Zions Bancorporation, National Association (ZION) 10-K 1 Mar 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	zion
Entity Registrant Name	ZIONS BANCORPORATION /UT/
Entity Central Index Key	109,380
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 8,745,683,795
Entity Common Stock, Shares Outstanding		196,514,295

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deposits	$ 52,621	$ 53,236
Current Fiscal Year End Date	--12-31
Held-to-maturity Securities, Fair Value	$ 762
Preferred Stock, Shares Authorized	4,400	4,400
Common Stock, Shares Authorized	350,000	350,000
Common Stock, Shares, Issued	197,532	203,085
Common stock, outstanding shares	197,532	203,085
ASSETS
Cash and due from banks	$ 548	$ 737
Money market investments:
Interest-bearing deposits	782	1,411
Federal funds sold and security resell agreements	514	568
Investment securities:
Available-for-sale, at fair value	15,161	13,372
Trading account, at fair value	148	115
Marketable Securities	16,079	14,355
Loans held for sale	44	172
Loans, net of allowance
Loans and leases, net of unearned income and fees	44,780	42,649
Less allowance for loan losses	518	567
Loans, net of allowance	44,262	42,082
Other noninterest-bearing investments	1,029	884
Premises, equipment and software net	1,094	1,020
Goodwill	1,014	1,014
Core deposit and other intangibles	2	8
Other real estate owned	4	4
Other assets	916	984
Total assets	66,288	63,239
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing demand	23,886	24,115
Interest-bearing:
Savings and Money Market	25,620	26,364
Time	3,115	2,757
Federal funds and other short-term borrowings	4,976	827
Long-term debt	383	535
Reserve for unfunded lending commitments	58	65
Other liabilities	571	942
Total liabilities	58,609	55,605
Shareholders' equity:
Preferred stock, without par value, authorized 4,400 shares	566	710
Common stock, without par value; authorized 350,000 shares; issued and outstanding 197,532 and 203,085 shares	4,445	4,725
Retained earnings	2,807	2,321
Accumulated Other Comprehensive Income (Loss)	139	122
Total shareholders' equity	7,679	7,634
Total liabilities and shareholders' equity	66,288	63,239
Fair Value, Inputs, Level 2 [Member]
Investment securities:
Trading account, at fair value	148	115
Estimate of Fair Value Measurement [Member]
Loans, net of allowance
Loans, net of allowance		42,111
Interest-bearing:
Time		2,744
Long-term debt		552
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Held-to-maturity Securities, Fair Value	762	$ 850
Interest-bearing:
Time	3,099
Long-term debt	$ 402

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Held-to-maturity, fair value	$ 762
Preferred stock, authorized shares	4,400	4,400
Common stock, authorized shares	350,000	350,000
Common stock, issued shares	197,532	203,085
Common stock, outstanding shares	197,532	203,085

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest income:
Interest and fees on loans	$ 1,847	$ 1,729	$ 1,686
Interest on money market investments	19	21	23
Interest on securities	326	204	124
Total interest income	2,192	1,954	1,833
Interest expense:
Interest on deposits	59	49	49
Interest on short- and long-term borrowings	68	38	69
Total interest expense	127	87	118
Net interest income	2,065	1,867	1,715
Provision for loan losses	24	93	40
Net interest income after provision for loan losses	2,041	1,774	1,675
Noninterest income:
Service charges and fees on deposit accounts	171	171	168
Other service charges, commissions and fees	217	208	187
Wealth management and trust income	42	37	31
Loan sales and servicing income	25	35	31
Capital markets and foreign exchange	30	22	26
Noninterest income, Customer-related Fees	485	473	443
Dividends and other investment income	40	24	30
Securities gains (losses), net	14	7	(127)
Impairment losses on investment securities:
Other	5	12	11
Noninterest Income	544	516	357
Noninterest expense:
Salaries and employee benefits	1,011	983	973
Occupancy, net	129	125	120
Furniture, equipment, and software	130	125	123
Other real estate expense, net	1	2	1
Credit-related expense	29	26	29
Provision for unfunded lending commitments	(7)	(10)	(6)
Professional and legal services	54	55	50
Advertising	22	22	25
FDIC premiums	53	40	34
Amortization of core deposit and other Intangibles	6	8	9
Other	223	213	225
Noninterest Expense	1,649	1,585	1,581
Income before income taxes	936	705	451
Income taxes	344	236	142
Net income	592	469	309
Preferred stock dividends	(40)	(48)	(62)
Preferred Stock Redemption			0
Net earnings applicable to common shareholders	$ 550	$ 411	$ 247
Weighted average common shares outstanding during the period:
Basic shares	200,776	203,855	203,265
Diluted shares	209,653	204,269	203,698
Net earnings per common share:
Basic, per share	$ 2.71	$ 2	$ 1.20
Diluted, per share	$ 2.60	$ 1.99	$ 1.20

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 592	$ 469	$ 309
Other comprehensive income, net of tax:
Net unrealized holding losses on investment securities	(2)	(74)	(23)
Reclassification of HTM securities to AFS securities	0	0	11
Reclassification to earnings for realized securities losses	0	0	86
Net unrealized gains (losses) on other noninterest-bearing investments	3	2	(3)
Net unrealized holding gains (losses) on derivative instruments	(3)	5	7
Reclassification adjustment for increase in interest income recognized in earnings on derivative instruments	(2)	(7)	(6)
Pension and postretirement	(12)	(7)	(1)
Effect of new tax rates from Tax Cuts and Jobs Act of 2017	25	0	0
Other comprehensive income, net of tax	(17)	(67)	73
Comprehensive income	$ 575	$ 402	$ 382

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($) shares in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares			203,015
Balance at Dec. 31, 2014	$ 7,369,000,000	$ 1,004,000,000	$ 4,724,000,000	$ 1,769,000,000	$ (128,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	309,000,000			309,000,000
Other comprehensive income (loss)	73,000,000				73,000,000
Preferred stock redemption	176,000,000	176,000,000	$ (3,000,000)	3,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,402
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	40,000,000		$ 40,000,000
Dividends on preferred stock	(62,000,000)	(0.22)		(62,000,000)
Dividends on common stock	(45,000,000)			(45,000,000)
Increase (Decrease) in Deferred Compensation	(1,000,000)			(1,000,000)
Balance at Dec. 31, 2015	7,507,000,000	828,000,000	$ 4,767,000,000	1,967,000,000	(55,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares			204,417
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	469,000,000			469,000,000
Other comprehensive income (loss)	(67,000,000)				(67,000,000)
Preferred stock redemption	$ 126,000,000	118,000,000	$ (2,000,000)	10,000,000
Stock Repurchased During Period, Shares	3,000		(2,889)
Stock Repurchased and Retired During Period, Value	$ (90,000,000)
Subordinated debt converted to preferred stock	(90,000,000)		$ (90,000,000)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,557
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	46,000,000		$ 46,000,000
Dividends on preferred stock	(48,000,000)	(0.28)		(48,000,000)
Dividends on common stock	(58,000,000)			(58,000,000)
Increase (Decrease) in Deferred Compensation	1,000,000			1,000,000
Balance at Dec. 31, 2016	$ 7,634,000,000	710,000,000	$ 4,725,000,000	2,321,000,000	(122,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares	203,085		203,085
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 592,000,000			592,000,000
Other Comprehensive Income (Loss), before Tax	8,000,000				8,000,000
Other comprehensive income (loss)	(17,000,000)
Preferred stock redemption	$ (144,000,000)	(144,000,000)	$ 2,000,000	(2,000,000)
Stock Repurchased During Period, Shares	7,000		(7,009)
Stock Repurchased and Retired During Period, Value	$ (320,000,000)		$ (320,000,000)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			1,456
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	38,000,000		$ 38,000,000
Dividends on preferred stock	(40,000,000)	(0.44)		(40,000,000)
Dividends on common stock	(89,000,000)			(89,000,000)
Effect of new tax rates from Tax Cuts and Jobs Act of 2017	0			25,000,000	(25,000,000)
Balance at Dec. 31, 2017	$ 7,679,000,000	$ 566,000,000	$ 4,445,000,000	$ 2,807,000,000	$ (139,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding shares	197,532		197,532

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 592	$ 469	$ 309
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	17	83	34
Depreciation and amortization	179	123	86
Securities losses (gains), net	25	26	25
Deferred income tax expense (benefit)	154	(8)	(30)
Net decrease (increase) in trading securities	(33)	(67)	22
Net decrease (increase) in loans held for sale	97	1	(6)
Change in other liabilities	29	1	(6)
Change in other assets	(89)	(10)	(67)
Other, net	(29)	(15)	(30)
Net cash provided by operating activities	928	596	464
CASH FLOWS FROM INVESTING ACTIVITIES
Net decrease in money market investments	683	4,749	1,837
Proceeds from maturities and paydowns of investment securities held-to-maturity	314	94	123
Purchases of investment securities held-to-maturity	(216)	(416)	(61)
Proceeds from sales, maturities, and paydowns of investment securities available-for-sale	2,412	3,787	1,681
Purchases of investment securities available-for-sale	(4,719)	(9,359)	(5,513)
Net change in loans and leases	(2,135)	(2,102)	(563)
Purchases and sales of other noninterest-bearing investments	(105)	(20)	31
Purchases of premises and equipment	(169)	(196)	(157)
Proceeds from sales of other real estate owned	8	20	25
Other, net	(8)	(7)	(18)
Net cash used in investing activities	(3,919)	(3,436)	(2,579)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in deposits	(614)	2,883	2,526
Net change in short-term funds borrowed	2,149	480	103
Proceeds from debt over 90 days and up to one year	5,100	0	0
Repayments of debt over 90 days and up to one year	(3,100)	0	0
Cash paid for preferred stock redemption	(144)	(126)	(176)
Repayments of long-term debt	(153)	(280)	(288)
Company common stock repurchased	(332)	(97)	(7)
Proceeds from Issuance of common stock	25	25	22
Dividends paid on common and preferred stock	(129)	(108)	(108)
Other, net	0	2	(1)
Net cash provided by financing activities	2,802	2,779	2,071
Net decrease in cash and due from banks	(189)	(61)	(44)
Cash and due from banks at beginning of period	737	798	842
Cash and due from banks at end of period	548	737	798
Interest paid	118	83	102
Net cash paid for income taxes	246	214	132
Loans held for investment transfered to other real estate owned	6	15	12
Loans held for investment reclassified to loans held for sale, net	25	50	5
Available for sale securities purchased, not settled	5	395	0
Adjusted cost of HTM securities reclassifed as AFS securities	$ 0	$ 0	$ 79

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Business Zions Bancorporation (“the Parent”) is a financial holding company headquartered in Salt Lake City, Utah, which owns and operates a commercial bank. The Parent and its subsidiaries (collectively “the Company”) provide a full range of banking and related services in 11 western and southwestern states through seven separately managed and branded units as follows: Zions Bank, in Utah, Idaho and Wyoming; California Bank & Trust (“CB&T”); Amegy Bank (“Amegy”), in Texas; National Bank of Arizona (“NBAZ”); Nevada State Bank (“NSB”); Vectra Bank Colorado (“Vectra”), in Colorado and New Mexico; and The Commerce Bank of Washington (“TCBW”) which operates under that name in Washington and under the name The Commerce Bank of Oregon (“TCBO”) in Oregon. Pursuant to a Board resolution adopted November 21, 2014, TCBO merged into TCBW effective March 31, 2015. The Parent also owns and operates certain nonbank subsidiaries that engage in financial services. Basis of Financial Statement Presentation The consolidated financial statements include the accounts of the Parent and its majority-owned subsidiaries (“the Company,” “we,” “our,” “us”). Unconsolidated investments where we have the ability to exercise significant influence over the operating and financial policies of the respective investee are accounted for using the equity method of accounting; those that are not consolidated or accounted for using the equity method of accounting are accounted for under cost or fair value accounting. All significant intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and prevailing practices within the financial services industry. References to GAAP, including standards promulgated by the Financial Accounting Standards Board (“FASB”), are made according to sections of the Accounting Standards Codification (“ASC”). Changes to the ASC are made with Accounting Standards Updates (“ASU”) that include consensus issues of the Emerging Issues Task Force (“EITF”). In certain cases, ASUs are issued jointly with International Financial Reporting Standards. In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform with the current year presentation. These reclassifications did not affect net income or shareholders’ equity. Variable Interest Entities A variable interest entity (“VIE”) is consolidated when a company is the primary beneficiary of the VIE. Current accounting guidance requires continuous analysis on a qualitative rather than a quantitative basis to determine the primary beneficiary of a VIE. At the commencement of our involvement, and periodically thereafter, we consider our consolidation conclusions for all entities with which we are involved. As of December 31, 2017 and 2016 , no VIEs have been consolidated in the Company’s financial statements. Statement of Cash Flows For purposes of presentation in the consolidated statements of cash flows, “cash and cash equivalents” are defined as those amounts included in cash and due from banks in the consolidated balance sheets. Fair Value Estimates We measure many of our assets and liabilities on a fair value basis. Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. To improve consistency and comparability in fair value measurements, GAAP has established a hierarchy to prioritize the valuation inputs among three levels. The Company prioritizes quoted prices in active markets, and minimizes reliance on unobservable inputs when possible. When observable market prices are not available, fair value is estimated using modeling techniques such as discounted cash flow analysis. These modeling techniques use assumptions that market participants would consider in pricing the asset or the liability, including assumptions about the risk inherent in a particular valuation technique, the effect of a restriction on the sale or use of an asset, the life of the asset and applicable growth rate, the risk of nonperformance, and other related assumptions. Changes in market conditions may reduce the availability of quoted prices or observable data. When market data is not available, the Company uses valuation techniques requiring more management judgment to estimate the appropriate fair value. See Note 3 of the Notes to Consolidated Financial Statements for further information regarding the use of fair value estimates. Security Resell Agreements Security resell agreements represent overnight and term agreements with the majority maturing within 30 days. These agreements are generally treated as collateralized financing transactions and are carried at amounts at which the securities were acquired plus accrued interest. Either the Company, or in some instances third parties on its behalf, take possession of the underlying securities. The fair value of such securities is monitored throughout the contract term to ensure that asset values remain sufficient to protect against counterparty default. We are permitted by contract to sell or repledge certain securities that we accept as collateral for security resell agreements. If sold, our obligation to return the collateral is recorded as “securities sold, not yet purchased” and included as a liability in “Federal funds and other short-term borrowings.” At December 31, 2017 , we held $287 million of securities for which we were permitted by contract to sell or repledge. Security resell agreements averaged $360 million during 2017 , and the maximum amount outstanding at any month-end during 2017 was $1.8 billion . Investment Securities We classify our investment securities according to their purpose and holding period. Gains or losses on the sale of securities are recognized using the specific identification method and recorded in noninterest income. Held-to-maturity (“HTM”) debt securities are carried at amortized cost with purchase discounts or premiums accreted or amortized into interest income over the contractual life of the security. The Company has the intent and ability to hold such securities until maturity. Available-for-sale (“AFS”) securities are stated at fair value and generally consist of debt securities held for investment. Unrealized gains and losses of AFS securities, after applicable taxes, are recorded as a component of other comprehensive income (“OCI”). We review quarterly our investment securities portfolio for any declines in value that are considered to be other-than-temporary impairment (“OTTI”). The process, methodology, and factors considered to evaluate securities for OTTI are discussed further in Note 5 . Trading securities are stated at fair value and consist of securities acquired for short-term appreciation or other trading purposes. Realized and unrealized gains and losses are recorded in trading income, which is included in “Capital markets and foreign exchange.” The fair values of investment securities, as estimated under current accounting guidance, are discussed in Note 3 . Loans and Allowance for Credit Losses Loans are reported at the principal amount outstanding, net of unearned income. Unearned income, which includes deferred fees net of deferred direct loan origination costs, is amortized to interest income over the life of the loan using the interest method. Interest income is recognized on an accrual basis. At the time of origination, we determine whether loans will be held for investment or held for sale. We may subsequently change our intent to hold loans for investment and reclassify them as held for sale. Loans held for sale are carried at the lower of aggregate cost or fair value. A valuation allowance is recorded when cost exceeds fair value based on reviews at the time of reclassification and periodically thereafter. Gains and losses are recorded in noninterest income based on the difference between sales proceeds and carrying value. We evaluate loans throughout their lives for signs of credit deterioration, which may impact the loan’s status, and potentially impact our accounting for that loan. Loan status categories include past due as to contractual payments, nonaccrual, impaired, and restructured (including troubled debt restructurings (“TDRs”)). Our accounting policies for these loan statuses and our estimation of the related allowance for loan losses (“ALLL”) are discussed further in Note 6 . In the ordinary course of business, we transfer portions of loans under participation agreements to manage credit risk and our portfolio concentration. We evaluate the loan participations to determine if they meet the appropriate accounting guidance to qualify as sales. Certain purchased loans require separate accounting procedures that are also discussed in Note 6 . The allowance for credit losses (“ACL”) includes the ALLL and the reserve for unfunded lending commitments (“RULC”), and represents our estimate of losses inherent in the loan portfolio that may be recognized from loans and lending commitments that are not recoverable. Further discussion of our estimation process for the ACL is included in Note 6 . Other Noninterest-Bearing Investments These investments include investments in private equity funds (referred to in this document as private equity investments “PEIs”), venture capital securities, securities acquired for various debt and regulatory requirements, bank-owned life insurance, and certain other noninterest-bearing investments. See further discussions in Notes 5 , 15 and 3 . Certain PEIs and venture capital securities are accounted for under the equity method and reported at fair value. Changes in fair value and gains and losses from sales are recognized in noninterest income. The values assigned to the securities where no market quotations exist are based upon available information and may not necessarily represent amounts that will ultimately be realized. Such estimated amounts depend on future circumstances and will not be realized until the individual securities are liquidated. Bank-owned life insurance is accounted for at fair value based on the cash surrender values (“CSVs”) of the general account insurance policies. A third party service provides these values. Other PEIs and those acquired for various debt and regulatory requirements are accounted for at cost. Periodic reviews are conducted for impairment by comparing carrying values with estimates of fair value determined according to the previous discussion. Premises, Equipment and Software, Net Premises, equipment and software are stated at cost, net of accumulated depreciation and amortization. Depreciation, computed primarily on the straight-line method, is charged to operations over the estimated useful lives of the properties, generally 25 to 40 years for buildings, 3 to 10 years for furniture and equipment, and 3 to 10 years for software, including capitalized costs related to the Company’s technology initiatives. Leasehold improvements are amortized over the terms of the respective leases or the estimated useful lives of the improvements, whichever is shorter. Goodwill and Identifiable Intangible Assets Goodwill and intangible assets deemed to have indefinite lives are not amortized. We subject these assets to annual specified impairment tests as of the beginning of the fourth quarter and more frequently if changing conditions warrant. Core deposit assets and other intangibles with finite useful lives are generally amortized on an accelerated basis using an estimated useful life of up to 12 years. Business Combinations Business combinations are accounted for under the acquisition method of accounting. Upon initially obtaining control, we recognize 100% of all acquired assets and all assumed liabilities regardless of the percentage owned. The assets and liabilities are recorded at their estimated fair values, with goodwill being recorded when such fair values are less than the cost of acquisition. Certain transaction and restructuring costs are expensed as incurred. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill over the measurement period, which cannot exceed one year from the acquisition date. Results of operations of the acquired business are included in our statement of income from the date of acquisition. Other Real Estate Owned Other real estate owned (“OREO”) consists principally of commercial and residential real estate obtained in partial or total satisfaction of loan obligations. Amounts are recorded initially at fair value (less any selling costs) based on property appraisals at the time of transfer and subsequently at the lower of cost or fair value (less any selling costs). Derivative Instruments We use derivative instruments, including interest rate swaps and floors and basis swaps, as part of our overall interest rate risk management strategy. These instruments enable us to manage to desired asset and liability duration and to reduce interest rate risk exposure by matching estimated repricing periods of interest-sensitive assets and liabilities. We also execute derivative instruments with commercial banking customers to facilitate their risk management strategies. These derivatives are immediately hedged by offsetting derivatives with third parties such that we minimize our net risk exposure as a result of such transactions. We record all derivatives at fair value in the balance sheet as either other assets or other liabilities. See further discussion in Note 7 . Commitments and Letters of Credit In the ordinary course of business, we enter into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the ALLL. The RULC is presented separately in the balance sheet. Revenue Recognition Service charges and fees on deposit accounts are recognized in accordance with published deposit account agreements for customer accounts or contractual agreements for commercial accounts. Other service charges, commissions and fees include interchange fees, bank services, and other fees, which are generally recognized at the time of transaction or as the services are performed. Share-Based Compensation Share-based compensation generally includes grants of stock options, restricted stock, restricted stock units (“RSUs”), and other awards to employees and non-employee directors. We recognize compensation expense in the statement of income based on the grant-date value of the associated share-based awards. See further discussion in Note 17 . Income Taxes Deferred tax assets and liabilities are determined based on temporary differences between financial statement asset and liability amounts and their respective tax bases, and are measured using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized subject to management’s judgment that realization is more likely than not. Unrecognized tax benefits for uncertain tax positions relate primarily to state tax contingencies. See further discussion in Note 18 . Net Earnings Per Common Share Net earnings per common share is based on net earnings applicable to common shareholders, which is net of preferred stock dividends. Basic net earnings per common share is based on the weighted average outstanding common shares during each year. Unvested share-based awards with rights to receive nonforfeitable dividends are considered participating securities and included in the computation of basic earnings per share. Diluted net earnings per common share is based on the weighted average outstanding common shares during each year, including common stock equivalents. Stock options, restricted stock, RSUs, and stock warrants are converted to common stock equivalents using the treasury stock method. Diluted net earnings per common share excludes common stock equivalents whose effect is antidilutive. See further discussion in Note 19 .

Other Recent Accounting Pronoun

Other Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Other Recent Accounting Pronouncements [Abstract]
Certain Recent Accounting Pronouncements [Text Block]	RECENT ACCOUNTING PRONOUNCEMENTS Standard Description Date of adoption Effect on the financial statements or other significant matters Standards not adopted by the Company during 2017 ASU 2014-09, The core principle of the new guidance is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. The banking industry does not expect significant changes because major sources of revenue are from financial instruments that have been excluded from the scope of the new standard, (including loans, derivatives, debt and equity securities, etc.). However, these new standards affect other fees charged by banks, such as asset management fees, credit card interchange fees, deposit account fees, etc. Adoption may be made on a full retrospective basis with practical expedients, or on a modified retrospective basis with a cumulative effect adjustment. Additionally, the new guidance significantly increases the disclosures related to revenue recognition practices. January 1, 2018 Approximately 85% of our revenue, including all of our interest income and a portion of our noninterest income, is out of scope of the guidance. The contracts that are in scope of the guidance are primarily related to service charges and fees on deposit accounts, wealth management and trust income, and other service charges, commissions and fees. We have completed our review of these contracts and have not identified any material changes in the timing of revenue recognition. We adopted this guidance January 1, 2018 using the modified retrospective transition method. There was no material impact at adoption to the Company’s consolidated financial statements. ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The standard provides revised accounting guidance related to the accounting for and reporting of financial instruments. Some of the main provisions include: January 1, 2018 We do not have a significant amount of equity securities classified as AFS. Additionally, we do not have any financial liabilities accounted for under the fair value option. Therefore, the transition adjustment upon adoption of this guidance as of January 1, 2018 was not material. We are refining our valuation models to better account for an exit price, which will not change our financial statements, but will have an impact on our disclosures. Standard Description Date of adoption Effect on the financial statements or other significant matters Standards not adopted by the Company during 2017 (continued) ASC 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvement to Accounting for Hedging Activities The purpose of this standard is to better align a company’s financial reporting for hedging activities, with the economic objectives of those activities. The standard is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. The standard requires a modified retrospective transition method that requires recognition of the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. January 1, 2018 We early adopted this guidance as of January 1, 2018. The adoption of this guidance did not have a material impact on our consolidated financial statements at transition. ASU 2016-02, Leases (Topic 842) The standard requires that a lessee recognize assets and liabilities for leases with lease terms of more than 12 months. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, the standard will require both types of leases to be recognized on the balance sheet. It also requires disclosures to better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. January 1, 2019 We are currently evaluating the potential impact of this guidance on the Company’s financial statements. As of December 31, 2017, the Company had minimum noncancelable operating lease payments of $245 million that are being evaluated. The implementation team is working on gathering all key lease data elements to meet the requirements of the new guidance. Additionally, we are implementing new lease software that will accommodate the new accounting requirements. ASU 2017-08, Nonrefundable Fees and Other Costs (Subtopic 310-20). Premium Amortization on Purchased Callable Debt Securities The amendments in this ASU shorten the amortization period for certain callable debt securities held at a premium. The standard requires the premium to be amortized to the earliest call date. The update does not change the accounting for securities held at a discount. January 1, 2019 Our initial analysis suggests this guidance will not have a material impact on the Company’s financial statements, but we will continue to monitor its impact as we move closer to implementation. ASU 2016-13, Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments The standard significantly changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The standard replaces today’s “incurred loss” approach with an “expected loss” model for instruments such as loans and HTM securities that are measured at amortized cost. The standard requires credit losses relating to AFS debt securities to be recorded through an ACL rather than a reduction of the carrying amount. It also changes the accounting for purchased credit-impaired (“PCI”)debt securities and loans. The standard retains many of the current disclosure requirements in current GAAP and expands certain disclosure requirements. Early adoption of the guidance is permitted as of January 1, 2019. January 1, 2020 We have formed an implementation team led jointly by Credit and the Corporate Controller’s group, that also includes other lines of business and functions within the Company. The implementation team is working on developing models that can meet the requirements of the new guidance. While this standard may potentially have a material impact on the Company’s financial statements, we are still in process of conducting our evaluation. Standard Description Date of adoption Effect on the financial statements or other significant matters Standards not adopted by the Company during 2017 (continued) ASU 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment The standard eliminates the requirement to calculate the implied fair value of goodwill (i.e. Step 2 of the current goodwill impairment test) to measure a goodwill impairment charge. Instead, entities would record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value (i.e., measure the charge based on Step 1 of the current guidance). The standard does not change the guidance on completing Step 1 of the goodwill impairment test. The standard also continues to allow entities to perform the optional qualitative goodwill impairment assessment before determining whether to proceed to Step 1. The standard is effective for the Company as of January 1, 2020. Early adoption is allowed for any goodwill impairment test performed after January 1, 2017. January 1, 2020 We do not currently expect this guidance will have a material impact on the Company’s financial statements since the fair values of our reporting units were not lower than their respective carrying amounts at the time of our goodwill impairment analysis for 2017. Standard Description Date of adoption Effect on the financial statements Standards adopted by the Company during 2017 ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting The standard requires entities to recognize the income tax effects of share-based awards in the income statement when the awards vest or are settled (i.e. the additional paid-in capital pools will be eliminated). The guidance on employers’ accounting for an employee’s use of shares to satisfy the employer’s statutory income tax withholding obligation and for forfeitures is changing. The standard also provides an entity the option to make an entity-wide accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. January 1, 2017 Upon adoption of this ASU, there was no material impact from the cumulative effect adjustment to retained earnings. We elected to account for forfeitures when they occur and to reflect excess tax benefits in the operating section of the statement of cash flows on a prospective basis. ASU 2018-02, Income Statement — Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income The standard allows a one-time movement between Accumulated Other Comprehensive Income (“AOCI”) and Retained Earnings to adjust for amounts that would otherwise be stranded in AOCI as a result of implementing changes due to the enactment of H.R. 1, known as the Tax Cuts and Jobs Act. The standard is effective for public companies for fiscal years beginning after December 15, 2018, with early adoption, including in an interim period, permitted. December 31, 2017 The Company adopted this standard for the 2017 fiscal year financial statements with a $25 million adjusting entry between AOCI and Retained Earnings.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE Fair Value Measurement Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. To measure fair value, a hierarchy has been established that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs. This hierarchy uses three levels of inputs to measure the fair value of assets and liabilities as follows: Level 1 – Quoted prices in active markets for identical assets or liabilities in active markets that the Company has the ability to access; Level 2 – Observable inputs other than Level 1 including quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in less active markets, observable inputs other than quoted prices that are used in the valuation of an asset or liability, and inputs that are derived principally from or corroborated by observable market data by correlation or other means; and Level 3 – Unobservable inputs supported by little or no market activity for financial instruments whose value is determined by pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. The level in the fair value hierarchy within which the fair value measurement is classified is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Market activity is presumed to be orderly in the absence of evidence of forced or disorderly sales, although such sales may still be indicative of fair value. Applicable accounting guidance precludes the use of blockage factors or liquidity adjustments due to the quantity of securities held by an entity. We use fair value to measure certain assets and liabilities on a recurring basis when fair value is the primary measure for accounting. Fair value is used on a nonrecurring basis to measure certain assets when adjusting carrying values, such as the application of lower of cost or fair value accounting, including recognition of impairment on assets. Fair value is also used when providing required disclosures for certain financial instruments. Fair Value Policies and Procedures We have various policies, processes and controls in place to ensure that fair values are reasonably developed, reviewed and approved for use. These include a Securities Valuation Committee, comprised of executive management, that reviews and approves on a quarterly basis the key components of fair value estimation, including critical valuation assumptions for Level 3 modeling. A Model Risk Management Group conducts model validations, including internal models, and sets policies and procedures for revalidation, including the timing of revalidation. Third Party Service Providers We use a third party pricing service to measure fair value for approximately 92% of our AFS Level 2 securities. Fair value measurements for other AFS Level 2 securities generally use certain inputs corroborated by market data and include standard discounted cash flow analysis. For Level 2 securities, the third party pricing service provides documentation on an ongoing basis that presents market corroborative data, including detail pricing information and market reference data. The documentation includes benchmark yields, reported trades, broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data, including information from the vendor trading platform. We review, test and validate this information as appropriate. Absent observable trade data, we do not adjust prices from our third party sources. The following describes the hierarchy designations, valuation methodologies, and key inputs to measure fair value on a recurring basis for designated financial instruments: Available-for-Sale U.S. Treasury, Agencies and Corporations U.S. Treasury securities are measured under Level 1 using quoted market prices when available. U.S. agencies and corporations are measured under Level 2 generally using the previously discussed third party pricing service. Municipal Securities Municipal securities are measured under Level 2 generally using the third party pricing service or an internal model. Valuation inputs include Baa municipal curves, as well as Federal Home Loan Bank (“FHLB”) and LIBOR swap curves. Our valuation methodology for non-rated municipal securities changed at year-end of 2015 to utilize more observable inputs, primarily municipal market yield curves, compared to our previous valuation method. The resulting values were determined to be Level 2. Money Market Mutual Funds and Other Money market mutual funds and other securities are measured under Level 1 or Level 2. For Level 1, quoted market prices are used which may include net asset values (“NAVs”) or their equivalents. Level 2 valuations generally use quoted prices for similar securities. Trading Account Securities in the trading account are generally measured under Level 2 using third party pricing service providers as described previously. Bank-Owned Life Insurance Bank-owned life insurance (“BOLI”) is measured under Level 2 according to CSVs of the insurance policies that are provided by a third party service. Nearly all policies are general account policies with CSVs based on the Company’s claims on the assets of the insurance companies. The insurance companies’ investments include predominantly fixed income securities consisting of investment-grade corporate bonds and various types of mortgage instruments. Management regularly reviews its BOLI investment performance, including concentrations among insurance providers. Private Equity Investments PEIs are measured under Level 3. The majority of these investments are held in Zions’ Small Business Investment Company (“SBIC”) and are early stage venture investments. The fair value measurements of these investments are reviewed on a quarterly basis by the Securities Valuation Committee. The Equity Investments Committee, consisting of executives familiar with the investments, reviews periodic financial information, including audited financial statements when available. Certain valuation analytics may be employed that include current and projected financial performance, recent financing activities, economic and market conditions, market comparables, market liquidity, sales restrictions, and other factors. A significant change in the expected performance of the individual investment would result in a change in the fair value measurement of the investment. The amount of unfunded commitments to invest is disclosed in Note 15 . Certain restrictions apply for the redemption of these investments and certain investments are prohibited by the Volcker Rule. See discussion in Notes 5 and 15 . Agriculture Loan Servicing This asset results from our servicing of agriculture loans approved and funded by Federal Agricultural Mortgage Corporation (“FAMC”). We provide this servicing under an agreement with FAMC for loans they own. The asset’s fair value represents our projection of the present value of future cash flows measured under Level 3 using discounted cash flow methodologies. Interest-Only Strips Interest-only strips are created as a by-product of the securitization process. When the guaranteed portions of Small Business Administration (“SBA”) 7(a) loans are pooled, interest-only strips may be created in the pooling process. The asset’s fair value represents our projection of the present value of future cash flows measured under Level 3 using discounted cash flow methodologies. Deferred Compensation Plan Assets and Obligations Invested assets in the deferred compensation plan consist of shares of registered investment companies. These mutual funds are valued under Level 1 at quoted market prices, which represents the NAV of shares held by the plan at the end of the period. Derivatives Derivatives are measured according to their classification as either exchange-traded or over-the-counter. Exchange-traded derivatives consist of foreign currency exchange contracts measured under Level 1 because they are traded in active markets. Over-the-counter derivatives, including those for customers, consist of interest rate swaps and options. These derivatives are measured under Level 2 using third party services. Observable market inputs include yield curves (the LIBOR swap curve and relevant overnight index swap curves), foreign exchange rates, commodity prices, option volatilities, counterparty credit risk, and other related data. Credit valuation adjustments are required to reflect nonperformance risk for both the Company and the respective counterparty. These adjustments are determined generally by applying a credit spread to the total expected exposure of the derivative. Securities Sold, Not Yet Purchased Securities sold, not yet purchased, included in “Federal funds and other short-term borrowings” on the balance sheet, are measured under Level 1 using quoted market prices. If not available, quoted prices under Level 2 for similar securities are used. Quantitative Disclosure by Fair Value Hierarchy Assets and liabilities measured at fair value by class on a recurring basis are summarized as follows: (In millions) December 31, 2017 Level 1 Level 2 Level 3 Total ASSETS Investment securities: Available-for-sale: U.S. Treasury, agencies and corporations $ 25 $ 13,706 $ — $ 13,731 Municipal securities 1,334 1,334 Other debt securities 24 24 Money market mutual funds and other 71 1 72 Total Available-for-sale 96 15,065 — 15,161 Trading account 148 148 Other noninterest-bearing investments: Bank-owned life insurance 507 507 Private equity investments 95 95 Other assets: Agriculture loan servicing and interest-only strips 18 18 Deferred compensation plan assets 102 102 Derivatives: Interest rate related and other 1 1 Interest rate swaps for customers 28 28 Foreign currency exchange contracts 9 9 Total Assets $ 207 $ 15,749 $ 113 $ 16,069 LIABILITIES Securities sold, not yet purchased $ 95 $ — $ — $ 95 Other liabilities: Deferred compensation plan obligations 102 102 Derivatives: Interest rate swaps for customers 33 33 Foreign currency exchange contracts 7 7 Total Liabilities $ 204 $ 33 $ — $ 237 (In millions) December 31, 2016 Level 1 Level 2 Level 3 Total ASSETS Investment securities: Available-for-sale: U.S. Treasury, agencies and corporations $ — $ 12,009 $ — $ 12,009 Municipal securities 1,154 1,154 Other debt securities 24 24 Money market mutual funds and other 184 1 185 Total Available-for-sale 184 13,188 — 13,372 Trading account 115 115 Other noninterest-bearing investments: Bank-owned life insurance 497 497 Private equity investments 1 18 73 91 Other assets: Agriculture loan servicing and interest-only strips 20 20 Deferred compensation plan assets 91 91 Derivatives: Interest rate related and other 4 4 Interest rate swaps for customers 49 49 Foreign currency exchange contracts 11 11 Total Assets $ 304 $ 13,853 $ 93 $ 14,250 LIABILITIES Securities sold, not yet purchased $ 25 $ — $ — $ 25 Other liabilities: Deferred compensation plan obligations 91 91 Derivatives: Interest rate related and other 1 1 Interest rate swaps for customers 49 49 Foreign currency exchange contracts 9 9 Total Liabilities $ 125 $ 50 $ — $ 175 1 The level 1 PEIs amount relates to the portion of our SBIC investments that are now publicly traded. Reconciliation of Level 3 Fair Value Measurements The following reconciles the beginning and ending balances of assets and liabilities that are measured at fair value by class on a recurring basis using Level 3 inputs: Level 3 Instruments December 31, 2017 December 31, 2016 (In millions) Private Ag loan svcg and int-only strips Private Ag loan svcg and int-only strips Balance at beginning of year $ 73 $ 20 $ 58 $ 14 Securities gains, net 7 — 6 — Other noninterest income — (1 ) — 6 Purchases 20 — 10 — Redemptions and paydowns (5 ) (1 ) (1 ) — Balance at end of year $ 95 $ 18 $ 73 $ 20 No transfers of assets or liabilities occurred among Levels 1, 2 or 3 for 2017 and 2016 . The preceding reconciling amounts using Level 3 inputs include the following realized gains/losses in the statement of income: (In millions) Year Ended December 31, 2017 2016 Equity securities gains, net $ 3 $ 6 Nonrecurring Fair Value Measurements Included in the balance sheet amounts are the following amounts of assets that had fair value changes measured on a nonrecurring basis: (In millions) Fair value at December 31, 2017 Gains (losses) from Level 1 Level 2 Level 3 Total ASSETS Private equity investments, carried at cost $ — $ — $ 1 $ 1 $ (1 ) Impaired loans — 9 — 9 (5 ) Other real estate owned — — — — — Total $ — $ 9 $ 1 $ 10 $ (6 ) (In millions) Fair value at December 31, 2016 Gains (losses) from Level 1 Level 2 Level 3 Total ASSETS Private equity investments, carried at cost $ — $ — $ 1 $ 1 $ (1 ) Impaired loans — 52 — 52 (36 ) Other real estate owned — 1 — 1 (2 ) Total $ — $ 53 $ 1 $ 54 $ (39 ) The previous fair values may not be current as of the dates indicated, but rather as of the date the fair value change occurred, such as a charge for impairment. Accordingly, carrying values may not equal current fair value. We recognized net gains of $2 million in 2017 and $4 million in 2016 from the sale of OREO properties that had a carrying value at the time of sale of approximately $6 million in 2017 and $13 million in 2016 . Previous to their sale in these years, we recognized an insignificant amount of impairment on these properties in 2017 and 2016 . PEIs carried at cost were measured at fair value for impairment purposes according to the methodology previously discussed for these investments. Amounts of PEIs carried at cost were $10 million and $13 million at December 31, 2017 and 2016 , respectively. Amounts of other noninterest-bearing investments carried at cost were $338 million and $211 million at December 31, 2017 and 2016 , respectively, which were comprised of Federal Reserve and FHLB stock. PEIs accounted for using the equity method were $36 million at December 31, 2017 and $38 million at December 31, 2016 . Impaired (or nonperforming) loans that are collateral-dependent were measured at fair value based on the fair value of the collateral. OREO was measured initially at fair value based on collateral appraisals at the time of transfer and subsequently at the lower of cost or fair value. Measurement of fair value for collateral-dependent loans and OREO was based on third party appraisals that utilize one or more valuation techniques (income, market and/or cost approaches). Any adjustments to calculated fair value were made based on recently completed and validated third party appraisals, third party appraisal services, automated valuation services, or our informed judgment. Evaluations were made to determine that the appraisal process met the relevant concepts and requirements of applicable accounting guidance. Automated valuation services may be used primarily for residential properties when values from any of the previous methods were not available within 90 days of the balance sheet date. These services use models based on market, economic, and demographic values. The use of these models has only occurred in a very few instances and the related property valuations have not been sufficiently significant to consider disclosure under Level 3 rather than Level 2. Impaired loans that are not collateral-dependent were measured based on the present value of future cash flows discounted at the expected coupon rates over the lives of the loans. Because the loans were not discounted at market interest rates, the valuations do not represent fair value and have been excluded from the nonrecurring fair value balance in the preceding schedules. Fair Value of Certain Financial Instruments Following is a summary of the carrying values and estimated fair values of certain financial instruments: December 31, 2017 December 31, 2016 (Dollar amounts in millions) Carrying value Estimated fair value Level Carrying value Estimated fair value Level Financial assets: Held-to-maturity investment securities $ 770 $ 762 2 $ 868 $ 850 2 Loans and leases (including loans held for sale), net of allowance 44,306 44,226 3 42,254 42,111 3 Financial liabilities: Time deposits 3,115 3,099 2 2,757 2,744 2 Other short-term borrowings 3,600 3,600 2 500 500 2 Long-term debt (less fair value hedges) 383 402 2 535 552 2 This summary excludes financial assets and liabilities for which carrying value approximates fair value and financial instruments that are recorded at fair value on a recurring basis. Financial instruments for which carrying values approximate fair value include cash and due from banks, money market investments, demand, savings and money market deposits, federal funds purchased and other short-term borrowings, and security repurchase agreements. The estimated fair value of demand, savings and money market deposits is the amount payable on demand at the reporting date. Carrying value is used because the accounts have no stated maturity and the customer has the ability to withdraw funds immediately. HTM investment securities primarily consist of municipal securities. They were measured at fair value according to the methodology previously discussed. Loans are measured at fair value according to their status as nonimpaired or impaired. For nonimpaired loans, fair value is estimated by discounting future cash flows using the LIBOR yield curve adjusted by a factor which reflects the credit and interest rate risk inherent in the loan. These future cash flows are then reduced by the estimated “life-of-the-loan” aggregate credit losses in the loan portfolio. These adjustments for lifetime future credit losses are derived from the methods used to estimate the ALLL for our loan portfolio and are adjusted quarterly as necessary to reflect the most recent loss experience. Impaired loans that are collateral-dependent are already considered to be held at fair value. Impaired loans that are not collateral-dependent have future cash flows reduced by the estimated “life-of-the-loan” credit loss derived from methods used to estimate the ALLL for these loans. See Impaired Loans in Note 6 for details on the impairment measurement method for impaired loans. Loans, other than those held for sale, are not normally purchased and sold by the Company, and there are no active trading markets for most of this portfolio. Time and foreign deposits, and any other short-term borrowings, are measured at fair value by discounting future cash flows using the LIBOR yield curve to the given maturity dates. Long-term debt is measured at fair value based on actual market trades (i.e., an asset value) when available, or discounting cash flows to maturity using the LIBOR yield curve adjusted for credit spreads. These fair value disclosures represent our best estimates based on relevant market information and information about the financial instruments. Fair value estimates are based on judgments regarding current economic conditions, future expected loss experience, risk characteristics of the various instruments, and other factors. These estimates are subjective in nature, involve uncertainties and matters of significant judgment, and cannot be determined with precision. Changes in these methodologies and assumptions could significantly affect the estimates.

