		44,441
Fair Value, measurements, recurring | Quoted Prices in Active Markets for Identical Assets, Level 1 | Equity securities
Assets:
Investment securities available for sale	46	[1]	44	[2]
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2
Assets:
Trading account assets	411,967		330,499
Loans held for sale, estimated fair value	198,488		154,816
Investment securities available for sale	8,217,669		8,395,231
Derivative asset	164,854		153,568
Liabilities:
Trading account liabilities	355,296		270,163
Derivative liabilities	85,790		91,084
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Interest rate contracts
Assets:
Derivative asset	85,698		71,511
Liabilities:
Derivative liabilities	16,902		16,073
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Equity Contract
Assets:
Derivative asset	70,199		76,487
Liabilities:
Derivative liabilities	67,959		74,319
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Foreign exchange contracts
Assets:
Derivative asset	8,957		5,570
Liabilities:
Derivative liabilities	929		692
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | US Treasury and government agency
Assets:
Investment securities available for sale	1,169,071		1,015,502
Liabilities:
Trading account liabilities	0
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | State and political subdivisions
Assets:
Trading account assets	1,030
Investment securities available for sale	416,042		467,315
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Other debt obligations
Assets:
Trading account assets	3,972
Investment securities available for sale	0		0
Liabilities:
Trading account liabilities	7,756
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Other equity securities
Assets:
Trading account assets	166
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Interest rate contracts
Assets:
Trading account assets	369,042		296,239
Liabilities:
Trading account liabilities	310,602		236,763
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Commodity contracts for customers
Assets:
Trading account assets	21,568		25,569
Liabilities:
Trading account liabilities	21,471		25,448
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Foreign exchange contracts
Assets:
Trading account assets	14,607		8,268
Liabilities:
Trading account liabilities	13,883		7,527
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Other trading assets
Assets:
Trading account assets	1,582		423
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Collateralized mortgage obligations
Assets:
Investment securities available for sale	4,187,487		4,423,835
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Collateralized mortgage obligations
Assets:
Investment securities available for sale	2,445,069		2,488,579
Fair Value, measurements, recurring | Significant Other Observable Inputs, Level 2 | Other trading liabilities
Liabilities:
Trading account liabilities	1,584		425
Fair Value, measurements, recurring | Fair Value, Inputs, Level 3
Assets:
Trading account assets	1,436		1,590
Investment securities available for sale	80		4
Derivative asset	4,988		2,319
Other assets	35,213		35,488
Liabilities:
Derivative liabilities	1		1
Fair Value, measurements, recurring | Fair Value, Inputs, Level 3 | Interest rate contracts
Assets:
Derivative asset	4,988		2,319
Liabilities:
Derivative liabilities	1		1
Fair Value, measurements, recurring | Fair Value, Inputs, Level 3 | Other trading assets
Assets:
Trading account assets	1,436		1,590
Fair Value, measurements, recurring | Fair Value, Inputs, Level 3 | Equity securities
Assets:
Investment securities available for sale	$80	[1]	$4	[2]
[1]	Excludes $499 million of FHLB and Federal Reserve stock required to be owned by the Company at March 31, 2015. These securities are carried at par.
[2]	Excludes $500 million of FHLB and Federal Reserve stock required to be owned by the Company at December 31, 2014. These securities are carried at par.

Fair_Value_of_Financial_Instru5

Fair Value of Financial Instruments - Assets measured on a recurring basis (Details) (Fair Value, measurements, recurring, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2013
Other trading securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of year	$1,590		$1,645
Included in earnings	-154	[1]	47	[1]
Purchases, issuances, sales and settlements: [Abstract]
Balance, end of year	1,436		1,692
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	-154		47
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of year	4				6
Purchases, issuances, sales and settlements: [Abstract]
Purchases	76
Balance, end of year	80		6		6
Interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of year	2,318		890
Included in earnings	2,669	[1]	792	[1]
Purchases, issuances, sales and settlements: [Abstract]
Balance, end of year	4,987		1,682
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	2,669		792
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of year	35,488		30,065
Included in earnings	-3,034	[1]	-320	[1]
Purchases, issuances, sales and settlements: [Abstract]
Issuances	2,759		2,083
Balance, end of year	35,213		31,828
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held	($3,034)		($320)
[1]	Included in noninterest income in the Unaudited Condensed Consolidated Statements of Income.

