Huntington Bancshares (HBAN) 10-K 16 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	HUNTINGTON BANCSHARES INC/MD
Entity Central Index Key	49,196
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 14,498,375,048
Entity Common Stock, Shares Outstanding		1,072,026,681

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 1,520	$ 1,385
Interest-bearing deposits in banks	47	58
Trading account securities	86	133
Available-for-sale and other securities	15,469	15,563
Held-to-maturity securities	9,091	7,807
Loans held for sale	488	513
Loans and leases (includes $93 and $82 respectively, measured at fair value)
Commercial and industrial loans and leases	28,107	28,059
Commercial real estate loans	7,225	7,301
Automobile loans	12,100	10,969
Home equity loans	10,099	10,106
Residential mortgage loans	9,026	7,725
Loans Receivable, Gross, Recreation Finance	2,438	1,846
Other consumer loans	1,122	956
Loans and leases (includes $93 and $82 respectively, measured at fair value)(1)	70,117	66,962
Allowance for loan and lease losses	(691)	(638)
Net loans and leases	69,426	66,324
Bank owned life insurance	2,466	2,432
Premises and equipment	864	816
Goodwill	1,993	1,993
Other intangible assets	346	402
Servicing rights	238	226
Accrued income and other assets	2,151	2,062
Total assets	104,185	99,714
Deposits in domestic offices
Demand deposits—noninterest-bearing	21,546	22,836
Interest-bearing	55,495	52,772
Deposits	77,041	75,608
Short-term borrowings	5,056	3,693
Long-term debt	9,206	8,309
Accrued expenses and other liabilities	2,068	1,796
Total liabilities	93,371	89,406
Commitments and contingencies
Shareholders’ equity
Preferred stock	1,071	1,071
Common stock	11	11
Capital surplus	9,707	9,881
Less treasury shares, at cost	(35)	(27)
Accumulated other comprehensive loss	(528)	(401)
Retained earnings (deficit)	588	(227)
Total shareholders’ equity	10,814	10,308
Total liabilities and shareholders’ equity	$ 104,185	$ 99,714
Common shares authorized (par value of $0.01) (in shares)	1,500,000,000	1,500,000,000
Common shares issued (in shares)	1,075,294,946	1,088,641,251
Common shares outstanding (in shares)	1,072,026,681	1,085,688,538
Treasury shares outstanding (in shares)	3,268,265	2,952,713
Preferred Stock, Shares Authorized	6,617,808	6,617,808
Preferred shares issued (in shares)	2,702,571	2,702,571
Preferred shares outstanding (in shares)	1,098,006	1,098,006
Series A Preferred Stock
Shareholders’ equity
Total shareholders’ equity	$ 1,071	$ 1,071
Preferred shares outstanding (in shares)	362,506
Series B Preferred Stock
Shareholders’ equity
Preferred shares outstanding (in shares)	35,500

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets
Loans and leases, fair value	$ 93	$ 82
Shareholders’ equity
Common stock, par value (in usd per share)	$ 0.01	$ 0.01