Offsetting Assets and Liabiliti

Offsetting Assets and Liabilities	12 Months Ended
	Dec. 31, 2017
Gross and net information for selecting financial instruments [Abstract]
Cash, Cash Equivalents, and Short-term Investments [Text Block]	OFFSETTING ASSETS AND LIABILITIES Gross and net information for selected financial instruments in the balance sheet is as follows: December 31, 2017 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 809 $ (295 ) $ 514 $ — $ — $ 514 Derivatives (included in other assets) 38 — 38 (21 ) (1 ) 16 Total assets $ 847 $ (295 ) $ 552 $ (21 ) $ (1 ) $ 530 Liabilities: Federal funds and other short-term borrowings $ 5,271 $ (295 ) $ 4,976 $ — $ — $ 4,976 Derivatives (included in other liabilities) 40 — 40 (21 ) (6 ) 13 Total liabilities $ 5,311 $ (295 ) $ 5,016 $ (21 ) $ (6 ) $ 4,989 December 31, 2016 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 568 $ — $ 568 $ — $ — $ 568 Derivatives (included in other assets) 64 — 64 (17 ) — 47 Total assets $ 632 $ — $ 632 $ (17 ) $ — $ 615 Liabilities: Federal funds and other short-term borrowings $ 827 $ — $ 827 $ — $ — $ 827 Derivatives (included in other liabilities) 59 — 59 (17 ) (17 ) 25 Total liabilities $ 886 $ — $ 886 $ (17 ) $ (17 ) $ 852 Security repurchase and reverse repurchase (“resell”) agreements are offset, when applicable, in the balance sheet according to master netting agreements. Security repurchase agreements are included with “Federal funds and other short-term borrowings.” Derivative instruments may be offset under their master netting agreements; however, for accounting purposes, we present these items on a gross basis in the Company’s balance sheet. See Note 7 for further information regarding derivative instruments.

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2017
Investments [Abstract]
Investment Securities	INVESTMENTS Investment Securities Securities are classified as HTM, AFS or trading. HTM securities, which management has the intent and ability to hold until maturity, are carried at amortized cost. AFS securities are carried at fair value and unrealized gains and losses are reported as net increases or decreases to AOCI. Realized gains and losses on AFS securities are determined by using the cost basis of each individual security. Trading securities are carried at fair value with gains and losses recognized in current period earnings. The purchase premiums and discounts for both HTM and AFS securities are amortized and accreted at a constant effective yield to the contractual maturity date and no assumption is made concerning prepayments. As principal prepayments occur, the portion of the unamortized premium or discount associated with the principal reduction is recognized as interest income in the period the principal is reduced. Note 3 discusses the process to estimate fair value for investment securities. December 31, 2017 (In millions) Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 770 $ 5 $ 13 $ 762 Available-for-sale U.S. Treasury securities 25 — — 25 U.S. Government agencies and corporations: Agency securities 1,830 1 13 1,818 Agency guaranteed mortgage-backed securities 9,798 9 141 9,666 Small Business Administration loan-backed securities 2,227 10 15 2,222 Municipal securities 1,336 9 11 1,334 Other debt securities 25 — 1 24 Total available-for-sale debt securities 15,241 29 181 15,089 Money market mutual funds and other 72 — — 72 Total available-for-sale 15,313 29 181 15,161 Total investment securities $ 16,083 $ 34 $ 194 $ 15,923 December 31, 2016 (In millions) Amortized Gross Gross Estimated Held-to-maturity Municipal securities $ 868 $ 5 $ 23 $ 850 Available-for-sale U.S. Treasury securities — — — — U.S. Government agencies and corporations: Agency securities 1,846 2 9 1,839 Agency guaranteed mortgage-backed securities 7,986 7 110 7,883 Small Business Administration loan-backed securities 2,298 8 18 2,288 Municipal securities 1,182 1 29 1,154 Other debt securities 25 — 1 24 Total available-for-sale debt securities 13,337 18 167 13,188 Money market mutual funds and other 184 — — 184 Total available-for-sale 13,521 18 167 13,372 Total investment securities $ 14,389 $ 23 $ 190 $ 14,222 Maturities The amortized cost and estimated fair value of investment debt securities are shown subsequently as of December 31, 2017 by expected timing of principal payments. Actual principal payments may differ from contractual or expected principal payments because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Held-to-maturity Available-for-sale (In millions) Amortized cost Estimated fair value Amortized cost Estimated fair value Due in one year or less $ 180 $ 90 $ 2,499 $ 2,054 Due after one year through five years 372 336 5,727 5,575 Due after five years through ten years 159 230 4,331 4,485 Due after ten years 59 106 2,684 2,975 Total $ 770 $ 762 $ 15,241 $ 15,089 The following is a summary of the amount of gross unrealized losses for debt securities and the estimated fair value by length of time the securities have been in an unrealized loss position: December 31, 2017 Less than 12 months 12 months or more Total (In millions) Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 3 $ 263 $ 10 $ 292 $ 13 $ 555 Available-for-sale U.S. Government agencies and corporations: Agency securities 6 808 7 808 13 1,616 Agency guaranteed mortgage-backed securities 29 3,609 112 4,721 141 8,330 Small Business Administration loan-backed securities 3 408 12 649 15 1,057 Municipal securities 6 554 5 230 11 784 Other — — 1 14 1 14 Total available-for-sale 44 5,379 137 6,422 181 11,801 Total $ 47 $ 5,642 $ 147 $ 6,714 $ 194 $ 12,356 December 31, 2016 Less than 12 months 12 months or more Total (In millions) Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 15 $ 467 $ 8 $ 61 $ 23 $ 528 Available-for-sale U.S. Government agencies and corporations: Agency securities 9 950 — 127 9 1,077 Agency guaranteed mortgage-backed securities 102 6,649 7 326 109 6,975 Small Business Administration loan-backed securities 3 527 16 841 19 1,368 Municipal securities 28 992 — 9 28 1,001 Other — — 2 14 2 14 Total available-for-sale 142 9,118 25 1,317 167 10,435 Total $ 157 $ 9,585 $ 33 $ 1,378 $ 190 $ 10,963 At December 31, 2017 and 2016 , respectively, 667 and 642 HTM and 2,262 and 2,398 AFS investment securities were in an unrealized loss position. Other-Than-Temporary Impairment Ongoing Policy We review investment securities on a quarterly basis for the presence of OTTI. We assess whether OTTI is present when the fair value of a debt security is less than its amortized cost basis at the balance sheet date (the majority of the investment portfolio are debt securities). Under these circumstances, OTTI is considered to have occurred if (1) we have formed a documented intent to sell identified securities or initiated such sales; (2) it is “more likely than not” we will be required to sell the security before recovery of its amortized cost basis; or (3) the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. Noncredit-related OTTI in securities we intend to sell is recognized in earnings as is any credit-related OTTI in securities, regardless of our intent. Noncredit-related OTTI on AFS securities not expected to be sold is recognized in OCI. The amount of noncredit-related OTTI in a security is quantified as the difference in a security’s amortized cost after adjustment for credit impairment, and its lower fair value. Presentation of OTTI is made in the statement of income on a gross basis with an offset for the amount of OTTI recognized in OCI. Our OTTI evaluation process takes into consideration current market conditions; fair value in relationship to cost; extent and nature of change in fair value; severity and duration of the impairment; recent events specific to the issuer or industry; our assessment of the creditworthiness of the issuer, including external credit ratings, changes, recent downgrades, and trends; the cash flow priority position of the instrument that we hold in the case of structured securities; volatility of earnings and trends; current analysts’ evaluations; all available information relevant to the collectability of debt securities; and other key measures. In addition, for AFS securities with fair values below amortized cost, we must determine if we intend to sell the securities or if it is more likely than not that we will be required to sell the securities before recovery of their amortized cost basis. For HTM securities, we must determine we have the ability to hold the securities to maturity. We consider any other relevant factors before concluding our evaluation for the existence of OTTI in our securities portfolio. Other-Than-Temporary Impairment Conclusions The Company did not recognize any OTTI on its investment securities portfolio during 2017 . Unrealized losses relate to changes in interest rates subsequent to purchase and are not attributable to credit. At December 31, 2017 , we did not have an intent to sell identified securities with unrealized losses or initiate such sales, and we believe it is not more likely than not we would be required to sell such securities before recovery of their amortized cost basis. To determine the credit component of OTTI for all security types, we utilize projected cash flows. These cash flows are credit adjusted using, among other things, assumptions for default probability and loss severity. Certain other unobservable inputs such as prepayment rate assumptions are also utilized. In addition, certain internal models may be utilized. See Note 3 for further discussion. To determine the credit-related portion of OTTI in accordance with applicable accounting guidance, we use the security specific effective interest rate when estimating the present value of cash flows. The following summarizes gains and losses, including OTTI, that were recognized in the statement of income: 2017 2016 2015 (In millions) Gross gains Gross losses Gross gains Gross losses Gross gains Gross losses Investment securities: Available-for-sale $ — $ — $ — $ — $ 9 $ 148 Other noninterest-bearing investments 22 8 21 14 25 13 Total investments 22 8 21 14 34 161 Net gains (losses) $ 14 $ 7 $ (127 ) Statement of income information: Equity securities gains, net $ 14 $ 7 $ 12 Fixed income securities gains (losses), net — — (139 ) Net gains (losses) $ 14 $ 7 $ (127 ) Interest income by security type is as follows: (In millions) 2017 2016 2015 Taxable Nontaxable Total Taxable Nontaxable Total Taxable Nontaxable Total Investment securities: Held-to-maturity $ 10 $ 13 $ 23 $ 10 $ 13 $ 23 $ 13 $ 11 $ 24 Available-for-sale 277 24 301 166 12 178 95 3 98 Trading 2 — 2 3 — 3 2 — 2 Total $ 289 $ 37 $ 326 $ 179 $ 25 $ 204 $ 110 $ 14 $ 124 Investment securities with a carrying value of approximately $2.1 billion and $1.4 billion at December 31, 2017 and 2016 , respectively, were pledged to secure public and trust deposits, advances, and for other purposes as required by law. Securities are also pledged as collateral for security repurchase agreements. Private Equity Investments Effect of Volcker Rule The Company’s PEIs are subject to the provisions of the Dodd-Frank Act. The Volcker Rule of the Dodd-Frank Act prohibits banks and bank holding companies from holding PEIs, except for SBIC funds and certain other permitted exclusions, beyond a required deadline. The Federal Reserve Board announced in December 2016 that it would allow banks to apply for an additional five-year extension beyond the July 21, 2017 deadline to comply with the Dodd-Frank Act requirement for these investments. The Company applied for and was granted an extension for its eligible PEIs. All positions in the remaining portfolio of PEIs are subject to the extended deadline or other applicable exclusions. Of the recorded PEIs of $141 million at December 31, 2017 , approximately $3 million remain prohibited by the Volcker Rule. At December 31, 2017 , we have $31 million of unfunded commitments for PEIs, of which approximately $4 million relate to prohibited PEIs. We currently do not believe that this divestiture requirement will ultimately have a material impact on our financial statements. See other discussions related to PEI in Note 3 .

Loans And Allowance For Credit

Loans And Allowance For Credit Losses	12 Months Ended
	Dec. 31, 2017
Loans And Allowance For Credit Losses [Abstract]
Loans And Allowance For Credit Losses	LOANS AND ALLOWANCE FOR CREDIT LOSSES Loans and Loans Held for Sale Loans are summarized as follows according to major portfolio segment and specific loan class: December 31, (In millions) 2017 2016 Loans held for sale $ 44 $ 172 Commercial: Commercial and industrial $ 14,003 $ 13,452 Leasing 364 423 Owner-occupied 7,288 6,962 Municipal 1,271 778 Total commercial 22,926 21,615 Commercial real estate: Construction and land development 2,021 2,019 Term 9,103 9,322 Total commercial real estate 11,124 11,341 Consumer: Home equity credit line 2,777 2,645 1-4 family residential 6,662 5,891 Construction and other consumer real estate 597 486 Bankcard and other revolving plans 509 481 Other 185 190 Total consumer 10,730 9,693 Total loans $ 44,780 $ 42,649 Loan balances are presented net of unearned income and fees, which amounted to $65 million at December 31, 2017 and $77 million at December 31, 2016 . Owner-occupied and commercial real estate loans include unamortized premiums of approximately $16 million at December 31, 2017 and $20 million at December 31, 2016 . Municipal loans generally include loans to municipalities with the debt service being repaid from general funds or pledged revenues of the municipal entity, or to private commercial entities or 501(c)(3) not-for-profit entities utilizing a pass-through municipal entity to achieve favorable tax treatment. Land development loans included in the construction and land development loan class were $220 million at December 31, 2017 , and $290 million at December 31, 2016 . Loans with a carrying value of approximately $25.6 billion at December 31, 2017 and $24.0 billion at December 31, 2016 have been pledged at the Federal Reserve and the FHLB of Des Moines as collateral for current and potential borrowings. We sold loans totaling $0.9 billion in 2017 , $1.4 billion in 2016 , and $1.4 billion in 2015 , that were classified as loans held for sale. The sold loans were derecognized from the balance sheet. Loans classified as loans held for sale primarily consist of conforming residential mortgages and the guaranteed portion of SBA loans. The loans are mainly sold to U.S. government agencies or participated to third parties. At times, we have continuing involvement in the transferred loans in the form of servicing rights or a guarantee from the respective issuer. Amounts added to loans held for sale during these same periods were $0.8 billion , $1.4 billion , and $1.4 billion , respectively. The principal balance of sold loans for which we retain servicing was approximately $2.2 billion at December 31, 2017 , and $2.0 billion at December 31, 2016 , and $2.0 billion at December 31, 2015. Income from loans sold, excluding servicing, was $13 million in 2017 , $18 million in 2016 , and $18 million in 2015 . Allowance for Credit Losses The ACL consists of the ALLL and the RULC. Allowance for Loan and Lease Losses The ALLL represents our estimate of probable and estimable losses inherent in the loan and lease portfolio as of the balance sheet date. Losses are charged to the ALLL when recognized. Generally, commercial and commercial real estate (“CRE”) loans are charged off or charged down when they are determined to be uncollectible in whole or in part, or when 180 days past due unless the loan is well secured and in process of collection. Consumer loans are either charged off or charged down to net realizable value no later than the month in which they become 180 days past due. Closed-end consumer loans that are not secured by residential real estate are either charged off or charged down to net realizable value no later than the month in which they become 120 days past due. We establish the amount of the ALLL by analyzing the portfolio at least quarterly, and we adjust the provision for loan losses so the ALLL is at an appropriate level at the balance sheet date. We determine our ALLL as the best estimate within a range of estimated losses. The methodologies we use to estimate the ALLL depend upon the impairment status and loan portfolio. The methodology for impaired loans is discussed subsequently. For commercial and CRE loans with commitments greater than $1 million , we assign internal risk grades using a comprehensive loan grading system based on financial and statistical models, individual credit analysis, and loan officer experience and judgment. The credit quality indicators discussed subsequently are based on this grading system. Estimated losses for these commercial and CRE loans are derived from a statistical analysis of our historical default and loss given default (“LGD”) experience over the period of January 2008 through the most recent full quarter. For consumer and small commercial and CRE loans with commitments less than or equal to $1 million , we primarily use roll rate models to forecast probable inherent losses. Roll rate models measure the rate at which these loans migrate from one delinquency category to the next worse delinquency category, and eventually to loss. We estimate roll rates for these loans using recent delinquency and loss experience by segmenting our loan portfolios into separate pools based on common risk characteristics and separately calculating historical delinquency and loss experience for each pool. These roll rates are then applied to current delinquency levels to estimate probable inherent losses. The current status and historical changes in qualitative and environmental factors may not be reflected in our quantitative models. Thus, after applying historical loss experience, as described above, we review the quantitatively derived level of ALLL for each segment using qualitative criteria and use those criteria to determine our qualitative estimate. We track various risk factors that influence our judgment regarding the level of the ALLL across the portfolio segments. These factors primarily include: • Changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices; • Changes in international, national, regional, and local economic and business conditions; • Changes in the nature and volume of the portfolio and in the terms of loans; • Changes in the experience, ability, and depth of lending management and other relevant staff; • Changes in the volume and severity of past due loans, the volume of nonaccrual loans, and the volume and severity of adversely classified or graded loans; • Changes in the quality of the loan review system; • Changes in the value of underlying collateral for collateral-dependent loans; • The existence and effect of any concentration of credit, and changes in the level of such concentrations; • The effect of other external factors such as competition and legal and regulatory requirements; The magnitude of the impact of these factors on our qualitative assessment of the ALLL changes from quarter to quarter according to changes made by management in its assessment of these factors, the extent these factors are already reflected in historic loss rates, and the extent changes in these factors diverge from one to another. We also consider the uncertainty inherent in the estimation process when evaluating the ALLL. Reserve for Unfunded Lending Commitments We also estimate a reserve for potential losses associated with off-balance sheet commitments, including standby letters of credit. We determine the RULC using the same procedures and methodologies that we use for the ALLL. The loss factors used in the RULC are the same as the loss factors used in the ALLL, and the qualitative adjustments used in the RULC are the same as the qualitative adjustments used in the ALLL. We adjust the Company’s unfunded lending commitments that are not unconditionally cancelable to an outstanding amount equivalent using credit conversion factors, and we apply the loss factors to the outstanding equivalents. Changes in Allowance for Credit Losses Assumptions During the first quarter of 2016, due to the consolidation of our separate banking charters, we enhanced our methodology to estimate the ACL on a company-wide basis. As described previously, for large commercial and CRE loans, we began estimating historic loss factors by separately calculating historic default and LGD rates, instead of directly calculating loss rates for groupings of probability of default and LGD grades using a loss migration approach. For small commercial and CRE loans, we began using roll rate models to estimate probable inherent losses. For consumer loans, we began pooling loans by current loan-to-value, where applicable. The impact of these changes was largely neutral to the total ACL at implementation. Changes in the allowance for credit losses are summarized as follows: December 31, 2017 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Balance at beginning of year $ 420 $ 116 $ 31 $ 567 Additions: Provision for loan losses 23 (18 ) 19 24 Deductions: Gross loan and lease charge-offs (118 ) (9 ) (17 ) (144 ) Recoveries 46 14 11 71 Net loan and lease (charge-offs) recoveries (72 ) 5 (6 ) (73 ) Balance at end of year $ 371 $ 103 $ 44 $ 518 Reserve for unfunded lending commitments Balance at beginning of year $ 54 $ 11 $ — $ 65 Provision credited to earnings (6 ) (1 ) — (7 ) Balance at end of year $ 48 $ 10 $ — $ 58 Total allowance for credit losses Allowance for loan losses $ 371 $ 103 $ 44 $ 518 Reserve for unfunded lending commitments 48 10 — 58 Total allowance for credit losses $ 419 $ 113 $ 44 $ 576 December 31, 2016 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Balance at beginning of year $ 454 $ 114 $ 38 $ 606 Additions: Provision for loan losses 93 — — 93 Deductions: Gross loan and lease charge-offs (170 ) (12 ) (16 ) (198 ) Recoveries 43 14 9 66 Net loan and lease charge-offs (127 ) 2 (7 ) (132 ) Balance at end of year $ 420 $ 116 $ 31 $ 567 Reserve for unfunded lending commitments Balance at beginning of year $ 58 $ 16 $ 1 $ 75 Provision credited to earnings (4 ) (5 ) (1 ) (10 ) Balance at end of year $ 54 $ 11 $ — $ 65 Total allowance for credit losses Allowance for loan losses $ 420 $ 116 $ 31 $ 567 Reserve for unfunded lending commitments 54 11 — 65 Total allowance for credit losses $ 474 $ 127 $ 31 $ 632 The ALLL and outstanding loan balances according to the Company’s impairment method are summarized as follows: December 31, 2017 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Individually evaluated for impairment $ 26 $ 1 $ 4 $ 31 Collectively evaluated for impairment 345 102 40 487 Purchased loans with evidence of credit deterioration — — — — Total $ 371 $ 103 $ 44 $ 518 Outstanding loan balances Individually evaluated for impairment $ 314 $ 69 $ 76 $ 459 Collectively evaluated for impairment 22,598 11,048 10,648 44,294 Purchased loans with evidence of credit deterioration 14 7 6 27 Total $ 22,926 $ 11,124 $ 10,730 $ 44,780 December 31, 2016 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Individually evaluated for impairment $ 56 $ 3 $ 6 $ 65 Collectively evaluated for impairment 364 113 25 502 Purchased loans with evidence of credit deterioration — — — — Total $ 420 $ 116 $ 31 $ 567 Outstanding loan balances Individually evaluated for impairment $ 466 $ 78 $ 75 $ 619 Collectively evaluated for impairment 21,111 11,231 9,611 41,953 Purchased loans with evidence of credit deterioration 38 32 7 77 Total $ 21,615 $ 11,341 $ 9,693 $ 42,649 Nonaccrual and Past Due Loans Loans are generally placed on nonaccrual status when payment in full of principal and interest is not expected, or the loan is 90 days or more past due as to principal or interest, unless the loan is both well secured and in the process of collection. Factors we consider in determining whether a loan is placed on nonaccrual include delinquency status, collateral-value, borrower or guarantor financial statement information, bankruptcy status, and other information which would indicate that the full and timely collection of interest and principal is uncertain. A nonaccrual loan may be returned to accrual status when all delinquent interest and principal become current in accordance with the terms of the loan agreement; the loan, if secured, is well secured; the borrower has paid according to the contractual terms for a minimum of six months; and analysis of the borrower indicates a reasonable assurance of the ability and willingness to maintain payments. Payments received on nonaccrual loans are applied as a reduction to the principal outstanding. Closed-end loans with payments scheduled monthly are reported as past due when the borrower is in arrears for two or more monthly payments. Similarly, open-end credit such as charge-card plans and other revolving credit plans are reported as past due when the minimum payment has not been made for two or more billing cycles. Other multi-payment obligations (i.e., quarterly, semiannual, etc.), single payment, and demand notes are reported as past due when either principal or interest is due and unpaid for a period of 30 days or more. Nonaccrual loans are summarized as follows: December 31, (In millions) 2017 2016 Loans held for sale $ 12 $ 40 Commercial: Commercial and industrial $ 195 $ 354 Leasing 8 14 Owner-occupied 90 74 Municipal 1 1 Total commercial 294 443 Commercial real estate: Construction and land development 4 7 Term 36 29 Total commercial real estate 40 36 Consumer: Home equity credit line 13 11 1-4 family residential 55 36 Construction and other consumer real estate — 2 Bankcard and other revolving plans — 1 Other — — Total consumer loans 68 50 Total $ 402 $ 529 Past due loans (accruing and nonaccruing) are summarized as follows: December 31, 2017 (In millions) Current 30-89 days past due 90+ days past due Total past due Total loans Accruing loans 90+ days past due Nonaccrual loans that are current 1 Loans held for sale $ 44 $ — $ — $ — $ 44 $ — $ 12 Commercial: Commercial and industrial $ 13,887 $ 60 $ 56 $ 116 $ 14,003 $ 13 $ 146 Leasing 363 1 — 1 364 — 8 Owner-occupied 7,219 29 40 69 7,288 4 49 Municipal 1,271 — — — 1,271 — 1 Total commercial 22,740 90 96 186 22,926 17 204 Commercial real estate: Construction and land development 2,014 3 4 7 2,021 — — Term 9,079 13 11 24 9,103 2 25 Total commercial real estate 11,093 16 15 31 11,124 2 25 Consumer: Home equity credit line 2,763 9 5 14 2,777 — 5 1-4 family residential 6,621 16 25 41 6,662 1 27 Construction and other consumer real estate 590 6 1 7 597 1 — Bankcard and other revolving plans 506 2 1 3 509 1 — Other 184 1 — 1 185 — — Total consumer loans 10,664 34 32 66 10,730 3 32 Total $ 44,497 $ 140 $ 143 $ 283 $ 44,780 $ 22 $ 261 December 31, 2016 (In millions) Current 30-89 days past due 90+ days past due Total past due Total loans Accruing loans 90+ days past due Nonaccrual loans that are current 1 Loans held for sale $ 172 $ — $ — $ — $ 172 $ — $ 40 Commercial: Commercial and industrial $ 13,306 $ 72 $ 74 $ 146 $ 13,452 $ 10 $ 287 Leasing 423 — — — 423 — 14 Owner-occupied 6,894 40 28 68 6,962 8 43 Municipal 778 — — — 778 — 1 Total commercial 21,401 112 102 214 21,615 18 345 Commercial real estate: Construction and land development 2,010 7 2 9 2,019 1 1 Term 9,291 9 22 31 9,322 12 18 Total commercial real estate 11,301 16 24 40 11,341 13 19 Consumer: Home equity credit line 2,635 4 6 10 2,645 1 5 1-4 family residential 5,857 12 22 34 5,891 — 11 Construction and other consumer real estate 479 3 4 7 486 3 — Bankcard and other revolving plans 478 2 1 3 481 1 1 Other 189 1 — 1 190 — — Total consumer loans 9,638 22 33 55 9,693 5 17 Total $ 42,340 $ 150 $ 159 $ 309 $ 42,649 $ 36 $ 381 1 Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected. Credit Quality Indicators In addition to the past due and nonaccrual criteria, we also analyze loans using loan risk grading systems, which vary based on the size and type of credit risk exposure. The internal risk grades assigned to loans follow our definitions of Pass, Special Mention, Substandard, and Doubtful, which are consistent with published definitions of regulatory risk classifications. Definitions of Pass, Special Mention, Substandard, and Doubtful are summarized as follows: Pass – A Pass asset is higher quality and does not fit any of the other categories described below. The likelihood of loss is considered low. Special Mention – A Special Mention asset has potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the Bank’s credit position at some future date. Substandard – A Substandard asset is inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Assets so classified have well-defined weaknesses and are characterized by the distinct possibility that the Bank may sustain some loss if deficiencies are not corrected. Doubtful – A Doubtful asset has all the weaknesses inherent in a Substandard asset with the added characteristics that the weaknesses make collection or liquidation in full highly questionable and improbable. We generally assign internal risk grades to commercial and CRE loans with commitments greater than $1 million based on financial and statistical models, individual credit analysis, and loan officer experience and judgment. For these larger loans, we assign one of multiple grades within the Pass classification or one of the following four grades: Special Mention, Substandard, Doubtful, and Loss. Loss indicates that the outstanding balance has been charged off. We confirm our internal risk grades quarterly, or as soon as we identify information that affects the credit risk of the loan. For consumer loans and certain small commercial and CRE loans with commitments less than or equal to $1 million , we generally assign internal risk grades similar to those described previously based on automated rules that depend on refreshed credit scores, payment performance, and other risk indicators. These are generally assigned either a Pass or Substandard grade and are reviewed as we identify information that might warrant a grade change. Outstanding loan balances (accruing and nonaccruing) categorized by these credit quality classifications are summarized as follows: December 31, 2017 (In millions) Pass Special mention Sub- standard Doubtful Total loans Total allowance Commercial: Commercial and industrial $ 13,001 $ 395 $ 606 $ 1 $ 14,003 Leasing 342 6 16 — 364 Owner-occupied 6,920 93 275 — 7,288 Municipal 1,257 13 1 — 1,271 Total commercial 21,520 507 898 1 22,926 $ 371 Commercial real estate: Construction and land development 2,002 15 4 — 2,021 Term 8,816 138 149 — 9,103 Total commercial real estate 10,818 153 153 — 11,124 103 Consumer: Home equity credit line 2,759 — 18 — 2,777 1-4 family residential 6,602 — 60 — 6,662 Construction and other consumer real estate 596 — 1 — 597 Bankcard and other revolving plans 507 — 2 — 509 Other 185 — — — 185 Total consumer loans 10,649 — 81 — 10,730 44 Total $ 42,987 $ 660 $ 1,132 $ 1 $ 44,780 $ 518 December 31, 2016 (In millions) Pass Special mention Sub- standard Doubtful Total loans Total allowance Commercial: Commercial and industrial $ 12,185 $ 266 $ 998 $ 3 $ 13,452 Leasing 387 5 30 1 423 Owner-occupied 6,560 96 306 — 6,962 Municipal 765 7 6 — 778 Total commercial 19,897 374 1,340 4 21,615 $ 420 Commercial real estate: Construction and land development 1,942 52 25 — 2,019 Term 9,096 82 144 — 9,322 Total commercial real estate 11,038 134 169 — 11,341 116 Consumer: Home equity credit line 2,629 — 16 — 2,645 1-4 family residential 5,851 — 40 — 5,891 Construction and other consumer real estate 482 — 4 — 486 Bankcard and other revolving plans 478 — 3 — 481 Other 189 — 1 — 190 Total consumer loans 9,629 — 64 — 9,693 31 Total $ 40,564 $ 508 $ 1,573 $ 4 $ 42,649 $ 567 Impaired Loans Loans are considered impaired when, based on current information and events, it is probable that we will be unable to collect all amounts due in accordance with the contractual terms of the loan agreement, including scheduled interest payments. For our non-purchased credit-impaired loans, if a nonaccrual loan has a balance greater than $1 million , or if a loan is a TDR, including TDRs that subsequently default, or if the loan is no longer reported as a TDR, we individually evaluate the loan for impairment and estimate a specific reserve for the loan for all portfolio segments under applicable accounting guidance. Smaller nonaccrual loans are pooled for ALLL estimation purposes. PCI loans are included in impaired loans and are accounted for under separate accounting guidance. See subsequent discussion under Purchased Loans. When a loan is impaired, we estimate a specific reserve for the loan based on the projected present value of the loan’s future cash flows discounted at the loan’s effective interest rate, the observable market price of the loan, or the fair value of the loan’s underlying collateral. The process of estimating future cash flows also incorporates the same determining factors discussed previously under nonaccrual loans. When we base the impairment amount on the fair value of the loan’s underlying collateral, we generally charge-off the portion of the balance that is impaired, such that these loans do not have a specific reserve in the ALLL. Payments received on impaired loans that are accruing are recognized in interest income, according to the contractual loan agreement. Payments received on impaired loans that are on nonaccrual are not recognized in interest income, but are applied as a reduction to the principal outstanding. The amount of interest income recognized on a cash basis during the time the loans were impaired within the years ended December 31, 2017 and 2016 was not significant. Information on impaired loans individually evaluated is summarized as follows, including the average recorded investment and interest income recognized for the years ended December 31, 2017 and 2016 : December 31, 2017 Year Ended (In millions) Unpaid principal balance Recorded investment Total recorded investment Related allowance Average recorded investment Interest with no allowance with allowance Commercial: Commercial and industrial $ 293 $ 80 $ 142 $ 222 $ 24 $ 289 $ 6 Owner-occupied 120 79 23 102 2 97 6 Municipal 1 1 — 1 — 1 — Total commercial 414 160 165 325 26 387 12 Commercial real estate: Construction and land development 8 4 2 6 — 8 — Term 56 36 12 48 — 49 12 Total commercial real estate 64 40 14 54 — 57 12 Consumer: Home equity credit line 25 13 9 22 — 21 1 1-4 family residential 67 28 29 57 4 52 1 Construction and other consumer real estate 2 1 1 2 — 2 — Other 1 1 — 1 — 1 1 Total consumer loans 95 43 39 82 4 76 3 Total $ 573 $ 243 $ 218 $ 461 $ 30 $ 520 $ 27 December 31, 2016 Year Ended (In millions) Unpaid principal balance Recorded investment Total recorded investment Related allowance Average recorded investment Interest with no allowance with allowance Commercial: Commercial and industrial $ 470 $ 82 $ 311 $ 393 $ 52 $ 333 $ 5 Owner-occupied 115 71 30 101 3 99 9 Municipal 1 1 — 1 — 1 — Total commercial 586 154 341 495 55 433 14 Commercial real estate: Construction and land development 22 7 6 13 — 11 2 Term 92 53 17 70 2 76 13 Total commercial real estate 114 60 23 83 2 87 15 Consumer: Home equity credit line 24 16 7 23 — 22 1 1-4 family residential 59 27 28 55 6 57 2 Construction and other consumer real estate 3 1 2 3 — 2 — Other 2 1 — 1 — 2 — Total consumer loans 88 45 37 82 6 83 3 Total $ 788 $ 259 $ 401 $ 660 $ 63 $ 603 $ 32 Modified and Restructured Loans Loans may be modified in the normal course of business for competitive reasons or to strengthen the Company’s position. Loan modifications and restructurings may also occur when the borrower experiences financial difficulty and needs temporary or permanent relief from the original contractual terms of the loan. Loans that have been modified to accommodate a borrower who is experiencing financial difficulties, and for which the Company has granted a concession that it would not otherwise consider, are considered troubled debt restructurings (“TDRs”). We consider many factors in determining whether to agree to a loan modification involving concessions, and seek a solution that will both minimize potential loss to the Company and attempt to help the borrower. We evaluate borrowers’ current and forecasted future cash flows, their ability and willingness to make current contractual or proposed modified payments, the value of the underlying collateral (if applicable), the possibility of obtaining additional security or guarantees, and the potential costs related to a repossession or foreclosure and the subsequent sale of the collateral. TDRs are classified as either accrual or nonaccrual loans. A loan on nonaccrual and restructured as a TDR will remain on nonaccrual status until the borrower has proven the ability to perform under the modified structure for a minimum of six months, and there is evidence that such payments can and are likely to continue as agreed. Performance prior to the restructuring, or significant events that coincide with the restructuring, are included in assessing whether the borrower can meet the new terms and may result in the loan being returned to accrual at the time of restructuring or after a shorter performance period. If the borrower’s ability to meet the revised payment schedule is uncertain, the loan remains classified as a nonaccrual loan. A TDR loan that specifies an interest rate that at the time of the restructuring is greater than or equal to the rate the Bank is willing to accept for a new loan with comparable risk may not be reported as a TDR or an impaired loan in the calendar years subsequent to the restructuring if it is in compliance with its modified terms. Selected information on TDRs at year-end that includes the recorded investment on an accruing and nonaccruing basis by loan class and modification type is summarized in the following schedules: December 31, 2017 Recorded investment resulting from the following modification types: (In millions) Interest rate below market Maturity or term extension Principal forgiveness Payment deferral Other 1 Multiple modification types 2 Total Accruing Commercial: Commercial and industrial $ — $ 2 $ — $ — $ 12 $ 33 $ 47 Owner-occupied 1 1 — — 7 14 23 Total commercial 1 3 — — 19 47 70 Commercial real estate: Construction and land development — — — — — 2 2 Term 6 — — 1 — 7 14 Total commercial real estate 6 — — 1 — 9 16 Consumer: Home equity credit line — 2 9 — 1 3 15 1-4 family residential 1 — 6 1 2 26 36 Construction and other consumer real estate — 1 — — — 1 2 Total consumer loans 1 3 15 1 3 30 53 Total accruing 8 6 15 2 22 86 139 Nonaccruing Commercial: Commercial and industrial — 3 5 2 28 24 62 Owner-occupied 1 2 — 1 1 5 10 Municipal — 1 — — — — 1 Total commercial 1 6 5 3 29 29 73 Commercial real estate: Construction and land development — — — — — — — Term 2 — — — — 3 5 Total commercial real estate 2 — — — — 3 5 Consumer: Home equity credit line — — 1 — — — 1 1-4 family residential — — 2 — 1 5 8 Construction and other consumer real estate — — — — — — — Total consumer loans — — 3 — 1 5 9 Total nonaccruing 3 6 8 3 30 37 87 Total $ 11 $ 12 $ 23 $ 5 $ 52 $ 123 $ 226 1 Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc. 2 Includes TDRs that resulted from a combination of any of the previous modification types. December 31, 2016 Recorded investment resulting from the following modification types: (In millions) Interest rate below market Maturity or term extension Principal forgiveness Payment deferral Other 1 Multiple modification types 2 Total Accruing Commercial: Commercial and industrial $ — $ 19 $ — $ — $ — $ 28 $ 47 Owner-occupied 3 — 1 — 8 10 22 Total commercial 3 19 1 — 8 38 69 Commercial real estate: Construction and land development — 4 — — — 4 8 Term 4 — — 1 2 10 17 Total commercial real estate 4 4 — 1 2 14 25 Consumer: Home equity credit line — 1 10 — — 3 14 1-4 family residential 3 1 6 — 2 30 42 Construction and other consumer real estate — — — — — 1 1 Total consumer loans 3 2 16 — 2 34 57 Total accruing 10 25 17 1 12 86 151 Nonaccruing Commercial: Commercial and industrial 1 — — 1 33 25 60 Owner-occupied — 1 — 3 1 12 17 Municipal — 1 — — — — 1 Total commercial 1 2 — 4 34 37 78 Commercial real estate: Construction and land development — — — — 2 — 2 Term 2 1 — — 2 3 8 Total commercial real estate 2 1 — — 4 3 10 Consumer: Home equity credit line — — 1 — — 1 2 1-4 family residential — — 2 — 1 5 8 Construction and other consumer real estate — — — 2 — — 2 Total consumer loans — — 3 2 1 6 12 Total nonaccruing 3 3 3 6 39 46 100 Total $ 13 $ 28 $ 20 $ 7 $ 51 $ 132 $ 251 1 Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc. 2 Includes TDRs that resulted from a combination of any of the previous modification types. Unfunded lending commitments on TDRs amounted to approximately $22 million at December 31, 2017 and $14 million at December 31, 2016 . The total recorded investment of all TDRs in which interest rates were modified below market was $120 million at December 31, 2017 and $128 million at December 31, 2016 , respectively. These loans are included in the previous schedule in the columns for interest rate below market and multiple modification types. The net financial impact on interest income due to interest rate modifications below market for accruing TDRs is summarized in the following schedule: (In millions) 2017 2016 Consumer: 1-4 family residential $ (1 ) $ (1 ) Total consumer loans (1 ) (1 ) Total decrease to interest income 1 $ (1 ) $ (1 ) 1 Calculated based on the difference between the modified rate and the premodified rate applied to the recorded investment. On an ongoing basis, we monitor the performance of all TDRs according to their restructured terms. Subsequent payment default is defined in terms of delinquency, when principal or interest payments are past due 90 days or more for commercial loans, or 60 days or more for consumer loans. The recorded investment of accruing and nonaccruing TDRs that had a payment default during the period listed below (and are still in default at year-end) and are within 12 months or less of being modified as TDRs is as follows: (In millions) December 31, 2017 December 31, 2016 Accruing Nonaccruing Total Accruing Nonaccruing Total Commercial: Commercial and industrial $ 1 $ 3 $ 4 $ — $ — $ — Owner-occupied — 1 1 — 1 1 Total commercial 1 4 5 — 1 1 Consumer: Construction and other consumer real estate — — — — 2 2 Total consumer loans — — — — 2 2 Total $ 1 $ 4 $ 5 $ — $ 3 $ 3 Note: Total loans modified as TDRs during the 12 months previous to December 31, 2017 and 2016 were $94 million and $73 million , respectively. At December 31, 2017 and December 31, 2016 , the amount of foreclosed residential real estate property held by the Company was less than $1 million and $2 million , and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure was approximately $10 million for both periods, respectively. Concentrations of Credit Risk Credit risk is the possibility of loss from the failure of a borrower, guarantor, or another obligor to fully perform under the terms of a credit-related contract. Credit risks (whether on- or off-balance sheet) may occur when individual borrowers, groups of borrowers, or counterparties have similar economic characteristics, including industries, geographies, collateral types, sponsors, etc., and are similarly affected by changes in economic or other conditions. Credit risk also includes the loss that would be recognized subsequent to the reporting date if counterparties failed to perform as contracted. See Note 7 for a discussion of counterparty risk associated with the Company’s derivative transactions. We perform an ongoing analysis of our loan portfolio to evaluate whether there is any significant exposure to any concentrations of credit risk. Based on this analysis, we believ