Fair_Value_of_Financial_Instru6

Fair Value of Financial Instruments - Assets measured on nonrecurring basis (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Securities - Fair Value	$1,297,565				$1,275,963
OREO, fair value	17,764		25,817
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Securities - Fair Value	1,297,565				1,275,963
Fair Value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Securities - Fair Value	3,205		3,462
Investment securities held to maturity recorded as other than temporary impairment losses	-285		-146
Impaired loans, fair value	132,336	[1]	169,546	[1]
Impaired loans, total gains (losses)	-3,304	[1]	-4,344	[1]
OREO, total gains (losses)	-1,259		577
Fair Value, measurements, nonrecurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Securities - Fair Value	3,205		3,462
Impaired loans, fair value	132,336	[1]	169,546	[1]
OREO, fair value	$17,764		$25,817
[1]	Total gains (losses) represent charge-offs on impaired loans for which adjustments are based on the appraised value of the collateral.

Fair_Value_of_Financial_Instru7

Fair Value of Financial Instruments - Quantitative information about unobservable inputs for material assets and liabilities measured using fair value (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014	Mar. 31, 2014
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment Securities - Fair Value	1,297,565,000		$1,275,963,000
OREO, fair value	17,764,000			25,817,000
Fair Value, measurements, recurring | Other trading securities
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Other trading asset, fair value	1,436,000
Fair Value, measurements, recurring | Interest rate contracts
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Interest rate contracts, fair value	4,987,000
Fair Value, measurements, recurring | Other assets
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Other assets -MSRs, fair value	35,213,000
Fair Value, measurements, nonrecurring
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment Securities - Fair Value	3,205,000			3,462,000
Impaired loans, fair value	132,336,000	[1]		169,546,000	[1]
Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment Securities - Fair Value	1,297,565,000		1,275,963,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Other trading securities | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Default rate	8.90%
Prepayment rate	7.30%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing (pull-through) rate	59.60%
Cap grid rate	1.10%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Other assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate	11.20%
Cost to service	67
Discount rate	10.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Other trading securities | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate	5.40%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing (pull-through) rate	6.40%
Cap grid rate	0.30%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Other assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate	6.10%
Cost to service	57
Discount rate	10.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Other trading securities | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate	9.80%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing (pull-through) rate	98.70%
Cap grid rate	2.50%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Other assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate	49.50%
Cost to service	566
Discount rate	11.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment Securities - Fair Value	3,205,000			3,462,000
Impaired loans, fair value	132,336,000	[1]		169,546,000	[1]
OREO, fair value	17,764,000			$25,817,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Default rate	7.50%
Prepayment rate	9.60%
Loss severity rate	61.20%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate	26.80%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | OREO | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate	8.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Minimum | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate	0.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Maximum | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate	100.00%
[1]	Total gains (losses) represent charge-offs on impaired loans for which adjustments are based on the appraised value of the collateral.

Fair_Value_of_Financial_Instru8

Fair Value of Financial Instruments - Carrying value and estimated fair value (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$3,964,357	$3,388,405	$4,273,672	$3,598,460
Investment securities held to maturity	1,373,542	1,348,354
Investment securities held to maturity, estimated fair value	1,297,565	1,275,963
Deposits	62,900,681	61,189,716
Federal funds purchased and securities sold under agreements to repurchase	909,683	1,129,503
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, estimated fair value	3,964,357	3,388,405
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deposits, estimated fair value	63,012,674	61,263,812
FHLB and other borrowings, estimated fair value	4,925,458	4,786,152
Federal funds purchased and securities sold under agreements to repurchase, estimated fair value	909,683	1,129,503
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities held to maturity, estimated fair value	1,297,565	1,275,963
Loans, net, estimated fair value	55,263,025	54,551,442
Reported value measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,964,357	3,388,405
Investment securities held to maturity	1,373,542	1,348,354
Loans, net	57,856,599	56,686,743
Deposits	62,900,681	61,189,716
FHLB and other borrowings	4,919,141	4,809,843
Federal funds purchased and securities sold under agreements to repurchase	909,683	1,129,503
Estimate of fair value measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, estimated fair value	3,964,357	3,388,405
Investment securities held to maturity, estimated fair value	1,297,565	1,275,963
Loans, net, estimated fair value	55,263,025	54,551,442
Deposits, estimated fair value	63,012,674	61,263,812
FHLB and other borrowings, estimated fair value	4,925,458	4,786,152
Federal funds purchased and securities sold under agreements to repurchase, estimated fair value	$909,683	$1,129,503