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest and fee income:
Loans and leases	$ 2,838,000	$ 2,178,000	$ 1,760,000
Available-for-sale and other securities
Taxable	303,000	223,000	202,000
Tax-exempt	77,000	59,000	42,000
Held-to-maturity securities	193,000	138,000	87,000
Other	22,000	34,000	24,000
Total interest income	3,433,000	2,632,000	2,115,000
Interest expense
Deposits	180,000	102,000	82,000
Short-term borrowings	25,000	5,000	2,000
Federal Home Loan Bank advances	0	0	1,000
Subordinated notes and other long-term debt	226,000	156,000	79,000
Total interest expense	431,000	263,000	164,000
Net interest income	3,002,000	2,369,000	1,951,000
Provision for credit losses	201,000	191,000	100,000
Net interest income after provision for credit losses	2,801,000	2,178,000	1,851,000
Service charges on deposit accounts	353,000	324,000	280,000
Cards and payment processing income	206,000	169,000	143,000
Fees and Commissions, Fiduciary and Trust Activities	156,000	123,000	116,000
Mortgage banking income	131,000	128,000	112,000
Insurance income	81,000	84,000	81,000
Capital markets fees	76,000	60,000	54,000
Bank owned life insurance income	67,000	58,000	52,000
Gain on sale of loans	56,000	47,000	33,000
Net gains on sales of securities	0	2,000	3,000
Impairment losses recognized in earnings on available-for-sale securities	(4,000)	(2,000)	(2,000)
Other Income	185,000	157,000	167,000
Total noninterest income	1,307,000	1,150,000	1,039,000
Personnel costs	1,524,000	1,349,000	1,122,000
Outside data processing and other services	313,000	305,000	231,000
Net occupancy	212,000	153,000	122,000
Equipment	171,000	165,000	125,000
Deposit and other insurance expense	78,000	54,000	45,000
Professional services	69,000	105,000	50,000
Marketing	60,000	63,000	52,000
Amortization of intangibles	56,000	30,000	28,000
Other expense	231,000	184,000	201,000
Total noninterest expense	2,714,000	2,408,000	1,976,000
Income before income taxes	1,394,000	920,000	914,000
Provision for income taxes	208,000	208,000	221,000
Net income	1,186,000	712,000	693,000
Dividends on preferred shares	76,000	65,000	32,000
Net income available to common shareholders	$ 1,110,000	$ 647,000	$ 661,000
Average common shares—basic (in shares)	1,084,686	904,438	803,412
Average common shares—diluted (in shares)	1,136,186	918,790	817,129
Per common share:
Net income - basic (in USD per share)	$ 1.02	$ 0.72	$ 0.82
Net income - diluted (in USD per share)	1	0.70	0.81
Cash dividends declared, prior period (in USD per share)	$ 0.35	$ 0.29	$ 0.25
Impairment losses on available-for-sale securities:
Total OTTI losses	$ (4,000)	$ (6,000)	$ (3,000)
Noncredit-related portion of loss recognized in other comprehensive income	0	4,000	1,000
Impairment losses recognized in earnings on available-for-sale securities	$ (4,000)	$ (2,000)	$ (2,000)

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 1,186,000	$ 712,000	$ 693,000
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent	2,000	1,000	13,000
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax	2,000	1,000	13,000
Unrealized gains (losses) on available-for-sale and other securities:
Unrealized net gains (losses) on available-for-sale and other securities arising during the period, net of reclassification for net realized gains and losses	39,000	202,000	20,000
Total unrealized gains (losses) on available-for-sale securities	(37,000)	(201,000)	(7,000)
Unrealized gains on cash flow hedging derivatives, net of reclassifications to income	3,000	1,000	8,000
Change in accumulated unrealized gains (losses) for pension and other post-retirement obligations	0	25,000	(5,000)
Other comprehensive loss, net of tax	(34,000)	(175,000)	(4,000)
Comprehensive income	$ 1,152,000	$ 537,000	$ 689,000