Derivative Instruments And Hedg

Derivative Instruments And Hedging Activities	12 Months Ended
	Dec. 31, 2017
Summary of Derivative Instruments [Abstract]
Derivative Instruments And Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Objectives Our objectives in using derivatives are to add stability to interest income or expense, to modify the duration of specific assets or liabilities as we consider advisable, to manage exposure to interest rate movements or other identified risks, and/or to directly offset derivatives sold to our customers. We apply hedge accounting to certain derivatives executed for risk management purposes as described in more detail subsequently. However, we do not apply hedge accounting to all of the derivatives involved in our risk management activities. Derivatives not designated as accounting hedges are not speculative and are used to economically manage our exposure to interest rate movements and other identified risks, but do not meet the strict hedge accounting requirements. Accounting We record all derivatives on the balance sheet at fair value. Note 3 discusses the process to estimate fair value for derivatives. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and the resulting accounting designation. Derivatives used to hedge the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives used to hedge the exposure to variability in expected cash flows, or other types of forecasted transactions, are considered cash flow hedges. For derivatives designated as fair value hedges, changes in the fair value of the derivative are recognized in earnings together with changes in the fair value of the related hedged item. The net amount, if any, representing hedge ineffectiveness, is reflected in earnings. In previous years, we used fair value hedges to manage interest rate exposure to certain long-term debt. These hedges have been terminated and their remaining balances were completely amortized into earnings during 2015. For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivative are recorded in OCI and recognized in earnings when the hedged transaction affects earnings. The ineffective portion of changes in the fair value of cash flow hedges is recognized directly in earnings. We use interest rate swaps as part of our cash flow hedging strategy to hedge the variable cash flows associated with designated commercial loans. These interest rate swap agreements designated as cash flow hedges involve the receipt of fixed-rate amounts in exchange for variable-rate payments over the life of the agreements without exchange of the underlying notional amount. During 2016 we closed our branch in Grand Cayman, Grand Cayman Islands B.W.I. and no longer have foreign operations. No derivatives were designated as hedges of investments in foreign operations during 2017 . We assess the effectiveness of each hedging relationship by comparing the changes in fair value or cash flows on the derivative hedging instrument with the changes in fair value or cash flows on the designated hedged item or transaction. For derivatives not designated as accounting hedges, changes in fair value are recognized in earnings. The remaining balances of any derivative instruments terminated prior to maturity, including amounts in AOCI for cash flow hedges, are accreted or amortized to interest income or expense over the period to their previously stated maturity dates. Amounts in AOCI are reclassified to interest income as interest is earned on related variable-rate loans and as amounts for terminated hedges are accreted or amortized to earnings. Collateral and Credit Risk Exposure to credit risk arises from the possibility of nonperformance by counterparties. No significant losses on derivative instruments have occurred as a result of counterparty nonperformance. Financial institutions which are well-capitalized and well-established are the counterparties for those derivatives entered into for asset-liability management and to offset derivatives sold to our customers. The Company reduces its counterparty exposure for derivative contracts by centrally clearing all eligible derivatives. For those derivatives that are not centrally cleared, the counterparties are typically financial institutions or customers of the Company. For those that are financial institutions, we manage our credit exposure through the use of a Credit Support Annex (“CSA”) to International Swaps and Derivative Association master agreements. Eligible collateral types are documented by the CSA and controlled under the Company’s general credit policies. Collateral balances are typically monitored on a daily basis. A valuation haircut policy reflects the fact that collateral may fall in value between the date the collateral is called and the date of liquidation or enforcement. In practice, all of the Company’s collateral held as credit risk mitigation under a CSA is cash. We offer interest rate swaps to our customers to assist them in managing their exposure to changing interest rates. Upon issuance, all of these customer swaps are immediately offset through matching derivative contracts, such that the Company minimizes its interest rate risk exposure resulting from such transactions. Most of these customers do not have the capability for centralized clearing. Therefore, we manage the credit risk through loan underwriting which includes a credit risk exposure formula for the swap, the same collateral and guarantee protection applicable to the loan and credit approvals, limits, and monitoring procedures. Fee income from customer swaps is included in other service charges, commissions and fees. No significant losses on derivative instruments have occurred as a result of counterparty nonperformance. Nevertheless, the related credit risk is considered and measured when and where appropriate. See Notes 6 and 15 for further discussion of our underwriting, collateral requirements, and other procedures used to address credit risk. Our derivative contracts require us to pledge collateral for derivatives that are in a net liability position at a given balance sheet date. Certain of these derivative contracts contain credit-risk-related contingent features that include the requirement to maintain a minimum debt credit rating. We may be required to pledge additional collateral if a credit-risk-related feature were triggered, such as a downgrade of our credit rating. However, in past situations, not all counterparties have demanded that additional collateral be pledged when provided for under their contracts. At December 31, 2017 , the fair value of our derivative liabilities was $40 million , for which we were required to pledge cash collateral of approximately $38 million in the normal course of business. If our credit rating were downgraded one notch by either Standard & Poor’s or Moody’s at December 31, 2017 , the additional amount of collateral we could be required to pledge is approximately $1 million . As a result of the Dodd-Frank Act, all newly eligible derivatives entered into are cleared through a central clearinghouse. Derivatives that are centrally cleared do not have credit-risk-related features that require additional collateral if our credit rating were downgraded. Derivative Amounts Selected information with respect to notional amounts and recorded gross fair values at December 31, 2017 and 2016 , and the related gain (loss) of derivative instruments for the years then ended is summarized as follows: December 31, 2017 December 31, 2016 Notional amount Fair value Notional amount Fair value (In millions) Other assets Other liabilities Other assets Other liabilities Derivatives designated as hedging instruments Cash flow hedges: Interest rate swaps $ 1,138 $ — $ — $ 1,388 $ 2 $ 1 Derivatives not designated as hedging instruments Interest rate swaps 223 1 — 235 2 — Interest rate swaps for customers 1 4,550 28 33 4,162 49 49 Foreign exchange 913 9 7 424 11 9 Total derivatives not designated as hedging instruments 5,686 38 40 4,821 62 58 Total derivatives $ 6,824 $ 38 $ 40 $ 6,209 $ 64 $ 59 1 Notional amounts include both the customer swaps and the offsetting derivative contracts. Year Ended December 31, 2017 Year Ended December 31, 2016 Amount of derivative gain (loss) recognized/reclassified (In millions) OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense Derivatives designated as hedging instruments Cash flow hedges: 1 Interest rate swaps $ (8 ) $ 4 $ 8 $ 11 Derivatives not designated as hedging instruments Interest rate swaps $ (1 ) $ 1 Interest rate swaps for customers 11 14 Foreign exchange 17 11 Total derivatives $ (8 ) $ 4 $ 27 $ — $ 8 $ 11 $ 26 $ — Note: These schedules are not intended to present at any given time the Company’s long/short position with respect to its derivative contracts. 1 Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss). For the 12 months following December 31, 2017 , we estimate that $1 million will be reclassified from AOCI into interest income. The fair value of derivative assets was reduced by a net credit valuation adjustment of $2 million at December 31, 2017 and 2016 , respectively. The fair value of derivative liabilities was reduced by a net debit valuation adjustment of $1 million at December 31, 2017 and 2016 , respectively. These adjustments are required to reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment Disclosure [Text Block]	. PREMISES, EQUIPMENT AND SOFTWARE, NET Premises, equipment and software, net are summarized as follows: (In millions) December 31, 2017 2016 Land $ 234 $ 229 Buildings 720 683 Furniture and equipment 451 458 Leasehold improvements 135 140 Software 401 355 Total 1,941 1,865 Less accumulated depreciation and amortization 847 845 Net book value $ 1,094 $ 1,020

Goodwill And Other Intangible A

Goodwill And Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets Disclosure [Text Block]	. GOODWILL AND OTHER INTANGIBLE ASSETS Core deposit and other intangible assets and related accumulated amortization are as follows at December 31 : Gross carrying amount Accumulated amortization Net carrying amount (In millions) 2017 2016 2017 2016 2017 2016 Core deposit intangibles $ 167 $ 167 $ (165 ) $ (159 ) $ 2 $ 8 Customer relationships and other intangibles 28 28 (28 ) (28 ) — — Total $ 195 $ 195 $ (193 ) $ (187 ) $ 2 $ 8 The amount of amortization expense of core deposit and other intangible assets is separately reflected in the statement of income. Estimated amortization expense for core deposit and other intangible assets is $2 million in 2018 , less than $1 million in 2019 , and nothing thereafter. Changes in the carrying amount of goodwill for operating segments with goodwill are as follows: (In millions) Zions Bank CB&T Amegy Consolidated Company Balance at December 31, 2015 $ 20 $ 379 $ 615 $ 1,014 Impairment losses — — — — Balance at December 31, 2016 20 379 615 1,014 Impairment losses — — — — Balance at December 31, 2017 $ 20 $ 379 $ 615 $ 1,014 A company-wide annual impairment test is conducted as of October 1 of each year and updated on a more frequent basis when events or circumstances indicate that impairment could have taken place. Results of the testing for 2017 and 2016 concluded that no impairment was present in any of the operating segments.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Deposit Liabilities Disclosures [Text Block]	DEPOSITS At December 31, 2017 , the scheduled maturities of all time deposits were as follows: (In millions) 2018 $ 2,584 2019 256 2020 132 2021 85 2022 57 Thereafter 1 Total $ 3,115 The contractual maturities of time deposits with a denomination of $100,000 and over were as follows: (In millions) December 31, 2017 Three months or less $ 1,023 After three months through six months 485 After six months through twelve months 508 After twelve months 312 Total $ 2,328 Time deposits in denominations that meet or exceed the current FDIC insurance limit of $250,000 were $1.9 billion and $1.4 billion at December 31, 2017 and 2016 , respectively. Time deposits under $250,000 were $1.2 billion and $1.4 billion at December 31, 2017 and 2016 , respectively. Deposit overdrafts reclassified as loan balances were $14 million and $11 million at December 31, 2017 and 2016 , respectively.

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2017
Short-term Debt [Abstract]
Short-Term Borrowings	SHORT-TERM BORROWINGS Selected information for FHLB advances and other short-term borrowings is as follows: (Dollar amounts in millions) 2017 2016 2015 Federal Home Loan Bank advances Average amount outstanding $ 2,657 $ 37 $ — Average rate 1.13 % 0.59 % — % Highest month-end balance 3,750 750 — Year-end balance 3,600 500 — Average rate on outstandings at year-end 1.44 % 0.75 % — % Other short-term borrowings, year-end balances Federal funds purchased 927 106 111 Security repurchase agreements 354 196 206 Securities sold, not yet purchased 95 25 30 Total Federal Home Loan Bank advances and other short-term borrowings $ 4,976 $ 827 $ 347 ZB, N.A. may borrow from the FHLB under their lines of credit that are secured under blanket pledge arrangements. ZB, N.A. maintained unencumbered collateral with carrying amounts adjusted for the types of collateral pledged, equal to at least 100% of the outstanding advances. At December 31, 2017 , the amount available for FHLB advances was approximately $8.9 billion . ZB, N.A. may also borrow from the Federal Reserve based on the amount of collateral pledged to a Federal Reserve Bank. At December 31, 2017 , the amount available for additional Federal Reserve borrowings was approximately $5.8 billion . Federal funds purchased and security repurchase agreements generally mature in less than 30 days. Our participation in security repurchase agreements is on an overnight or term basis (e.g., 30 or 60 days). ZB, N.A. executes overnight repurchase agreements with sweep accounts in conjunction with a master repurchase agreement. When this occurs, securities under the Bank’s control are pledged and interest is paid on the collected balance of the customers’ accounts. For the non-sweep overnight and term repurchase agreements, securities are transferred to the applicable counterparty. The counterparty, in certain instances, is contractually entitled to sell or repledge securities accepted as collateral. Of the total security repurchase agreements at December 31, 2017 , $31 million were overnight and $323 million were term.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Long-term Debt, Unclassified [Abstract]
Debt Disclosure [Text Block]	LONG-TERM DEBT Long-term debt is summarized as follows: December 31, (In millions) 2017 2016 Subordinated notes $ 247 $ 246 Senior notes 135 288 Capital lease obligations 1 1 Total $ 383 $ 535 The preceding carrying values represent the par value of the debt adjusted for any unamortized premium or discount or unamortized debt issuance costs. Subordinated Notes Subordinated notes were issued by the Parent and consist of the following at December 31, 2017 : (Dollar amounts in millions) Subordinated notes Coupon rate Balance Par amount Maturity 5.65% $ 160 $ 162 Nov 2023 6.95% 87 88 Sep 2028 Total $ 247 $ 250 These notes are unsecured, and interest is payable semiannually on the 5.65% notes and quarterly on the 6.95% notes. Interest payments on the 5.65% notes commenced May 15, 2014 to the earliest possible redemption date of November 15, 2018 , after which they are payable quarterly at an annual floating rate equal to 3mL+4.19% . For the 6.95% notes, interest payments commenced December 15, 2013 to the earliest possible redemption date of September 15, 2023 , after which the interest rate changes to an annual floating rate equal to 3mL+3.89% . Senior Notes Senior notes were issued by the Parent and consist of the following at December 31, 2017 : (Dollar amounts in millions) Senior notes Coupon rate Balance Par amount Maturity 4.50% $ 135 $ 136 June 2023 These notes are unsecured and interest is payable semiannually. The notes were issued under a shelf registration filed with the SEC and were sold via the Company’s online auction process and direct sales. The notes are not redeemable prior to maturity. Debt Maturities and Redemptions During 2017, $153 million of our senior notes matured. During 2016, we elected to exercise our right to redeem junior subordinated debentures related to trust preferred securities. The following amounts of long-term debt matured or were redeemed during 2016 : (Dollar amounts in millions) Note type Par amount Trust preferred: 3mL+2.85% (3.38%) $ 51 3mL+1.90% (2.22%) 36 3mL+1.78% (2.29%) 62 3mL+3.15% (3.75%) 8 3mL+2.89% (3.42%) 8 Total trust preferred 165 Senior notes: 3.60% 11 4.00% 89 Total senior notes 100 Total $ 265 Debt Extinguishment Costs During 2017 , we had no debt extinguishment costs, compared with less than $1 million in 2016 and $3 million in 2015 . Maturities of Long-term Debt Maturities of long-term debt are as follows for the years succeeding December 31, 2017 : (In millions) Consolidated Parent only 2018 $ — $ — 2019 1 — 2020 — — 2021 — — 2022 — — Thereafter 382 382 Total $ 383 $ 382 The consolidated Zions Bancorporation long-term debt maturities include $1 million of capital lease obligations in addition to the subordinated and senior debt issued by the Parent.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Shareholders' Equity	13. SHAREHOLDERS’ EQUITY Preferred Stock Preferred stock is without par value and has a liquidation preference of $1,000 per share, or $25 per depositary share. Except for Series I and J, all preferred shares were issued in the form of depositary shares, with each depositary share representing a 1/40 th ownership interest in a share of the preferred stock. All preferred shares are registered with the SEC. In general, preferred shareholders may receive asset distributions before common shareholders; however, preferred shareholders have only limited voting rights generally with respect to certain provisions of the preferred stock, the issuance of senior preferred stock, and the election of directors. Preferred stock dividends reduce earnings applicable to common shareholders and are paid on the 15th day of the months indicated in the following schedule. Dividends are approved by the Board of Directors and are subject to regulatory non-objection to a stress test and capital plan submitted to the Federal Reserve pursuant to the annual Horizontal Capital Review, also referred to as Comprehensive Capital Analysis and Review (“HCR/CCAR”) process. Redemption of the preferred stock is at the Company’s option after the expiration of any applicable redemption restrictions. The redemption amount is computed at the per share liquidation preference plus any declared but unpaid dividends. Redemptions are subject to certain regulatory provisions, including the previously noted capital plan non-objection for a submitted capital plan in a given year. Preferred stock is summarized as follows: Shares at (Dollar amounts in millions) Carrying value at Authorized Outstanding Dividends payable Earliest redemption date Rate following earliest redemption date Dividends payable after rate change 2017 2016 (thousands) (thousands) Rate (when applicable) Series A $ 67 $ 67 140,000 66,139 > of 4.0% or 3mL+0.52% Qtrly Mar,Jun,Sep,Dec Dec 15, 2011 Series F — 144 — — 7.9% Qtrly Mar,Jun,Sep,Dec Jun 15, 2017 Series G 138 138 200,000 138,391 6.3% Qtrly Mar,Jun,Sep,Dec Mar 15, 2023 annual float-ing rate = 3mL+4.24% Series H 126 126 126,221 126,221 5.75% Qtrly Mar,Jun,Sep,Dec Jun 15, 2019 Series I 99 99 300,893 98,555 5.8% Semi-annually Jun,Dec Jun 15, 2023 annual float-ing rate = 3mL+3.8% Qtrly Mar,Jun,Sep,Dec Series J 136 136 195,152 136,368 7.2% Semi-annually Mar,Sep Sep 15, 2023 annual float-ing rate = 3mL+4.44% Qtrly Mar,Jun,Sep,Dec Total $ 566 $ 710 Preferred Stock Redemptions During 2017, we redeemed all outstanding shares of our 7.9% Series F preferred stock for a cash payment of approximately $144 million . The total reduction to net earnings applicable to common shareholders associated with the preferred stock redemption was $2 million due to the accelerated recognition of preferred stock issuance costs. During 2016 , we launched a cash tender offer to purchase up to $120 million par amount of certain outstanding preferred stock. Our preferred stock decreased by $118 million as a result of the tender offer, including the purchase of $26 million of our Series I preferred stock, $59 million of our Series J preferred stock, and $33 million of our Series G preferred stock for an aggregate cash payment of $126 million . The total reduction to net earnings applicable to common shareholders associated with the preferred stock redemption was $10 million . The size and terms of the redemptions in 2017 and 2016 were determined in accordance with the Company’s 2016 and 2015 capital plans. These preferred stock redemptions benefit the Company by decreasing the amount of preferred dividends paid. Common Stock The Company’s common stock is traded on the NASDAQ Global Select Market. As of December 31, 2017, there were 198 million shares of no par common stock outstanding. The Company continued its common stock repurchase program during 2017 and repurchased 7 million shares of common shares outstanding with a fair value of $320 million at an average price of $45.66 per share. During the first quarter of 2018, the Company repurchased an additional 2 million shares of common stock outstanding with a fair value of $115 million at an average price of $53.46 per share, leaving $120 million of repurchase capacity remaining in the 2017 capital plan (which spans the timeframe of July 2017 to June 2018). During 2016 the Company repurchased 3 million shares of common shares outstanding with a fair value of $90 million at an average price of $31.15 per share. Common Stock Warrants As of December 31, 2017, 29.3 million common stock warrants with an exercise price of $35.37 were outstanding. These warrants expire on May 22, 2020. In addition, as of December 31, 2017, 5.8 million common stock warrants with an exercise price of $36.27 per share were outstanding. These warrants expire on November 14, 2018 and were associated with the preferred stock issued under the Troubled Asset Relief Program which was redeemed in 2012. Between January 1, 2018 and February 20, 2018, 1.0 million shares of common stock were issued from the cashless exercise of 3.2 million common stock warrants which expire on November 14, 2018. After these common stock warrant exercises, 29.3 million and 2.6 million common stock warrants, which expire on May 22, 2020 and November 14, 2018, respectively, remain outstanding. Accumulated Other Comprehensive Income During 2017, $25 million was reclassified from AOCI to retained earnings as a result of the decreased corporate income tax rate from the Tax Cuts and Jobs Act of 2017. Changes in AOCI by component are as follows: (In millions) Net unrealized gains (losses) on investment securities Net unrealized gains (losses) on derivatives and other Pension and post-retirement Total 2017 Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Other comprehensive income (loss) before reclassifications, net of tax (2 ) (1 ) 9 6 Amounts reclassified from AOCI, net of tax — (2 ) 4 2 Effect of new tax rates from Tax Cuts and Jobs Act of 2017 (20 ) (1 ) (4 ) (25 ) Other comprehensive income (loss) (22 ) (4 ) 9 (17 ) Balance at December 31, 2017 $ (114 ) $ (3 ) $ (22 ) $ (139 ) Income tax expense (benefit) included in other comprehensive income (loss) $ 19 $ (1 ) $ 11 $ 29 2016 Balance at December 31, 2015 $ (18 ) $ 1 $ (38 ) $ (55 ) Other comprehensive income (loss) before reclassifications, net of tax (74 ) 7 2 (65 ) Amounts reclassified from AOCI, net of tax — (7 ) 5 (2 ) Other comprehensive income (loss) (74 ) — 7 (67 ) Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Income tax expense (benefit) included in other comprehensive income (loss) $ (45 ) $ — $ 5 $ (40 ) Statement of Income (SI) Balance Sheet (BS) (In millions) Amounts reclassified from AOCI 1 Details about AOCI components 2017 2016 2015 Affected line item Net realized gains (losses) on investment securities $ — $ — $ (139 ) SI Securities losses, net Income tax expense (benefit) — — (53 ) $ — $ — $ (86 ) Net unrealized gains on derivative instruments $ 4 $ 11 $ 9 SI Interest and fees on loans Income tax expense 2 4 3 $ 2 $ 7 $ 6 Amortization of net actuarial loss $ (7 ) $ (8 ) $ (6 ) SI Salaries and employee benefits Income tax benefit (3 ) (3 ) (2 ) $ (4 ) $ (5 ) $ (4 ) 1 Negative reclassification amounts indicate decreases to earnings in the statement of income and increases to balance sheet assets. The opposite applies to positive reclassification amounts. Deferred Compensation Deferred compensation consists of invested assets, including the Company’s common stock, which are held in rabbi trusts for certain employees and directors. At both December 31, 2017 and 2016 , the cost of the common stock included in retained earnings was approximately $14 million . We consolidate the fair value trust invested assets along with the total obligations and include them in other assets and other liabilities, respectively, in the balance sheet. At December 31, 2017 and 2016 , total invested assets were approximately $102 million and $91 million and total obligations were approximately $116 million and $105 million , respectively.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2017
Regulatory Capital Requirements [Abstract]
Regulatory Matters	14. REGULATORY MATTERS We are subject to various regulatory capital requirements administered by federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory – and possibly additional discretionary – actions by regulators that, if undertaken, could have a direct material effect on our financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, we must meet specific capital guidelines that involve quantitative measures of our assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. Required capital levels are also subject to judgmental review by regulators. In 2013, the Federal Reserve Board (“FRB”), FDIC, and OCC published final rules (the “Basel III Capital Rules”) establishing a new comprehensive capital framework for U.S. banking organizations. The rules implemented the Basel Committee’s December 2010 framework, commonly referred to as Basel III, for strengthening international capital standards as well as certain provisions of the Dodd-Frank Act. The Basel III capital rules became effective for the Company on January 1, 2015 and were subject to phase-in periods for certain of their components. In November 2017, the FRB, FDIC and OCC published a final rule for non-advanced approaches banks that extends the regulatory capital treatment applicable during 2017 under the regulatory capital rules for certain items. We met all capital adequacy requirements under the Basel III Capital Rules as of December 31, 2017. Under prior Basel I capital standards, the effects of AOCI items included in capital were excluded for purposes of determining regulatory capital and capital ratios. As a “non-advanced approaches banking organization,” we made a one-time permanent election as of January 1, 2015 to continue to exclude these items, as allowed under the Basel III Capital Rules. Quantitative measures established by regulation to ensure capital adequacy require us to maintain minimum amounts and ratios of Total and Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital (as defined) to average assets (as defined). “Well-capitalized” levels are also published as a guideline to evaluate capital positions. As of December 31, 2017 , all capital ratios of the Company and its subsidiary bank exceeded the “well-capitalized” levels under the regulatory framework for prompt corrective action. Dividends declared by our subsidiary bank in any calendar year may not, without the approval of the appropriate federal regulators, exceed specified criteria. The dividends that ZB, N.A. can pay are restricted by current and historical earning levels, retained earnings, and risk-based and other regulatory capital requirements and limitations. Appropriate capital levels and distributions of capital to shareholders for the Company and other SIFI are also subject to annual “stress tests” performed as a part of the Federal Reserve’s HCR/CCAR process. The stress tests seek to comprehensively measure all risks to which the institution is exposed, including credit, liquidity, market, operating and other risks, the losses that could result from those risk exposures under adverse scenarios, and the institution’s resulting capital levels. These stress tests have both a qualitative and a quantitative component. The qualitative component evaluates the robustness of the Company’s risk identification, stress risk modeling, policies, capital planning, governance processes, and other components of a Capital Adequacy Process. The quantitative process subjects the Company’s balance sheet and other risk characteristics to stress testing and independent determination by the Federal Reserve using its own models. Most capital actions, including for example, payment of dividends and repurchasing stock, are subject to non-objection by the Federal Reserve to a capital plan based on both the qualitative and quantitative assessments of the plan. Because the Company’s subsidiary bank has assets greater than $10 billion also it is subject to annual stress testing and capital planning processes examined by the OCC, known as the Dodd-Frank Act Stress Test (“DFAST”). The actual capital amounts and ratios at December 31, 2017 and 2016 for the Company and its subsidiary bank under Basel III are as follows: (Dollar amounts in millions) December 31, 2017 To be well-capitalized Amount Ratio Amount Ratio Transitional Basis Basel III Regulatory Capital Rules Total capital (to risk-weighted assets) The Company $ 7,628 14.8 % $ 5,146 10.0 % ZB, National Association 7,306 14.2 5,130 10.0 Tier 1 capital (to risk-weighted assets) The Company 6,805 13.2 4,116 8.0 ZB, National Association 6,730 13.1 4,104 8.0 Common equity tier 1 capital (to risk-weighted assets) The Company 6,239 12.1 3,345 6.5 ZB, National Association 5,899 11.5 3,334 6.5 Tier 1 capital (to average assets) The Company 6,805 10.5 na na 1 ZB, National Association 6,730 10.4 3,227 5.0 December 31, 2016 To be well-capitalized (Dollar amounts in millions) Amount Ratio Amount Ratio Transitional Basis Basel III Regulatory Capital Rules Total capital (to risk-weighted assets) The Company $ 7,609 15.2 % $ 4,994 10.0 % ZB, National Association 7,278 14.6 4,983 10.0 Tier 1 capital (to risk-weighted assets) The Company 6,738 13.5 3,995 8.0 ZB, National Association 6,655 13.4 3,986 8.0 Common equity tier 1 capital (to risk-weighted assets) The Company 6,028 12.1 3,246 6.5 ZB, National Association 5,824 11.7 3,239 6.5 Tier 1 capital (to average assets) The Company 6,738 11.1 na na 1 ZB, National Association 6,655 11.0 3,027 5.0 1 There is no Tier 1 leverage ratio component in the definition of a well-capitalized bank holding company . Zions is also subject to “capital conservation buffer” regulatory requirements. When fully phased-in, the Basel III capital rules will also require the Company and its subsidiary bank to maintain a 2.5% “capital conservation buffer” designed to absorb losses during periods of economic stress, composed entirely of Common Equity Tier 1 (“CET1”), on top of the minimum risk-weighted asset ratios, effectively resulting in minimum ratios of (i) CET1 to risk-weighted assets of at least 7.0%, (ii) Tier 1 capital to risk-weighted assets of at least 8.5%, and (iii) Total capital to risk-weighted assets of at least 10.5%. Banking institutions with a ratio of CET1 to risk-weighted assets above the minimum but below the capital conservation buffer will face constraints on dividends, equity repurchases, and compensation based on the amount of the shortfall. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and progressively increases over time, as determined by regulation. Zions’ triggers and limits under actual conditions and baseline projections are more restrictive than the capital conservation buffer requirements.

Commitments, Guarantees, Contin

Commitments, Guarantees, Contingent Liabilities, and Related Parties	12 Months Ended
	Dec. 31, 2017
Guarantees, Commitments And Contingencies [Abstract]
Commitments Contingencies and Guarantees [Text Block]	COMMITMENTS, GUARANTEES, CONTINGENT LIABILITIES, AND RELATED PARTIES Commitments and Guarantees We use certain financial instruments, including derivative instruments, in the normal course of business to meet the financing needs of our customers, to reduce our own exposure to fluctuations in interest rates, and to make a market in U.S. Government, agency, corporate, and municipal securities. These financial instruments involve, to varying degrees, elements of credit, liquidity, and interest rate risk in excess of the amounts recognized in the balance sheet. Derivative instruments are discussed in Notes 7 and 3 . Contractual amounts of the off-balance sheet financial instruments used to meet the financing needs of our customers are as follows: December 31, (In millions) 2017 2016 Net unfunded commitments to extend credit 1 $ 19,583 $ 18,274 Standby letters of credit: Financial 721 771 Performance 196 196 Commercial letters of credit 31 60 Total unfunded lending commitments $ 20,531 $ 19,301 1 Net of participations. Commitments to extend credit are agreements to lend to a customer 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 the payment of a fee. The amount of collateral obtained, if deemed necessary by us upon extension of credit, is based on our initial credit evaluation of the counterparty. Types of collateral vary, but may include accounts receivable, inventory, property, plant and equipment, and income-producing properties. While establishing commitments to extend credit creates credit risk, a significant portion of such commitments is expected to expire without being drawn upon. As of December 31, 2017 , $6.2 billion of commitments expire in 2018 . We use the same credit policies and procedures in making commitments to extend credit and conditional obligations as we do for on-balance sheet instruments. These policies and procedures include credit approvals, limits, and monitoring. We issue standby and commercial letters of credit as conditional commitments generally to guarantee the performance of a customer to a third party. The guarantees are primarily issued to support public and private borrowing arrangements, including commercial paper, bond financing, and similar transactions. Standby letters of credit include remaining commitments of $610 million expiring in 2018 and $307 million expiring thereafter through 2027 . The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. We generally hold marketable securities and cash equivalents as collateral when necessary. At December 31, 2017 , the Company recorded $5 million as a liability for these guarantees, which consisted of $1 million attributable to the RULC and $4 million of deferred commitment fees. Certain mortgage loans sold have limited recourse provisions for periods ranging from three months to one year. The amount of losses resulting from the exercise of these provisions has not been significant. At December 31, 2017 , we had unfunded commitments for PEIs of $31 million . These obligations have no stated maturity. PEIs related to these commitments prohibited by the Volcker Rule were $4 million . See the related discussion about these investments in Note 5 . The contractual or notional amount of financial instruments indicates a level of activity associated with a particular financial instrument class and is not a reflection of the actual level of risk. As of December 31, 2017 and 2016 , the regulatory risk-weighted values assigned to all off-balance sheet financial instruments and derivative instruments described herein were $6.8 billion and $6.5 billion , respectively. At December 31, 2017 , we were required to maintain cash balances of $366 million with the Federal Reserve Banks to meet minimum balance requirements in accordance with FRB regulations. Leases We have commitments for leasing premises and equipment under the terms of noncancelable capital and operating leases expiring from 2018 and 2052 . Premises leased under capital leases at December 31, 2017 , were $1 million , and were essentially amortized with accumulated amortization totaling approximately $1 million . Amortization applicable to premises leased under capital leases is included in depreciation expense. Future aggregate minimum rental payments under existing noncancelable operating leases at December 31, 2017 , are as follows: (in millions) 2018 $ 40 2019 39 2020 36 2021 29 2022 25 Thereafter 76 Total $ 245 Future aggregate minimum rental payments have been reduced by noncancelable subleases as follows: $2 million in 2018 , $2 million in 2019 , and $1 million in 2020 . Aggregate rental expense on operating leases amounted to $61 million in 2017 , $65 million in 2016 , and $63 million in 2015 . Legal Matters We are subject to litigation in court and arbitral proceedings, as well as proceedings, investigations, examinations and other actions brought or considered by governmental and self-regulatory agencies. Litigation may relate to lending, deposit and other customer relationships, vendor and contractual issues, employee matters, intellectual property matters, personal injuries and torts, regulatory and legal compliance, and other matters. While most matters relate to individual claims, we are also subject to putative class action claims and similar broader claims. Proceedings, investigations, examinations and other actions brought or considered by governmental and self-regulatory agencies may relate to our banking, investment advisory, trust, securities, and other products and services; our customers’ involvement in money laundering, fraud, securities violations and other illicit activities or our policies and practices relating to such customer activities; and our compliance with the broad range of banking, securities and other laws and regulations applicable to us. At any given time, we may be in the process of responding to subpoenas, requests for documents, data and testimony relating to such matters and engaging in discussions to resolve the matters. As of December 31, 2017, we were subject to the following material litigation and governmental inquiries: • a civil suit, Shou-En Wang v. CB&T, brought against us in the Superior Court for Los Angeles County, Central District in April 2016. The case relates to our depositor relationships with customers who were promoters of an investment program that allegedly misappropriated investors’ funds. This case is in an early phase, with initial motion practice having been completed and discovery being underway. • a civil suit, McFarland as Trustee for International Manufacturing Group v. CB&T, et. al. , brought against us in the United States Bankruptcy Court for the Eastern District of California in May 2016. The Trustee seeks to recover loan payments previously repaid to us by our customer, International Manufacturing Group (“IMG”), alleging that IMG, along with its principal, obtained loans and made loan repayments in furtherance of an alleged Ponzi scheme. This case is in an early phase with initial motion practice having been completed and discovery being underway. • a civil suit, JTS Communities, Inc. et. al v. CB&T, Jun Enkoji and Dawn Satow , brought against us in the Superior Court for Sacramento County, California in June 2017. In this case four investors in IMG seek to hold us liable for losses arising from their investments in that company, alleging that we conspired with and knowingly assisted IMG and its principal in furtherance of an alleged Ponzi Scheme. This case is in an early phase with motion practice having been completed but discovery not having been commenced. • a civil class action lawsuit, Evans v. CB&T , brought against us in the United States District Court for the Eastern District of California in May 2017. This case was filed on behalf of a class of up to 50 investors in IMG and seeks to hold us liable for losses of class members arising from their investments in IMG, alleging that we conspired with and knowingly assisted IMG and its principal in furtherance of an alleged Ponzi Scheme. In the fourth quarter of 2017, the District Court dismissed all claims against the Company. On January 17, 2018, the plaintiff filed an appeal with the Court of Appeals for the Ninth Circuit. • a Private Attorney General Act (“PAGA”) claim under California law, Lawson v. CB&T , brought against us in the Superior Court for the County of San Diego, California, in February 2016. In this case, the plaintiff alleges, on behalf of herself and other current or former employees of the Company who worked in California on a non-exempt basis, violations by the Company of California wage and hour laws. The case is in the early stages of motion practice, to date mainly involving questions of venue and scope of employees covered by the PAGA claims. • a civil case, Lifescan Inc. and Johnson & Johnson Health Care Services v. Jeffrey Smith, et al. , brought against us in the United States District Court for the District of New Jersey in the fourth quarter of 2017. In this case, certain manufacturers and distributors of medical products seek to hold us liable for allegedly fraudulent practices of a borrower of the Company which filed for bankruptcy protection in 2017. At least quarterly, we review outstanding and new legal matters, utilizing then available information. In accordance with applicable accounting guidance, if we determine that a loss from a matter is probable and the amount of the loss can be reasonably estimated, we establish an accrual for the loss. In the absence of such a determination, no accrual is made. Once established, accruals are adjusted to reflect developments relating to the matters. In our review, we also assess whether we can determine the range of reasonably possible losses for significant matters in which we are unable to determine that the likelihood of a loss is remote. Because of the difficulty of predicting the outcome of legal matters, discussed subsequently, we are able to meaningfully estimate such a range only for a limited number of matters. Based on information available as of December 31, 2017, we estimated that the aggregate range of reasonably possible losses for those matters to be from $0 million to roughly $20 million in excess of amounts accrued. The matters underlying the estimated range will change from time to time, and actual results may vary significantly from this estimate. Those matters for which a meaningful estimate is not possible are not included within this estimated range and, therefore, this estimated range does not represent our maximum loss exposure. Based on our current knowledge, we believe that our current estimated liability for litigation and other legal actions and claims, reflected in our accruals and determined in accordance with applicable accounting guidance, is adequate and that liabilities in excess of the amounts currently accrued, if any, arising from litigation and other legal actions and claims for which an estimate as previously described is possible, will not have a material impact on our financial condition, results of operations, or cash flows. However, in light of the significant uncertainties involved in these matters, and the very large or indeterminate damages sought in some of these matters, an adverse outcome in one or more of these matters could be material to our financial condition, results of operations, or cash flows for any given reporting period. Any estimate or determination relating to the future resolution of litigation, arbitration, governmental or self-regulatory examinations, investigations or actions or similar matters is inherently uncertain and involves significant judgment. This is particularly true in the early stages of a legal matter, when legal issues and facts have not been well articulated, reviewed, analyzed, and vetted through discovery, preparation for trial or hearings, substantive and productive mediation or settlement discussions, or other actions. It is also particularly true with respect to class action and similar claims involving multiple defendants, matters with complex procedural requirements or substantive issues or novel legal theories, and examinations, investigations and other actions conducted or brought by governmental and self-regulatory agencies, in which the normal adjudicative process is not applicable. Accordingly, we usually are unable to determine whether a favorable or unfavorable outcome is remote, reasonably likely, or probable, or to estimate the amount or range of a probable or reasonably likely loss, until relatively late in the course of a legal matter, sometimes not until a number of years have elapsed. Accordingly, our judgments and estimates relating to claims will change from time to time in light of developments and actual outcomes will differ from our estimates. These differences may be material. Related Party Transactions We have no material related party transactions requiring disclosure. In the ordinary course of business, the Company and its subsidiary bank extend credit to related parties, including executive officers, directors, principal shareholders, and their associates and related interests. These related party loans are made in compliance with applicable banking regulations.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2017
Defined Benefit Plan [Abstract]
Retirement Plans	RETIREMENT PLANS Defined Benefit Plans Pension – This qualified noncontributory defined benefit plan is frozen to new participation. No service-related benefits have been accrued since July 1, 2013. All participants in the Plan are currently 100% vested in their benefits. Plan assets consist principally of corporate equity securities, mutual fund investments, real estate, and fixed income investments. Plan benefits are paid as a lump-sum cash value or an annuity at retirement age. Contributions to the plan are based on actuarial recommendation and pension regulations. Although there was no minimum regulatory contribution required in 2017 and 2016, we elected to contribute $4 million to the pension plan in 2016. Currently, it is expected tha t no m inimum regulatory contributions will be required in 2018 . Supplemental Retirement – These unfunded nonqualified plans are for certain current and former employees. Each year, Company contributions to these plans are made in amounts sufficient to meet benefit payments to plan participants. Postretirement Medical/Life – This unfunded health care and life insurance plan provides postretirement medical benefits to certain full-time employees who meet minimum age and service requirements. The plan also provides specified life insurance benefits to certain employees. The plan is contributory with retiree contributions adjusted annually, and contains other cost-sharing features such as deductibles and coinsurance. Plan coverage is provided by self-funding or health maintenance organization options. Our contribution towards the retiree medical premium has been permanently frozen at an amount that does not increase in any future year. Retirees pay the difference between the full premium rates and our capped contribution. Because our contribution rate is capped, there is no effect on the postretirement plan from assumed increases or decreases in health care cost trends. Each year, Company contributions to the plan are made in amounts sufficient to meet the portion of the premiums that are the Company’s responsibility. The following presents the change in benefit obligation, change in fair value of plan assets, and funded status, of the plans and amounts recognized in the balance sheet as of the measurement date of December 31: Pension Supplemental Postretirement (In millions) 2017 2016 2017 2016 2017 2016 Change in benefit obligation: Benefit obligation at beginning of year $ 165 $ 173 $ 10 $ 10 $ 1 $ 1 Interest cost 6 7 1 1 — — Actuarial loss (gain) 2 (2 ) — — — — Benefits paid (19 ) (13 ) (1 ) (1 ) — — Benefit obligation at end of year 154 165 10 10 1 1 Change in fair value of plan assets: Fair value of plan assets at beginning of year 161 157 — — — — Actual return on plan assets 26 13 — — — — Employer contributions — 4 1 1 — — Benefits paid (19 ) (13 ) (1 ) (1 ) — — Fair value of plan assets at end of year 168 161 — — — — Funded status $ 14 $ (4 ) $ (10 ) $ (10 ) $ (1 ) $ (1 ) Amounts recognized in balance sheet: Asset (liability) for pension/postretirement benefits $ 14 $ (4 ) $ (10 ) $ (10 ) $ (1 ) $ (1 ) Accumulated other comprehensive income (loss) (28 ) (48 ) (2 ) (2 ) — — Accumulated other comprehensive income (loss) consists of: Net loss $ (28 ) $ (48 ) $ (2 ) $ (2 ) $ — $ — The pension asset and the liability for supplement retirement/postretirement benefits are included in other assets and other liabilities, respectively, in the balance sheet. The accumulated benefit obligation is the same as the benefit obligation shown in the preceding schedule. During the third quarter of 2017, the Company revised its pension plan to offer certain participants a temporary opportunity to make an election to receive an immediate distribution from the pension plan. The window was available between August 1, 2017 and November 24, 2017. The impact of these distributions is included in “benefits paid” in the preceding schedule and in “settlement loss” shown in the net period benefit cost (credit) schedule. The amounts in AOCI (loss) at December 31, 2017 expected to be recognized as an expense component of net periodic benefit cost in 2018 for the plans are estimated as follows: (In millions) Pension Supplemental Postretirement Net loss $ (2 ) $ — $ — The following presents the components of net periodic benefit cost (credit) for the plans: Pension Supplemental Postretirement (In millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Interest cost $ 6 $ 7 $ 7 $ 1 $ 1 $ 1 $ — $ — $ — Expected return on plan assets (11 ) (11 ) (12 ) — — — — — — Amortization of net actuarial loss 4 6 6 — — — — — — Settlement loss 3 2 — — — — — — — Net periodic benefit cost $ 2 $ 4 $ 1 $ 1 $ 1 $ 1 $ — $ — $ — Weighted average assumptions based on the pension plan are the same where applicable for each of the plans and are as follows: 2017 2016 2015 Used to determine benefit obligation at year-end: Discount rate 3.50 % 4.10 % 4.20 % Used to determine net periodic benefit cost for the years ended December 31: Discount rate 4.10 4.20 3.95 Expected long-term return on plan assets 7.25 7.50 7.50 The discount rate reflects the yields available on long-term, high-quality fixed income debt instruments with cash flows similar to the obligations of the pension plan, and is reset annually on the measurement date. The expected long-term rate of return on plan assets is based on a review of the target asset allocation of the plan. This rate is intended to approximate the long-term rate of return that we anticipate receiving on the plan’s investments, considering the mix of the assets that the plan holds as investments, the expected return on these underlying investments, the diversification of these investments, and the rebalancing strategies employed. An expected long-term rate of return is assumed for each asset class and an underlying inflation rate assumption is determined. Benefit payments to the plans’ participants are estimated as follows for the years succeeding December 31, 2017 : (In millions) Pension Supplemental Postretirement 2018 $ 10 $ 2 $ — 2019 10 1 — 2020 10 1 — 2021 10 1 — 2022 9 1 — Years 2023 - 2027 45 3 — We are also obligated under other supplemental retirement plans for certain current and former employees. Our liability for these plans was $6 million at both December 31, 2017 and 2016 , respectively. For the pension plan, the investment strategy is predicated on its investment objectives and the risk and return expectations of asset classes appropriate for the plan. Investment objectives have been established by considering the plan’s liquidity needs and time horizon and the fiduciary standards under the Employee Retirement Income Security Act of 1974. The asset allocation strategy is developed to meet the plan’s long-term needs in a manner designed to control volatility and to reflect risk tolerance. Target investment allocation percentages as of December 31, 2017 are 65% in equity, 30% in fixed income and cash, and 5% in real estate assets. The following presents the fair values of pension plan investments according to the fair value hierarchy described in Note 3 , and the weighted average allocations: (In millions) December 31, 2017 December 31, 2016 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Company common stock $ 12 $ 12 $ 10 $ 10 Mutual funds: Debt 7 7 6 6 Guaranteed deposit account $ 9 9 $ 11 11 In addition to the investments listed in the previous schedule, as of December 31, 2017 , pension plan investments valued using NAV as the practical expedient for fair value consist of $97 million in equity investments, $31 million in debt investments, and $8 million in real estate investments, which are in pooled separate accounts, as well as $4 million in limited partnerships. As of December 31, 2016 , pension plan investments valued using NAV as the practical expedient for fair value consist of $92 million in equity investments, $29 million in debt instruments, and $8 million in real estate investments, which are in pooled separate accounts, as well as $5 million in limited partnerships. No transfers of assets occurred among Levels 1, 2 or 3 during 2017 or 2016 . The following describes the pension plan investments and the valuation methodologies used to measure their fair value: Company common stock – Shares of the Company’s common stock are valued at the last reported sales price on the last business day of the plan year in the active market where individual securities are traded. Mutual funds – These funds are valued at quoted market prices which represent the NAVs of shares held by the plan at year-end. Insurance company pooled separate accounts – These funds are invested in by more than one investor. They are offered through separate accounts of the trustee’s insurance company and managed by internal and professional advisors. Participation units in these accounts are valued at the NAV as the practical expedient for fair value as determined by the insurance company. Guaranteed deposit account – This account is a group annuity product issued by the trustee’s insurance company with guaranteed crediting rates established at the beginning of each calendar year. The account balance is stated at fair value as estimated by the trustee. The account is credited with deposits made, plus earnings at guaranteed crediting rates, less withdrawals and administrative expenses. The underlying investments generally include investment-grade public and privately traded debt securities, mortgage loans and, to a lesser extent, real estate and other equity investments. Market value adjustments are applied at the time of redemption if certain withdrawal limits are exceeded. Additional fair value quantitative information for the guaranteed deposit account is as follows: Principal valuation techniques Significant unobservable inputs Range (weighted average) of significant input values For the underlying investments – reported fair values when available for market traded investments; when not applicable, discounted cash flows under an income approach using U.S. Treasury rates and spreads based on cash flow timing and quality of assets. Earnings at guaranteed crediting rate Gross guaranteed crediting rate must be greater than or equal to contractual minimum crediting rate Composite market value factor At December 31, 2017 0.992941 - 1.037825 (actual = 1.023838) 2016 0.979009 - 1.036866 (actual = 1.021418) The Company’s Benefits Committee evaluates the methodology and factors used, including review of the contract, economic conditions, industry and market developments, and overall credit ratings of the underlying investments. Limited partnerships – These partnerships invest in limited partnerships, limited liability companies, or similar investment vehicles that consist of PEIs in a wide variety of investment types, including venture and growth capital, real estate, energy and natural resources, and other private investments. The plan’s investments are valued by the limited partnerships at NAV as the practical expedient for fair value. The estimation process takes into account the plan’s proportional interests credited with realized and unrealized earnings from the underlying investments and charged for operating expenses and distributions. Investments are increased by capital calls and are part of an overall capital commitment by the plan of up to approximately $9 million at December 31, 2017 . The following presents additional information as of December 31, 2017 and 2016 for the pooled separate accounts and limited partnerships whose fair values under Levels 2 and 3 are based on NAV per share: Investment Unfunded commitments (in millions, approximately) Redemption Frequency Notice period Pooled separate accounts na Daily < $1 million, 1 day >= $1 million, 3 days Limited partnerships $ 1 Investments in these limited partnerships are illiquid and voluntary withdrawal is prohibited. The following reconciles the beginning and ending balances of assets measured at fair value on a recurring basis using Level 3 inputs: Level 3 Instruments Year Ended December 31, 2017 2016 (In millions) Guaranteed deposit account Balance at beginning of year $ 11 $ 9 Purchases 17 15 Sales (19 ) (13 ) Balance at end of year $ 9 $ 11 Shares of Company common stock were 233,849 at both December 31, 2017 and 2016 . Dividends received by the plan were not significant in 2017 and 2016 . Defined Contribution Plan The Company offers a 401(k) and employee stock ownership plan under which employees select from several investment alternatives. Employees can contribute up to 80% of their earnings subject to the annual maximum allowed contribution. The Company matches 100% of the first 3% of employee contributions and 50% of the next 2% of employee contributions. Matching contributions to participants, which were shares of the Company’s common stock purchased in the open market, amounted to $26 million in 2017 , 2016, and 2015 . The 401(k) plan also has a noncontributory profit sharing feature which is discretionary and may range from 0% to 4% of eligible compensation based upon the Company’s return on average common equity for the year. The profit sharing expense was computed at a contribution rate of 1.75% in 2017 , 1% in 2016 , and 1% in 2015 . The profit sharing expense was $11 million in 2017 , and $6 million in both 2016 and 2015 . The profit sharing contribution to participants consisted of shares of the Company’s common stock purchased in the open market.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation	SHARE-BASED COMPENSATION We have a share-based compensation incentive plan which allows us to grant stock options, restricted stock, RSUs, and other awards to employees and non-employee directors. Total shares authorized under the plan were 9,000,000 at December 31, 2017 , of which 5,009,248 were available for future grants. All share-based payments to employees, including grants of employee stock options, are recognized in the statement of income based on their grant date values. The value of an equity award is estimated on the grant date using a fair value-based model without regard to service or performance vesting conditions, but does consider post-vesting restrictions. We classify all share-based awards as equity instruments. Compensation expense is included in salaries and employee benefits in the statement of income, with the corresponding increase included in common stock. Substantially all awards of stock options, restricted stock, and RSUs have graded vesting that is recognized on a straight-line basis over the vesting period. Compensation expense and the related tax benefit for all share-based awards were as follows: (In millions) 2017 2016 2015 Compensation expense $ 25 $ 26 $ 25 Reduction of income tax expense 19 9 8 During 2017, as a result of our adoption of ASU 2016-09, the tax effects recognized from the exercise of stock options and the vesting of restricted stock and RSUs was recorded as a $9 million reduction of income tax expense. Also, upon the adoption of ASU 2016-09, we elected to account for forfeitures of share-based compensation awards as they occur, rather than estimating forfeitures as was previously done. There was no material impact from the cumulative effect adjustment to retained earnings from this change. Prior to our adoption of ASU 2016-09, the tax effects recognized from the exercise of stock options and the vesting of restricted stock and RSUs increased common stock by approximately $2 million in 2016 and decreased common stock by approximately $1 million in 2015. These amounts are included in the net activity under employee plans and related tax benefits in the statement of changes in shareholders’ equity. During 2017, we reduced share-based compensation expense by $1 million as a result of using a valuation model to estimate a liquidity discount on RSUs with post-vesting restrictions. As of December 31, 2017 , compensation expense not yet recognized for nonvested share-based awards was approximately $26 million , which is expected to be recognized over a weighted average period of 2.3 years. Stock Options Stock options granted to employees generally vest at the rate of one third each year and expire seven years after the date of grant. For all stock options granted in 2017 , 2016 , and 2015 , we used the Black-Scholes option pricing model to estimate the grant date value of stock options in determining compensation expense. The following summarizes the weighted average value at grant date and the significant assumptions used in applying the Black-Scholes model for options granted: 2017 2016 2015 Weighted average value for options granted $ 10.69 $ 5.24 $ 6.17 Weighted average assumptions used: Expected dividend yield 1.8 % 1.3 % 1.3 % Expected volatility 30.0 % 30.0 % 25.0 % Risk-free interest rate 1.81 % 1.21 % 1.57 % Expected life (in years) 5.0 5.0 5.0 The assumptions for expected dividend yield, expected volatility, and expected life reflect management’s judgment and include consideration of historical experience. Expected volatility is based in part on historical volatility. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. The following summarizes our stock option activity for the three years ended December 31, 2017 : Number of shares Weighted average exercise price Balance at December 31, 2014 5,630,502 $ 31.60 Granted 740,300 29.01 Exercised (1,165,287 ) 25.11 Expired (1,322,067 ) 48.44 Forfeited (79,353 ) 28.09 Balance at December 31, 2015 3,804,095 27.30 Granted 789,651 21.25 Exercised (1,055,532 ) 23.75 Expired (56,297 ) 61.60 Forfeited (44,007 ) 27.66 Balance at December 31, 2016 3,437,910 26.44 Granted 195,882 44.18 Exercised (941,761 ) 26.03 Expired (58,257 ) 66.20 Forfeited (73,203 ) 25.63 Balance at December 31, 2017 2,560,571 27.06 Outstanding stock options exercisable as of: December 31, 2017 1,648,367 $ 26.55 December 31, 2016 1,892,136 27.60 December 31, 2015 2,187,259 26.35 We issue new authorized common shares for the exercise of stock options. The total intrinsic value of stock options exercised was approximately $17 million in 2017 , $10 million in 2016 , and $7 million in 2015 . Cash received from the exercise of stock options was $23 million in 2017 , $24 million in 2016 , and $23 million in 2015 . Additional selected information on stock options at December 31, 2017 follows: Outstanding stock options Exercisable stock options Exercise price range Number of shares Weighted average exercise price Weighted average remaining contractual life (years) Number of shares Weighted average exercise price $ 0.32 to $19.99 198,402 $ 17.39 1.4 1 198,402 $ 17.39 $20.00 to $24.99 744,058 21.50 4.3 276,953 22.33 $25.00 to $29.99 1,346,781 28.35 3.5 1,094,021 28.30 $30.00 to $39.99 32,191 30.10 3.4 32,191 30.10 $40.00 to $44.99 192,339 44.17 6.1 — — $45.00 to $47.10 46,800 47.10 0.3 46,800 47.10 2,560,571 27.06 3.7 1 1,648,367 26.55 1 The weighted average remaining contractual life excludes 21,252 stock options without a fixed expiration date that were assumed with the Amegy acquisition. They expire between the date of termination and one year from the date of termination, depending upon certain circumstances. The aggregate intrinsic value of outstanding stock options at December 31, 2017 and 2016 was $61 million and $59 million , respectively, while the aggregate intrinsic value of exercisable options was $40 million and $31 million at the same respective dates. For exercisable options, the weighted average remaining contractual life was 2.9 years and 3.0 years at December 31, 2017 and 2016 , respectively, excluding the stock options previously noted without a fixed expiration date. At December 31, 2017 , 912,204 stock options with a weighted average exercise price of $27.99 , a weighted average remaining life of 5.1 years, and an aggregate intrinsic value of $21 million , were expected to vest. Restricted Stock and Restricted Stock Units Restricted stock is common stock with certain restrictions that relate to trading and the possibility of forfeiture. Generally, restricted stock vests over four years. Holders of restricted stock have full voting rights and receive dividend equivalents during the vesting period. In addition, holders of restricted stock can make an election to be subject to income tax on the grant date rather than the vesting date. RSUs represent rights to one share of common stock for each unit and generally vest over four years. Holders of RSUs receive dividend equivalents during the vesting period, but do not have voting rights. Compensation expense is determined based on the number of restricted shares or RSUs granted and the market price of our common stock at the issue date. During 2017, 2016, and 2015, we granted 20,711 , 32,310 , and 31,080 RSUs, respectively, to non-employee directors. The RSUs vested immediately upon grant. The following summarizes our restricted stock activity for the three years ended December 31, 2017 : Number of shares Weighted average issue price Nonvested restricted shares at December 31, 2014 161,220 $ 21.82 Issued 22,441 29.02 Vested (123,161 ) 22.32 Forfeited (1,130 ) 23.54 Nonvested restricted shares at December 31, 2015 59,370 23.49 Issued 36,594 24.43 Vested (32,709 ) 20.80 Nonvested restricted shares at December 31, 2016 63,255 25.43 Issued 314 44.55 Vested (24,591 ) 24.90 Nonvested restricted shares at December 31, 2017 38,978 25.91 The following summarizes our RSU activity for the three years ended December 31, 2017 : Number of restricted stock units Weighted average grant price Restricted stock units at December 31, 2014 1,769,420 $ 25.64 Granted 790,929 29.06 Vested (673,385 ) 24.78 Forfeited (88,421 ) 27.17 Restricted stock units at December 31, 2015 1,798,543 27.39 Granted 1,033,167 21.69 Vested (724,713 ) 25.88 Forfeited (59,839 ) 26.28 Restricted stock units at December 31, 2016 2,047,158 25.08 Granted 587,396 41.78 Vested (803,492 ) 26.19 Forfeited (121,249 ) 28.12 Restricted stock units at December 31, 2017 1,709,813 30.08 The total value at grant date of restricted stock and RSUs vested during the year was $22 million in 2017 and $19 million in both 2016 and 2015 . At December 31, 2017 , 38,978 shares of restricted stock and 1,181,384 RSUs were expected to vest with an aggregate intrinsic value of $2 million and $60 million , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	INCOME TAXES Income tax expense is summarized as follows: (In millions) 2017 2016 2015 Federal: Current $ 166 $ 217 $ 158 Deferred 146 (4 ) (32 ) Total Federal 312 213 126 State: Current 24 27 14 Deferred 8 (4 ) 2 Total State 32 23 16 Total $ 344 $ 236 $ 142 Income tax expense computed at the statutory federal income tax rate of 35% reconciles to actual income tax expense as follows: (In millions) 2017 2016 2015 Income tax expense at statutory federal rate $ 327 $ 247 $ 158 State income taxes including credits, net 21 15 10 Other nondeductible expenses 3 3 3 Nontaxable income (33 ) (25 ) (20 ) Share-based compensation (8 ) — — Tax credits and other taxes 1 (2 ) (3 ) Tax Cuts and Jobs Act of 2017 47 — — Other (14 ) (2 ) (6 ) Total $ 344 $ 236 $ 142 The tax effects of temporary differences that give rise to significant portions of the deferred tax assets (“DTA”) and deferred tax liabilities are presented below: (In millions) December 31, 2017 2016 Gross deferred tax assets: Book loan loss deduction in excess of tax $ 143 $ 241 Pension and postretirement 8 19 Deferred compensation 48 87 Security investments and derivative fair value adjustments 40 57 Net operating losses, capital losses and tax credits 2 5 FDIC-supported transactions 2 5 Other 34 46 277 460 Valuation allowance (2 ) (4 ) Total deferred tax assets 275 456 Gross deferred tax liabilities: Core deposits and purchase accounting — (1 ) Premises and equipment, due to differences in depreciation (51 ) (8 ) Federal Home Loan Bank stock dividends (3 ) (4 ) Leasing operations (52 ) (75 ) Prepaid expenses (5 ) (7 ) Prepaid pension reserves (11 ) (17 ) Mortgage servicing (7 ) (10 ) Subordinated debt modification (9 ) (31 ) Deferred loan fees (23 ) (25 ) Equity investments (21 ) (28 ) Total deferred tax liabilities (182 ) (206 ) Net deferred tax assets $ 93 $ 250 On December 22, 2017, H.R. 1, known as the Tax Cuts and Jobs Act (“the Act”), was signed into law. The Act makes significant changes to the U.S. Internal Revenue Code of 1986, including a decrease in the current corporate federal income tax rate to 21% from 35%, effective January 1, 2018. In conjunction with the enactment of the Act, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the accounting for certain income tax effects of the Act that may not be complete by the time financial statements are issued. The Company evaluated all available information and made reasonable estimates of the impact of the Act to substantially all components of its net DTA. The provisional impact of the Act on the net DTA resulted in a non-cash charge of $47 million recorded through income tax expense. The Company anticipates that additional adjustments to net DTA and income tax expense may be made in 2018 as the Company’s initial determination of the tax basis of deferred items such as foregone interest, equity investments in flow-through entities, certain employee compensation arrangements, FDIC-supported transactions and premises and equipment are finalized. These adjustments will be recorded in the financial statements in the reporting period when such adjustments are determined; however, SAB 118 requires all impacts from the Act to be recorded prior to December 22, 2018, which is one year from the enactment date of the Act. In 2017 , the Company early adopted the guidance in ASU 2018-02, which allows reclassification from AOCI to retained earnings for the stranded tax effects related to the change in the corporate income tax rate from the Act. The early adoption of the guidance resulted in a $25 million increase to retained earnings out of AOCI as of December 31, 2017 . The amount of net DTAs is included with other assets in the balance sheet. The $2 million and $4 million valuation allowances at December 31, 2017 and 2016 , respectively, were for certain acquired net operating loss carryforwards included in our acquisition of the remaining interests in a less significant subsidiary. At December 31, 2017 , excluding the $2 million , the tax effect of remaining net operating loss and tax credit carryforwards was less than $1 million expiring through 2030 . We evaluate the DTAs on a regular basis to determine whether an additional valuation allowance is required. In conducting this evaluation, we have considered all available evidence, both positive and negative, based on the more likely than not criteria that such assets will be realized. This evaluation includes, but is not limited to: (1) available carryback potential to prior tax years; (2) potential future reversals of existing deferred tax liabilities, which historically have a reversal pattern generally consistent with DTAs; (3) potential tax planning strategies; and (4) future projected taxable income. Based on this evaluation, and considering the weight of the positive evidence compared to the negative evidence, we have concluded that an additional valuation allowance is not required as of December 31, 2017 . We have a liability for unrecognized tax benefits relating to uncertain tax positions for tax credits on technology initiatives. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: (In millions) 2017 2016 2015 Balance at beginning of year $ 4 $ 5 $ 3 Tax positions related to current year: Additions 1 1 1 Reductions — — — Tax positions related to prior years: Additions 1 1 1 Reductions — — — Settlements with taxing authorities — — — Lapses in statutes of limitations — (3 ) — Balance at end of year $ 6 $ 4 $ 5 At December 31, 2017 and 2016 , the liability for unrecognized tax benefits included approximately $5 million and $3 million , respectively (net of the federal tax benefit on state issues) that, if recognized, would affect the effective tax rate. The amount of gross unrecognized tax benefits that may increase or decrease during the 12 months subsequent to December 31, 2017 , is dependent on the timing and outcome of various federal and state examinations. Interest and penalties related to unrecognized tax benefits are included in income tax expense in the statement of income. At December 31, 2017 and 2016 , accrued interest and penalties recognized in the balance sheet, net of any federal and/or state tax benefits, were less than $1 million . The Company and its subsidiaries file income tax returns in U.S. federal and various state jurisdictions. The Company is no longer subject to income tax examinations for years prior to 2013 for federal returns and 2012 for certain state returns.