Comprehensive_Income_Details

Comprehensive Income (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Equity [Abstract]
Unrealized holding gains (losses) arising during period from securities available for sale, pretax	$64,790	$40,962
Unrealized holding gains (losses) arising during period from securities available for sale, tax expense (benefit)	28,202	14,722
Unrealized holding gains (losses) arising during period from securities available for sale, after tax	36,588	26,240
Less: reclassification adjustment for net gains on sale of securities in net income, pretax	32,832	16,434
Less: reclassification adjustment for net gains on sale of securities in net income, tax expense (benefit)	14,292	5,908
Less: reclassification adjustment for net gains on sale of securities in net income, after tax	18,540	10,526
Net change in unrealized gains (losses) on securities available for sale, pretax	31,958	24,528
Net change in unrealized gains (losses) on securities available for sale, tax expense (benefit)	13,910	8,814
Net change in unrealized holding gains on securities available for sale	18,048	15,714
Change in unamortized net holding losses on investment securities held to maturity, pretax	3,142	4,774
Change in unamortized net holding losses on investment securities held to maturity, tax expense (benefit)	1,368	1,716
Change in unamortized net holding losses on investment securities held to maturity, after tax	1,774	3,058
Other Comprehensive Income (Loss), Non-credit Related Impairment on Investment Securities Held to Maturity, pretax	87	235
Other Comprehensive Income (Loss), Non-credit Related Impairment on Investment Securities Held to Maturity, tax expense (benefit)	38	84
Less: non-credit related impairment on investment securities held to maturity	49	151
Change in unamortized non-credit related impairment on investment securities held to maturity, pretax	276	385
Change in unamortized non-credit related impairment on investment securities held to maturity, tax expense (benefit)	120	139
Change in unamortized non-credit related impairment on investment securities held to maturity, after tax	156	246
Net change in unamortized holding losses on securities held to maturity, pretax	3,331	4,924
Net change in unamortized holding losses on securities held to maturity, tax expense (benefit)	1,450	1,771
Net change in unamortized holding losses on securities held to maturity	1,881	3,153
Unrealized holding gains (losses) arising during period from cash flow hedge instruments, pretax	3,646	-1,261
Unrealized holding gains (losses) arising during period from cash flow hedge instruments, tax expense (benefit)	1,587	-454
Unrealized holding gains (losses) arising during period from cash flow hedge instruments, after tax	2,059	-807
Change in defined benefit plans, pretax	2,716	-2,672
Change in defined benefit plans, tax expense (benefit)	1,001	-1,001
Change in defined benefit plans, after tax	1,715	-1,671
Other comprehensive income (loss), pretax	41,651	25,519
Other comprehensive income (loss), tax expense (benefit)	17,948	9,130
Other comprehensive income, net of tax	$23,703	$16,389