Net Earnings Per Common Share

Net Earnings Per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Earnings Per Common Share	NET EARNINGS PER COMMON SHARE Basic and diluted net earnings per common share based on the weighted average outstanding shares are summarized as follows: (In millions, except per share amounts) 2017 2016 2015 Basic: Net income $ 592 $ 469 $ 309 Less common and preferred dividends 131 115 108 Undistributed earnings 461 354 201 Less undistributed earnings applicable to nonvested shares 4 4 2 Undistributed earnings applicable to common shares 457 350 199 Distributed earnings applicable to common shares 88 57 45 Total earnings applicable to common shares $ 545 $ 407 $ 244 Weighted average common shares outstanding (in thousands) 200,776 203,855 203,265 Net earnings per common share $ 2.71 $ 2.00 $ 1.20 Diluted: Total earnings applicable to common shares $ 545 $ 407 $ 244 Weighted average common shares outstanding (in thousands) 200,776 203,855 203,265 Additional weighted average dilutive shares (in thousands) 8,877 414 433 Weighted average diluted common shares outstanding (in thousands) 209,653 204,269 203,698 Net earnings per common share $ 2.60 $ 1.99 $ 1.20 For 2017 and 2016, preferred dividends were increased by $2 million and $10 million , respectively, from costs related to the full redemption of the Company’s Series F preferred stock in 2017 and partial redemption of the Company’s Series I, J, and G preferred stock in 2016. See further discussion in Note 13 .

Operating Segment Information

Operating Segment Information	12 Months Ended
	Dec. 31, 2017
Operating Segment Information [Abstract]
Segment Reporting Disclosure [Text Block]	OPERATING SEGMENT INFORMATION We manage our operations and prepare management reports and other information with a primary focus on geographical area. Our banking operations are managed under their own individual brand names, including Zions Bank, Amegy Bank, California Bank & Trust, National Bank of Arizona, Nevada State Bank, Vectra Bank Colorado, and The Commerce Bank of Washington. Performance assessment and resource allocation are based upon this geographical structure. We use an internal funds transfer pricing (“FTP”) allocation system to report results of operations for business segments. This process continues to be refined. Total average loans and deposits presented for the banking segments do not include intercompany amounts between banking segments, but may include deposits with the Other segment. Prior period amounts have been reclassified to reflect these changes. As of December 31, 2017 , our banking business is conducted through 7 locally managed and branded segments in distinct geographical areas. Performance assessment and resource allocation are based upon this geographical structure. Zions Bank operates 97 branches in Utah, 23 branches in Idaho, and 1 branch in Wyoming. CB&T operates 92 branches in California. Amegy operates 73 branches in Texas. NBAZ operates 58 branches in Arizona. NSB operates 50 branches in Nevada. Vectra operates 36 branches in Colorado and 1 branch in New Mexico. TCBW operates 1 branch in Washington and 1 branch in Oregon. The operating segment identified as “Other” includes the Parent, certain nonbank financial service subsidiaries, centralized back-office functions, and eliminations of transactions between segments. The major components of net interest income at the Bank’s back-office include the revenue associated with the investments securities portfolio and the offset of the FTP costs and benefits provided to the business segments. Throughout 2016 consolidation efforts continued, which resulted in transitioning full-time equivalents from the business segments to the Company’s back-office units. Due to the continuing nature and timing of this change, the Company’s back-office units retained more direct expenses in 2016 than in prior years. In the first quarter of 2017 we made changes to the FTP process and internal allocation of central expenses to better reflect the performance of business segments. Prior period amounts have been revised to reflect the impact of these changes had they been instituted in 2016. The following schedule does not present total assets or income tax expense for each operating segment, but instead presents average loans, average deposits and income before income taxes because these are the metrics that management uses when evaluating performance and making decisions pertaining to the operating segments. The Parent’s net interest income includes interest expense on other borrowed funds. The Parent’s financial statements in Note 22 provide more information about the Parent’s activities. The condensed statement of income identifies the components of income and expense which affect the operating amounts presented in the Other segment. The accounting policies of the individual operating segments are the same as those of the Company. Transactions between operating segments are primarily conducted at fair value, resulting in profits that are eliminated for reporting consolidated results of operations. The following is a summary of selected operating segment information: (In millions) Zions Bank Amegy CB&T 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 650 $ 624 $ 544 $ 483 $ 460 $ 387 $ 476 $ 434 $ 377 Provision for loan losses 19 (22 ) (28 ) 25 163 91 (5 ) (9 ) (4 ) Net interest income after provision for loan losses 631 646 572 458 297 296 481 443 381 Noninterest income 151 149 133 118 123 121 75 67 63 Noninterest expense 436 424 430 336 326 373 299 290 294 Income before income taxes $ 346 $ 371 $ 275 $ 240 $ 94 $ 44 $ 257 $ 220 $ 150 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 12,481 $ 12,538 $ 12,118 $ 11,021 $ 10,595 $ 10,148 $ 9,539 $ 9,211 $ 8,556 Total average deposits 15,986 15,991 15,688 11,096 11,130 11,495 11,030 10,827 10,063 (In millions) NBAZ NSB Vectra 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 206 $ 190 $ 152 $ 134 $ 122 $ 94 $ 126 $ 120 $ 101 Provision for loan losses (8 ) (3 ) 8 (11 ) (28 ) (28 ) 1 (8 ) 5 Net interest income after provision for loan losses 214 193 144 145 150 122 125 128 96 Noninterest income 40 40 36 40 39 36 25 23 21 Noninterest expense 148 144 133 139 137 131 101 97 98 Income before income taxes $ 106 $ 89 $ 47 $ 46 $ 52 $ 27 $ 49 $ 54 $ 19 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 4,267 $ 4,086 $ 3,811 $ 2,357 $ 2,284 $ 2,344 $ 2,644 $ 2,469 $ 2,400 Total average deposits 4,762 4,576 4,311 4,254 4,137 3,891 2,756 2,720 2,792 (In millions) TCBW Other Consolidated Company 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 46 $ 38 $ 28 $ (56 ) $ (121 ) $ 32 $ 2,065 $ 1,867 $ 1,715 Provision for loan losses 2 — (3 ) 1 — (1 ) 24 93 40 Net interest income after provision for loan losses 44 38 31 (57 ) (121 ) 33 2,041 1,774 1,675 Noninterest income 5 5 4 90 70 (57 ) 544 516 357 Noninterest expense 20 19 17 170 148 105 1,649 1,585 1,581 Income (loss) before income taxes $ 29 $ 24 $ 18 $ (137 ) $ (199 ) $ (129 ) $ 936 $ 705 $ 451 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 926 $ 791 $ 707 $ 266 $ 88 $ 87 $ 43,501 $ 42,062 $ 40,171 Total average deposits 1,107 1,007 879 1,209 207 (481 ) 52,200 50,595 48,638

Quarterly Financial Information

Quarterly Financial Information	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	QUARTERLY FINANCIAL INFORMATION (UNAUDITED) Financial information by quarter for 2017 and 2016 is as follows: (In millions, except per share amounts) Quarters First Second Third Fourth Year 2017 Gross interest income $ 515 $ 558 $ 557 $ 562 $ 2,192 Net interest income 489 528 522 526 2,065 Provision for loan losses 23 7 5 (11 ) 24 Noninterest income 132 132 140 140 544 Noninterest expense 414 405 413 417 1,649 Income before income taxes 184 248 244 260 936 Net income 139 168 161 124 592 Preferred stock dividends (10 ) (12 ) (8 ) (10 ) (40 ) Preferred stock redemption — (2 ) — — (2 ) Net earnings applicable to common shareholders 129 154 153 114 550 Net earnings per common share: Basic 0.63 0.76 0.75 0.57 2.71 Diluted 0.61 0.73 0.72 0.54 2.60 2016 Gross interest income $ 475 $ 487 $ 491 $ 501 $ 1,954 Net interest income 453 465 469 480 1,867 Provision for loan losses 42 35 19 (3 ) 93 Noninterest income 117 126 145 128 516 Noninterest expense 396 382 403 404 1,585 Income before income taxes 132 174 192 207 705 Net income 91 114 127 137 469 Preferred stock dividends (12 ) (14 ) (10 ) (12 ) (48 ) Preferred stock redemption — (10 ) — — (10 ) Net earnings applicable to common shareholders 79 90 117 125 411 Net earnings per common share: Basic 0.38 0.44 0.57 0.61 2.00 Diluted 0.38 0.44 0.57 0.60 1.99 Certain prior year amounts have been reclassified to conform with the current year presentation. These reclassifications did not affect net income. See related discussion in Note 1 . Individual quarter information may be different than previously reported due to rounding.
Quarterly Financial Information [Table Text Block]	(In millions, except per share amounts) Quarters First Second Third Fourth Year 2017 Gross interest income $ 515 $ 558 $ 557 $ 562 $ 2,192 Net interest income 489 528 522 526 2,065 Provision for loan losses 23 7 5 (11 ) 24 Noninterest income 132 132 140 140 544 Noninterest expense 414 405 413 417 1,649 Income before income taxes 184 248 244 260 936 Net income 139 168 161 124 592 Preferred stock dividends (10 ) (12 ) (8 ) (10 ) (40 ) Preferred stock redemption — (2 ) — — (2 ) Net earnings applicable to common shareholders 129 154 153 114 550 Net earnings per common share: Basic 0.63 0.76 0.75 0.57 2.71 Diluted 0.61 0.73 0.72 0.54 2.60 2016 Gross interest income $ 475 $ 487 $ 491 $ 501 $ 1,954 Net interest income 453 465 469 480 1,867 Provision for loan losses 42 35 19 (3 ) 93 Noninterest income 117 126 145 128 516 Noninterest expense 396 382 403 404 1,585 Income before income taxes 132 174 192 207 705 Net income 91 114 127 137 469 Preferred stock dividends (12 ) (14 ) (10 ) (12 ) (48 ) Preferred stock redemption — (10 ) — — (10 ) Net earnings applicable to common shareholders 79 90 117 125 411 Net earnings per common share: Basic 0.38 0.44 0.57 0.61 2.00 Diluted 0.38 0.44 0.57 0.60 1.99

Parent Company Financial Inform

Parent Company Financial Information	12 Months Ended
	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	PARENT COMPANY FINANCIAL INFORMATION CONDENSED BALANCE SHEETS (In millions) December 31, 2017 2016 ASSETS Cash and due from banks $ — $ 2 Interest-bearing deposits 332 529 Investment securities: Available-for-sale, at fair value 30 40 Other noninterest-bearing investments 36 29 Investments in subsidiaries: Commercial bank 7,620 7,570 Other subsidiaries 41 6 Other assets 32 81 Total assets $ 8,091 $ 8,257 LIABILITIES AND SHAREHOLDERS’ EQUITY Other liabilities $ 30 $ 89 Long-term debt: Due to others 382 534 Total liabilities 412 623 Shareholders’ equity: Preferred stock 566 710 Common stock 4,445 4,725 Retained earnings 2,807 2,321 Accumulated other comprehensive income (loss) (139 ) (122 ) Total shareholders’ equity 7,679 7,634 Total liabilities and shareholders’ equity $ 8,091 $ 8,257 CONDENSED STATEMENTS OF INCOME (In millions) Year Ended December 31, 2017 2016 2015 Interest income: Commercial bank $ — $ 1 $ 1 Other loans and securities 1 2 3 Total interest income 1 3 4 Interest expense: Affiliated trusts — 3 4 Other borrowed funds 25 34 64 Total interest expense 25 37 68 Net interest loss (24 ) (34 ) (64 ) Other income: Dividends from consolidated subsidiaries: Commercial bank 587 263 234 Securities gains, net — — 37 Other income 7 4 13 Total other income 594 267 284 Expenses: Salaries and employee benefits 24 23 25 Other operating expenses 8 (14 ) 10 Total expenses 32 9 35 Income before income taxes and undistributed income of consolidated subsidiaries 538 224 185 Income tax benefit (42 ) (19 ) (27 ) Income before equity in undistributed income of consolidated subsidiaries 580 243 212 Equity in undistributed income (loss) of consolidated subsidiaries: Commercial bank 12 230 108 Other subsidiaries — (4 ) (11 ) Net income 592 469 309 Preferred stock dividends (40 ) (48 ) (62 ) Preferred stock redemption (2 ) (10 ) — Net earnings applicable to common shareholders $ 550 $ 411 $ 247 CONDENSED STATEMENTS OF CASH FLOWS (In millions) Year Ended December 31, 2017 2016 2015 CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 592 $ 469 $ 309 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed income of consolidated subsidiaries (12 ) (226 ) (97 ) Other, net (56 ) (31 ) 78 Net cash provided by operating activities 524 212 290 CASH FLOWS FROM INVESTING ACTIVITIES Net decrease in money market investments 196 347 132 Collection of advances to subsidiaries — — 56 Advances to subsidiaries — — (41 ) Proceeds from sales and maturities of investment securities 20 4 125 Purchases of investment securities — — (47 ) Decrease of investment in subsidiaries — — 15 Other, net 2 7 4 Net cash provided by investing activities 218 358 244 CASH FLOWS FROM FINANCING ACTIVITIES Repayments of long-term debt (164 ) (280 ) (271 ) Proceeds from issuance of common stock 25 25 22 Cash paid for preferred stock redemptions (144 ) (126 ) (176 ) Company common stock repurchased (332 ) (97 ) (7 ) Dividends paid on preferred stock (40 ) (50 ) (63 ) Dividends paid on common stock (89 ) (58 ) (45 ) Net cash used in financing activities (744 ) (586 ) (540 ) Net decrease in cash and due from banks (2 ) (16 ) (6 ) Cash and due from banks at beginning of year 2 18 24 Cash and due from banks at end of year $ — $ 2 $ 18 The Parent paid interest of $26 million in 2017 , $35 million in 2016 , and $51 million in 2015 .

Summary Of Significant Accoun30

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Business	Business Zions Bancorporation (“the Parent”) is a financial holding company headquartered in Salt Lake City, Utah, which owns and operates a commercial bank. The Parent and its subsidiaries (collectively “the Company”) provide a full range of banking and related services in 11 western and southwestern states through seven separately managed and branded units as follows: Zions Bank, in Utah, Idaho and Wyoming; California Bank & Trust (“CB&T”); Amegy Bank (“Amegy”), in Texas; National Bank of Arizona (“NBAZ”); Nevada State Bank (“NSB”); Vectra Bank Colorado (“Vectra”), in Colorado and New Mexico; and The Commerce Bank of Washington (“TCBW”) which operates under that name in Washington and under the name The Commerce Bank of Oregon (“TCBO”) in Oregon. Pursuant to a Board resolution adopted November 21, 2014, TCBO merged into TCBW effective March 31, 2015. The Parent also owns and operates certain nonbank subsidiaries that engage in financial services.
Basis Of Financial Statement Presentation	Basis of Financial Statement Presentation The consolidated financial statements include the accounts of the Parent and its majority-owned subsidiaries (“the Company,” “we,” “our,” “us”). Unconsolidated investments where we have the ability to exercise significant influence over the operating and financial policies of the respective investee are accounted for using the equity method of accounting; those that are not consolidated or accounted for using the equity method of accounting are accounted for under cost or fair value accounting. All significant intercompany accounts and transactions have been eliminated in consolidation. The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and prevailing practices within the financial services industry. References to GAAP, including standards promulgated by the Financial Accounting Standards Board (“FASB”), are made according to sections of the Accounting Standards Codification (“ASC”). Changes to the ASC are made with Accounting Standards Updates (“ASU”) that include consensus issues of the Emerging Issues Task Force (“EITF”). In certain cases, ASUs are issued jointly with International Financial Reporting Standards. In preparing the consolidated financial statements, we are required to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain prior year amounts have been reclassified to conform with the current year presentation. These reclassifications did not affect net income or shareholders’ equity.
Reclassification Policy	Certain prior year amounts have been reclassified to conform with the current year presentation.
Variable Interest Entities	Variable Interest Entities A variable interest entity (“VIE”) is consolidated when a company is the primary beneficiary of the VIE. Current accounting guidance requires continuous analysis on a qualitative rather than a quantitative basis to determine the primary beneficiary of a VIE. At the commencement of our involvement, and periodically thereafter, we consider our consolidation conclusions for all entities with which we are involved. As of December 31, 2017 and 2016 , no VIEs have been consolidated in the Company’s financial statements.
Statement Of Cash Flows	Statement of Cash Flows For purposes of presentation in the consolidated statements of cash flows, “cash and cash equivalents” are defined as those amounts included in cash and due from banks in the consolidated balance sheets.
Security Resell Agreements	Security Resell Agreements Security resell agreements represent overnight and term agreements with the majority maturing within 30 days. These agreements are generally treated as collateralized financing transactions and are carried at amounts at which the securities were acquired plus accrued interest. Either the Company, or in some instances third parties on its behalf, take possession of the underlying securities. The fair value of such securities is monitored throughout the contract term to ensure that asset values remain sufficient to protect against counterparty default. We are permitted by contract to sell or repledge certain securities that we accept as collateral for security resell agreements. If sold, our obligation to return the collateral is recorded as “securities sold, not yet purchased” and included as a liability in “Federal funds and other short-term borrowings.” At December 31, 2017 , we held $287 million of securities for which we were permitted by contract to sell or repledge. Security resell agreements averaged $360 million during 2017 , and the maximum amount outstanding at any month-end during 2017 was $1.8 billion .
Investment Securities	Investment Securities We classify our investment securities according to their purpose and holding period. Gains or losses on the sale of securities are recognized using the specific identification method and recorded in noninterest income. Held-to-maturity (“HTM”) debt securities are carried at amortized cost with purchase discounts or premiums accreted or amortized into interest income over the contractual life of the security. The Company has the intent and ability to hold such securities until maturity. Available-for-sale (“AFS”) securities are stated at fair value and generally consist of debt securities held for investment. Unrealized gains and losses of AFS securities, after applicable taxes, are recorded as a component of other comprehensive income (“OCI”). We review quarterly our investment securities portfolio for any declines in value that are considered to be other-than-temporary impairment (“OTTI”). The process, methodology, and factors considered to evaluate securities for OTTI are discussed further in Note 5 . Trading securities are stated at fair value and consist of securities acquired for short-term appreciation or other trading purposes. Realized and unrealized gains and losses are recorded in trading income, which is included in “Capital markets and foreign exchange.” The fair values of investment securities, as estimated under current accounting guidance, are discussed in Note 3 .
Loans And Allowance For Credit Losses	Loans and Allowance for Credit Losses Loans are reported at the principal amount outstanding, net of unearned income. Unearned income, which includes deferred fees net of deferred direct loan origination costs, is amortized to interest income over the life of the loan using the interest method. Interest income is recognized on an accrual basis. At the time of origination, we determine whether loans will be held for investment or held for sale. We may subsequently change our intent to hold loans for investment and reclassify them as held for sale. Loans held for sale are carried at the lower of aggregate cost or fair value. A valuation allowance is recorded when cost exceeds fair value based on reviews at the time of reclassification and periodically thereafter. Gains and losses are recorded in noninterest income based on the difference between sales proceeds and carrying value. We evaluate loans throughout their lives for signs of credit deterioration, which may impact the loan’s status, and potentially impact our accounting for that loan. Loan status categories include past due as to contractual payments, nonaccrual, impaired, and restructured (including troubled debt restructurings (“TDRs”)). Our accounting policies for these loan statuses and our estimation of the related allowance for loan losses (“ALLL”) are discussed further in Note 6 . In the ordinary course of business, we transfer portions of loans under participation agreements to manage credit risk and our portfolio concentration. We evaluate the loan participations to determine if they meet the appropriate accounting guidance to qualify as sales. Certain purchased loans require separate accounting procedures that are also discussed in Note 6 . The allowance for credit losses (“ACL”) includes the ALLL and the reserve for unfunded lending commitments (“RULC”), and represents our estimate of losses inherent in the loan portfolio that may be recognized from loans and lending commitments that are not recoverable. Further discussion of our estimation process for the ACL is included in Note 6 .
Other Real Estate Owned	Other Real Estate Owned Other real estate owned (“OREO”) consists principally of commercial and residential real estate obtained in partial or total satisfaction of loan obligations. Amounts are recorded initially at fair value (less any selling costs) based on property appraisals at the time of transfer and subsequently at the lower of cost or fair value (less any selling costs).
Nonmarketable Securities	Other Noninterest-Bearing Investments These investments include investments in private equity funds (referred to in this document as private equity investments “PEIs”), venture capital securities, securities acquired for various debt and regulatory requirements, bank-owned life insurance, and certain other noninterest-bearing investments. See further discussions in Notes 5 , 15 and 3 . Certain PEIs and venture capital securities are accounted for under the equity method and reported at fair value. Changes in fair value and gains and losses from sales are recognized in noninterest income. The values assigned to the securities where no market quotations exist are based upon available information and may not necessarily represent amounts that will ultimately be realized. Such estimated amounts depend on future circumstances and will not be realized until the individual securities are liquidated. Bank-owned life insurance is accounted for at fair value based on the cash surrender values (“CSVs”) of the general account insurance policies. A third party service provides these values. Other PEIs and those acquired for various debt and regulatory requirements are accounted for at cost. Periodic reviews are conducted for impairment by comparing carrying values with estimates of fair value determined according to the previous discussion.
Premises And Equipment	Premises, Equipment and Software, Net Premises, equipment and software are stated at cost, net of accumulated depreciation and amortization. Depreciation, computed primarily on the straight-line method, is charged to operations over the estimated useful lives of the properties, generally 25 to 40 years for buildings, 3 to 10 years for furniture and equipment, and 3 to 10 years for software, including capitalized costs related to the Company’s technology initiatives. Leasehold improvements are amortized over the terms of the respective leases or the estimated useful lives of the improvements, whichever is shorter.
Business Combinations	Business Combinations Business combinations are accounted for under the acquisition method of accounting. Upon initially obtaining control, we recognize 100% of all acquired assets and all assumed liabilities regardless of the percentage owned. The assets and liabilities are recorded at their estimated fair values, with goodwill being recorded when such fair values are less than the cost of acquisition. Certain transaction and restructuring costs are expensed as incurred. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill over the measurement period, which cannot exceed one year from the acquisition date. Results of operations of the acquired business are included in our statement of income from the date of acquisition.
Goodwill And Identifiable Intangible Assets	Goodwill and Identifiable Intangible Assets Goodwill and intangible assets deemed to have indefinite lives are not amortized. We subject these assets to annual specified impairment tests as of the beginning of the fourth quarter and more frequently if changing conditions warrant. Core deposit assets and other intangibles with finite useful lives are generally amortized on an accelerated basis using an estimated useful life of up to 12 years.
Derivative Instruments	Derivative Instruments We use derivative instruments, including interest rate swaps and floors and basis swaps, as part of our overall interest rate risk management strategy. These instruments enable us to manage to desired asset and liability duration and to reduce interest rate risk exposure by matching estimated repricing periods of interest-sensitive assets and liabilities. We also execute derivative instruments with commercial banking customers to facilitate their risk management strategies. These derivatives are immediately hedged by offsetting derivatives with third parties such that we minimize our net risk exposure as a result of such transactions. We record all derivatives at fair value in the balance sheet as either other assets or other liabilities. See further discussion in Note 7 .
Commitments And Letters Of Credit	Commitments and Letters of Credit In the ordinary course of business, we enter into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the ALLL. The RULC is presented separately in the balance sheet.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition Service charges and fees on deposit accounts are recognized in accordance with published deposit account agreements for customer accounts or contractual agreements for commercial accounts. Other service charges, commissions and fees include interchange fees, bank services, and other fees, which are generally recognized at the time of transaction or as the services are performed.
Share-Based Compensation	Share-Based Compensation Share-based compensation generally includes grants of stock options, restricted stock, restricted stock units (“RSUs”), and other awards to employees and non-employee directors. We recognize compensation expense in the statement of income based on the grant-date value of the associated share-based awards. See further discussion in Note 17 .
Income Taxes	Income Taxes Deferred tax assets and liabilities are determined based on temporary differences between financial statement asset and liability amounts and their respective tax bases, and are measured using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized subject to management’s judgment that realization is more likely than not. Unrecognized tax benefits for uncertain tax positions relate primarily to state tax contingencies. See further discussion in Note 18 .
Net Earnings Per Common Share	Net Earnings Per Common Share Net earnings per common share is based on net earnings applicable to common shareholders, which is net of preferred stock dividends. Basic net earnings per common share is based on the weighted average outstanding common shares during each year. Unvested share-based awards with rights to receive nonforfeitable dividends are considered participating securities and included in the computation of basic earnings per share. Diluted net earnings per common share is based on the weighted average outstanding common shares during each year, including common stock equivalents. Stock options, restricted stock, RSUs, and stock warrants are converted to common stock equivalents using the treasury stock method. Diluted net earnings per common share excludes common stock equivalents whose effect is antidilutive. See further discussion in Note 19 .