Comprehensive_Income_AOCI_Deta

Comprehensive Income - AOCI (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Comprehensive Income [Roll Forward]
Beginning balance	($51,357)	($87,936)
Other comprehensive income (loss) before reclassifications	39,189	24,536
Amounts reclassified from accumulated other comprehensive income (loss)	-15,486	-8,147
Other comprehensive income, net of tax	23,703	16,389
Ending balance	-27,654	-71,547
Unrealized Gains (Losses) on Securities Available for Sale and Transferred to Held to Maturity
Accumulated Comprehensive Income [Roll Forward]
Beginning balance	4,469	-31,490
Other comprehensive income (loss) before reclassifications	36,588	26,240
Amounts reclassified from accumulated other comprehensive income (loss)	-16,766	-7,468
Other comprehensive income, net of tax	19,822	18,772
Ending balance	24,291	-12,718
Accumulated (Gains) Losses on Cash Flow Hedging Instruments
Accumulated Comprehensive Income [Roll Forward]
Beginning balance	-7,189	-5,289
Other comprehensive income (loss) before reclassifications	2,650	-1,553
Amounts reclassified from accumulated other comprehensive income (loss)	-591	746
Other comprehensive income, net of tax	2,059	-807
Ending balance	-5,130	-6,096
Defined Benefit Plan Adjustment
Accumulated Comprehensive Income [Roll Forward]
Beginning balance	-41,121	-41,921
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	1,715	-1,671
Other comprehensive income, net of tax	1,715	-1,671
Ending balance	-39,406	-43,592
Unamortized Impairment Losses on Investment Securities Held to Maturity
Accumulated Comprehensive Income [Roll Forward]
Beginning balance	-7,516	-9,236
Other comprehensive income (loss) before reclassifications	-49	-151
Amounts reclassified from accumulated other comprehensive income (loss)	156	246
Other comprehensive income, net of tax	107	95
Ending balance	($7,409)	($9,141)

Comprehensive_Income_Reclassif

Comprehensive Income - Reclassifications out of AOCI (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest on investment securities held to maturity	$6,702		$7,246
Interest and fees on loans	543,842		508,506
Interest and fees on FHLB advances	-19,106		-16,364
Net income (loss) before income tax expense (benefit)	193,549		158,494
Income tax (expense) benefit	-51,782		-43,567
Net income	141,767		114,927
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains on Securities Available for Sale and Transferred to Held to Maturity
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	32,832	[1]	16,434	[1]
Interest on investment securities held to maturity	-3,142	[1]	-4,774	[1]
Net income (loss) before income tax expense (benefit)	29,690	[1]	11,660	[1]
Income tax (expense) benefit	-12,924	[1]	-4,192	[1]
Net income	16,766	[1]	7,468	[1]
Reclassification out of Accumulated Other Comprehensive Income | Accumulated (Gains) Losses on Cash Flow Hedging Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and fees on loans	2,813	[1]	612	[1]
Interest and fees on FHLB advances	-1,766	[1]	-1,775	[1]
Net income (loss) before income tax expense (benefit)	1,047	[1]	-1,163	[1]
Income tax (expense) benefit	-456	[1]	417	[1]
Net income	591	[1]	-746	[1]
Reclassification out of Accumulated Other Comprehensive Income | Defined Benefit Plan Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic expense	-2,716	[1],[2]	2,672	[1],[2]
Income tax (expense) benefit	1,001	[1]	-1,001	[1]
Net income	-1,715	[1]	1,671	[1]
Reclassification out of Accumulated Other Comprehensive Income | Unamortized Impairment Losses on Investment Securities Held to Maturity
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest on investment securities held to maturity	-276	[1]	-385	[1]
Income tax (expense) benefit	120	[1]	139	[1]
Net income	($156)	[1]	($246)	[1]
[1]	Amounts in parentheses indicate debits to the consolidated statement of income.
[2]	These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 18, Benefit Plans, in the Notes to the December 31, 2014, Consolidated Financial Statements for additional details).