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis	(In millions) December 31, 2017 Level 1 Level 2 Level 3 Total ASSETS Investment securities: Available-for-sale: U.S. Treasury, agencies and corporations $ 25 $ 13,706 $ — $ 13,731 Municipal securities 1,334 1,334 Other debt securities 24 24 Money market mutual funds and other 71 1 72 Total Available-for-sale 96 15,065 — 15,161 Trading account 148 148 Other noninterest-bearing investments: Bank-owned life insurance 507 507 Private equity investments 95 95 Other assets: Agriculture loan servicing and interest-only strips 18 18 Deferred compensation plan assets 102 102 Derivatives: Interest rate related and other 1 1 Interest rate swaps for customers 28 28 Foreign currency exchange contracts 9 9 Total Assets $ 207 $ 15,749 $ 113 $ 16,069 LIABILITIES Securities sold, not yet purchased $ 95 $ — $ — $ 95 Other liabilities: Deferred compensation plan obligations 102 102 Derivatives: Interest rate swaps for customers 33 33 Foreign currency exchange contracts 7 7 Total Liabilities $ 204 $ 33 $ — $ 237 (In millions) December 31, 2016 Level 1 Level 2 Level 3 Total ASSETS Investment securities: Available-for-sale: U.S. Treasury, agencies and corporations $ — $ 12,009 $ — $ 12,009 Municipal securities 1,154 1,154 Other debt securities 24 24 Money market mutual funds and other 184 1 185 Total Available-for-sale 184 13,188 — 13,372 Trading account 115 115 Other noninterest-bearing investments: Bank-owned life insurance 497 497 Private equity investments 1 18 73 91 Other assets: Agriculture loan servicing and interest-only strips 20 20 Deferred compensation plan assets 91 91 Derivatives: Interest rate related and other 4 4 Interest rate swaps for customers 49 49 Foreign currency exchange contracts 11 11 Total Assets $ 304 $ 13,853 $ 93 $ 14,250 LIABILITIES Securities sold, not yet purchased $ 25 $ — $ — $ 25 Other liabilities: Deferred compensation plan obligations 91 91 Derivatives: Interest rate related and other 1 1 Interest rate swaps for customers 49 49 Foreign currency exchange contracts 9 9 Total Liabilities $ 125 $ 50 $ — $ 175 1 The level 1 PEIs amount relates to the portion of our SBIC investments that are now publicly traded.
Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis Using Level 3 Inputs	Level 3 Instruments December 31, 2017 December 31, 2016 (In millions) Private Ag loan svcg and int-only strips Private Ag loan svcg and int-only strips Balance at beginning of year $ 73 $ 20 $ 58 $ 14 Securities gains, net 7 — 6 — Other noninterest income — (1 ) — 6 Purchases 20 — 10 — Redemptions and paydowns (5 ) (1 ) (1 ) — Balance at end of year $ 95 $ 18 $ 73 $ 20
Schedule Of Realized Gains (Losses) Using Level 3 Inputs	(In millions) Year Ended December 31, 2017 2016 Equity securities gains, net $ 3 $ 6
Schedule Of Assets With Fair Value Changes On Nonrecurring Basis	(In millions) Fair value at December 31, 2017 Gains (losses) from Level 1 Level 2 Level 3 Total ASSETS Private equity investments, carried at cost $ — $ — $ 1 $ 1 $ (1 ) Impaired loans — 9 — 9 (5 ) Other real estate owned — — — — — Total $ — $ 9 $ 1 $ 10 $ (6 ) (In millions) Fair value at December 31, 2016 Gains (losses) from Level 1 Level 2 Level 3 Total ASSETS Private equity investments, carried at cost $ — $ — $ 1 $ 1 $ (1 ) Impaired loans — 52 — 52 (36 ) Other real estate owned — 1 — 1 (2 ) Total $ — $ 53 $ 1 $ 54 $ (39 )
Schedule Of Carrying Values And Estimated Fair Values Of Financial Instruments	December 31, 2017 December 31, 2016 (Dollar amounts in millions) Carrying value Estimated fair value Level Carrying value Estimated fair value Level Financial assets: Held-to-maturity investment securities $ 770 $ 762 2 $ 868 $ 850 2 Loans and leases (including loans held for sale), net of allowance 44,306 44,226 3 42,254 42,111 3 Financial liabilities: Time deposits 3,115 3,099 2 2,757 2,744 2 Other short-term borrowings 3,600 3,600 2 500 500 2 Long-term debt (less fair value hedges) 383 402 2 535 552 2 December 31, 2017 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 809 $ (295 ) $ 514 $ — $ — $ 514 Derivatives (included in other assets) 38 — 38 (21 ) (1 ) 16 Total assets $ 847 $ (295 ) $ 552 $ (21 ) $ (1 ) $ 530 Liabilities: Federal funds and other short-term borrowings $ 5,271 $ (295 ) $ 4,976 $ — $ — $ 4,976 Derivatives (included in other liabilities) 40 — 40 (21 ) (6 ) 13 Total liabilities $ 5,311 $ (295 ) $ 5,016 $ (21 ) $ (6 ) $ 4,989 December 31, 2016 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 568 $ — $ 568 $ — $ — $ 568 Derivatives (included in other assets) 64 — 64 (17 ) — 47 Total assets $ 632 $ — $ 632 $ (17 ) $ — $ 615 Liabilities: Federal funds and other short-term borrowings $ 827 $ — $ 827 $ — $ — $ 827 Derivatives (included in other liabilities) 59 — 59 (17 ) (17 ) 25 Total liabilities $ 886 $ — $ 886 $ (17 ) $ (17 ) $ 852

Offsetting Assets and Liabili32

Offsetting Assets and Liabilities Gross and net information for selecting financial instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value, by Balance Sheet Grouping [Table Text Block]	December 31, 2017 December 31, 2016 (Dollar amounts in millions) Carrying value Estimated fair value Level Carrying value Estimated fair value Level Financial assets: Held-to-maturity investment securities $ 770 $ 762 2 $ 868 $ 850 2 Loans and leases (including loans held for sale), net of allowance 44,306 44,226 3 42,254 42,111 3 Financial liabilities: Time deposits 3,115 3,099 2 2,757 2,744 2 Other short-term borrowings 3,600 3,600 2 500 500 2 Long-term debt (less fair value hedges) 383 402 2 535 552 2 December 31, 2017 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 809 $ (295 ) $ 514 $ — $ — $ 514 Derivatives (included in other assets) 38 — 38 (21 ) (1 ) 16 Total assets $ 847 $ (295 ) $ 552 $ (21 ) $ (1 ) $ 530 Liabilities: Federal funds and other short-term borrowings $ 5,271 $ (295 ) $ 4,976 $ — $ — $ 4,976 Derivatives (included in other liabilities) 40 — 40 (21 ) (6 ) 13 Total liabilities $ 5,311 $ (295 ) $ 5,016 $ (21 ) $ (6 ) $ 4,989 December 31, 2016 (In millions) Gross amounts not offset in the balance sheet Description Gross amounts recognized Gross amounts offset in the balance sheet Net amounts presented in the balance sheet Financial instruments Cash collateral received/pledged Net amount Assets: Federal funds sold and security resell agreements $ 568 $ — $ 568 $ — $ — $ 568 Derivatives (included in other assets) 64 — 64 (17 ) — 47 Total assets $ 632 $ — $ 632 $ (17 ) $ — $ 615 Liabilities: Federal funds and other short-term borrowings $ 827 $ — $ 827 $ — $ — $ 827 Derivatives (included in other liabilities) 59 — 59 (17 ) (17 ) 25 Total liabilities $ 886 $ — $ 886 $ (17 ) $ (17 ) $ 852

Investment Securities - (Tables

Investment Securities - (Tables)	12 Months Ended
	Dec. 31, 2017
Investments [Abstract]
Summary of Investment Securities [Table Text Block]	December 31, 2017 (In millions) Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 770 $ 5 $ 13 $ 762 Available-for-sale U.S. Treasury securities 25 — — 25 U.S. Government agencies and corporations: Agency securities 1,830 1 13 1,818 Agency guaranteed mortgage-backed securities 9,798 9 141 9,666 Small Business Administration loan-backed securities 2,227 10 15 2,222 Municipal securities 1,336 9 11 1,334 Other debt securities 25 — 1 24 Total available-for-sale debt securities 15,241 29 181 15,089 Money market mutual funds and other 72 — — 72 Total available-for-sale 15,313 29 181 15,161 Total investment securities $ 16,083 $ 34 $ 194 $ 15,923 December 31, 2016 (In millions) Amortized Gross Gross Estimated Held-to-maturity Municipal securities $ 868 $ 5 $ 23 $ 850 Available-for-sale U.S. Treasury securities — — — — U.S. Government agencies and corporations: Agency securities 1,846 2 9 1,839 Agency guaranteed mortgage-backed securities 7,986 7 110 7,883 Small Business Administration loan-backed securities 2,298 8 18 2,288 Municipal securities 1,182 1 29 1,154 Other debt securities 25 — 1 24 Total available-for-sale debt securities 13,337 18 167 13,188 Money market mutual funds and other 184 — — 184 Total available-for-sale 13,521 18 167 13,372 Total investment securities $ 14,389 $ 23 $ 190 $ 14,222
Investments Classified by Contractual Maturity Date [Table Text Block]	Held-to-maturity Available-for-sale (In millions) Amortized cost Estimated fair value Amortized cost Estimated fair value Due in one year or less $ 180 $ 90 $ 2,499 $ 2,054 Due after one year through five years 372 336 5,727 5,575 Due after five years through ten years 159 230 4,331 4,485 Due after ten years 59 106 2,684 2,975 Total $ 770 $ 762 $ 15,241 $ 15,089
Gain (Loss) on Investments [Table Text Block]	The following summarizes gains and losses, including OTTI, that were recognized in the statement of income: 2017 2016 2015 (In millions) Gross gains Gross losses Gross gains Gross losses Gross gains Gross losses Investment securities: Available-for-sale $ — $ — $ — $ — $ 9 $ 148 Other noninterest-bearing investments 22 8 21 14 25 13 Total investments 22 8 21 14 34 161 Net gains (losses) $ 14 $ 7 $ (127 ) Statement of income information: Equity securities gains, net $ 14 $ 7 $ 12 Fixed income securities gains (losses), net — — (139 ) Net gains (losses) $ 14 $ 7 $ (127 )
Schedule of Unrealized Loss on Investments [Table Text Block]	December 31, 2017 Less than 12 months 12 months or more Total (In millions) Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 3 $ 263 $ 10 $ 292 $ 13 $ 555 Available-for-sale U.S. Government agencies and corporations: Agency securities 6 808 7 808 13 1,616 Agency guaranteed mortgage-backed securities 29 3,609 112 4,721 141 8,330 Small Business Administration loan-backed securities 3 408 12 649 15 1,057 Municipal securities 6 554 5 230 11 784 Other — — 1 14 1 14 Total available-for-sale 44 5,379 137 6,422 181 11,801 Total $ 47 $ 5,642 $ 147 $ 6,714 $ 194 $ 12,356 December 31, 2016 Less than 12 months 12 months or more Total (In millions) Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Gross unrealized losses Estimated fair value Held-to-maturity Municipal securities $ 15 $ 467 $ 8 $ 61 $ 23 $ 528 Available-for-sale U.S. Government agencies and corporations: Agency securities 9 950 — 127 9 1,077 Agency guaranteed mortgage-backed securities 102 6,649 7 326 109 6,975 Small Business Administration loan-backed securities 3 527 16 841 19 1,368 Municipal securities 28 992 — 9 28 1,001 Other — — 2 14 2 14 Total available-for-sale 142 9,118 25 1,317 167 10,435 Total $ 157 $ 9,585 $ 33 $ 1,378 $ 190 $ 10,963
Tax and Nontaxable Interest Income by Investment Type [Table Text Block]	(In millions) 2017 2016 2015 Taxable Nontaxable Total Taxable Nontaxable Total Taxable Nontaxable Total Investment securities: Held-to-maturity $ 10 $ 13 $ 23 $ 10 $ 13 $ 23 $ 13 $ 11 $ 24 Available-for-sale 277 24 301 166 12 178 95 3 98 Trading 2 — 2 3 — 3 2 — 2 Total $ 289 $ 37 $ 326 $ 179 $ 25 $ 204 $ 110 $ 14 $ 124

Loans And Allowance For Credi34

Loans And Allowance For Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Loans And Allowance For Credit Losses [Abstract]
Summary Of Major Portfolio Segment And Specific Loan Class	December 31, (In millions) 2017 2016 Loans held for sale $ 44 $ 172 Commercial: Commercial and industrial $ 14,003 $ 13,452 Leasing 364 423 Owner-occupied 7,288 6,962 Municipal 1,271 778 Total commercial 22,926 21,615 Commercial real estate: Construction and land development 2,021 2,019 Term 9,103 9,322 Total commercial real estate 11,124 11,341 Consumer: Home equity credit line 2,777 2,645 1-4 family residential 6,662 5,891 Construction and other consumer real estate 597 486 Bankcard and other revolving plans 509 481 Other 185 190 Total consumer 10,730 9,693 Total loans $ 44,780 $ 42,649
Summary Of Changes in The Allowance For Credit Losses	December 31, 2017 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Balance at beginning of year $ 420 $ 116 $ 31 $ 567 Additions: Provision for loan losses 23 (18 ) 19 24 Deductions: Gross loan and lease charge-offs (118 ) (9 ) (17 ) (144 ) Recoveries 46 14 11 71 Net loan and lease (charge-offs) recoveries (72 ) 5 (6 ) (73 ) Balance at end of year $ 371 $ 103 $ 44 $ 518 Reserve for unfunded lending commitments Balance at beginning of year $ 54 $ 11 $ — $ 65 Provision credited to earnings (6 ) (1 ) — (7 ) Balance at end of year $ 48 $ 10 $ — $ 58 Total allowance for credit losses Allowance for loan losses $ 371 $ 103 $ 44 $ 518 Reserve for unfunded lending commitments 48 10 — 58 Total allowance for credit losses $ 419 $ 113 $ 44 $ 576 December 31, 2016 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Balance at beginning of year $ 454 $ 114 $ 38 $ 606 Additions: Provision for loan losses 93 — — 93 Deductions: Gross loan and lease charge-offs (170 ) (12 ) (16 ) (198 ) Recoveries 43 14 9 66 Net loan and lease charge-offs (127 ) 2 (7 ) (132 ) Balance at end of year $ 420 $ 116 $ 31 $ 567 Reserve for unfunded lending commitments Balance at beginning of year $ 58 $ 16 $ 1 $ 75 Provision credited to earnings (4 ) (5 ) (1 ) (10 ) Balance at end of year $ 54 $ 11 $ — $ 65 Total allowance for credit losses Allowance for loan losses $ 420 $ 116 $ 31 $ 567 Reserve for unfunded lending commitments 54 11 — 65 Total allowance for credit losses $ 474 $ 127 $ 31 $ 632
Summary Of ALLL And Outstanding Loan Balances According To The Company's Impairment Method	December 31, 2017 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Individually evaluated for impairment $ 26 $ 1 $ 4 $ 31 Collectively evaluated for impairment 345 102 40 487 Purchased loans with evidence of credit deterioration — — — — Total $ 371 $ 103 $ 44 $ 518 Outstanding loan balances Individually evaluated for impairment $ 314 $ 69 $ 76 $ 459 Collectively evaluated for impairment 22,598 11,048 10,648 44,294 Purchased loans with evidence of credit deterioration 14 7 6 27 Total $ 22,926 $ 11,124 $ 10,730 $ 44,780 December 31, 2016 (In millions) Commercial Commercial real estate Consumer Total Allowance for loan losses Individually evaluated for impairment $ 56 $ 3 $ 6 $ 65 Collectively evaluated for impairment 364 113 25 502 Purchased loans with evidence of credit deterioration — — — — Total $ 420 $ 116 $ 31 $ 567 Outstanding loan balances Individually evaluated for impairment $ 466 $ 78 $ 75 $ 619 Collectively evaluated for impairment 21,111 11,231 9,611 41,953 Purchased loans with evidence of credit deterioration 38 32 7 77 Total $ 21,615 $ 11,341 $ 9,693 $ 42,649
Summary Of Nonaccrual Loans	Nonaccrual loans are summarized as follows: December 31, (In millions) 2017 2016 Loans held for sale $ 12 $ 40 Commercial: Commercial and industrial $ 195 $ 354 Leasing 8 14 Owner-occupied 90 74 Municipal 1 1 Total commercial 294 443 Commercial real estate: Construction and land development 4 7 Term 36 29 Total commercial real estate 40 36 Consumer: Home equity credit line 13 11 1-4 family residential 55 36 Construction and other consumer real estate — 2 Bankcard and other revolving plans — 1 Other — — Total consumer loans 68 50 Total $ 402 $ 529
Summary Of Past Due Loans (Accruing And Nonaccruing)	Past due loans (accruing and nonaccruing) are summarized as follows: December 31, 2017 (In millions) Current 30-89 days past due 90+ days past due Total past due Total loans Accruing loans 90+ days past due Nonaccrual loans that are current 1 Loans held for sale $ 44 $ — $ — $ — $ 44 $ — $ 12 Commercial: Commercial and industrial $ 13,887 $ 60 $ 56 $ 116 $ 14,003 $ 13 $ 146 Leasing 363 1 — 1 364 — 8 Owner-occupied 7,219 29 40 69 7,288 4 49 Municipal 1,271 — — — 1,271 — 1 Total commercial 22,740 90 96 186 22,926 17 204 Commercial real estate: Construction and land development 2,014 3 4 7 2,021 — — Term 9,079 13 11 24 9,103 2 25 Total commercial real estate 11,093 16 15 31 11,124 2 25 Consumer: Home equity credit line 2,763 9 5 14 2,777 — 5 1-4 family residential 6,621 16 25 41 6,662 1 27 Construction and other consumer real estate 590 6 1 7 597 1 — Bankcard and other revolving plans 506 2 1 3 509 1 — Other 184 1 — 1 185 — — Total consumer loans 10,664 34 32 66 10,730 3 32 Total $ 44,497 $ 140 $ 143 $ 283 $ 44,780 $ 22 $ 261 December 31, 2016 (In millions) Current 30-89 days past due 90+ days past due Total past due Total loans Accruing loans 90+ days past due Nonaccrual loans that are current 1 Loans held for sale $ 172 $ — $ — $ — $ 172 $ — $ 40 Commercial: Commercial and industrial $ 13,306 $ 72 $ 74 $ 146 $ 13,452 $ 10 $ 287 Leasing 423 — — — 423 — 14 Owner-occupied 6,894 40 28 68 6,962 8 43 Municipal 778 — — — 778 — 1 Total commercial 21,401 112 102 214 21,615 18 345 Commercial real estate: Construction and land development 2,010 7 2 9 2,019 1 1 Term 9,291 9 22 31 9,322 12 18 Total commercial real estate 11,301 16 24 40 11,341 13 19 Consumer: Home equity credit line 2,635 4 6 10 2,645 1 5 1-4 family residential 5,857 12 22 34 5,891 — 11 Construction and other consumer real estate 479 3 4 7 486 3 — Bankcard and other revolving plans 478 2 1 3 481 1 1 Other 189 1 — 1 190 — — Total consumer loans 9,638 22 33 55 9,693 5 17 Total $ 42,340 $ 150 $ 159 $ 309 $ 42,649 $ 36 $ 381 1 Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.
Summary Of Outstanding Loan Balances (Accruing And Nonaccruing) Categorized By Credit Quality Indicators	December 31, 2017 (In millions) Pass Special mention Sub- standard Doubtful Total loans Total allowance Commercial: Commercial and industrial $ 13,001 $ 395 $ 606 $ 1 $ 14,003 Leasing 342 6 16 — 364 Owner-occupied 6,920 93 275 — 7,288 Municipal 1,257 13 1 — 1,271 Total commercial 21,520 507 898 1 22,926 $ 371 Commercial real estate: Construction and land development 2,002 15 4 — 2,021 Term 8,816 138 149 — 9,103 Total commercial real estate 10,818 153 153 — 11,124 103 Consumer: Home equity credit line 2,759 — 18 — 2,777 1-4 family residential 6,602 — 60 — 6,662 Construction and other consumer real estate 596 — 1 — 597 Bankcard and other revolving plans 507 — 2 — 509 Other 185 — — — 185 Total consumer loans 10,649 — 81 — 10,730 44 Total $ 42,987 $ 660 $ 1,132 $ 1 $ 44,780 $ 518 December 31, 2016 (In millions) Pass Special mention Sub- standard Doubtful Total loans Total allowance Commercial: Commercial and industrial $ 12,185 $ 266 $ 998 $ 3 $ 13,452 Leasing 387 5 30 1 423 Owner-occupied 6,560 96 306 — 6,962 Municipal 765 7 6 — 778 Total commercial 19,897 374 1,340 4 21,615 $ 420 Commercial real estate: Construction and land development 1,942 52 25 — 2,019 Term 9,096 82 144 — 9,322 Total commercial real estate 11,038 134 169 — 11,341 116 Consumer: Home equity credit line 2,629 — 16 — 2,645 1-4 family residential 5,851 — 40 — 5,891 Construction and other consumer real estate 482 — 4 — 486 Bankcard and other revolving plans 478 — 3 — 481 Other 189 — 1 — 190 Total consumer loans 9,629 — 64 — 9,693 31 Total $ 40,564 $ 508 $ 1,573 $ 4 $ 42,649 $ 567
Summary Of Information On Impaired Loans	December 31, 2017 Year Ended (In millions) Unpaid principal balance Recorded investment Total recorded investment Related allowance Average recorded investment Interest with no allowance with allowance Commercial: Commercial and industrial $ 293 $ 80 $ 142 $ 222 $ 24 $ 289 $ 6 Owner-occupied 120 79 23 102 2 97 6 Municipal 1 1 — 1 — 1 — Total commercial 414 160 165 325 26 387 12 Commercial real estate: Construction and land development 8 4 2 6 — 8 — Term 56 36 12 48 — 49 12 Total commercial real estate 64 40 14 54 — 57 12 Consumer: Home equity credit line 25 13 9 22 — 21 1 1-4 family residential 67 28 29 57 4 52 1 Construction and other consumer real estate 2 1 1 2 — 2 — Other 1 1 — 1 — 1 1 Total consumer loans 95 43 39 82 4 76 3 Total $ 573 $ 243 $ 218 $ 461 $ 30 $ 520 $ 27 December 31, 2016 Year Ended (In millions) Unpaid principal balance Recorded investment Total recorded investment Related allowance Average recorded investment Interest with no allowance with allowance Commercial: Commercial and industrial $ 470 $ 82 $ 311 $ 393 $ 52 $ 333 $ 5 Owner-occupied 115 71 30 101 3 99 9 Municipal 1 1 — 1 — 1 — Total commercial 586 154 341 495 55 433 14 Commercial real estate: Construction and land development 22 7 6 13 — 11 2 Term 92 53 17 70 2 76 13 Total commercial real estate 114 60 23 83 2 87 15 Consumer: Home equity credit line 24 16 7 23 — 22 1 1-4 family residential 59 27 28 55 6 57 2 Construction and other consumer real estate 3 1 2 3 — 2 — Other 2 1 — 1 — 2 — Total consumer loans 88 45 37 82 6 83 3 Total $ 788 $ 259 $ 401 $ 660 $ 63 $ 603 $ 32
Summary Of Selected Information On TDRs That Includes Recorded Investment On An Accruing And Nonaccruing Basis By Loan Class And Modification Type	December 31, 2017 Recorded investment resulting from the following modification types: (In millions) Interest rate below market Maturity or term extension Principal forgiveness Payment deferral Other 1 Multiple modification types 2 Total Accruing Commercial: Commercial and industrial $ — $ 2 $ — $ — $ 12 $ 33 $ 47 Owner-occupied 1 1 — — 7 14 23 Total commercial 1 3 — — 19 47 70 Commercial real estate: Construction and land development — — — — — 2 2 Term 6 — — 1 — 7 14 Total commercial real estate 6 — — 1 — 9 16 Consumer: Home equity credit line — 2 9 — 1 3 15 1-4 family residential 1 — 6 1 2 26 36 Construction and other consumer real estate — 1 — — — 1 2 Total consumer loans 1 3 15 1 3 30 53 Total accruing 8 6 15 2 22 86 139 Nonaccruing Commercial: Commercial and industrial — 3 5 2 28 24 62 Owner-occupied 1 2 — 1 1 5 10 Municipal — 1 — — — — 1 Total commercial 1 6 5 3 29 29 73 Commercial real estate: Construction and land development — — — — — — — Term 2 — — — — 3 5 Total commercial real estate 2 — — — — 3 5 Consumer: Home equity credit line — — 1 — — — 1 1-4 family residential — — 2 — 1 5 8 Construction and other consumer real estate — — — — — — — Total consumer loans — — 3 — 1 5 9 Total nonaccruing 3 6 8 3 30 37 87 Total $ 11 $ 12 $ 23 $ 5 $ 52 $ 123 $ 226 1 Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc. 2 Includes TDRs that resulted from a combination of any of the previous modification types. December 31, 2016 Recorded investment resulting from the following modification types: (In millions) Interest rate below market Maturity or term extension Principal forgiveness Payment deferral Other 1 Multiple modification types 2 Total Accruing Commercial: Commercial and industrial $ — $ 19 $ — $ — $ — $ 28 $ 47 Owner-occupied 3 — 1 — 8 10 22 Total commercial 3 19 1 — 8 38 69 Commercial real estate: Construction and land development — 4 — — — 4 8 Term 4 — — 1 2 10 17 Total commercial real estate 4 4 — 1 2 14 25 Consumer: Home equity credit line — 1 10 — — 3 14 1-4 family residential 3 1 6 — 2 30 42 Construction and other consumer real estate — — — — — 1 1 Total consumer loans 3 2 16 — 2 34 57 Total accruing 10 25 17 1 12 86 151 Nonaccruing Commercial: Commercial and industrial 1 — — 1 33 25 60 Owner-occupied — 1 — 3 1 12 17 Municipal — 1 — — — — 1 Total commercial 1 2 — 4 34 37 78 Commercial real estate: Construction and land development — — — — 2 — 2 Term 2 1 — — 2 3 8 Total commercial real estate 2 1 — — 4 3 10 Consumer: Home equity credit line — — 1 — — 1 2 1-4 family residential — — 2 — 1 5 8 Construction and other consumer real estate — — — 2 — — 2 Total consumer loans — — 3 2 1 6 12 Total nonaccruing 3 3 3 6 39 46 100 Total $ 13 $ 28 $ 20 $ 7 $ 51 $ 132 $ 251 1 Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc. 2 Includes TDRs that resulted from a combination of any of the previous modification types.
Schedule Of Net Financial Impact On Interest Income Due To Interest Rate Modifications Below Market For Accruing TDR Loans	(In millions) 2017 2016 Consumer: 1-4 family residential $ (1 ) $ (1 ) Total consumer loans (1 ) (1 ) Total decrease to interest income 1 $ (1 ) $ (1 ) 1 Calculated based on the difference between the modified rate and the premodified rate applied to the recorded investment.
Schedule Of Investment Of Accruing And Nonaccruing Loans Modified As Troubled Debt Restructurings	(In millions) December 31, 2017 December 31, 2016 Accruing Nonaccruing Total Accruing Nonaccruing Total Commercial: Commercial and industrial $ 1 $ 3 $ 4 $ — $ — $ — Owner-occupied — 1 1 — 1 1 Total commercial 1 4 5 — 1 1 Consumer: Construction and other consumer real estate — — — — 2 2 Total consumer loans — — — — 2 2 Total $ 1 $ 4 $ 5 $ — $ 3 $ 3 Note: Total loans modified as TDRs during the 12 months previous to December 31, 2017 and 2016 were $94 million and $73 million , respectively.
Schedule Of Outstanding Balances Of All Required Payments And The Related Carrying Amounts For PCI Loans	December 31, (In millions) 2017 2016 Commercial $ 25 $ 49 Commercial real estate 9 51 Consumer 7 9 Outstanding balance $ 41 $ 109 Carrying amount $ 27 $ 77 Less ALLL — 1 Carrying amount, net $ 27 $ 76
Schedule Of Changes In The Accretable Yield For PCI Loans	(In millions) 2017 2016 Balance at beginning of year $ 33 $ 40 Accretion (20 ) (24 ) Reclassification from nonaccretable difference — 11 Disposals and other 1 6 Balance at end of year $ 14 $ 33

Derivative Instruments And He35

Derivative Instruments And Hedging Activities Amount of Derivative Gain/Loss Recognized/Reclassified (Tables)	12 Months Ended
	Dec. 31, 2017
Summary of Derivative Instruments [Abstract]
Schedule of Derivative Instruments	December 31, 2017 December 31, 2016 Notional amount Fair value Notional amount Fair value (In millions) Other assets Other liabilities Other assets Other liabilities Derivatives designated as hedging instruments Cash flow hedges: Interest rate swaps $ 1,138 $ — $ — $ 1,388 $ 2 $ 1 Derivatives not designated as hedging instruments Interest rate swaps 223 1 — 235 2 — Interest rate swaps for customers 1 4,550 28 33 4,162 49 49 Foreign exchange 913 9 7 424 11 9 Total derivatives not designated as hedging instruments 5,686 38 40 4,821 62 58 Total derivatives $ 6,824 $ 38 $ 40 $ 6,209 $ 64 $ 59 1 Notional amounts include both the customer swaps and the offsetting derivative contracts.
Schedule Of Gain (Loss) Of Derivative Instruments	Year Ended December 31, 2017 Year Ended December 31, 2016 Amount of derivative gain (loss) recognized/reclassified (In millions) OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense Derivatives designated as hedging instruments Cash flow hedges: 1 Interest rate swaps $ (8 ) $ 4 $ 8 $ 11 Derivatives not designated as hedging instruments Interest rate swaps $ (1 ) $ 1 Interest rate swaps for customers 11 14 Foreign exchange 17 11 Total derivatives $ (8 ) $ 4 $ 27 $ — $ 8 $ 11 $ 26 $ — Note: These schedules are not intended to present at any given time the Company’s long/short position with respect to its derivative contracts. 1 Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss). For the 12 months following December 31, 2017 , we estimate that $1 million will be reclassified from AOCI into interest income.

Goodwill And Other Intangible36

Goodwill And Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortizing Intangible Assets	Gross carrying amount Accumulated amortization Net carrying amount (In millions) 2017 2016 2017 2016 2017 2016 Core deposit intangibles $ 167 $ 167 $ (165 ) $ (159 ) $ 2 $ 8 Customer relationships and other intangibles 28 28 (28 ) (28 ) — — Total $ 195 $ 195 $ (193 ) $ (187 ) $ 2 $ 8
Schedule Of Goodwill	(In millions) Zions Bank CB&T Amegy Consolidated Company Balance at December 31, 2015 $ 20 $ 379 $ 615 $ 1,014 Impairment losses — — — — Balance at December 31, 2016 20 379 615 1,014 Impairment losses — — — — Balance at December 31, 2017 $ 20 $ 379 $ 615 $ 1,014

Deposits Deposits (Scheduled Ma

Deposits Deposits (Scheduled Maturities Of Time Deposits) (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits (Scheduled Maturities Of All Time Deposits) [Abstract]
Time Deposit Maturities [Table Text Block]	(In millions) 2018 $ 2,584 2019 256 2020 132 2021 85 2022 57 Thereafter 1 Total $ 3,115
Time Deposits Denomination of $100,000 and Over [Table Text Block]	(In millions) December 31, 2017 Three months or less $ 1,023 After three months through six months 485 After six months through twelve months 508 After twelve months 312 Total $ 2,328

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Short-term Debt [Line Items]
Summary Of Short-Term Borrowings	(Dollar amounts in millions) 2017 2016 2015 Federal Home Loan Bank advances Average amount outstanding $ 2,657 $ 37 $ — Average rate 1.13 % 0.59 % — % Highest month-end balance 3,750 750 — Year-end balance 3,600 500 — Average rate on outstandings at year-end 1.44 % 0.75 % — % Other short-term borrowings, year-end balances Federal funds purchased 927 106 111 Security repurchase agreements 354 196 206 Securities sold, not yet purchased 95 25 30 Total Federal Home Loan Bank advances and other short-term borrowings $ 4,976 $ 827 $ 347

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Instrument [Line Items]
Schedule of Maturities of Long-term Debt [Table Text Block]	(In millions) Consolidated Parent only 2018 $ — $ — 2019 1 — 2020 — — 2021 — — 2022 — — Thereafter 382 382 Total $ 383 $ 382
Schedule Of Long-Term Debt	December 31, (In millions) 2017 2016 Subordinated notes $ 247 $ 246 Senior notes 135 288 Capital lease obligations 1 1 Total $ 383 $ 535
Schedule Of Subordinated Notes	(Dollar amounts in millions) Subordinated notes Coupon rate Balance Par amount Maturity 5.65% $ 160 $ 162 Nov 2023 6.95% 87 88 Sep 2028 Total $ 247 $ 250
Schedule Of Senior Medium-Term Notes	(Dollar amounts in millions) Senior notes Coupon rate Balance Par amount Maturity 4.50% $ 135 $ 136 June 2023
Debt Redemptions and Repurchases	(Dollar amounts in millions) Note type Par amount Trust preferred: 3mL+2.85% (3.38%) $ 51 3mL+1.90% (2.22%) 36 3mL+1.78% (2.29%) 62 3mL+3.15% (3.75%) 8 3mL+2.89% (3.42%) 8 Total trust preferred 165 Senior notes: 3.60% 11 4.00% 89 Total senior notes 100 Total $ 265

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Summary Of Preferred Stock	Preferred stock is summarized as follows: Shares at (Dollar amounts in millions) Carrying value at Authorized Outstanding Dividends payable Earliest redemption date Rate following earliest redemption date Dividends payable after rate change 2017 2016 (thousands) (thousands) Rate (when applicable) Series A $ 67 $ 67 140,000 66,139 > of 4.0% or 3mL+0.52% Qtrly Mar,Jun,Sep,Dec Dec 15, 2011 Series F — 144 — — 7.9% Qtrly Mar,Jun,Sep,Dec Jun 15, 2017 Series G 138 138 200,000 138,391 6.3% Qtrly Mar,Jun,Sep,Dec Mar 15, 2023 annual float-ing rate = 3mL+4.24% Series H 126 126 126,221 126,221 5.75% Qtrly Mar,Jun,Sep,Dec Jun 15, 2019 Series I 99 99 300,893 98,555 5.8% Semi-annually Jun,Dec Jun 15, 2023 annual float-ing rate = 3mL+3.8% Qtrly Mar,Jun,Sep,Dec Series J 136 136 195,152 136,368 7.2% Semi-annually Mar,Sep Sep 15, 2023 annual float-ing rate = 3mL+4.44% Qtrly Mar,Jun,Sep,Dec Total $ 566 $ 710
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Statement of Income (SI) Balance Sheet (BS) (In millions) Amounts reclassified from AOCI 1 Details about AOCI components 2017 2016 2015 Affected line item Net realized gains (losses) on investment securities $ — $ — $ (139 ) SI Securities losses, net Income tax expense (benefit) — — (53 ) $ — $ — $ (86 ) Net unrealized gains on derivative instruments $ 4 $ 11 $ 9 SI Interest and fees on loans Income tax expense 2 4 3 $ 2 $ 7 $ 6 Amortization of net actuarial loss $ (7 ) $ (8 ) $ (6 ) SI Salaries and employee benefits Income tax benefit (3 ) (3 ) (2 ) $ (4 ) $ (5 ) $ (4 ) 1 Negative reclassification amounts indicate decreases to earnings in the statement of income and increases to balance sheet assets. The opposite applies to positive reclassification amounts.
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	Changes in AOCI by component are as follows: (In millions) Net unrealized gains (losses) on investment securities Net unrealized gains (losses) on derivatives and other Pension and post-retirement Total 2017 Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Other comprehensive income (loss) before reclassifications, net of tax (2 ) (1 ) 9 6 Amounts reclassified from AOCI, net of tax — (2 ) 4 2 Effect of new tax rates from Tax Cuts and Jobs Act of 2017 (20 ) (1 ) (4 ) (25 ) Other comprehensive income (loss) (22 ) (4 ) 9 (17 ) Balance at December 31, 2017 $ (114 ) $ (3 ) $ (22 ) $ (139 ) Income tax expense (benefit) included in other comprehensive income (loss) $ 19 $ (1 ) $ 11 $ 29 2016 Balance at December 31, 2015 $ (18 ) $ 1 $ (38 ) $ (55 ) Other comprehensive income (loss) before reclassifications, net of tax (74 ) 7 2 (65 ) Amounts reclassified from AOCI, net of tax — (7 ) 5 (2 ) Other comprehensive income (loss) (74 ) — 7 (67 ) Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Income tax expense (benefit) included in other comprehensive income (loss) $ (45 ) $ — $ 5 $ (40 )
Shareholders' Equity	13. SHAREHOLDERS’ EQUITY Preferred Stock Preferred stock is without par value and has a liquidation preference of $1,000 per share, or $25 per depositary share. Except for Series I and J, all preferred shares were issued in the form of depositary shares, with each depositary share representing a 1/40 th ownership interest in a share of the preferred stock. All preferred shares are registered with the SEC. In general, preferred shareholders may receive asset distributions before common shareholders; however, preferred shareholders have only limited voting rights generally with respect to certain provisions of the preferred stock, the issuance of senior preferred stock, and the election of directors. Preferred stock dividends reduce earnings applicable to common shareholders and are paid on the 15th day of the months indicated in the following schedule. Dividends are approved by the Board of Directors and are subject to regulatory non-objection to a stress test and capital plan submitted to the Federal Reserve pursuant to the annual Horizontal Capital Review, also referred to as Comprehensive Capital Analysis and Review (“HCR/CCAR”) process. Redemption of the preferred stock is at the Company’s option after the expiration of any applicable redemption restrictions. The redemption amount is computed at the per share liquidation preference plus any declared but unpaid dividends. Redemptions are subject to certain regulatory provisions, including the previously noted capital plan non-objection for a submitted capital plan in a given year. Preferred stock is summarized as follows: Shares at (Dollar amounts in millions) Carrying value at Authorized Outstanding Dividends payable Earliest redemption date Rate following earliest redemption date Dividends payable after rate change 2017 2016 (thousands) (thousands) Rate (when applicable) Series A $ 67 $ 67 140,000 66,139 > of 4.0% or 3mL+0.52% Qtrly Mar,Jun,Sep,Dec Dec 15, 2011 Series F — 144 — — 7.9% Qtrly Mar,Jun,Sep,Dec Jun 15, 2017 Series G 138 138 200,000 138,391 6.3% Qtrly Mar,Jun,Sep,Dec Mar 15, 2023 annual float-ing rate = 3mL+4.24% Series H 126 126 126,221 126,221 5.75% Qtrly Mar,Jun,Sep,Dec Jun 15, 2019 Series I 99 99 300,893 98,555 5.8% Semi-annually Jun,Dec Jun 15, 2023 annual float-ing rate = 3mL+3.8% Qtrly Mar,Jun,Sep,Dec Series J 136 136 195,152 136,368 7.2% Semi-annually Mar,Sep Sep 15, 2023 annual float-ing rate = 3mL+4.44% Qtrly Mar,Jun,Sep,Dec Total $ 566 $ 710 Preferred Stock Redemptions During 2017, we redeemed all outstanding shares of our 7.9% Series F preferred stock for a cash payment of approximately $144 million . The total reduction to net earnings applicable to common shareholders associated with the preferred stock redemption was $2 million due to the accelerated recognition of preferred stock issuance costs. During 2016 , we launched a cash tender offer to purchase up to $120 million par amount of certain outstanding preferred stock. Our preferred stock decreased by $118 million as a result of the tender offer, including the purchase of $26 million of our Series I preferred stock, $59 million of our Series J preferred stock, and $33 million of our Series G preferred stock for an aggregate cash payment of $126 million . The total reduction to net earnings applicable to common shareholders associated with the preferred stock redemption was $10 million . The size and terms of the redemptions in 2017 and 2016 were determined in accordance with the Company’s 2016 and 2015 capital plans. These preferred stock redemptions benefit the Company by decreasing the amount of preferred dividends paid. Common Stock The Company’s common stock is traded on the NASDAQ Global Select Market. As of December 31, 2017, there were 198 million shares of no par common stock outstanding. The Company continued its common stock repurchase program during 2017 and repurchased 7 million shares of common shares outstanding with a fair value of $320 million at an average price of $45.66 per share. During the first quarter of 2018, the Company repurchased an additional 2 million shares of common stock outstanding with a fair value of $115 million at an average price of $53.46 per share, leaving $120 million of repurchase capacity remaining in the 2017 capital plan (which spans the timeframe of July 2017 to June 2018). During 2016 the Company repurchased 3 million shares of common shares outstanding with a fair value of $90 million at an average price of $31.15 per share. Common Stock Warrants As of December 31, 2017, 29.3 million common stock warrants with an exercise price of $35.37 were outstanding. These warrants expire on May 22, 2020. In addition, as of December 31, 2017, 5.8 million common stock warrants with an exercise price of $36.27 per share were outstanding. These warrants expire on November 14, 2018 and were associated with the preferred stock issued under the Troubled Asset Relief Program which was redeemed in 2012. Between January 1, 2018 and February 20, 2018, 1.0 million shares of common stock were issued from the cashless exercise of 3.2 million common stock warrants which expire on November 14, 2018. After these common stock warrant exercises, 29.3 million and 2.6 million common stock warrants, which expire on May 22, 2020 and November 14, 2018, respectively, remain outstanding. Accumulated Other Comprehensive Income During 2017, $25 million was reclassified from AOCI to retained earnings as a result of the decreased corporate income tax rate from the Tax Cuts and Jobs Act of 2017. Changes in AOCI by component are as follows: (In millions) Net unrealized gains (losses) on investment securities Net unrealized gains (losses) on derivatives and other Pension and post-retirement Total 2017 Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Other comprehensive income (loss) before reclassifications, net of tax (2 ) (1 ) 9 6 Amounts reclassified from AOCI, net of tax — (2 ) 4 2 Effect of new tax rates from Tax Cuts and Jobs Act of 2017 (20 ) (1 ) (4 ) (25 ) Other comprehensive income (loss) (22 ) (4 ) 9 (17 ) Balance at December 31, 2017 $ (114 ) $ (3 ) $ (22 ) $ (139 ) Income tax expense (benefit) included in other comprehensive income (loss) $ 19 $ (1 ) $ 11 $ 29 2016 Balance at December 31, 2015 $ (18 ) $ 1 $ (38 ) $ (55 ) Other comprehensive income (loss) before reclassifications, net of tax (74 ) 7 2 (65 ) Amounts reclassified from AOCI, net of tax — (7 ) 5 (2 ) Other comprehensive income (loss) (74 ) — 7 (67 ) Balance at December 31, 2016 $ (92 ) $ 1 $ (31 ) $ (122 ) Income tax expense (benefit) included in other comprehensive income (loss) $ (45 ) $ — $ 5 $ (40 ) Statement of Income (SI) Balance Sheet (BS) (In millions) Amounts reclassified from AOCI 1 Details about AOCI components 2017 2016 2015 Affected line item Net realized gains (losses) on investment securities $ — $ — $ (139 ) SI Securities losses, net Income tax expense (benefit) — — (53 ) $ — $ — $ (86 ) Net unrealized gains on derivative instruments $ 4 $ 11 $ 9 SI Interest and fees on loans Income tax expense 2 4 3 $ 2 $ 7 $ 6 Amortization of net actuarial loss $ (7 ) $ (8 ) $ (6 ) SI Salaries and employee benefits Income tax benefit (3 ) (3 ) (2 ) $ (4 ) $ (5 ) $ (4 ) 1 Negative reclassification amounts indicate decreases to earnings in the statement of income and increases to balance sheet assets. The opposite applies to positive reclassification amounts. Deferred Compensation Deferred compensation consists of invested assets, including the Company’s common stock, which are held in rabbi trusts for certain employees and directors. At both December 31, 2017 and 2016 , the cost of the common stock included in retained earnings was approximately $14 million . We consolidate the fair value trust invested assets along with the total obligations and include them in other assets and other liabilities, respectively, in the balance sheet. At December 31, 2017 and 2016 , total invested assets were approximately $102 million and $91 million and total obligations were approximately $116 million and $105 million , respectively.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2017
Regulatory Capital Requirements [Abstract]
Summary Of Actual Capital Amounts And Ratios For The Company And Its Three Largest Subsidiary Banks	(Dollar amounts in millions) December 31, 2017 To be well-capitalized Amount Ratio Amount Ratio Transitional Basis Basel III Regulatory Capital Rules Total capital (to risk-weighted assets) The Company $ 7,628 14.8 % $ 5,146 10.0 % ZB, National Association 7,306 14.2 5,130 10.0 Tier 1 capital (to risk-weighted assets) The Company 6,805 13.2 4,116 8.0 ZB, National Association 6,730 13.1 4,104 8.0 Common equity tier 1 capital (to risk-weighted assets) The Company 6,239 12.1 3,345 6.5 ZB, National Association 5,899 11.5 3,334 6.5 Tier 1 capital (to average assets) The Company 6,805 10.5 na na 1 ZB, National Association 6,730 10.4 3,227 5.0 December 31, 2016 To be well-capitalized (Dollar amounts in millions) Amount Ratio Amount Ratio Transitional Basis Basel III Regulatory Capital Rules Total capital (to risk-weighted assets) The Company $ 7,609 15.2 % $ 4,994 10.0 % ZB, National Association 7,278 14.6 4,983 10.0 Tier 1 capital (to risk-weighted assets) The Company 6,738 13.5 3,995 8.0 ZB, National Association 6,655 13.4 3,986 8.0 Common equity tier 1 capital (to risk-weighted assets) The Company 6,028 12.1 3,246 6.5 ZB, National Association 5,824 11.7 3,239 6.5 Tier 1 capital (to average assets) The Company 6,738 11.1 na na 1 ZB, National Association 6,655 11.0 3,027 5.0 1 There is no Tier 1 leverage ratio component in the definition of a well-capitalized bank holding company .