Supplemental_Disclosure_for_St2

Supplemental Disclosure for Statement of Cash Flows (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Supplemental disclosures of cash flow information:
Interest paid	$90,984	$55,675
Net income taxes paid (refunded)	2,212	-708
Supplemental schedule of noncash investing and financing activities:
Transfer of loans and loans held for sale to OREO	2,718	8,920
Change in unrealized gain (loss) on available for sale securities	31,958	24,528
Issuance of restricted stock, net of cancellations	458	-547
Business combinations:
Assets acquired	0	116,152
Liabilities assumed	$0	$18,329

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$509,029	$495,299
Allocated provision for loan losses	42,031	37,266
Noninterest income	249,270	219,328
Noninterest expense	522,719	518,867
Net income (loss) before income tax expense (benefit)	193,549	158,494
Income tax expense (benefit)	51,782	43,567
Net income	141,767	114,927
Less: net income attributable to noncontrolling interests	657	453
Net income attributable to shareholder	141,110	114,474
Average assets	85,087,155	73,359,144
Operating Segments | Consumer and Commercial Banking
Segment Reporting Information [Line Items]
Net interest income	482,365	453,867
Allocated provision for loan losses	30,294	36,621
Noninterest income	176,317	174,257
Noninterest expense	424,608	429,925
Net income (loss) before income tax expense (benefit)	203,780	161,578
Income tax expense (benefit)	71,323	60,188
Net income	132,457	101,390
Less: net income attributable to noncontrolling interests	228	17
Net income attributable to shareholder	132,229	101,373
Average assets	52,605,892	47,781,589
Operating Segments | Corporate and Investment Banking
Segment Reporting Information [Line Items]
Net interest income	39,932	32,077
Allocated provision for loan losses	11,025	1,010
Noninterest income	49,487	47,235
Noninterest expense	40,186	31,214
Net income (loss) before income tax expense (benefit)	38,208	47,088
Income tax expense (benefit)	13,373	17,540
Net income	24,835	29,548
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to shareholder	24,835	29,548
Average assets	11,833,948	6,418,599
Operating Segments | Treasury
Segment Reporting Information [Line Items]
Net interest income	18,382	4,625
Allocated provision for loan losses	0	0
Noninterest income	33,856	22,013
Noninterest expense	5,097	3,640
Net income (loss) before income tax expense (benefit)	47,141	22,998
Income tax expense (benefit)	16,500	8,567
Net income	30,641	14,431
Less: net income attributable to noncontrolling interests	429	436
Net income attributable to shareholder	30,212	13,995
Average assets	13,572,927	12,334,277
Corporate, Non-Segment | Corporate Support and Other
Segment Reporting Information [Line Items]
Net interest income	-31,650	4,730
Allocated provision for loan losses	712	-365
Noninterest income	-10,390	-24,177
Noninterest expense	52,828	54,088
Net income (loss) before income tax expense (benefit)	-95,580	-73,170
Income tax expense (benefit)	-49,414	-42,728
Net income	-46,166	-30,442
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to shareholder	-46,166	-30,442
Average assets	$7,074,388	$6,824,679

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Aug. 01, 2014	Mar. 16, 2012
Related Party Transaction [Line Items]
Securities purchased under agreements to resell	$274,389,000	$566,539,000
Securities sold under agreements to repurchase	27,378,000	435,684,000
BSI | Line of Credit | BBVA Compass Bancshares, Inc.
Related Party Transaction [Line Items]
Due from related parties			150,000,000
BSI | Revolving Credit Facility | Line of Credit | BBVA Compass Bancshares, Inc.
Related Party Transaction [Line Items]
Due from related parties				420,000,000
BBVA
Related Party Transaction [Line Items]
Securities purchased under agreements to resell	0	97,970,000
Securities sold under agreements to repurchase	212,000	435,684,000
Derivatives designated as hedging instrument | BBVA
Related Party Transaction [Line Items]
Related party transaction, amount of transaction	1,164,000	1,693,000
Free-standing derivatives not designated as hedging instrument | Free-standing derivative instruments – risk management and other purposes | BBVA
Related Party Transaction [Line Items]
Related party transaction, amount of transaction	($10,055,000)	$9,512,000

Subsequent_Event_Details

Subsequent Event (Details) (Subsequent Event, USD $)	0 Months Ended
	Apr. 10, 2015
Senior Notes
Subsequent Event [Line Items]
Minimum maturity period	7 days
Subordinated Notes
Subsequent Event [Line Items]
Minimum maturity period	5 years
3.875% Notes | Unsecured Subordinated Notes due 2025
Subsequent Event [Line Items]
Principal amount	700,000,000
Stated interest rate	3.88%