Commitments, Guarantees, Cont42

Commitments, Guarantees, Contingent Liabilities, and Related Parties Operating Leases, Future Aggregate Minimum Rental Payments (Tables) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Operating Leased Assets [Line Items]
Summary of Unfunded Commitments and Redemption [Table Text Block]	December 31, (In millions) 2017 2016 Net unfunded commitments to extend credit 1 $ 19,583 $ 18,274 Standby letters of credit: Financial 721 771 Performance 196 196 Commercial letters of credit 31 60 Total unfunded lending commitments $ 20,531 $ 19,301
Operating Leases, Future Minimum Payments Due	$ 245
Operating Leases, Future Minimum Payments Due, Next Twelve Months	40
Operating Leases, Future Minimum Payments, Due in Two Years	39
Operating Leases, Future Minimum Payments, Due in Three Years	36
Operating Leases, Future Minimum Payments, Due in Four Years	29
Operating Leases, Future Minimum Payments, Due in Five Years	25
Operating Leases, Future Minimum Payments, Due Thereafter	$ 76

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Defined Benefit Plan [Abstract]
Retirement Plans, Unfunded Commitments and Redemption [Table Text Block]	Investment Unfunded commitments (in millions, approximately) Redemption Frequency Notice period Pooled separate accounts na Daily < $1 million, 1 day >= $1 million, 3 days Limited partnerships $ 1 Investments in these limited partnerships are illiquid and voluntary withdrawal is prohibited.
Schedule Of Amounts In Accumulated Other Comprehensive Income (Loss) Expected To Be Recognized As An Expense Component Of Net Periodic Benefit Cost For The Plans	(In millions) Pension Supplemental Postretirement Net loss $ (2 ) $ — $ —
Schedule Of Weighted Average Assumptions Based On The Pension Plan	2017 2016 2015 Used to determine benefit obligation at year-end: Discount rate 3.50 % 4.10 % 4.20 % Used to determine net periodic benefit cost for the years ended December 31: Discount rate 4.10 4.20 3.95 Expected long-term return on plan assets 7.25 7.50 7.50

Retirement Plans Weighted avera

Retirement Plans Weighted average assumptions on pension plan (Tables)	12 Months Ended
	Dec. 31, 2017
Weighted average assumptions on pension plan [Abstract]
Schedule Of Weighted Average Assumptions Based On The Pension Plan	2017 2016 2015 Used to determine benefit obligation at year-end: Discount rate 3.50 % 4.10 % 4.20 % Used to determine net periodic benefit cost for the years ended December 31: Discount rate 4.10 4.20 3.95 Expected long-term return on plan assets 7.25 7.50 7.50

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Compensation Expense And Related Tax Benefit For All Share-Based Awards	(In millions) 2017 2016 2015 Compensation expense $ 25 $ 26 $ 25 Reduction of income tax expense 19 9 8
Summary Of Stock Option Activity	Number of shares Weighted average exercise price Balance at December 31, 2014 5,630,502 $ 31.60 Granted 740,300 29.01 Exercised (1,165,287 ) 25.11 Expired (1,322,067 ) 48.44 Forfeited (79,353 ) 28.09 Balance at December 31, 2015 3,804,095 27.30 Granted 789,651 21.25 Exercised (1,055,532 ) 23.75 Expired (56,297 ) 61.60 Forfeited (44,007 ) 27.66 Balance at December 31, 2016 3,437,910 26.44 Granted 195,882 44.18 Exercised (941,761 ) 26.03 Expired (58,257 ) 66.20 Forfeited (73,203 ) 25.63 Balance at December 31, 2017 2,560,571 27.06 Outstanding stock options exercisable as of: December 31, 2017 1,648,367 $ 26.55 December 31, 2016 1,892,136 27.60 December 31, 2015 2,187,259 26.35

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Schedule Of Income Taxes (Benefit)	(In millions) 2017 2016 2015 Federal: Current $ 166 $ 217 $ 158 Deferred 146 (4 ) (32 ) Total Federal 312 213 126 State: Current 24 27 14 Deferred 8 (4 ) 2 Total State 32 23 16 Total $ 344 $ 236 $ 142
Schedule Of Statutory Federal Income Tax Rate Reconciles To Actual Income Tax Expense (Benefit)	(In millions) 2017 2016 2015 Income tax expense at statutory federal rate $ 327 $ 247 $ 158 State income taxes including credits, net 21 15 10 Other nondeductible expenses 3 3 3 Nontaxable income (33 ) (25 ) (20 ) Share-based compensation (8 ) — — Tax credits and other taxes 1 (2 ) (3 ) Tax Cuts and Jobs Act of 2017 47 — — Other (14 ) (2 ) (6 ) Total $ 344 $ 236 $ 142
Schedule Of Tax Effects Of Deferred Tax Assets And Deferred Tax Liabilities	(In millions) December 31, 2017 2016 Gross deferred tax assets: Book loan loss deduction in excess of tax $ 143 $ 241 Pension and postretirement 8 19 Deferred compensation 48 87 Security investments and derivative fair value adjustments 40 57 Net operating losses, capital losses and tax credits 2 5 FDIC-supported transactions 2 5 Other 34 46 277 460 Valuation allowance (2 ) (4 ) Total deferred tax assets 275 456 Gross deferred tax liabilities: Core deposits and purchase accounting — (1 ) Premises and equipment, due to differences in depreciation (51 ) (8 ) Federal Home Loan Bank stock dividends (3 ) (4 ) Leasing operations (52 ) (75 ) Prepaid expenses (5 ) (7 ) Prepaid pension reserves (11 ) (17 ) Mortgage servicing (7 ) (10 ) Subordinated debt modification (9 ) (31 ) Deferred loan fees (23 ) (25 ) Equity investments (21 ) (28 ) Total deferred tax liabilities (182 ) (206 ) Net deferred tax assets $ 93 $ 250
Schedule Of Reconciliation Of Gross Unrecognized Tax Benefits	(In millions) 2017 2016 2015 Balance at beginning of year $ 4 $ 5 $ 3 Tax positions related to current year: Additions 1 1 1 Reductions — — — Tax positions related to prior years: Additions 1 1 1 Reductions — — — Settlements with taxing authorities — — — Lapses in statutes of limitations — (3 ) — Balance at end of year $ 6 $ 4 $ 5

Operating Segment Information O

Operating Segment Information Operating Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Operating Segment Information [Abstract]
Schedule of Segment Reporting Information, by Segment	(In millions) Zions Bank Amegy CB&T 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 650 $ 624 $ 544 $ 483 $ 460 $ 387 $ 476 $ 434 $ 377 Provision for loan losses 19 (22 ) (28 ) 25 163 91 (5 ) (9 ) (4 ) Net interest income after provision for loan losses 631 646 572 458 297 296 481 443 381 Noninterest income 151 149 133 118 123 121 75 67 63 Noninterest expense 436 424 430 336 326 373 299 290 294 Income before income taxes $ 346 $ 371 $ 275 $ 240 $ 94 $ 44 $ 257 $ 220 $ 150 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 12,481 $ 12,538 $ 12,118 $ 11,021 $ 10,595 $ 10,148 $ 9,539 $ 9,211 $ 8,556 Total average deposits 15,986 15,991 15,688 11,096 11,130 11,495 11,030 10,827 10,063 (In millions) NBAZ NSB Vectra 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 206 $ 190 $ 152 $ 134 $ 122 $ 94 $ 126 $ 120 $ 101 Provision for loan losses (8 ) (3 ) 8 (11 ) (28 ) (28 ) 1 (8 ) 5 Net interest income after provision for loan losses 214 193 144 145 150 122 125 128 96 Noninterest income 40 40 36 40 39 36 25 23 21 Noninterest expense 148 144 133 139 137 131 101 97 98 Income before income taxes $ 106 $ 89 $ 47 $ 46 $ 52 $ 27 $ 49 $ 54 $ 19 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 4,267 $ 4,086 $ 3,811 $ 2,357 $ 2,284 $ 2,344 $ 2,644 $ 2,469 $ 2,400 Total average deposits 4,762 4,576 4,311 4,254 4,137 3,891 2,756 2,720 2,792 (In millions) TCBW Other Consolidated Company 2017 2016 2015 2017 2016 2015 2017 2016 2015 SELECTED INCOME STATEMENT DATA Net interest income $ 46 $ 38 $ 28 $ (56 ) $ (121 ) $ 32 $ 2,065 $ 1,867 $ 1,715 Provision for loan losses 2 — (3 ) 1 — (1 ) 24 93 40 Net interest income after provision for loan losses 44 38 31 (57 ) (121 ) 33 2,041 1,774 1,675 Noninterest income 5 5 4 90 70 (57 ) 544 516 357 Noninterest expense 20 19 17 170 148 105 1,649 1,585 1,581 Income (loss) before income taxes $ 29 $ 24 $ 18 $ (137 ) $ (199 ) $ (129 ) $ 936 $ 705 $ 451 SELECTED AVERAGE BALANCE SHEET DATA Total average loans $ 926 $ 791 $ 707 $ 266 $ 88 $ 87 $ 43,501 $ 42,062 $ 40,171 Total average deposits 1,107 1,007 879 1,209 207 (481 ) 52,200 50,595 48,638

Parent Company Financial Info48

Parent Company Financial Information (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Quarterly Financial Information [Table Text Block]	(In millions, except per share amounts) Quarters First Second Third Fourth Year 2017 Gross interest income $ 515 $ 558 $ 557 $ 562 $ 2,192 Net interest income 489 528 522 526 2,065 Provision for loan losses 23 7 5 (11 ) 24 Noninterest income 132 132 140 140 544 Noninterest expense 414 405 413 417 1,649 Income before income taxes 184 248 244 260 936 Net income 139 168 161 124 592 Preferred stock dividends (10 ) (12 ) (8 ) (10 ) (40 ) Preferred stock redemption — (2 ) — — (2 ) Net earnings applicable to common shareholders 129 154 153 114 550 Net earnings per common share: Basic 0.63 0.76 0.75 0.57 2.71 Diluted 0.61 0.73 0.72 0.54 2.60 2016 Gross interest income $ 475 $ 487 $ 491 $ 501 $ 1,954 Net interest income 453 465 469 480 1,867 Provision for loan losses 42 35 19 (3 ) 93 Noninterest income 117 126 145 128 516 Noninterest expense 396 382 403 404 1,585 Income before income taxes 132 174 192 207 705 Net income 91 114 127 137 469 Preferred stock dividends (12 ) (14 ) (10 ) (12 ) (48 ) Preferred stock redemption — (10 ) — — (10 ) Net earnings applicable to common shareholders 79 90 117 125 411 Net earnings per common share: Basic 0.38 0.44 0.57 0.61 2.00 Diluted 0.38 0.44 0.57 0.60 1.99
Condensed Balance Sheets	(In millions) December 31, 2017 2016 ASSETS Cash and due from banks $ — $ 2 Interest-bearing deposits 332 529 Investment securities: Available-for-sale, at fair value 30 40 Other noninterest-bearing investments 36 29 Investments in subsidiaries: Commercial bank 7,620 7,570 Other subsidiaries 41 6 Other assets 32 81 Total assets $ 8,091 $ 8,257 LIABILITIES AND SHAREHOLDERS’ EQUITY Other liabilities $ 30 $ 89 Long-term debt: Due to others 382 534 Total liabilities 412 623 Shareholders’ equity: Preferred stock 566 710 Common stock 4,445 4,725 Retained earnings 2,807 2,321 Accumulated other comprehensive income (loss) (139 ) (122 ) Total shareholders’ equity 7,679 7,634 Total liabilities and shareholders’ equity $ 8,091 $ 8,257
Condensed Statements Of Income	(In millions) Year Ended December 31, 2017 2016 2015 Interest income: Commercial bank $ — $ 1 $ 1 Other loans and securities 1 2 3 Total interest income 1 3 4 Interest expense: Affiliated trusts — 3 4 Other borrowed funds 25 34 64 Total interest expense 25 37 68 Net interest loss (24 ) (34 ) (64 ) Other income: Dividends from consolidated subsidiaries: Commercial bank 587 263 234 Securities gains, net — — 37 Other income 7 4 13 Total other income 594 267 284 Expenses: Salaries and employee benefits 24 23 25 Other operating expenses 8 (14 ) 10 Total expenses 32 9 35 Income before income taxes and undistributed income of consolidated subsidiaries 538 224 185 Income tax benefit (42 ) (19 ) (27 ) Income before equity in undistributed income of consolidated subsidiaries 580 243 212 Equity in undistributed income (loss) of consolidated subsidiaries: Commercial bank 12 230 108 Other subsidiaries — (4 ) (11 ) Net income 592 469 309 Preferred stock dividends (40 ) (48 ) (62 ) Preferred stock redemption (2 ) (10 ) — Net earnings applicable to common shareholders $ 550 $ 411 $ 247
Condensed Statements Of Cash Flows	(In millions) Year Ended December 31, 2017 2016 2015 CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 592 $ 469 $ 309 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed income of consolidated subsidiaries (12 ) (226 ) (97 ) Other, net (56 ) (31 ) 78 Net cash provided by operating activities 524 212 290 CASH FLOWS FROM INVESTING ACTIVITIES Net decrease in money market investments 196 347 132 Collection of advances to subsidiaries — — 56 Advances to subsidiaries — — (41 ) Proceeds from sales and maturities of investment securities 20 4 125 Purchases of investment securities — — (47 ) Decrease of investment in subsidiaries — — 15 Other, net 2 7 4 Net cash provided by investing activities 218 358 244 CASH FLOWS FROM FINANCING ACTIVITIES Repayments of long-term debt (164 ) (280 ) (271 ) Proceeds from issuance of common stock 25 25 22 Cash paid for preferred stock redemptions (144 ) (126 ) (176 ) Company common stock repurchased (332 ) (97 ) (7 ) Dividends paid on preferred stock (40 ) (50 ) (63 ) Dividends paid on common stock (89 ) (58 ) (45 ) Net cash used in financing activities (744 ) (586 ) (540 ) Net decrease in cash and due from banks (2 ) (16 ) (6 ) Cash and due from banks at beginning of year 2 18 24 Cash and due from banks at end of year $ — $ 2 $ 18

Summary Of Significant Accoun49

Summary Of Significant Accounting Policies (Details) $ in Millions	Dec. 31, 2017USD ($)States	Dec. 31, 2017USD ($)States	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of States in which Entity Operates | States	11	11
Security resell agreements maturity days	30
Customer Securities for which Entity has Right to Sell or Repledge, Fair Value	$ 287	$ 287
Security resell agreements maximum amount, outstanding	$ 1,800	$ 1,800
Percentage of acquired assets and all assumed liabilities recognized in business combination	100.00%
Estimated useful lives of core deposit assets and other intangibles (in years)	12 years
Number of variable interest entities consolidated	0	0	0
Security resell agreements average amount		$ 360
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	25 years
Minimum [Member] | Furniture And Equipment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	3 years
Minimum [Member] | Software License Arrangement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	3 years
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	40 years
Maximum [Member] | Furniture And Equipment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	10 years
Maximum [Member] | Software License Arrangement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives of properties, Minimum (in years)	10 years

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Other noninterest-bearing investments valued under the cost method	$ 10,000,000	$ 13,000,000
Fair value of AFS securities	15,161,000,000	13,372,000,000
Net gains on sale of OREO properties	(1,000,000)	(2,000,000)	$ (1,000,000)
Principal amount of other real estate owned property sold	6,000,000	13,000,000
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	338,000,000	211,000,000
Equity Method Investments, Fair Value Disclosure	36,000,000	38,000,000
OREO Properties [Member]
Derivatives, Fair Value [Line Items]
Net gains on sale of OREO properties	2,000,000	4,000,000
Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	15,065,000,000	13,188,000,000
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	0	$ 0
Third Party Pricing Service [Member] | Level 2 [Member]
Derivatives, Fair Value [Line Items]
Fair value of AFS securities	$ 0.92

Fair Value (Schedule Of Assets

Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	$ 15,161	$ 13,372
Trading account, at fair value	148	115
Total assets	16,069	14,250
Securities sold, not yet purchased	95	25
Financial and Nonfinancial Liabilities, Fair Value Disclosure	237	175
Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	72	185
Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	507	497
Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	95	91
Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	18	20
Warranty, Rights and Obligations, Fair Value Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	102	91
Other liabilities	102	91
Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	13,731	12,009
Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	1,334	1,154
Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	24	24
Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	38	64
Other liabilities	40
Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	1	4
Other liabilities		1
Derivatives [Member] | Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	28	49
Other liabilities	33	49
Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	9	11
Other liabilities	7	9
Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		59
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	96	184
Other assets		91
Total assets	207	304
Securities sold, not yet purchased	95	25
Financial and Nonfinancial Liabilities, Fair Value Disclosure	204	125
Level 1 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	71	184
Level 1 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments		18
Level 1 [Member] | Warranty, Rights and Obligations, Fair Value Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	102
Other liabilities	102	91
Level 1 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	25	0
Level 1 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	9	11
Other liabilities	7
Level 1 [Member] | Derivatives [Member] | Foreign Currency Exchange Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	9	11
Other liabilities	7	9
Level 1 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		9
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	15,065	13,188
Trading account, at fair value	148	115
Total assets	15,749	13,853
Securities sold, not yet purchased	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	33	50
Level 2 [Member] | Mutual Funds And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	1	1
Level 2 [Member] | Bank-owned life insurance [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	507	497
Level 2 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments
Level 2 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	13,706	12,009
Level 2 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	1,334	1,154
Level 2 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	24	24
Level 2 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	29	53
Other liabilities	33
Level 2 [Member] | Derivatives [Member] | Interest Rate Related And Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	1
Other liabilities		1
Level 2 [Member] | Derivatives [Member] | Interest Rate Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets		4
Level 2 [Member] | Derivatives [Member] | Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets		49
Other liabilities		49
Level 2 [Member] | Derivatives [Member] | Interest Rate Swaps For Customers [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	28
Other liabilities	33
Level 2 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		50
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0	0
Total assets	113	93
Securities sold, not yet purchased	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Private Equity [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other noninterest-bearing investments	95	73
Fair Value, Inputs, Level 3 [Member] | Interest-Only-Strip [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	18	20
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member] | U.S. Treasury, Agencies And Corporations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	0	0
Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member] | Municipal Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities
Fair Value, Inputs, Level 3 [Member] | Asset-Backed Securities [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities
Fair Value, Inputs, Level 3 [Member] | Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets	0	0
Other liabilities	$ 0
Fair Value, Inputs, Level 3 [Member] | Derivatives [Member] | Total Return Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities		$ 0

Fair Value (Schedule Of Asset52

Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis Using Level 3 Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Instruments, Gain (Loss) [Table Text Block]	Year Ended December 31, 2017 Year Ended December 31, 2016 Amount of derivative gain (loss) recognized/reclassified (In millions) OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense OCI Reclassified from AOCI to interest income Noninterest income (expense) Offset to interest expense Derivatives designated as hedging instruments Cash flow hedges: 1 Interest rate swaps $ (8 ) $ 4 $ 8 $ 11 Derivatives not designated as hedging instruments Interest rate swaps $ (1 ) $ 1 Interest rate swaps for customers 11 14 Foreign exchange 17 11 Total derivatives $ (8 ) $ 4 $ 27 $ — $ 8 $ 11 $ 26 $ — Note: These schedules are not intended to present at any given time the Company’s long/short position with respect to its derivative contracts. 1 Amounts recognized in OCI and reclassified from AOCI represent the effective portion of the derivative gain (loss). For the 12 months following December 31, 2017 , we estimate that $1 million will be reclassified from AOCI into interest income.
Total net gains (losses) included in, Other noninterest expense	$ 223	$ 213	$ 225
Servicing Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	20	14
Total net gains (losses) included in, Equity securities gains, net	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Noninterest Income	(1)	6
Total net gains (losses) included in, Purchases	0	0
Total net gains (losses) included in, Redemptions and paydowns	1	0
Fair value of assets, Ending balance	18	20	14
Private Equity Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	73	58
Total net gains (losses) included in, Equity securities gains, net	7	6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Noninterest Income	0	0
Total net gains (losses) included in, Purchases	20	10
Total net gains (losses) included in, Redemptions and paydowns	5	1
Fair value of assets, Ending balance	$ 95	$ 73	$ 58

Fair Value (Schedule Of Realize

Fair Value (Schedule Of Realized Gains (Losses) Using Level 3 Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Level 3 Equity securities gains (losses), net [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Realized gains (losses) from Level 3 inputs		$ 6
Fixed Income Securities Gains (Losses), Net [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Realized gains (losses) from Level 3 inputs	$ 3

Fair Value (Schedule Of Asset54

Fair Value (Schedule Of Assets With Fair Value Changes On Nonrecurring Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal amount of other real estate owned property sold	$ 6	$ 13
Impaired Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	9	52
Gains (losses) from fair value changes	(5)	(36)
Private equity investments, carried at cost [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	1	1
Gains (losses) from fair value changes	(1)	(1)
Other Real Estate Owned [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	1
Gains (losses) from fair value changes	0	(2)
Nonrecurring Fair Value Measurements Asset Totals [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	10	54
Total gains (losses) from fair value changes measured on nonrecurring basis [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gains (losses) from fair value changes	(6)	(39)
Level 1 [Member] | Impaired Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Level 1 [Member] | Private equity investments, carried at cost [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Level 1 [Member] | Other Real Estate Owned [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Level 1 [Member] | Nonrecurring Fair Value Measurements Asset Totals [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Level 2 [Member] | Impaired Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	9	52
Level 2 [Member] | Private equity investments, carried at cost [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Level 2 [Member] | Other Real Estate Owned [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	1
Level 2 [Member] | Nonrecurring Fair Value Measurements Asset Totals [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	9	53
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Fair Value, Inputs, Level 3 [Member] | Private equity investments, carried at cost [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	1	1
Fair Value, Inputs, Level 3 [Member] | Other Real Estate Owned [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	0	0
Fair Value, Inputs, Level 3 [Member] | Nonrecurring Fair Value Measurements Asset Totals [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets measured on nonrecurring basis	$ 1	$ 1

Fair Value (Schedule Of Carryin

Fair Value (Schedule Of Carrying Values And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity, fair value	$ 762
Loans and Leases Receivable, Net Amount	44,262	$ 42,082
Time deposits	3,115	2,757
Long-term debt (less fair value hedges)	383	535
Carrying Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Loans and Leases Receivable, Net Amount		42,254
Other Short-term Borrowings		500
Long-term debt (less fair value hedges)		535
Estimated Fair Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Loans and Leases Receivable, Net Amount		42,111
Time deposits		2,744
Other Short-term Borrowings		500
Long-term debt (less fair value hedges)		552
Fair Value, Inputs, Level 2 [Member] | Carrying Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity Securities	770	868
Time deposits	3,115
Other Short-term Borrowings	3,600
Long-term debt (less fair value hedges)	383
Fair Value, Inputs, Level 2 [Member] | Estimated Fair Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity, fair value	762	$ 850
Time deposits	3,099
Other Short-term Borrowings	3,600
Long-term debt (less fair value hedges)	402
Fair Value, Inputs, Level 3 [Member] | Carrying Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Loans and Leases Receivable, Net Amount	44,306
Fair Value, Inputs, Level 3 [Member] | Estimated Fair Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Loans and Leases Receivable, Net Amount	$ 44,226

Offsetting Assets and Liabili56

Offsetting Assets and Liabilities Cash and Money Market Investments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets [Member] | Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	$ 809	$ 568
Gross amounts offset in the balance sheet	(295)	0
Net amounts presented in the balance sheet	514	568
Gross amounts not offset in the balance sheet	0	0
Cash Collateral Received/Pledged	0	0
Net amount	514	568
Assets [Member] | Derivative Financial Instruments, Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	38	64
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	38	64
Gross amounts not offset in the balance sheet	(21)	(17)
Cash Collateral Received/Pledged	(1)	0
Net amount	16	47
Assets [Member] | Assets, Total [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	847	632
Gross amounts offset in the balance sheet	(295)	0
Net amounts presented in the balance sheet	552	632
Gross amounts not offset in the balance sheet	(21)	(17)
Cash Collateral Received/Pledged	(1)	0
Net amount	530	615
Other Liabilities [Member] | Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	5,271	827
Gross amounts offset in the balance sheet	(295)	0
Net amounts presented in the balance sheet	4,976	827
Gross amounts not offset in the balance sheet	0	0
Cash Collateral Received/Pledged	0	0
Net amount	4,976	827
Other Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	40	59
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	40	59
Gross amounts not offset in the balance sheet	(21)	(17)
Cash Collateral Received/Pledged	(6)	(17)
Net amount	13	25
Other Liabilities [Member] | Liabilities, Total [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	5,311	886
Gross amounts offset in the balance sheet	(295)	0
Net amounts presented in the balance sheet	5,016	886
Gross amounts not offset in the balance sheet	(21)	(17)
Cash Collateral Received/Pledged	(6)	(17)
Net amount	$ 4,989	$ 852

Investment Securities (Narrativ

Investment Securities (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)Securities	Dec. 31, 2016USD ($)Securities	Dec. 31, 2015USD ($)
Investment [Line Items]
Interest on securities	$ 326	$ 204	$ 124
Number of HTM investment securities in an unrealized loss position | Securities	667	642
Number of AFS investment securities in an unrealized loss position | Securities	2,262	2,398
Carrying value of pledged securities	$ 2,100	$ 1,400
Available-for-sale Securities, Amortized Cost Basis	15,313	$ 13,521
Private equity investments prohibited by Volker rule	3
Commitments for Private Equity and Other Noninterest-bearing Investments	31
Private Equity Investments	141
Commitments for Private Equity or Other Non-Interest Bearing Investments Prohibited by the Volcker Rule	$ 4

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Held-to-maturity, fair value	$ 762
Available-for-sale debt securities, Amortized cost	15,241	$ 13,337
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	29	18
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	181	167
Available-for-sale debt securities, Estimated fair value	15,089	13,188
Available-for-sale, at fair value	15,161	13,372
Available-for-sale Securities, Amortized Cost Basis	15,313	13,521
Available-for-sale, Gross unrealized gains, Recognized in OCI	29	18
Available-for-sale, Gross unrealized losses, Recognized in OCI	181	167
amortized cost of investment securities	16,083	14,389
Gross Unrealized Gains of Investment Securities Recognized in OCI	34	23
Gross Unrealized Losses of Investment Securities Recognized in OCI	194	190
Estimated Fair Value of Investment Securities	15,923	14,222
Municipal Securities [Member]
Investment [Line Items]
Held-to-maturity, fair value	762	850
Held-to-maturity, Amortized cost	770	868
Available-for-sale debt securities, Amortized cost	1,336	1,182
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	9	1
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	11	29
Available-for-sale debt securities, Estimated fair value	1,334	1,154
Held-to-maturity Securities, Unrecognized Holding Gain	5	5
Held-to-maturity Securities, Unrecognized Holding Loss	13	23
US Treasury Securities [Member]
Investment [Line Items]
Available-for-sale debt securities, Amortized cost	25	0
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	0	0
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	0	0
Available-for-sale debt securities, Estimated fair value	25	0
Available-for-sale, Other debt securities [Member]
Investment [Line Items]
Available-for-sale debt securities, Amortized cost	25	25
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	0	0
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	1	1
Available-for-sale debt securities, Estimated fair value	24	24
Agency Securities [Member]
Investment [Line Items]
Available-for-sale debt securities, Amortized cost	1,830	1,846
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	1	2
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	13	9
Available-for-sale debt securities, Estimated fair value	1,818	1,839
Agency Guaranteed Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale debt securities, Amortized cost	9,798	7,986
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	9	7
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	141	110
Available-for-sale debt securities, Estimated fair value	9,666	7,883
Small Business Administration Loan-Backed Securities [Member]
Investment [Line Items]
Available-for-sale debt securities, Amortized cost	2,227	2,298
Available-for-sale debt securities, Gross unrealized gains, Recognized in OCI	10	8
Available-for-sale debt securities, Gross unrealized losses, Recognized in OCI	15	18
Available-for-sale debt securities, Estimated fair value	2,222	2,288
Mutual Funds And Stock [Member]
Investment [Line Items]
Available-for-sale, at fair value	72	184
Available-for-sale Securities, Amortized Cost Basis	72	184
Available-for-sale, Gross unrealized gains, Recognized in OCI	0	0
Available-for-sale, Gross unrealized losses, Recognized in OCI	$ 0	$ 0

Investment Securities (Contract

Investment Securities (Contractual Maturities Debt Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Investments [Abstract]
Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost	$ 180
Held-to-maturity, Due in one year or less, Estimated fair value	90
Held-to-maturity, Due after one year through five years, Estimated fair value	336
Held-to-maturity, Due after five years through ten years, Estimated fair value	230
Held-to-maturity, Due after ten years, Estimated fair value	106
Held-to-maturity, Amortized cost	770
Held-to-maturity, fair value	762
Available-for-sale, Due in one year or less, Amortized cost	2,499
Available-for-sale, Due in one year or less, Estimated fair value	2,054
Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost	372
Available-for-sale, Due after one year through five years, Amortized cost	5,727
Available-for-sale, Due after one year through five years, Estimated fair value	5,575
Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost	159
Available-for-sale, Due after five years through ten years, Amortized cost	4,331
Available-for-sale, Due after five years through ten years, Estimated fair value	4,485
Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Amortized Cost	59
Available-for-sale, Due after ten years, Amortized cost	2,684
Available-for-sale, Due after ten years, Estimated fair value	2,975
Available-for-sale, Amortized cost	15,241	$ 13,337
Available-for-sale, Estimated fair value	$ 15,089	$ 13,188

Investment Securities (Summar60

Investment Securities (Summary Of Amount Of Gross Unrealized Losses For Debt Securities And Estimated Fair Value) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	$ 44	$ 142
Available-for-sale, Less than 12 months - Estimated fair value	5,379	9,118
Available-for-sale, 12 months or more - Gross unrealized losses	137	25
Available-for-sale, 12 months or more - Estimated fair value	6,422	1,317
Available-for-sale, Total - Gross unrealized losses	181	167
Available-for-sale, Total - Estimated fair value	11,801	10,435
Investment Securities Gross Unrealized Losses Less Than 12 Months	47	157
Investment Securities Estimated Fair Value Less Than 12 Months	5,642	9,585
Investment Securities Gross Unrealized Losses 12 Months or More	147	33
Investment Securities Estimated Fair Value 12 Months or More	6,714	1,378
Investment Securities Gross Unrealized Losses Total	194	190
Investment Securities Estimated Fair Value Total	12,356	10,963
Municipal Securities [Member]
Investment [Line Items]
Held-to-maturity, Less than 12 months - Gross unrealized losses	3	15
Held-to-maturity, Less than 12 months - Estimated fair value	263	467
Held-to-maturity, 12 months or more - Gross unrealized losses	10	8
Held-to-maturity, 12 months or more - Estimated fair value	292	61
Held-to-maturity, Total - Gross unrealized losses	13	23
Held-to-maturity, Total - Estimated fair value	555	528
Available-for-sale, Less than 12 months - Gross unrealized losses	6	28
Available-for-sale, Less than 12 months - Estimated fair value	554	992
Available-for-sale, 12 months or more - Gross unrealized losses	5	0
Available-for-sale, 12 months or more - Estimated fair value	230	9
Available-for-sale, Total - Gross unrealized losses	11	28
Available-for-sale, Total - Estimated fair value	784	1,001
Available-for-sale, Unrealized losses, Other [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	0	0
Available-for-sale, Less than 12 months - Estimated fair value	0	0
Available-for-sale, 12 months or more - Gross unrealized losses	1	2
Available-for-sale, 12 months or more - Estimated fair value	14	14
Available-for-sale, Total - Gross unrealized losses	1	2
Available-for-sale, Total - Estimated fair value	14	14
Agency Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	6	9
Available-for-sale, Less than 12 months - Estimated fair value	808	950
Available-for-sale, 12 months or more - Gross unrealized losses	7	0
Available-for-sale, 12 months or more - Estimated fair value	808	127
Available-for-sale, Total - Gross unrealized losses	13	9
Available-for-sale, Total - Estimated fair value	1,616	1,077
Agency Guaranteed Mortgage-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	29	102
Available-for-sale, Less than 12 months - Estimated fair value	3,609	6,649
Available-for-sale, 12 months or more - Gross unrealized losses	112	7
Available-for-sale, 12 months or more - Estimated fair value	4,721	326
Available-for-sale, Total - Gross unrealized losses	141	109
Available-for-sale, Total - Estimated fair value	8,330	6,975
Small Business Administration Loan-Backed Securities [Member]
Investment [Line Items]
Available-for-sale, Less than 12 months - Gross unrealized losses	3	3
Available-for-sale, Less than 12 months - Estimated fair value	408	527
Available-for-sale, 12 months or more - Gross unrealized losses	12	16
Available-for-sale, 12 months or more - Estimated fair value	649	841
Available-for-sale, Total - Gross unrealized losses	15	19
Available-for-sale, Total - Estimated fair value	$ 1,057	$ 1,368

Investment Securities (Gains An

Investment Securities (Gains And Losses, Including OTTI, Recognized In Statement Of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments [Abstract]
Equity securities gains (losses)	$ 14	$ 7	$ 12
Investment securities, Available-for-sale, Gross gains	0	0	9
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	0	0	148
Other noninterest-bearing investments, Nonmarketable equity securities, Gross gains	22	21	25
Other noninterest-bearing investments, Nonmarketable equity securities, Gross losses	8	14	13
Total investment securities and other noninterest-bearing investments, Gross gains	22	21	34
Total investment securities and other noninterest-bearing investments, Gross losses	8	14	161
Net losses	14	7	(127)
Fixed income securities gains (losses), net	$ 0	$ 0	$ (139)

Investment Securities Investmen

Investment Securities Investment Securities (Tax and Nontaxable Income by Investment Type) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment [Line Items]
Interest on securities	$ 326	$ 204	$ 124
Trading Securities [Member]
Investment [Line Items]
Interest on securities	2	3	2
Available-for-sale Securities [Member]
Investment [Line Items]
Interest on securities	301	178	98
Held-to-maturity Securities [Member]
Investment [Line Items]
Interest on securities	23	23	24
Taxable [Member]
Investment [Line Items]
Interest on securities	289	179	110
Taxable [Member] | Trading Securities [Member]
Investment [Line Items]
Interest on securities	2	3	2
Taxable [Member] | Available-for-sale Securities [Member]
Investment [Line Items]
Interest on securities	277	166	95
Taxable [Member] | Held-to-maturity Securities [Member]
Investment [Line Items]
Interest on securities	10	10	13
Nontaxable [Member]
Investment [Line Items]
Interest on securities	37	25	14
Nontaxable [Member] | Trading Securities [Member]
Investment [Line Items]
Interest on securities	0	0	0
Nontaxable [Member] | Available-for-sale Securities [Member]
Investment [Line Items]
Interest on securities	24	12	3
Nontaxable [Member] | Held-to-maturity Securities [Member]
Investment [Line Items]
Interest on securities	$ 13	$ 13	$ 11

Loans And Allowance For Credi63

Loans And Allowance For Credit Losses (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)moBilling_CyclesdPayments	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Subsequent Event [Line Items]
Loans and Leases Receivable, Deferred Income	$ 65,000,000	$ 77,000,000
Current Fiscal Year End Date	--12-31
Financing Receivable, Minimum Number Of Days Past Due for Nonaccrual Status | d	90
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 1,000,000
Financing Receivable, Nonaccrual, Threshold for Evaluation of Impairment	$ 1,000,000
Financing Receivable, Troubled Debt Restructurting, Minimum Number Of Months For Borrower To Meet Terms For TDR Status | mo	6
Total reversal amount to allowance for loan and lease losses due to an increased cash flows from acquired loans	$ 1,000,000
Unfunded Lending Commitments on Troubled Debt Restructuring	22,000,000	14,000,000
Recorded investment in loans modified with favorable interest rates	$ 120,000,000	128,000,000
Financing Receivable, Closed-end Loans, Minimum Number Of Monthly Payments in Arrears When Reported as Past Due | Payments	2
Financing Recevable, Open-end Credit, Number of Billing Cycles in Arrears When Reported as Past Due | Billing_Cycles	2
Financing Receivable, Other, Minimum Number of Days Unpaid When Reported as Past Due | d	30
Owner Occupied And Commercial Real Estate Loans Unamortized Premiums	$ 16,000,000	20,000,000
Land Development Loans	220,000,000	290,000,000
Loans and Leases Receivable, Collateral for Secured Borrowings	25,600,000,000	24,000,000,000
Principle amount of loans held for sale sold	900,000,000	1,400,000,000	$ 1,400,000,000
Payments for Origination and Purchases of Loans Held-for-sale	800,000,000
Additions to Loans Held For Sale		1,400,000,000	1,400,000,000
Principal Balance of Loans Sold, Serviced Loans	2,200,000,000	2,000,000,000
Income From Loans Sold Excluding Servicing			2,000,000,000
Loans and Leases Receivable, Gain (Loss) on Sales, Net	$ 13,000,000
Loans Sold and Serviced		18,000,000	18,000,000
Number Of Days For Consumer Loans To Be Charged Off | d	180
Loans Modified As Troubled Debt Restructurings Loans	$ 94,000,000	73,000,000
Total reversal amount to allowance for loan and lease losses due to increased cash flows from acquired loans		2,000,000	4,000,000
Additional interest income due to increased cash flows from acquired loans	18,000,000	19,000,000	$ 32,000,000
Other Real Estate, Foreclosed Assets, Residential Real Estate	1,000,000	2,000,000
Other Real Estate, In Process of Forecloseing Assets	$ 10,000,000	$ 10,000,000
Commercial Portfolio Segment [Member]
Subsequent Event [Line Items]
Financing Receivable, Subsequent Payment Default Period, Number Of Days | d	90
Consumer Portfolio Segment [Member]
Subsequent Event [Line Items]
Financing Receivable, Subsequent Payment Default Period, Number Of Days | d	60

Loans And Allowance For Credi64

Loans And Allowance For Credit Losses (Summary Of Major Portfolio Segment And Specific Loan Class) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$ 44	$ 172
Commercial and industrial	14,003	13,452
Leasing	364	423
Owner occupied	7,288	6,962
Municipal	1,271	778
Construction and land development	2,021	2,019
Term	9,103	9,322
Loans Receivable, Gross, Commercial, Real Estate	11,124	11,341
Home equity credit line	2,777	2,645
1-4 family residential	6,662	5,891
Construction and other consumer real estate	597	486
Bankcard and other revolving plans	509	481
Other	185	190
Loans and Leases Receivable, Gross	44,780	42,649
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, before Fees, Gross	22,926	21,615
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, before Fees, Gross	$ 10,730	$ 9,693

Loans And Allowance For Credi65

Loans And Allowance For Credit Losses (Summary Of Changes In The Allowance For Credit Losses) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Fiscal Year End Date									--12-31
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period				$ 567				$ 606	$ 567	$ 606
Provision for loan losses	$ (11)	$ 5	$ 7	23	$ (3)	$ 19	$ 35	42	24	93	$ 40
Gross loan and lease charge-offs									(144)	(198)
Recoveries									71	66
Net loan and lease charge-offs									(73)	(132)
Balance at end of period	518				567				518	567	606
Balance at beginning of period				65				75	65	75
Provision charged (credited) to earnings									(7)	(10)	(6)
Balance at end of period	58				65				58	65	75
Allowance for loan losses	518			567	567			606	567	606	606	$ 518	$ 567
Reserve for unfunded lending commitments	58			65	65			75	65	75	75	58	65
Total allowance for credit losses												576	632
Commercial [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period				420				454	420	454
Provision for loan losses									23	93
Gross loan and lease charge-offs									(118)	(170)
Recoveries									46	43
Net loan and lease charge-offs									(72)	(127)
Balance at end of period	371				420				371	420	454
Balance at beginning of period				54				58	54	58
Provision charged (credited) to earnings									(6)	(4)
Balance at end of period	48				54				48	54	58
Allowance for loan losses	371			420	420			454	420	454	454	371	420
Reserve for unfunded lending commitments	48			54	54			58	54	58	58	48	54
Total allowance for credit losses												419	474
Commercial Real Estate [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period				116				114	116	114
Provision for loan losses									(18)	0
Gross loan and lease charge-offs									(9)	(12)
Recoveries									14	14
Net loan and lease charge-offs									5	2
Balance at end of period	103				116				103	116	114
Balance at beginning of period				11				16	11	16
Provision charged (credited) to earnings									(1)	(5)
Balance at end of period	10				11				10	11	16
Allowance for loan losses	103			116	116			114	116	114	114	103	116
Reserve for unfunded lending commitments	10			11	11			16	11	16	16	10	11
Total allowance for credit losses												113	127
Consumer [Member]
Allowance for Credit Losses [Roll Forward]
Balance at beginning of period				31				38	31	38
Provision for loan losses									19	0
Gross loan and lease charge-offs									(17)	(16)
Recoveries									11	9
Net loan and lease charge-offs									(6)	(7)
Balance at end of period	44				31				44	31	38
Balance at beginning of period				0				1	0	1
Provision charged (credited) to earnings									0	(1)
Balance at end of period	0				0				0	0	1
Allowance for loan losses	44			31	31			38	31	38	38	44	31
Reserve for unfunded lending commitments	$ 0			$ 0	$ 0			$ 1	$ 0	$ 1	$ 1	0	0
Total allowance for credit losses												$ 44	$ 31

Loans And Allowance For Credi66

Loans And Allowance For Credit Losses (Summary Of ALLL And Outstanding Loan Balances According To The Company's Impairment Method) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Fiscal Year End Date	--12-31
Allowance for loan losses: Individually evaluated for impairment	$ (31)	$ (65)
Allowance for loan losses: Collectively evaluated for impairment	487	502
Allowance for loan losses: Purchased loans with evidence of credit deterioration		0
Financing Receivable, Allowance for Credit Losses	0
Allowance for loan losses: Total	518	567	$ 606
Loans and Leases Receivable, Gross	44,780	42,649
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Individually evaluated for impairment	(26)	(56)
Allowance for loan losses: Collectively evaluated for impairment	345	364
Financing Receivable, Allowance for Credit Losses	0	0
Allowance for loan losses: Total	371	420	454
Outstanding loan balances: Individually evaluated for impairment		466
Outstanding loan balances: Collectively evaluated for impairment		21,111
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Individually evaluated for impairment		(3)
Allowance for loan losses: Collectively evaluated for impairment		113
Outstanding loan balances: Individually evaluated for impairment		78
Outstanding loan balances: Collectively evaluated for impairment		11,231
Loans and Leases Receivable, Gross	11,124	11,341
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Individually evaluated for impairment	(1)
Allowance for loan losses: Collectively evaluated for impairment	102
Financing Receivable, Allowance for Credit Losses	0	0
Allowance for loan losses: Total	103	116	114
Loans and Leases Receivable, Gross	2,021	2,019
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Individually evaluated for impairment	(4)	(6)
Allowance for loan losses: Collectively evaluated for impairment	40	25
Financing Receivable, Allowance for Credit Losses	0	0
Allowance for loan losses: Total	44	31	$ 38
Outstanding loan balances: Individually evaluated for impairment		75
Outstanding loan balances: Collectively evaluated for impairment		9,611
Loans and Leases Receivable, Gross	185	190
Outstanding Loan Balances [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Outstanding loan balances: Individually evaluated for impairment	459	619
Outstanding loan balances: Collectively evaluated for impairment	44,294	41,953
Loans and Leases Receivable, Gross	44,780	42,649
Financing Receivable, Acquired Deteriorated Credit Quality		77
Certain Loans and Debt Securities Acquired in Transfer, with Related Allowance for Credit Losses Due to Subsequent Impairment	27
Outstanding Loan Balances [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Outstanding loan balances: Individually evaluated for impairment	314
Outstanding loan balances: Collectively evaluated for impairment	22,598
Loans and Leases Receivable, Gross	22,926	21,615
Certain Loans and Debt Securities Acquired in Transfer, with Related Allowance for Credit Losses Due to Subsequent Impairment	14	38
Outstanding Loan Balances [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Outstanding loan balances: Individually evaluated for impairment	69
Outstanding loan balances: Collectively evaluated for impairment	11,048
Loans and Leases Receivable, Gross	11,124	11,341
Certain Loans and Debt Securities Acquired in Transfer, with Related Allowance for Credit Losses Due to Subsequent Impairment	7	32
Outstanding Loan Balances [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Outstanding loan balances: Individually evaluated for impairment	76
Outstanding loan balances: Collectively evaluated for impairment	10,648
Loans and Leases Receivable, Gross	10,730	9,693
Certain Loans and Debt Securities Acquired in Transfer, with Related Allowance for Credit Losses Due to Subsequent Impairment	$ 6	$ 7

Loans And Allowance For Credi67

Loans And Allowance For Credit Losses (Summary Of Nonaccrual Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 402	$ 529
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	12	40
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	294	443
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	40	36
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	68	50
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	195	354
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	8	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	90	74
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	1	1
Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	4	7
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	36	29
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	13	11
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	55	36
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	0	2
Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 0	$ 1

Loans And Allowance For Credi68

Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Fiscal Year End Date		--12-31
Loans Receivable Held-for-sale, Net		$ 44	$ 172
Current		44,497	42,340
30-89 days past due		140	150
90+ days past due		143	159
Total past due		283	309
Loans and Leases Receivable, Gross		44,780	42,649
Accruing loans 90+ days past due		22	36
Nonaccrual loans that are current	[1]	261	381
Financing Receivable, Recorded Investment, Nonaccrual Status		402	529
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		12	40
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		294	443
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		22,740	21,401
30-89 days past due		90	112
90+ days past due		96	102
Total past due		186	214
Loans and Leases Receivable, Gross		22,926	21,615
Accruing loans 90+ days past due		17	18
Nonaccrual loans that are current		204	345
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		7	9
Loans and Leases Receivable, Gross		2,021	2,019
Financing Receivable, Recorded Investment, Nonaccrual Status		40	36
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		14	10
Loans and Leases Receivable, Gross		2,777	2,645
Financing Receivable, Recorded Investment, Nonaccrual Status		13	11
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		1	1
Loans and Leases Receivable, Gross		185	190
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		116	146
Loans and Leases Receivable, Gross		14,003	13,452
Financing Receivable, Recorded Investment, Nonaccrual Status		195	354
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		1	0
Loans and Leases Receivable, Gross		364	423
Financing Receivable, Recorded Investment, Nonaccrual Status		8	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		69	68
Loans and Leases Receivable, Gross		7,288	6,962
Financing Receivable, Recorded Investment, Nonaccrual Status		90	74
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		0	0
Loans and Leases Receivable, Gross		1,271	778
Financing Receivable, Recorded Investment, Nonaccrual Status		1	1
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		24	31
Loans and Leases Receivable, Gross		9,103	9,322
Financing Receivable, Recorded Investment, Nonaccrual Status		36	29
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		11,093	11,301
30-89 days past due		16	16
90+ days past due		15	24
Total past due		31	40
Loans and Leases Receivable, Gross		11,124	11,341
Accruing loans 90+ days past due		2	13
Nonaccrual loans that are current		25	19
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		41	34
Loans and Leases Receivable, Gross		6,662	5,891
Financing Receivable, Recorded Investment, Nonaccrual Status		55	36
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		7	7
Loans and Leases Receivable, Gross		597	486
Financing Receivable, Recorded Investment, Nonaccrual Status		0	2
Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total past due		3	3
Loans and Leases Receivable, Gross		509	481
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		10,664	9,638
30-89 days past due		34	22
90+ days past due		32	33
Total past due		66	55
Loans and Leases Receivable, Gross		10,730	9,693
Accruing loans 90+ days past due		3	5
Nonaccrual loans that are current		32	17
Financing Receivable, Recorded Investment, Nonaccrual Status		68	50
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		660	508
Revolving Credit Facility [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			478
30-89 days past due			2
90+ days past due			1
Accruing loans 90+ days past due			1
Revolving Credit Facility [Member] | Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		506
30-89 days past due		2
90+ days past due		1
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		44	172
30-89 days past due		0	0
90+ days past due		0	0
Total past due		0	0
Loans and Leases Receivable, Gross		44	172
Accruing loans 90+ days past due		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status		12	40
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			2,010
30-89 days past due			7
90+ days past due			2
Accruing loans 90+ days past due			1
Commercial Real Estate [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,014
30-89 days past due		3
90+ days past due		4
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	1
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			2,635
30-89 days past due			4
90+ days past due			6
Accruing loans 90+ days past due			1
Home Equity Line of Credit [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,763
30-89 days past due		9
90+ days past due		5
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		5	5
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			189
30-89 days past due			1
90+ days past due			0
Accruing loans 90+ days past due			0
Consumer [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		184
30-89 days past due		1
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			13,306
30-89 days past due			72
90+ days past due			74
Accruing loans 90+ days past due			10
Commercial And Industrial [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		13,887
30-89 days past due		60
90+ days past due		56
Accruing loans 90+ days past due		13
Financing Receivable, Recorded Investment, Nonaccrual Status		146	287
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			423
30-89 days past due			0
90+ days past due			0
Accruing loans 90+ days past due			0
Leasing [Member] | Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		363
30-89 days past due		1
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		8	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			6,894
30-89 days past due			40
90+ days past due			28
Accruing loans 90+ days past due			8
Owner Occupied [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		7,219
30-89 days past due		29
90+ days past due		40
Accruing loans 90+ days past due		4
Financing Receivable, Recorded Investment, Nonaccrual Status		49	43
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			778
30-89 days past due			0
90+ days past due			0
Accruing loans 90+ days past due			0
Municipal [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		1,271
30-89 days past due		0
90+ days past due		0
Accruing loans 90+ days past due		0
Financing Receivable, Recorded Investment, Nonaccrual Status		1	1
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			9,291
30-89 days past due			9
90+ days past due			22
Accruing loans 90+ days past due			12
Term [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		9,079
30-89 days past due		13
90+ days past due		11
Accruing loans 90+ days past due		2
Financing Receivable, Recorded Investment, Nonaccrual Status		25	18
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			5,857
30-89 days past due			12
90+ days past due			22
Accruing loans 90+ days past due			0
1-4 Family Residential [Member] | 1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		6,621
30-89 days past due		16
90+ days past due		25
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		27	11
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current			479
30-89 days past due			3
90+ days past due			4
Accruing loans 90+ days past due			3
Construction And Other Consumer Real Estate [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		590
30-89 days past due		6
90+ days past due		1
Accruing loans 90+ days past due		1
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 0	$ 0
[1]	Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.

Loans And Allowance For Credi69

Loans And Allowance For Credit Losses (Summary Of Outstanding Loan Balances (Accruing And Nonaccruing) Categorized By Credit Quality Indicators) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Fiscal Year End Date	--12-31
Commercial and industrial	$ 14,003	$ 13,452
Leasing	364	423
Commercial Lending Loans - Owner Occupied	7,288	6,962
Loans and Leases Receivable, Gross, Commercial, Governments	1,271	778
Construction and land development	2,021	2,019
Term	9,103	9,322
Loans Receivable, Gross, Commercial, Real Estate	11,124	11,341
Loans and Leases Receivable, Gross, Consumer, Home Equity	2,777	2,645
1-4 family residential	6,662	5,891
Loans and Leases Receivable, Gross, Consumer, Construction	597	486
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	509	481
Loans and Leases Receivable, Gross, Consumer, Other	185	190
Loans and Leases Receivable, Gross	44,780	42,649
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	14,003	13,452
Leasing	364	423
Commercial Lending Loans - Owner Occupied	7,288	6,962
Loans and Leases Receivable, Gross, Commercial, Governments	1,271	778
Loans and Leases Receivable, before Fees, Gross	22,926	21,615
Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	2,021
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development		2,019
Term	9,103	9,322
Loans Receivable, Gross, Commercial, Real Estate	11,124	11,341
Loans and Leases Receivable, Gross	2,021	2,019
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	2,777	2,645
1-4 family residential	6,662	5,891
Loans and Leases Receivable, Gross, Consumer, Construction	597	486
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	509	481
Loans and Leases Receivable, Gross, Consumer, Other	185	190
Loans and Leases Receivable, Gross	185	190
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	10,730	9,693
Loans and Leases Receivable, Gross	10,730	9,693
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross	42,987	40,564
Pass [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	13,001	12,185
Leasing	342	387
Commercial Lending Loans - Owner Occupied	6,920	6,560
Loans and Leases Receivable, Gross, Commercial, Governments	1,257	765
Loans and Leases Receivable, before Fees, Gross	21,520	19,897
Pass [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	2,002
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development		1,942
Term	8,816	9,096
Loans Receivable, Gross, Commercial, Real Estate	10,818	11,038
Pass [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	2,759	2,629
1-4 family residential	6,602	5,851
Loans and Leases Receivable, Gross, Consumer, Construction	596	482
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	507	478
Loans and Leases Receivable, Gross, Consumer, Other	185	189
Pass [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	10,649	9,629
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross	660	508
Special Mention [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	395	266
Leasing	6	5
Commercial Lending Loans - Owner Occupied	93	96
Loans and Leases Receivable, Gross, Commercial, Governments	13	7
Loans and Leases Receivable, before Fees, Gross	507	374
Special Mention [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	15
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development		52
Term	138	82
Loans Receivable, Gross, Commercial, Real Estate	153	134
Special Mention [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	0	0
1-4 family residential	0	0
Loans and Leases Receivable, Gross, Consumer, Construction	0	0
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	0	0
Loans and Leases Receivable, Gross, Consumer, Other	0	0
Special Mention [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	0	0
Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross	1,132	1,573
Sub-Standard [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	606	998
Leasing	16	30
Commercial Lending Loans - Owner Occupied	275	306
Loans and Leases Receivable, Gross, Commercial, Governments	1	6
Loans and Leases Receivable, before Fees, Gross	898	1,340
Sub-Standard [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	4
Sub-Standard [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development		25
Term	149	144
Loans Receivable, Gross, Commercial, Real Estate	153	169
Sub-Standard [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	18	16
1-4 family residential	60	40
Loans and Leases Receivable, Gross, Consumer, Construction	1	4
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	2	3
Loans and Leases Receivable, Gross, Consumer, Other	0	1
Sub-Standard [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	81	64
Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross	1	4
Doubtful [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	1	3
Leasing	0	1
Commercial Lending Loans - Owner Occupied	0	0
Loans and Leases Receivable, Gross, Commercial, Governments	0	0
Loans and Leases Receivable, before Fees, Gross	1	4
Doubtful [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	0
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development		0
Term	0	0
Loans Receivable, Gross, Commercial, Real Estate	0	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity	0	0
1-4 family residential	0	0
Loans and Leases Receivable, Gross, Consumer, Construction	0	0
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	0	0
Loans and Leases Receivable, Gross, Consumer, Other	0	0
Doubtful [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	0	0
Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross	518	567
Total Allowance [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	371	420
Total Allowance [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Receivable, Gross, Commercial, Real Estate	103	116
Total Allowance [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, before Fees, Gross	$ 44	$ 31

Loans And Allowance For Credi70

Loans And Allowance For Credit Losses (Summary Of Information On Impaired Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Current Fiscal Year End Date	--12-31
Impaired Financing Receivable, Average Recorded Investment	$ 520	$ 603
Impaired Financing Receivable, Recorded Investment	461	660
Impaired Financing Receivable, Related Allowance	30	63
Impaired Financing Receivable, Interest Income, Accrual Method	27	32
Impaired Financing Receivable, Unpaid Principal Balance	573	788
Commercial And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	289	333
Impaired Financing Receivable, Recorded Investment	222	393
Impaired Financing Receivable, Related Allowance	24	52
Impaired Financing Receivable, Interest Income, Accrual Method	6	5
Impaired Financing Receivable, Unpaid Principal Balance	293	470
Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	97	99
Impaired Financing Receivable, Recorded Investment	102	101
Impaired Financing Receivable, Related Allowance	2	3
Impaired Financing Receivable, Interest Income, Accrual Method	6	9
Impaired Financing Receivable, Unpaid Principal Balance	120	115
Municipal [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	1	1
Impaired Financing Receivable, Recorded Investment	1	1
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, Unpaid Principal Balance	1	1
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	387	433
Impaired Financing Receivable, Recorded Investment	325	495
Impaired Financing Receivable, Related Allowance	26	55
Impaired Financing Receivable, Interest Income, Accrual Method	12	14
Impaired Financing Receivable, Unpaid Principal Balance	414	586
Term [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	49	76
Impaired Financing Receivable, Recorded Investment	48	70
Impaired Financing Receivable, Related Allowance	0	2
Impaired Financing Receivable, Interest Income, Accrual Method	12	13
Impaired Financing Receivable, Unpaid Principal Balance	56	92
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	57	87
Impaired Financing Receivable, Recorded Investment	54	83
Impaired Financing Receivable, Related Allowance	0	2
Impaired Financing Receivable, Interest Income, Accrual Method	12	15
Impaired Financing Receivable, Unpaid Principal Balance	64	114
Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	21	22
Impaired Financing Receivable, Recorded Investment	22	23
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Interest Income, Accrual Method	1	1
Impaired Financing Receivable, Unpaid Principal Balance	25	24
One Through Four Family Residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	52	57
Impaired Financing Receivable, Recorded Investment	57	55
Impaired Financing Receivable, Related Allowance	4	6
Impaired Financing Receivable, Interest Income, Accrual Method	1	2
Impaired Financing Receivable, Unpaid Principal Balance	67	59
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	2	2
Impaired Financing Receivable, Recorded Investment	2	3
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Impaired Financing Receivable, Unpaid Principal Balance	2	3
Consumer Other Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	1	2
Impaired Financing Receivable, Recorded Investment	1	1
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Interest Income, Accrual Method	1	0
Impaired Financing Receivable, Unpaid Principal Balance	1	2
Commercial Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	8	11
Impaired Financing Receivable, Recorded Investment	6	13
Impaired Financing Receivable, Related Allowance	0	0
Impaired Financing Receivable, Interest Income, Accrual Method	0	2
Impaired Financing Receivable, Unpaid Principal Balance	8	22
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	76	83
Impaired Financing Receivable, Recorded Investment	82	82
Impaired Financing Receivable, Related Allowance	4	6
Impaired Financing Receivable, Interest Income, Accrual Method	3	3
Impaired Financing Receivable, Unpaid Principal Balance	95	88
Impaired Financing Receivable Recorded Investment With an Allowance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	218	401
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	23
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	165	341
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Term [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	12
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	14	23
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	9
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | One Through Four Family Residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	29
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Consumer Other Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Commercial Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	2
Impaired Financing Receivable Recorded Investment With an Allowance [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	39	37
Impaired Financing Receivable Recorded Investment With No Allowance [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	243	259
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Commercial And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	80	82
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	79	71
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1	1
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	160	154
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Term [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	36	53
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	40	60
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	13	16
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | One Through Four Family Residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	28	27
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1	1
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Consumer Other Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	1	1
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Commercial Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	4	7
Impaired Financing Receivable Recorded Investment With No Allowance [Member] | Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	43	45
Impaired Financing Receivable Related Allowance [Member] | Commercial And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 142	311
Impaired Financing Receivable Related Allowance [Member] | Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		30
Impaired Financing Receivable Related Allowance [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0
Impaired Financing Receivable Related Allowance [Member] | Term [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		17
Impaired Financing Receivable Related Allowance [Member] | Home Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		7
Impaired Financing Receivable Related Allowance [Member] | One Through Four Family Residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		28
Impaired Financing Receivable Related Allowance [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		2
Impaired Financing Receivable Related Allowance [Member] | Consumer Other Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0
Impaired Financing Receivable Related Allowance [Member] | Commercial Real Estate Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		$ 6

Loans And Allowance For Credi71

Loans And Allowance For Credit Losses (Summary Of Selected Information On TDRs That Includes Recorded Investment On An Accruing And Nonaccruing Basis By Loan Class And Modification Type) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Current Fiscal Year End Date		--12-31
Loans Receivable, Gross, Commercial and Industrial		$ 14,003	$ 13,452
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		5	3
Loans and Leases Receivable, Gross, Consumer, Construction		597	486
Loans and Leases Receivable, Gross, Consumer, Mortgage		6,662	5,891
Loans and Leases Receivable, Gross, Consumer, Home Equity		2,777	2,645
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card		509	481
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		139	151
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		226	251
Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		4	0
Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		47	47
Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		62	60
Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1
Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		23	22
Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		10	17
Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	1
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		14,003	13,452
Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		70	69
Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		73	78
Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2	8
Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	2
Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		14	17
Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5	8
Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		16	25
Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5	10
Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		15	14
Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	2
One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		36	42
One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		8	8
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2
Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2	1
Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	2
Consumer Other Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		597	486
Loans and Leases Receivable, Gross, Consumer, Mortgage		6,662	5,891
Loans and Leases Receivable, Gross, Consumer, Home Equity		2,777	2,645
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card		509	481
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		5	1
Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2
Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		53	57
Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		9	12
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	0
Accruing [Member] | Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	0
Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Accruing [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	0
Accruing [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	0
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		4	3
Nonaccruing [Member] | Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		3	0
Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		1	1
Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2
Nonaccruing [Member] | Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		4	1
Nonaccruing [Member] | Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		0	2
Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		87	100
Multiple Modification Types [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		86	86
Multiple Modification Types [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		123	132
Multiple Modification Types [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		47	38
Multiple Modification Types [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		29	37
Multiple Modification Types [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		9	14
Multiple Modification Types [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	3
Multiple Modification Types [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		37	46
Multiple Modification Types [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		30	34
Multiple Modification Types [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5	6
Multiple Modification Types [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		33	28
Multiple Modification Types [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			10
Multiple Modification Types [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		14
Multiple Modification Types [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2
Multiple Modification Types [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			10
Multiple Modification Types [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		7
Multiple Modification Types [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			4
Multiple Modification Types [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		3	3
Multiple Modification Types [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		26	30
Multiple Modification Types [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		1	1
Multiple Modification Types [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		24	25
Multiple Modification Types [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			12
Multiple Modification Types [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5
Multiple Modification Types [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Multiple Modification Types [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Multiple Modification Types [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Multiple Modification Types [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			3
Multiple Modification Types [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3
Multiple Modification Types [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Multiple Modification Types [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	1
Multiple Modification Types [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		5	5
Multiple Modification Types [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	22	12
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	52	51
Other Recorded Investment Resulting From Following Modification [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	19	8
Other Recorded Investment Resulting From Following Modification [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	29	34
Other Recorded Investment Resulting From Following Modification [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	0	2
Other Recorded Investment Resulting From Following Modification [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	0	4
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	30	39
Other Recorded Investment Resulting From Following Modification [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	3	2
Other Recorded Investment Resulting From Following Modification [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	[1]	1	1
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		12	0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			8
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		7
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			2
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		1	0
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		2	2
Other Recorded Investment Resulting From Following Modification [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		28	33
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			2
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			2
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		1	1
Other Recorded Investment Resulting From Following Modification [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Payment Deferral [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2	1
Payment Deferral [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5	7
Payment Deferral [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Payment Deferral [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	4
Payment Deferral [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	1
Payment Deferral [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Payment Deferral [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	6
Payment Deferral [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	0
Payment Deferral [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	2
Payment Deferral [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		0	0
Payment Deferral [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Payment Deferral [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Payment Deferral [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Payment Deferral [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Payment Deferral [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Payment Deferral [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		1	0
Payment Deferral [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Payment Deferral [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		2	1
Payment Deferral [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			3
Payment Deferral [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Payment Deferral [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Payment Deferral [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Payment Deferral [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Payment Deferral [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Payment Deferral [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Payment Deferral [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		0	0
Payment Deferral [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	2
Principal Forgiveness [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		15	17
Principal Forgiveness [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		23	20
Principal Forgiveness [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	1
Principal Forgiveness [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		5	0
Principal Forgiveness [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Principal Forgiveness [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Principal Forgiveness [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		8	3
Principal Forgiveness [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		15	16
Principal Forgiveness [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	3
Principal Forgiveness [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		0	0
Principal Forgiveness [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Principal Forgiveness [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		9	10
Principal Forgiveness [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		6	6
Principal Forgiveness [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Principal Forgiveness [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		5	0
Principal Forgiveness [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Principal Forgiveness [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Principal Forgiveness [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		1	1
Principal Forgiveness [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		2	2
Principal Forgiveness [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Maturity Or Team Extension [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		6	25
Maturity Or Team Extension [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		12	28
Maturity Or Team Extension [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	19
Maturity Or Team Extension [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		6	2
Maturity Or Team Extension [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	4
Maturity Or Team Extension [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	1
Maturity Or Team Extension [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		6	3
Maturity Or Team Extension [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	2
Maturity Or Team Extension [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Maturity Or Team Extension [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		2	19
Maturity Or Team Extension [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Maturity Or Team Extension [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Maturity Or Team Extension [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Maturity Or Team Extension [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Maturity Or Team Extension [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Maturity Or Team Extension [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			4
Maturity Or Team Extension [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		2	1
Maturity Or Team Extension [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		0	1
Maturity Or Team Extension [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		1	0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		3	0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			1
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		0	0
Maturity Or Team Extension [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Interest Rate Below Market [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		8	10
Interest Rate Below Market [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		11	13
Interest Rate Below Market [Member] | Commercial Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	3
Interest Rate Below Market [Member] | Commercial Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	1
Interest Rate Below Market [Member] | Commercial Real Estate Portfolio Segment [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		6	4
Interest Rate Below Market [Member] | Commercial Real Estate Portfolio Segment [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2	2
Interest Rate Below Market [Member] | Nonaccruing Trouble Debt Restructuring [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		3	3
Interest Rate Below Market [Member] | Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1	3
Interest Rate Below Market [Member] | Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0	0
Interest Rate Below Market [Member] | Accruing [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		0	0
Interest Rate Below Market [Member] | Accruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			3
Interest Rate Below Market [Member] | Accruing [Member] | Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Interest Rate Below Market [Member] | Accruing [Member] | Construction And Land Development [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Interest Rate Below Market [Member] | Accruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			4
Interest Rate Below Market [Member] | Accruing [Member] | Term [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		6
Interest Rate Below Market [Member] | Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Interest Rate Below Market [Member] | Accruing [Member] | Home Equity Line of Credit [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Interest Rate Below Market [Member] | Accruing [Member] | One Through Four Family Residential [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		1	3
Interest Rate Below Market [Member] | Accruing [Member] | Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		0	0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans Receivable, Gross, Commercial and Industrial		0	1
Interest Rate Below Market [Member] | Nonaccruing [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		1
Interest Rate Below Market [Member] | Nonaccruing [Member] | Municipal [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Municipal [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			2
Interest Rate Below Market [Member] | Nonaccruing [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment		2
Interest Rate Below Market [Member] | Nonaccruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment			0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Home Equity Line of Credit [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Home Equity		0	0
Interest Rate Below Market [Member] | Nonaccruing [Member] | One Through Four Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Mortgage		0	0
Interest Rate Below Market [Member] | Nonaccruing [Member] | Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Loans and Leases Receivable, Gross, Consumer, Construction		$ 0	$ 0
[1]	Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc.2 Includes TDRs that resulted from a combination of any of the previous modification types.

Loans And Allowance For Credi72

Loans And Allowance For Credit Losses (Summary Of Net Financial Impact On Interest Income Due To Interest Rate Modifications Below Market For Accruing TDR Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	$ 1	$ 1
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	1	1
1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	$ 1	$ 1

Loans And Allowance For Credi73

Loans And Allowance For Credit Losses (Schedule Of Investment Of Accruing And Nonaccruing Loans Modified As Troubled Debt Restructurings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 5	$ 3
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	0
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	4	3
Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	4	0
Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	0
Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	3	0
Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	1
Owner Occupied [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	1
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	5	1
Commercial Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	1	0
Commercial Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	4	1
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Construction And Other Consumer Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Construction And Other Consumer Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	2
Consumer Loan [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	0	0
Consumer Loan [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 2

Loans And Allowance For Credi74

Loans And Allowance For Credit Losses (Schedule Of Outstanding Balances Of All Required Payments And The Related Carrying Amounts For PCI Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Loans And Allowance For Credit Losses [Abstract]
Commercial	$ 25	$ 49
Commercial real estate	9	51
Consumer	7	9
Outstanding balance	41	109
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net	27	77
ALLL	0	1
Carrying amount, net	$ 27	$ 76

Loans And Allowance For Credi75

Loans And Allowance For Credit Losses (Schedule Of Changes In The Accretable Yield For PCI Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans And Allowance For Credit Losses [Abstract]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	$ 20	$ 24
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference	0	11
Changes in Accretable Yield [Roll Forward]
Balance at beginning of period	33	40
Disposals and other	1	6
Balance at end of period	$ 14	$ 33

Derivative Instruments And He76

Derivative Instruments And Hedging Activities (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Instruments, Gain Reclassified from Accumulated OCI into Income, Effective Portion	$ 1,000,000
Derivatives designated for hedges of investments in foreign operations		$ 0
Fair values of derivative assets reduced (increased) by net credit valuation adjustments		2,000,000
Notional amount of bank and insurance trust preferred CDOs		6,824,000,000	$ 6,209,000,000
Cash collateral pledged for derivative liabilities		38,000,000
Additional collateral that would be required to be pledge if credit rating was downgraded by one notch		1,000,000
Derivative Credit Risk Valuation Adjustment, Derivative Liabilities		1,000,000	1,000,000
Other Liabilities [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability		40,000,000	59,000,000
Other Liabilities [Member] | Derivative Financial Instruments, Liabilities [Member]
Derivative [Line Items]
Gross amounts recognized		$ 40,000,000	$ 59,000,000

Derivative Instruments And He77

Derivative Instruments And Hedging Activities (Schedule Of Notional Amounts And Recorded Gross Fair Values And Related Gain (Loss) Of Derivative Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Total derivatives, Notional amount	$ 6,824	$ 6,209
Amount of derivative gain (loss), recognized in OCI	(8)	8
Amount of derivative gain (loss), Reclassified from AOCI to interest income	4	11
Derivatives instruments, Noninterest income (expense)	27	26
Derivatives designated as hedging instruments, Offset to interest expense	0	0
Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	38	64
Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	40	59
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Total derivatives, Notional amount	1,138	1,388
Amount of derivative gain (loss), recognized in OCI	(8)	8
Amount of derivative gain (loss), Reclassified from AOCI to interest income	4	11
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	0	2
Derivatives Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0	1
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Total derivatives, Notional amount	5,686	4,821
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	38	62
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	40	58
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Total derivatives, Notional amount	223	235
Derivatives instruments, Noninterest income (expense)	(1)	1
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	1	2
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	0	0
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member]
Derivative [Line Items]
Total derivatives, Notional amount	4,550	4,162
Derivatives instruments, Noninterest income (expense)	11	14
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	28	49
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps For Customers [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	33	49
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Total derivatives, Notional amount	913	424
Derivatives instruments, Noninterest income (expense)	17	11
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Assets [Member]
Derivative [Line Items]
Derivatives hedging instruments, assets	9	11
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Exchange [Member] | Other Liabilities [Member]
Derivative [Line Items]
Derivatives hedging instruments, liabilities	$ 7	$ 9

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Land	$ 234	$ 229
Investment Building and Building Improvements	720	683
Fixtures and Equipment, Gross	451	458
Leasehold Improvements, Gross	135	140
Capitalized Computer Software, Gross	401	355
Property, Plant and Equipment, Gross	1,941	1,865
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	847	845
Premises and equipment, net	$ 1,094	$ 1,020

Goodwill And Other Intangible79

Goodwill And Other Intangible Assets Goodwill and Other Intangible Assets (Narative) (Details) - USD ($)	12 Months Ended
	Dec. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Amortization of Intangible Assets			$ 6,000,000	$ 8,000,000	$ 9,000,000
Goodwill, Impairment Loss			0	$ 0
Bank Susidiaries except The Commerce Bank of Oregon [Member]
Goodwill [Line Items]
Goodwill, Impairment Loss			$ 0
Subsequent Event [Member]
Goodwill [Line Items]
Amortization of Intangible Assets	$ 1,000,000	$ 2,000,000

Goodwill And Other Intangible80

Goodwill And Other Intangible Assets (Amortizing Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 195	$ 195
Accumulated amortization	(193)	(187)
Net carrying amount	2	8
Goodwill impairment	0	0
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	167	167
Accumulated amortization	(165)	(159)
Net carrying amount	2	8
Customer Relationships And Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28	28
Accumulated amortization	(28)	(28)
Net carrying amount	$ 0	$ 0

Goodwill And Other Intangible81

Goodwill And Other Intangible Assets (Schedule Of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 1,014	$ 1,014
Impairment losses	0	0
Goodwill, Ending Balance	1,014	1,014
Zions Bank [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	20	20
Impairment losses	0	0
Goodwill, Ending Balance	20	20
California Bank And Trust [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	379	379
Impairment losses	0	0
Goodwill, Ending Balance	379	379
Amegy Corporation [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	615	615
Impairment losses	0	0
Goodwill, Ending Balance	$ 615	$ 615

Deposits (Narrative) (Details)

Deposits (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Time Deposits, Less than $250,000	$ 1,200	$ 1,400
Time Deposits, $250,000 or More, Domestic	1,900	1,400
Deposit overdrafts reclassified as loan balances	$ 14	$ 11

Deposits (Scheduled Maturities

Deposits (Scheduled Maturities Of All Time Deposits) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
2,018	$ 2,584
2,019	256
2,020	132
2,021	85
2,022	57
Thereafter	1
Time Deposits, total	$ 3,115	$ 2,757

Deposits Deposits (Time Deposit

Deposits Deposits (Time Deposits Denomination of $100,000 and Over) (Details) $ in Millions	Dec. 31, 2017USD ($)
Time Deposits (Denomination of $100,000 and Over) [Abstract]
Contractual Maturities, Time Deposits, $100,000 or More, Three Months or Less	$ 1,023
Contractual Maturities, Time Deposits, $100,000 or More, Three Months Through Six Months	485
Contractual Maturities, Time Deposits, $100,000 or More, Six Months Through 12 Months	508
Contractual Maturities, Time Deposits, $100,000 or More, after 12 Months	312
Time Deposits, $100,000 or More	$ 2,328

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Short-term Debt [Abstract]
Number of maturity days of short-term borrowings, maximum	30
Secured Debt, Repurchase Agreements Overnight	$ 31
Example1 of term repurchase security agreement term	30
Term repurchase securitiy agreement term example2	60
Secured Debt, Repurchase Agreements Term	$ 323
Percentage of outstanding advance for unencumbered collateral	100.00%
Amount available for FHLB advances	$ 9,000
Amount available for federal reserve borrowings	$ 6,000

Short-Term Borrowings (Summary

Short-Term Borrowings (Summary Of Short-Term Borrowings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Federal Home Loan Bank Certificates and Obligations (FHLB) [Member]
Short-term Debt [Line Items]
Average amount outstanding	$ 2,657	$ 37	$ 0
Weighted average rate	1.13%	0.59%	0.00%
Highest month-end balance	$ 3,750	$ 750	$ 0
Year-end balance	$ 3,600	$ 500	$ 0
Weighted average rate on outstandings at year-end	1.44%	0.75%	0.00%
Short-term Debt [Member]
Short-term Debt [Line Items]
Year-end balance	$ 4,976	$ 827	$ 347
Security Owned and Sold, Not yet Purchased Fair Value, Security Sold, Not yet Purchased	95	25	30
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Year-end balance	927	106	111
Security Repurchase Agreements [Member]
Short-term Debt [Line Items]
Year-end balance	$ 354	$ 196	$ 206

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	Sep. 15, 2023	Nov. 15, 2018	May 15, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Senior Notes				$ 153
Extinguishment of Debt, Amount				0	$ 1	$ 3
Capital Lease Obligations				$ 1	1
Junior Subordinated Notes					165
Long-term Debt, Interest Rate 6.95%				6.95%
Long-Term Debt, Interest Rate 5.65%				5.65%
Stock Redeemed or Called During Period, Value				$ 144	(126)	$ (176)
Subordinated debt converted to preferred stock					(90)
Senior medium-term notes				135	$ 288
Long-term debt, Parent only maturities				382
Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, Parent only maturities				$ 382
Subordinated Notes Interest Rate 5.65 Percent [Member]
Debt Instrument [Line Items]
New interest rate		3mL+4.19%
Interest payments begin			May 15, 2014
Subordinated Notes Interest Rate 6.95 Percent [Member]
Debt Instrument [Line Items]
New interest rate	3mL+3.89%

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Junior subordinated debentures related to trust preferred securities		$ 165
Subordinated notes	$ 247	246
Senior medium-term notes	135	288
Capital Lease Obligations	1	1
Long-term debt, total	$ 383	$ 535

Long-Term Debt (Schedule Of Sub

Long-Term Debt (Schedule Of Subordinated Notes) (Details) - USD ($) $ in Millions	Dec. 31, 2017	May 15, 2014	Dec. 31, 2016
Subordinated Borrowing [Line Items]
Long-Term Debt, Interest Rate 5.65%	5.65%
Subordinated notes, Balance	$ 247		$ 246
Subordinated Notes Par Amount			250
Long-term Debt, Interest Rate 6.95%	6.95%
Subordinated Notes Interest Rate 5.65 Percent [Member]
Subordinated Borrowing [Line Items]
Subordinated notes, Balance	$ 160
Subordinated Notes Par Amount			162
Subordinated notes, Maturity	Nov. 1, 2023
Interest payments begin		May 15, 2014
Subordinated Notes Interest Rate 6.95 Percent [Member]
Subordinated Borrowing [Line Items]
Subordinated notes, Balance	$ 87
Subordinated Notes Par Amount			$ 88
Subordinated notes, Maturity	Sep. 1, 2028

Long-Term Debt (Schedule Of Sen

Long-Term Debt (Schedule Of Senior Medium-Term Notes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Junior Subordinated Notes		$ 165
Senior medium-term notes	$ 135	288
Long-term Senior notes redeemed		100
Debt Redemptions and Repurchases, Par		265
Senior Medium-Term Notes four point five zero percent with maturity of June 2023 [Member]
Debt Instrument [Line Items]
Senior medium-term notes	$ 135
Senior Medium Term Notes, Par Amount		136
Schedule Of Maturities On Long-Term Debt	June 1, 2023
Long-Term Debt, Senior Note at 3.60% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed		11
Long-Term Debt, Senior Note at 4.00% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed		$ 89

Long-Term Debt (Schedule Of Mat

Long-Term Debt (Schedule Of Maturities On Long-Term Debt) (Details) $ in Millions	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Long-term debt, excluding associated hedges	$ 383
2,013	0
2,014	1
2,015	0
2,016	0
2,017	0
Thereafter	382
Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt, excluding associated hedges	382
2,013	0
2,014	0
2,015	0
2,016	0
2,017	0
Thereafter	$ 382

Long-Term Debt Long-Term Debt (

Long-Term Debt Long-Term Debt (Schedule Of Early Redemption)(Details) (Details) $ in Millions	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Junior Subordinated Notes	$ 165
Debt Redemptions and Repurchases, Par	265
Long-term Senior notes redeemed	100
Long-Term Debt, Senior Note at 3.60% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed	11
Long-Term Debt, Senior Note at 4.00% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed	89
Junior Subordinated Notes, Coupon Rate, 3mL 2.85% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	51
Junior Subordinated Notes, Coupon Rate, 3mL 1.90% 2.22% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	36
Junior Subordinated Notes, Coupon Rate, 3mL 1.78% 2.29% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	62
Junior Subordinated Notes, Coupon Rate, 3mL 3.15% 3.75% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	8
Junior Subordinated Notes, Coupon Rate, 3mL 2.89% 3.42% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	$ 8

Long-Term Debt Debt Extinguishm

Long-Term Debt Debt Extinguishment Costs (Details)	12 Months Ended
	Dec. 31, 2017
Extinguishment of Debt [Line Items]
Schedule of Debt Extinguishment Costs [Table Text Block]	During 2017 , we had no debt extinguishment costs, compared with less than $1 million in 2016 and $3 million in 2015 .

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)$ / shares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014shares
Schedule of Equity Method Investments [Line Items]
Current Fiscal Year End Date			--12-31
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax			$ 19	$ (45)
Liquidation preference of preferred stock (per share) | $ / shares			$ 1,000
Preferred stock, authorized shares | shares			4,400	4,400
Carrying value, Preferred stock			$ 566	$ 710
Common Stock			$ 4,445	$ 4,725
Common Stock, Shares, Issued | shares			197,532	203,085
Warrants sold | shares			29,300
Common stock issued for preferred stock redemption			$ 144	$ (126)	$ (176)
Preferred Stock Redemption Premium			$ 2
Stock Repurchased During Period, Shares | shares			7,000	3,000
Stock Repurchased and Retired During Period, Value	$ (115)		$ 320	$ 90
Treasury Stock Acquired, Average Cost Per Share | $ / shares	$ 53.46		$ 45.66	$ 31.15
Treasury Stock Acquired, Repurchase Authorization	120
Preferred Stock, Tender Offer				$ 120
Preferred Stock, Liquidation Preference, Value				$ 118
Payments for Repurchase of Redeemable Preferred Stock			$ 126
Preferred Stock Redemption			$ 10
Common stock, outstanding shares | shares			197,532	203,085
Total invested assets of trusts			$ 102	$ 91
Total obligations of trusts			116	105
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax			(1)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax			$ 11	5
Preferred stock, liquidation preference per depositary share | $ / shares			$ 25
Common Stock Held in Trust			$ 14	14.1
Warrant Exercise Price | $ / shares			$ 35.37
Depositary Share, Preferred Stock Ownership Interest			1/40
Troubled Asset Relief Program, Stock		$ 1
Effect of Change in Tax Rate, OCI			$ 25	0	0
Series I Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred stock, authorized shares | shares			300,893
Carrying value, Preferred stock			$ 99	99
Preferred Stock, Dividend Rate, Percentage			5.80%
Series A Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred stock, authorized shares | shares			140,000
Variable dividend payment rate			> of 4.0% or 3mL+0.52%
Carrying value, Preferred stock			$ 67	67
Series F Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred stock, authorized shares | shares			0
Carrying value, Preferred stock			$ 0	144
Preferred Stock, Dividend Rate, Percentage			7.90%
Series G Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred stock, authorized shares | shares			200,000
Carrying value, Preferred stock			$ 138	138
Preferred Stock, Dividend Rate, Percentage			6.30%
Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Common stock issued for preferred stock redemption			$ 144	(118)	(176)
Retained Earnings [Member]
Schedule of Equity Method Investments [Line Items]
Common stock issued for preferred stock redemption			$ 2	(10)	(3)
Warrant [Member]
Schedule of Equity Method Investments [Line Items]
Common stock warrants issued to the U.S. Treasury			5,800,000
Common Stock [Member]
Schedule of Equity Method Investments [Line Items]
Common stock issued for preferred stock redemption			$ (2)	$ 2	$ 3
Stock Repurchased During Period, Shares | shares			(7,009)	(2,889)
Stock Repurchased and Retired During Period, Value			$ 320
Common stock, outstanding shares | shares			197,532	203,085	204,417	203,015
Warrant Exercise Price [Member]
Schedule of Equity Method Investments [Line Items]
Common stock warrants issued to the U.S. Treasury			0
Series G Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred Stock, Liquidation Preference, Value				$ 33
Series I Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Preferred Stock, Liquidation Preference, Value				26
SERIES J STOCK [Member]
Schedule of Equity Method Investments [Line Items]
Preferred Stock, Liquidation Preference, Value				$ 59
Future [Member]
Schedule of Equity Method Investments [Line Items]
Troubled Asset Relief Program, Stock		29
Warrant [Member]
Schedule of Equity Method Investments [Line Items]
Troubled Asset Relief Program, Stock		3.2
Next Twelve Months [Member]
Schedule of Equity Method Investments [Line Items]
Troubled Asset Relief Program, Stock		$ 2.6

Shareholders' Equity (Summary O

Shareholders' Equity (Summary Of Preferred Stock) (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Common Stock Held in Trust	$ 14	$ 14.1
Preferred stock, authorized shares	4,400	4,400
Carrying value, Preferred stock	$ 566	$ 710
Series A Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Rate	> of 4.0% or 3mL+0.52%
Earliest redemption date	Dec. 15, 2011
Preferred stock, authorized shares	140,000
Outstanding Shares at December 31, 2012	66,139
Carrying value, Preferred stock	$ 67	67
Series F Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Earliest redemption date	Jun. 15, 2017
Preferred stock, authorized shares	0
Outstanding Shares at December 31, 2012	0
Carrying value, Preferred stock	$ 0	144
Preferred Stock, Dividend Rate, Percentage	7.90%
Series G Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Earliest redemption date	Mar. 15, 2023
Preferred stock, authorized shares	200,000
Outstanding Shares at December 31, 2012	138,391
Carrying value, Preferred stock	$ 138	138
Preferred Stock, Dividend Rate, Percentage	6.30%
Series H Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Earliest redemption date	Jun. 15, 2019
Preferred stock, authorized shares	126,221
Outstanding Shares at December 31, 2012	126,221
Carrying value, Preferred stock	$ 126	126
Preferred Stock, Dividend Rate, Percentage	5.75%
Series I Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Earliest redemption date	Jun. 15, 2023
Preferred stock, authorized shares	300,893
Outstanding Shares at December 31, 2012	98,555
Carrying value, Preferred stock	$ 99	99
Preferred Stock, Dividend Rate, Percentage	5.80%
Series J Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Earliest redemption date	Sep. 15, 2023
Preferred stock, authorized shares	195,152
Outstanding Shares at December 31, 2012	136,368
Carrying value, Preferred stock	$ 136	$ 136
Preferred Stock, Dividend Rate, Percentage	7.20%

Shareholders' Equity (Summary96

Shareholders' Equity (Summary Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated other comprehensive income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (139)				$ (122)				$ (139)	$ (122)	$ (55)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax									19	(45)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax									(1)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax									11	5
Other Comprehensive Income (Loss), Tax									29	(40)
Other comprehensive income (loss)									(17)	(67)	73
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax									6	(65)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax									2	(2)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									(47)	0	0
Effect of Change in Tax Rate, OCI									25	0	0
Income Tax Expense (Benefit)									344	236	142
Net Income (Loss) Available to Common Stockholders, Basic	114	$ 153	$ 154	$ 129	125	$ 117	$ 90	$ 79	550	411	247
Reclassification of amortization of net actuarial gains losses pension and post retirement from AOCI, gross									(7)	(8)	(6)
Reclassification of pension and postretirement from accumulated other comprehensive income, tax									(3)	(3)	(2)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(114)				(92)				(114)	(92)	(18)
Other comprehensive income (loss)									(22)	(74)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax									(2)	(74)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax									0	0	86
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									(20)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated other comprehensive income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3)				1				(3)	1	1
Other comprehensive income (loss)									(4)	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax									(1)	7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax									(2)	(7)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									(1)
Net Income (Loss) Available to Common Stockholders, Basic									2	7	6
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated other comprehensive income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (22)				$ (31)				(22)	(31)	(38)
Other comprehensive income (loss)									9	7
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax									9	2
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax									4	5	4
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									(4)
Fixed income securities gain loss [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive income [Line Items]
Gain (Loss) on Investments, Excluding Other than Temporary Impairments									0	0	(139)
Income Tax Expense (Benefit)									0	0	(53)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated other comprehensive income [Line Items]
Gain (Loss) on Derivative Instruments, Net, Pretax									4	11	9
Income Tax Expense (Benefit)									$ 2	$ 4	$ 3

Regulatory Matters (Summary Of

Regulatory Matters (Summary Of Actual Capital Amounts And Ratios For The Company And Its Three Largest Subsidiary Banks) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Parent Company [Member]
Total capital (to risk-weighted assets), Actual Amount	$ 7,628	$ 7,609
Capital to Risk Weighted Assets	14.80%	15.20%
Total capital (to risk-weighted assets), To be well capitalized, Amount	$ 5,146	$ 4,994
Total capital (to risk-weighted assets), To be well capitalized, Ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), Actual Amount	$ 6,805	$ 6,738
Tier One Leverage Capital to Average Assets	10.50%	11.10%
Tier 1 capital (to risk-weighted assets), Actual Ratio	13.20%	13.50%
Tier 1 capital (to risk-weighted assets), To be well capitalized, Amount	$ 4,116	$ 3,995
Tier 1 capital (to risk-weighted assets), To be well capitalized, Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 6,239	$ 6,028
Common Equity Tier One Capital Ratio	12.10%	12.10%
Common Equity Tier One Capital to be Well Capitalized	$ 3,345	$ 3,246
Common Equity Tier One Capital to be Well Capitalized Ratio	6.50%	6.50%
Tier One Capital	$ 6,805	$ 6,738
ZB National Association [Member]
Total capital (to risk-weighted assets), Actual Amount	$ 7,306	$ 7,278
Capital to Risk Weighted Assets	14.20%	14.60%
Total capital (to risk-weighted assets), To be well capitalized, Amount	$ 5,130	$ 4,983
Total capital (to risk-weighted assets), To be well capitalized, Ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), Actual Amount	$ 6,730	$ 6,655
Tier One Leverage Capital to Average Assets	10.40%	11.00%
Tier One Capital Required to be Well Capitalized	$ 3,227	$ 3,027
Tier 1 capital (to risk-weighted assets), Actual Ratio	13.10%	13.40%
Tier 1 capital (to risk-weighted assets), To be well capitalized, Amount	$ 4,104	$ 3,986
Tier 1 capital (to risk-weighted assets), To be well capitalized, Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 5,899	$ 5,824
Common Equity Tier One Capital Ratio	11.50%	11.70%
Common Equity Tier One Capital to be Well Capitalized	$ 3,334	$ 3,239
Common Equity Tier One Capital to be Well Capitalized Ratio	6.50%	6.50%
Tier One Capital	$ 6,730	$ 6,655
Tier One Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%

Guarantees, Commitments And Con

Guarantees, Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Guarantor Obligations [Line Items]
Current Fiscal Year End Date	--12-31
Operating Leases, Future Minimum Payments, Due in Three Years	$ 36
Operating Leases, Future Minimum Payments, Due in Four Years	29
Operating Leases, Future Minimum Payments, Due in Five Years	25
Operating Leases, Future Minimum Payments Due, Next Twelve Months	40
Operating Leases, Future Minimum Payments, Due Thereafter	76
Commitments to Extend Credit Expiring in One Year	6,200
standby letters of credit expiring in one year	610
Standby Letters of Credit, Thereafter	307
Guarantor Obligations, Current Carrying Value	5
Reserve for Unfunded Lending Commitments	1
Letters of Credit, Deferred Commitment Fees	4
Commitments for Private Equity and Other Noninterest-bearing Investments	31
Commitments for Private Equity or Other Non-Interest Bearing Investments Prohibited by the Volcker Rule	4
Risk-weighted values assigned to all off-balance sheet financial and derivative instruments	6,800	$ 6,500
Cash Reserve Deposit Required and Made	366
Capital Lease Obligations, Current	1
Accumulated Amortization, Deferred Finance Costs	1
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	2
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Two Years	2
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Three Years	1
Operating Leases, Rent Expense, Net	$ 61	$ 65	$ 63

Guarantees, Commitments And C99

Guarantees, Commitments And Contingencies (Schedule Of Guarantees Issued) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	$ 19,583	$ 18,274
Commercial letters of credit	31	60
Total Unfunded Lending Commitments	20,531	19,301
Financial Guarantee [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	721	771
Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	$ 196	$ 196

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 4,000
Owner Occupied And Commercial Real Estate Loans Unamortized Premiums	16,000	$ 20,000
Benefit liability other supplement retirement plans	$ 6,000	6,400
Shares of company common stock | shares	233,849
Rate of employee contribution from earnings	80.00%
Matching contribution allocation rate first time	100.00%
Employee contribution rate for first time matching	3.00%
Matching contribution allocation rate second time	50.00%
Employees contribution rate for second time matching	2.00%
Employer contribution in common stock	$ 26,100	25,500
Minimum range of eligible compensation for noncontributory profit sharing feature	0.00%
Maximum range of eligible compensation for noncontributory profit sharing feature	4.00%
Accrued profit sharing expense	$ 11,000	$ 6,000	$ 6,000
Contribution rate of profit sharing expenses	0.0175	0.01	0.01
Limited Partnerships, Capital Commitment	$ 9,000
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	65.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	30.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	5.00%
Limited Liability Partnerships [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	$ 4,000	$ 5,000
Common Stock [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	12,000	10,000
Common Stock [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	97,000	92,000
Debt [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	31,000	29,000
Real Estate Investment [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	$ 8,000	$ 8,000

Retirement Plans (Schedule Of N

Retirement Plans (Schedule Of Net Periodic Benefit Cost (Credit) For Pension And Postretirement Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 4
Settlement loss - net periodic benefit cost (credit)	3	$ 2	$ 0
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	10
Net gain (loss) in AOCI expected to be recognized in next year	(2)
Defined Benefit Plan, Benefit Obligation	154	165	173
Interest cost	6	7	7
Expected return on plan assets	(11)	(11)	(12)
Defined Benefit Plan, Amortization of Gain (Loss)	4	6	6
Defined Benefit Plan, Actuarial Net (Gains) Losses	2	(2)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	19	13
Defined Benefit Plan, Fair Value of Plan Assets	168	161	157
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	26	13
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	4
Defined Benefit Plan, Funded (Unfunded) Status of Plan	14	(4)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	14	(4)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	2	4	1
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	(28)	(48)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	(28)	(48)
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	10
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	10
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	10
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	9
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	45
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	2
Net gain (loss) in AOCI expected to be recognized in next year	0
Defined Benefit Plan, Benefit Obligation	10	10	10
Interest cost	1	1	1
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	1	1
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	1	1
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(10)	(10)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(10)	(10)
Settlement loss - net periodic benefit cost (credit)	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	1	1	1
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	(2)	(2)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	(2)	(2)
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	1
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	1
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	1
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	3
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	0
Net gain (loss) in AOCI expected to be recognized in next year	0
Defined Benefit Plan, Benefit Obligation	1	1	1
Interest cost	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0
Defined Benefit Plan, Actuarial Net (Gains) Losses	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	0	0
Defined Benefit Plan, Fair Value of Plan Assets	0	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(1)	(1)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(1)	(1)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	0	0	$ 0
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	0	0
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	0	$ 0
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	0
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 0

Retirement Plans (Summary Of Re

Retirement Plans (Summary Of Reconciliation Of The Beginning And Ending Balances Of Assets Measured At Fair Value On A Recurring Basis Using Level 3 Inputs) (Details) - Guaranteed Deposit Account [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 11
Fair value of plan assets at end of year	9	$ 11
Defined benefit plan investment purchases	17	15
Purchases	(19)	(13)
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	11	9
Fair value of plan assets at end of year	9	11
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	11
Fair value of plan assets at end of year	$ 9	$ 11

Retirement Plans (Schedule Of W

Retirement Plans (Schedule Of Weighted Average Assumptions Based On The Pension Plan) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan [Abstract]
Discount rate, benefit obligation	3.50%	4.10%	4.20%
Discount rate, net periodic benefit cost	410.00%	420.00%	395.00%
Expected long-term return on plan assets, net periodic benefit cost	725.00%	750.00%	750.00%

Retirement Plans (Summary Of Th

Retirement Plans (Summary Of The Fair Values Of Pension Plan Investments According To The Fair Value Hierarchy And The Weighted Average Allocations) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Guaranteed Deposit Account [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	$ 9	$ 11
Guaranteed Deposit Account [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	9	11	$ 9
Guaranteed Deposit Account [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	9	11
Limited Liability Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	4	5
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	12	10
Common Stock [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	12	10
Common Stock [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	97	92
Debt Investments [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	7	6
Debt Investments [Member] | Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	7	6
Debt Investments [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	31	29
Real Estate [Member] | Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan investments	$ 8	$ 8

Retirement Plans Fair values of

Retirement Plans Fair values of pension plan assets - Level 3 rolforward (Details) - Guaranteed Deposit Account [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan investment sales	$ (19)	$ (13)
Defined Benefit Plan, Fair Value of Plan Assets	9	11
Defined benefit plan investment purchases	17	15
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 9	$ 11	$ 9

Retirement Plans Retirement Pla

Retirement Plans Retirement Plans (Unfunded Commitments and Redemption) (Details) $ in Millions	Dec. 31, 2017USD ($)
Retirement Benefits [Abstract]
Retirement Plans, Limited Partnership, Unfunded Commitments	$ 1

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of Stock Options and the Vesting of Restricted Stock and RSUs	$ 9	$ 2	$ 1
Share-Based Compensation Expense, Change	$ 1
Restricted Stock	38,978
Restricted Stock Units expected to vest	1,181,384
Share Based Compensation Restricted Stock Value	$ 2
Share Based Compensation Restricted Stock Units Aggregate Intrinsic Value	$ 60
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price	$ 27.99
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	5 years 1 month 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 21
Restricted Stock Units Outstanding	1,709,813	2,047,158	1,798,543	1,769,420
Weighted Average Grant Price of Restricted Stock Forfeited	$ 28.12	$ 26.28	$ 27.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 27.06	$ 26.44	$ 27.30	$ 31.60
Stock Options without a fixed expiration date	21,252
Total shares authorized under stock option and incentive plan	9,000,000
Number of shares available for future grants of stock options or restricted stock	5,009,248
Compensation expense not yet recognized for nonvested share-based awards	$ 26
Nonvested share-based awards, expected weighted average period to be recognized, years	2 years 3 months 18 days
Total intrinsic value of stock options exercised	$ 17	$ 10	$ 7
Cash received from the exercise of stock options	23	24	$ 23
Aggregate intrinsic value of outstanding stock options	61	59
Aggregate intrinsic value of exercisable options	$ 40	$ 31
Outstanding stock options, Weighted average remaining contractual life (years)	3 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	912,204
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,560,571	3,437,910	3,804,095	5,630,502
Total fair value of restricted stock vesting	$ 22	$ 19.4
Weighted average issue price	$ 44.55	$ 24.43	$ 29.02
Total fair value granted	$ 22	$ 19.4
Stock Issued During Period, Shares, Restricted Stock Award, Gross	314	36,594	22,441
Restricted Stock Units Granted	587,396	1,033,167	790,929
Weighted Average Grant Price of Restricted Stock Units Granted	$ 41.78	$ 21.69	$ 29.06
Restricted Stock Units Vested	(803,492)	(724,713)	(673,385)
Weighted Average Grant Price of Restricted Stock Units Vested	$ 26.19	$ 25.88	$ 24.78
Equity Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock options, Weighted average remaining contractual life (years)	2 years 9 months 60 days	3 years
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Units Granted	20,711	32,310	31,080

Share-Based Compensation (Compe

Share-Based Compensation (Compensation Expense And Related Tax Benefit For All Share-Based Awards) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Compensation expense	$ 25	$ 26	$ 25
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 19	$ 9	$ 8

Share-Based Compensation (Weigh

Share-Based Compensation (Weighted Average Of Fair Value And Significant Assumptions Used In Applying Black-Scholes Model For Options Granted) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Weighted average of fair value for options granted	$ 10.69	$ 5.24	$ 6.17
Expected dividend yield	1.80%	1.30%	1.30%
Expected volatility	30.00%	30.00%	25.00%
Risk-free interest rate	1.81%	1.21%	1.57%
Expected life (in years)	5 years	5 years	5 years

Share-Based Compensation (Summa

Share-Based Compensation (Summary Of Stock Option Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance, Number of shares	3,437,910	3,804,095	5,630,502
Balance, Weighted average exercise price	$ 26.44	$ 27.30	$ 31.60
Granted, Number of shares	195,882	789,651		740,300
Granted, Weighted average exercise price	$ 44.18	$ 21.25		$ 29.01
Exercised, Number of shares	(941,761)	(1,055,532)	(1,165,287)
Exercised, Weighted average exercise price	$ 26.03	$ 23.75	$ 25.11
Expired, Number of shares	(58,257)	(56,297)	(1,322,067)
Expired, Weighted average exercise price	$ 66.20	$ 61.60	$ 48.44
Forfeited, Number of shares	(73,203)	(44,007)	(79,353)
Forfeited, Weighted average exercise price	$ 25.63	$ 27.66	$ 28.09
Balance, Number of shares	2,560,571	3,437,910	3,804,095	5,630,502
Balance, Weighted average exercise price	$ 27.06	$ 26.44	$ 27.30	$ 31.60
Outstanding stock options exercisable, Number of shares	1,648,367	1,892,136	2,187,259
Outstanding stock options exercisable, Weighted average exercise price	$ 26.55	$ 27.60	$ 26.35

Share-Based Compensation (Sched

Share-Based Compensation (Schedule Of Additional Selected Information On Stock Options) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	2,560,571	3,437,910	3,804,095	5,630,502
Outstanding stock options, Weighted average exercise price	$ 27.06	$ 26.44	$ 27.30	$ 31.60
Outstanding stock options, Weighted average remaining contractual life (years)	3 years 8 months 12 days
Exercisable stock options, Number of shares	1,648,367	1,892,136	2,187,259
Exercisable stock options, Weighted average exercise price	$ 26.55	$ 27.60	$ 26.35
Exercise Price Range $0.32 To $19.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	198,402
Outstanding stock options, Weighted average exercise price	$ 17.39
Outstanding stock options, Weighted average remaining contractual life (years)	1 year 5 months
Exercisable stock options, Number of shares	198,402
Exercisable stock options, Weighted average exercise price	$ 17.39
Exercise Price Range $20.00 To $24.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	744,058
Outstanding stock options, Weighted average exercise price	$ 21.50
Outstanding stock options, Weighted average remaining contractual life (years)	4 years 4 months
Exercisable stock options, Number of shares	276,953
Exercisable stock options, Weighted average exercise price	$ 22.33
Exercise Price Range $25.00 To $29.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	1,346,781
Outstanding stock options, Weighted average exercise price	$ 28.35
Outstanding stock options, Weighted average remaining contractual life (years)	3 years 6 months
Exercisable stock options, Number of shares	1,094,021
Exercisable stock options, Weighted average exercise price	$ 28.30
Exercise Price Range $30.00 To $39.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	32,191
Outstanding stock options, Weighted average exercise price	$ 30.10
Outstanding stock options, Weighted average remaining contractual life (years)	3 years 5 months
Exercisable stock options, Number of shares	32,191
Exercisable stock options, Weighted average exercise price	$ 30.10
Exercise Price Range Fourty Point Zero Zero To Fourty Four Point Nine Nine [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	192,339
Outstanding stock options, Weighted average exercise price	$ 44.17
Outstanding stock options, Weighted average remaining contractual life (years)	6 years 1 month
Exercisable stock options, Number of shares	0
Exercisable stock options, Weighted average exercise price	$ 0
Exercise Price Range $45.00 To $49.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding stock options, Number of shares	46,800
Outstanding stock options, Weighted average exercise price	$ 47.10
Outstanding stock options, Weighted average remaining contractual life (years)	3 months 24 days
Exercisable stock options, Number of shares	46,800
Exercisable stock options, Weighted average exercise price	$ 47.10

Share-Based Compensation (Su112

Share-Based Compensation (Summary Of Restricted Stock Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation [Abstract]
Nonvested restricted shares, Number of shares	38,978	63,255	59,370	161,220
Nonvested restricted shares, Weighted average issue price	$ 25.91	$ 25.43	$ 23.49	$ 21.82
Issued, Number of shares	314	36,594	22,441
Issued, Weighted average issue price	$ 44.55	$ 24.43	$ 29.02
Vested, Number of shares	(24,591)	(32,709)	(123,161)
Vested, Weighted average issue price	$ 24.90	$ 20.80	$ 22.32
Forfeited, Number of shares			(1,130)
Forfeited, Weighted average issue price			$ 23.54

Share-Based Compensation Share

Share-Based Compensation Share Based Compensation (Summmary of Restricted Stock Unit Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock Units Outstanding	1,709,813	2,047,158	1,798,543	1,769,420
Weighted Average Grant Price of Restricted Stock Units	$ 30.08	$ 25.08	$ 27.39	$ 25.64
Restricted Stock Units Granted	587,396	1,033,167	790,929
Weighted Average Grant Price of Restricted Stock Units Granted	$ 41.78	$ 21.69	$ 29.06
Restricted Stock Units Vested	(803,492)	(724,713)	(673,385)
Restricted Stock Units Forfeited	(121,249)	(59,839)	(88,421)
Weighted Average Grant Price of Restricted Stock Units Vested	$ 26.19	$ 25.88	$ 24.78
Weighted Average Grant Price of Restricted Stock Forfeited	$ 28.12	$ 26.28	$ 27.17

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Owned, Federal Income Tax Note [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 47	$ 0	$ 0
Current Fiscal Year End Date		--12-31
Effect of Change in Tax Rate, Early Adoption		$ 25
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions		$ 0	0	$ 0
Effective income tax rate reconciliation, at federal statutory income tax rate		35.00%
Deferred Tax Assets, Valuation Allowance	$ 2	$ 2	4
Deferred Tax Assets Net Operating Loss And Tax Credit Carry Forward Expiring Through Two Thousand Thirty			1
Tax Credit Carryforward, Expiration Date	Dec. 31, 2030
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 5	5	3
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 1	$ 1	$ 0.1

Income Taxes (Schedule Of Incom

Income Taxes (Schedule Of Income Taxes (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 1	$ 0.1
Current Federal, Income taxes (benefit)	166	217	$ 158
Deferred Federal Income taxes (benefit)	146	(4)	(32)
Federal Income taxes (benefit) total	312	213	126
Current State, Income taxes (benefit)	24	27	14
Deferred State, Income taxes (benefit)	8	(4)	2
State Income taxes (benefit) total	32	23	16
Income Tax Expense (Benefit), Total	$ 344	$ 236	$ 142

Income Taxes (Schedule Of Statu

Income Taxes (Schedule Of Statutory Federal Income Tax Rate Reconciles To Actual Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Deferred Tax Assets, Valuation Allowance	$ 2	$ 4
Income tax expense (benefit) at statutory federal rate	327	247	$ 158
State income taxes, net	21	15	10
Other nondeductible expenses	3	3	3
Nontaxable income	(33)	(25)	(20)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount	(8)	0	0
Tax credits and other taxes	(1)	(2)	(3)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	47	0	0
Other	(14)	(2)	(6)
Income Tax Expense (Benefit), Total	$ 344	$ 236	$ 142

Income Taxes (Schedule Of Tax E

Income Taxes (Schedule Of Tax Effects Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ 0	$ 0	$ 0
Gross deferred tax assets, Book loan loss deduction in excess of tax	143	241
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits	8	19
Gross deferred tax assets, Deferred compensation	48	87
Gross deferred tax assets, Security investments and derivative fair value adjustments	40	57
Gross deferred tax assets, Net operating losses, capital losses and tax credits	2	5
FDIC Supported Transactions	2	5
Gross deferred tax assets, Other	34	46
Gross deferred tax assets	277	460
Gross deferred tax assets, Valuation allowance	(2)	(4)
Total deferred tax assets	275	456
Gross deferred tax liabilities, Core deposits and purchase accounting	0	(1)
Gross deferred tax liabilities, Premises and equipment, due to differences in depreciation	(51)	(8)
Gross deferred tax liabilities, FHLB stock dividends	(3)	(4)
Gross deferred tax liabilities, Leasing operations	(52)	(75)
Gross deferred tax liabilities, Prepaid expenses	(5)	(7)
Gross deferred tax liabilities, Prepaid pension reserves	(11)	(17)
Deferred Tax Liabilities, Mortgage Servicing Rights	(7)	(10)
Gross deferred tax liabilities, Subordinated debt modification	(9)	(31)
Deferred Tax Liabilities, Financing Arrangements	(23)	(25)
Deferred Tax Liabilities, Investments	(21)	(28)
Total deferred tax liabilities	(182)	(206)
Net deferred tax assets	$ 93	$ 250

Income Taxes (Schedule Of Recon

Income Taxes (Schedule Of Reconciliation Of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Abstract]
Balance at beginning of year	$ 6	$ 4	$ 5	$ 3
Tax positions related to current year, Additions	1	1	1
Tax positions related to current year, Reductions	0	0	0
Tax positions related to prior years, Additions	1	1	1
Tax positions related to prior years, Reductions	0	0	0
Tax Adjustments, Settlements, and Unusual Provisions	0	0	0
Lapses in statutes of limitations	0	(3)	0
Balance at end of year	$ 6	$ 4	$ 5

Net Earnings Per Common Share (

Net Earnings Per Common Share (Basic And Diluted Net Earnings Per Common Share Based On The Weighted Average Outstanding Shares) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 124	$ 161	$ 168	$ 139	$ 137	$ 127	$ 114	$ 91	$ 592	$ 469	$ 309
Less common and preferred dividends, Basic									(131)	(115)	(108)
Undistributed Earnings, Diluted									461	354	201
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic									4	4	2
Undistributed earnings (loss) applicable to nonvested shares, Basic									457	350	199
Distributed earnings applicable to common shares, Basic									(88)	(57)	(45)
Net earnings (loss) applicable to common shareholders									$ 545	$ 407	$ 244
Weighted average common shares outstanding									200,776	203,855	203,265
Net earnings (loss) per common share, Basic	$ 0.57	$ 0.75	$ 0.76	$ 0.63	$ 0.61	$ 0.57	$ 0.44	$ 0.38	$ 2.71	$ 2	$ 1.20
Additional weighted average dilutive shares, Diluted									8,877	414	433
Weighted average diluted common shares outstanding, Diluted									209,653	204,269	203,698
Net earnings (loss) per common share, Diluted	$ 0.54	$ 0.72	$ 0.73	$ 0.61	$ 0.60	$ 0.57	$ 0.44	$ 0.38	$ 2.60	$ 1.99	$ 1.20

Net Earnings Per Common Share N

Net Earnings Per Common Share Net Earnings Per Common Share Narrative (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Preferred stock redemption	$ 0	$ 0	$ (2)	$ 0	$ 0	$ 0	$ (10)	$ 0
Dividends									$ (2)	$ (10)

Operating Segment Information (

Operating Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)Branches	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)Branches	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Current Fiscal Year End Date									--12-31
Interest Income (Expense), Net	$ 526	$ 522	$ 528	$ 489	$ 480	$ 469	$ 465	$ 453	$ 2,065	$ 1,867	$ 1,715
Provision for Loan and Lease Losses	(11)	5	7	23	(3)	19	35	42	24	93	40
Interest Income (Expense), after Provision for Loan Loss									2,041	1,774	1,675
Noninterest Income	140	140	132	132	128	145	126	117	544	516	357
Noninterest Expense	$ 417	413	405	414	404	403	382	396	$ 1,649	1,585	1,581
Number of community regional banks operating in distinct geographical areas	7								7
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 260	$ 244	$ 248	$ 184	$ 207	$ 192	$ 174	$ 132	$ 936	705	451
Income Tax Expense (Benefit)									344	236	142
Commerce Bank Of Washington [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									46	38	28
Provision for Loan and Lease Losses									2	0	(3)
Interest Income (Expense), after Provision for Loan Loss									44	38	31
Noninterest Income									5	5	4
Noninterest Expense									20	19	17
Income (Loss) from Continuing Operations before Income Taxes, Domestic									29	24	18
Average Loans And Leases									926	791	707
Average Deposits									1,107	1,007	879
California Bank And Trust [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									476	434	377
Provision for Loan and Lease Losses									(5)	(9)	(4)
Interest Income (Expense), after Provision for Loan Loss									481	443	381
Noninterest Income									75	67	63
Noninterest Expense									299	290	294
Income (Loss) from Continuing Operations before Income Taxes, Domestic									257	220	150
Average Loans And Leases									9,539	9,211	8,556
Average Deposits									11,030	10,827	10,063
Amegy Corporation [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									483	460	387
Provision for Loan and Lease Losses									25	163	91
Interest Income (Expense), after Provision for Loan Loss									458	297	296
Noninterest Income									118	123	121
Noninterest Expense									336	326	373
Income (Loss) from Continuing Operations before Income Taxes, Domestic									240	94	44
Average Loans And Leases									11,021	10,595	10,148
Average Deposits									11,096	11,130	11,495
Zions Bank [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									650	624	544
Provision for Loan and Lease Losses									19	(22)	(28)
Interest Income (Expense), after Provision for Loan Loss									631	646	572
Noninterest Income									151	149	133
Noninterest Expense									436	424	430
Income (Loss) from Continuing Operations before Income Taxes, Domestic									346	371	275
Average Loans And Leases									12,481	12,538	12,118
Average Deposits									15,986	15,991	15,688
Vectra Bank Colorado [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									126	120	101
Provision for Loan and Lease Losses									1	(8)	5
Interest Income (Expense), after Provision for Loan Loss									125	128	96
Noninterest Income									25	23	21
Noninterest Expense									101	97	98
Income (Loss) from Continuing Operations before Income Taxes, Domestic									49	54	19
Average Loans And Leases									2,644	2,469	2,400
Average Deposits									2,756	2,720	2,792
Nevada State Bank [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									134	122	94
Provision for Loan and Lease Losses									(11)	(28)	(28)
Interest Income (Expense), after Provision for Loan Loss									145	150	122
Noninterest Income									40	39	36
Noninterest Expense									139	137	131
Income (Loss) from Continuing Operations before Income Taxes, Domestic									46	52	27
Average Loans And Leases									2,357	2,284	2,344
Average Deposits									4,254	4,137	3,891
National Bank Of Arizona [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									206	190	152
Provision for Loan and Lease Losses									(8)	(3)	8
Interest Income (Expense), after Provision for Loan Loss									214	193	144
Noninterest Income									40	40	36
Noninterest Expense									148	144	133
Income (Loss) from Continuing Operations before Income Taxes, Domestic									106	89	47
Average Loans And Leases									4,267	4,086	3,811
Average Deposits									4,762	4,576	4,311
Consolidated Entities [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									2,065	1,867	1,715
Provision for Loan and Lease Losses									24	93	40
Interest Income (Expense), after Provision for Loan Loss									2,041	1,774	1,675
Noninterest Income									544	516	357
Noninterest Expense									1,649	1,585	1,581
Income (Loss) from Continuing Operations before Income Taxes, Domestic									936	705	451
Average Loans And Leases									43,501	42,062	40,171
Average Deposits									52,200	50,595	48,638
Other Segment [Member]
Segment Reporting Information [Line Items]
Interest Income (Expense), Net									(56)	(121)	32
Provision for Loan and Lease Losses									1	0	(1)
Interest Income (Expense), after Provision for Loan Loss									(57)	(121)	33
Noninterest Income									90	70	(57)
Noninterest Expense									170	148	105
Income (Loss) from Continuing Operations before Income Taxes, Domestic									(137)	(199)	(129)
Average Loans And Leases									266	88	87
Average Deposits									$ 1,209	$ 207	$ (481)
Vectra Bank Colorado [Member] | COLORADO
Segment Reporting Information [Line Items]
Number of Branches | Branches	36								36
Vectra Bank Colorado [Member] | New Mexico [Member]
Segment Reporting Information [Line Items]
Number of Branches | Branches	1								1
National Bank Of Arizona [Member]
Segment Reporting Information [Line Items]
Number of Branches | Branches	58								58
Commerce Bank Of Washington [Member] | WASHINGTON
Segment Reporting Information [Line Items]
Number of Branches | Branches	1								1
Commerce Bank Of Washington [Member] | OREGON
Segment Reporting Information [Line Items]
Number of Branches | Branches	1								1
California Bank And Trust [Member] | CALIFORNIA
Segment Reporting Information [Line Items]
Number of Branches | Branches	92								92
Zions Bank [Member] | UTAH
Segment Reporting Information [Line Items]
Number of Branches | Branches	97								97
Zions Bank [Member] | IDAHO
Segment Reporting Information [Line Items]
Number of Branches | Branches	23								23
Zions Bank [Member] | WYOMING
Segment Reporting Information [Line Items]
Number of Branches | Branches	1								1
Amegy Corporation [Member]
Segment Reporting Information [Line Items]
Number of Branches | Branches	73								73
Nevada State Bank [Member]
Segment Reporting Information [Line Items]
Number of Branches | Branches	50								50

Quarterly Financial Informat122

Quarterly Financial Information (Financial Information By Quarter) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Gross interest income	$ 562	$ 557	$ 558	$ 515	$ 501	$ 491	$ 487	$ 475	$ 2,192	$ 1,954	$ 1,833
Net interest income	526	522	528	489	480	469	465	453	2,065	1,867	1,715
Provision for loan losses	(11)	5	7	23	(3)	19	35	42	24	93	40
Noninterest Income	140	140	132	132	128	145	126	117	544	516	357
Noninterest expense	417	413	405	414	404	403	382	396	1,649	1,585	1,581
Income before income taxes	260	244	248	184	207	192	174	132	936	705	451
Net income (loss)	124	161	168	139	137	127	114	91	592	469	309
Preferred stock dividends	(10)	(8)	(12)	(10)	(12)	(10)	(14)	(12)
Other Preferred Stock Dividends and Adjustments									(40)	(48)	(62)
Preferred stock redemption	0	0	(2)	0	0	0	(10)	0
Preferred Stock Redemption											0
Net earnings applicable to common shareholders	$ 114	$ 153	$ 154	$ 129	$ 125	$ 117	$ 90	$ 79	$ 550	$ 411	$ 247
Basic, per share	$ 0.57	$ 0.75	$ 0.76	$ 0.63	$ 0.61	$ 0.57	$ 0.44	$ 0.38	$ 2.71	$ 2	$ 1.20
Diluted	$ 0.54	$ 0.72	$ 0.73	$ 0.61	$ 0.60	$ 0.57	$ 0.44	$ 0.38	$ 2.60	$ 1.99	$ 1.20

Parent Company Financial Inf123

Parent Company Financial Information (Condensed Balance Sheets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest paid	$ 118,000	$ 83,000	$ 102,000
Held-to-maturity, fair value	762,000
Cash and due from banks	548,000	737,000	798,000	$ 842,000
Interest-bearing deposits	782,000	1,411,000
Available-for-sale, at fair value	15,161,000	13,372,000
Other noninterest-bearing investments	1,029,000	884,000
Other assets	916,000	984,000
Total assets	66,288,000	63,239,000
Other liabilities	571,000	942,000
Long-term debt	383,000	535,000
Total liabilities	58,609,000	55,605,000
Preferred stock	566,000	710,000
Common Stock	4,445,000	4,725,000
Retained earnings	2,807,000	2,321,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(139,000)	(122,000)	(55,000)
Total shareholders' equity	7,679,000	7,634,000	7,507,000	7,369,000
Total liabilities and shareholders' equity	66,288,000	63,239,000
Allowance for loan losses	518,000	567,000	606,000
Parent Company [Member]
Interest paid	26,000	35,000	51,000
Cash and due from banks	0	2,000	$ 18,000	$ 24,000
Interest-bearing deposits	332,000	529,000
Held-to-maturity Securities		0
Available-for-sale, at fair value	30,000	40,000
Loans Receivable, Net		0
Other noninterest-bearing investments	36,000	29,000
Other assets	32,000	81,000
Total assets	8,091,000	8,257,000
Other liabilities	30,000	89,000
Total liabilities	412,000	623,000
Preferred stock	566,000	710,000
Common Stock	4,445,000	4,725,000
Retained earnings	2,807,000	2,321,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(139,000)	(122,000)
Total shareholders' equity	7,679,000	7,634,000
Total liabilities and shareholders' equity	8,091,000	8,257,000
Parent Company [Member] | Due To Others [Member]
Long-term debt	382,000	534,000
Parent Company [Member] | Other Operating Companies [Member]
Investments in subsidiaries	41,000	6,000
Parent Company [Member] | Commercial Banks And Bank Holding Company [Member]
Investments in subsidiaries	$ 7,620,000	$ 7,570,000

Parent Company Financial Inf124

Parent Company Financial Information (Condensed Statements Of Income) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other loans and securities									$ 1,847	$ 1,729	$ 1,686
Total interest income	$ 562	$ 557	$ 558	$ 515	$ 501	$ 491	$ 487	$ 475	2,192	1,954	1,833
Total interest expense									127	87	118
Net interest loss	(526)	(522)	(528)	(489)	(480)	(469)	(465)	(453)	(2,065)	(1,867)	(1,715)
Provision for loan losses	11	(5)	(7)	(23)	3	(19)	(35)	(42)	(24)	(93)	(40)
Net interest loss after provision for loan losses									2,041	1,774	1,675
Other income (loss)									(5)	(12)	(11)
Total noninterest income	140	140	132	132	128	145	126	117	544	516	357
Salaries and employee benefits									1,011	983	973
Extinguishment of Debt, Amount									0	1	3
Total noninterest expense	417	413	405	414	404	403	382	396	1,649	1,585	1,581
Income taxes (benefit)									344	236	142
Preferred stock dividends	(10)	(8)	(12)	(10)	(12)	(10)	(14)	(12)
Net earnings applicable to common shareholders	$ 114	$ 153	$ 154	$ 129	$ 125	$ 117	$ 90	$ 79	550	411	247
Parent Company [Member]
Commercial bank subsidiaries									0	1	1
Other loans and securities									1	2	3
Total interest income									1	3	4
Affiliated trusts									0	3	4
Other borrowed funds									25	34	64
Total interest expense									25	37	68
Net interest loss									24	34	64
Equity and fixed income securities gains (losses), net									0	0	37
Other income (loss)									(7)	(4)	(13)
Total noninterest income									594	267	284
Salaries and employee benefits									24	23	25
Other operating expenses									8	(14)	10
Total noninterest expense									32	9	35
Income (loss) before income taxes and undistributed income (loss) of consolidated subsidiaries									538	224	185
Income taxes (benefit)									(42)	(19)	(27)
Income before equity in undistributed income (loss) of consolidated subsidiaries									580	243	212
Net Income (Loss) Attributable to Parent									592	469	309
Preferred stock dividends									(40)	(48)	(62)
Preferred stock redemption									(2)	(10)	0
Net earnings applicable to common shareholders									550	411	247
Parent Company [Member] | Other Operating Companies [Member]
Equity in undistributed income (loss) of consolidated subsidiaries									0	(4)	(11)
Parent Company [Member] | Commercial Banks And Bank Holding Company [Member]
Dividends from consolidated subsidiaries									587	263	234
Equity in undistributed income (loss) of consolidated subsidiaries									$ 12	$ 230	$ 108

Parent Company Financial Inf125

Parent Company Financial Information (Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net cash used in operating activities	$ 928	$ 596	$ 464
Other, net	8	7	18
Net cash provided by (used in) investing activities	(3,919)	(3,436)	(2,579)
Net change in short-term funds borrowed	2,149	480	103
Repayments of long-term debt	(153)	(280)	(288)
Payments for Repurchase of Common Stock	(332)	(97)	(7)
Other, net	0	2	(1)
Net cash provided by (used in) financing activities	2,802	2,779	2,071
Net increase (decrease) in cash and due from banks	(189)	(61)	(44)
Cash and Due From Banks - Beginning of Year	548	737	798	$ 842
Interest paid	118	83	102
Extinguishment of Debt, Amount	0	1	3
Other Noncash Income (Expense)	(29)	(15)	(30)
Parent Company [Member]
Net income (loss) applicable to controlling interest	592	469	309
Undistributed net losses (income) of consolidated subsidiaries	(12)	(226)	(97)
Net cash used in operating activities	524	212	290
Net decrease (increase) in interest-bearing deposits	196	347	132
Collection of advances to subsidiaries	0	0	56
Advances to subsidiaries	0	0	(41)
Proceeds from Sale and Maturity of Marketable Securities	20	4	125
Purchases of investment securities	0	0	(47)
Decrease (increase) of investment in subsidiaries	0	0	15
Other, net	2	7	4
Net cash provided by (used in) investing activities	218	358	244
Repayments of long-term debt	(164)	(280)	(271)
Proceeds from issuance of common stock and warrants	25	25	22
Cash paid for preferred stock redemption	(144)	(126)	(176)
Payments for Repurchase of Common Stock	(332)	(97)	(7)
Dividends paid on preferred stock	(40)	(50)	(63)
Dividends, Common Stock, Cash	(89)	(58)	(45)
Net cash provided by (used in) financing activities	(744)	(586)	(540)
Net increase (decrease) in cash and due from banks	(2)	(16)	(6)
Cash and Due From Banks - Beginning of Year	0	2	18	$ 24
Interest paid	26	35	51
Other Noncash Income (Expense)	$ (56)	$ (31)	$ 78