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Capital Surplus	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings (Deficit)	Series A Preferred Stock	Series A Preferred StockRetained Earnings (Deficit)	Series B Preferred Stock	Series B Preferred StockRetained Earnings (Deficit)	Series C Preferred Stock	Series C Preferred StockPreferred Stock	Series C Preferred StockCapital Surplus	Series C Preferred StockRetained Earnings (Deficit)	Series D Preferred Stock	Series D Preferred StockPreferred Stock	Series D Preferred StockRetained Earnings (Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding			813,136		1,682
Beginning balance at Dec. 31, 2014	$ 6,328,000		$ 8,000	$ 7,222,000	$ (14,000)	$ (222,000)	$ (1,052,000)	$ 386,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	693,000						693,000
Other comprehensive income (loss)	(4,000)					(4,000)
Repurchase of common stock (in shares)			(23,036)
Repurchase of common stock	252,000		$ 0	252,000
Cash dividends declared:
Dividends, Common Stock, Cash	200,000						200,000
Dividends, Preferred Stock, Cash								31,000	$ 31,000	$ 1,000	$ 1,000
Recognition of the fair value of share-based compensation	51,000			51,000
Other share-based compensation activity (in shares)			6,784
Other share-based compensation activity	13,000		$ 0	16,000			3,000
Other (in shares)			86		359
Other	2,000		$ 0	(2,000)	$ 4,000		0
Ending balance at Dec. 31, 2015	6,595,000		$ 8,000	7,039,000	$ (18,000)	(226,000)	(594,000)	386,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding			796,970		2,041
Net income	712,000						712,000
Other comprehensive income (loss)	(175,000)					(175,000)
Issuance of common stock (in shares)			285,425
Issuance of common stock	2,767,000		$ 3,000	2,764,000
Issuance of preferred stock												$ 104,000	$ 100,000	$ 4,000		$ 585,000	$ 585,000
Cash dividends declared:
Dividends, Common Stock, Cash	275,000						275,000
Dividends, Preferred Stock, Cash								31,000	31,000	1,000	1,000	3,000			$ 3,000	31,000		$ 31,000
Recognition of the fair value of share-based compensation	66,000			66,000
Other share-based compensation activity (in shares)			5,924
Other share-based compensation activity	1,000		$ 0	5,000			4,000
Other (in shares)			322		912
Other	6,000		$ 0	(3,000)	$ 9,000		0
Ending balance at Dec. 31, 2016	10,308,000	$ 1,071,000	$ 11,000	9,881,000	$ (27,000)	(401,000)	(227,000)	1,071,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding			1,088,641		(2,953)
Net income	1,186,000						1,186,000
Other comprehensive income (loss)	(34,000)					(34,000)
Repurchase of common stock (in shares)			(19,430)
Repurchase of common stock	260,000		$ 0	260,000
Cash dividends declared:
Dividends, Common Stock, Cash	379,000						379,000
Dividends, Preferred Stock, Cash								31,000	$ 31,000	$ 1,000	$ 1,000	$ 6,000			$ 6,000	$ 38,000		$ 38,000
Recognition of the fair value of share-based compensation	92,000			92,000
Other share-based compensation activity (in shares)			5,923
Other share-based compensation activity	(19,000)		$ 0	(10,000)			(9,000)
TCJA, Reclassification from accumulated OCI to retained earnings	0					(93,000)	93,000
Other (in shares)			(161)		315
Other	4,000		$ 0	(4,000)	$ 8,000		0
Ending balance at Dec. 31, 2017	$ 10,814,000		$ 11,000	$ 9,707,000	$ (35,000)	$ (528,000)	$ 588,000	$ 1,071,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding			1,075,295		(3,268)

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash dividends declared:
Common stock, cash dividend per share (in USD per share)	$ 0.35	$ 0.29	$ 0.25
Series A Preferred Stock
Cash dividends declared:
Preferred stock dividend per share (in usd per share)	85	85	85
Series B Preferred Stock
Cash dividends declared:
Preferred stock dividend per share (in usd per share)	39.11	34.03	$ 29.84
Series C Preferred Stock
Cash dividends declared:
Preferred stock dividend per share (in usd per share)	58.76	26.28
Series D Preferred Stock
Cash dividends declared:
Preferred stock dividend per share (in usd per share)	$ 62.50	$ 51.04

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net income	$ 1,186,000	$ 712,000	$ 693,000
Adjustments to reconcile net income to net cash provided by (used for) operating activities:
Impairment of goodwill	0
Provision for credit losses	201,000	191,000	100,000
Depreciation and amortization	413,000	380,000	341,000
Share-based compensation expense	92,000	66,000	51,000
Deferred income tax expense	168,000	165,000	69,000
Net gains on sales of securities	0	2,000	3,000
Impairment losses recognized in earnings on available-for-sale securities	4,000	2,000	2,000
Net Change in:
Trading account securities	47,000	(96,000)	5,000
Loans held for sale	12,000	(123,000)	54,000
Accrued income and other assets	(420,000)	(96,000)	(234,000)
Accrued expense and other liabilities	233,000	4,000	(35,000)
Other, net	18,000	12,000	(10,000)
Net cash provided by (used in) operating activities	1,954,000	1,215,000	1,033,000
Investing activities
Change in interest bearing deposits in banks	39,000	26,000	13,000
Cash paid for acquisition of a business, net of cash received	0	(133,000)	(458,000)
Proceeds from:
Maturities and calls of available-for-sale and other securities	1,946,000	2,113,000	1,908,000
Maturities and calls of held-to-maturity securities	1,054,000	1,212,000	595,000
Sales of available-for-sale securities	2,490,000	6,154,000	163,000
Purchases of available-for-sale securities	(5,418,000)	(10,888,000)	(4,507,000)
Purchases of held-to-maturity securities	(1,356,000)	0	(379,000)
Net proceeds from sales of portfolio loans	603,000	2,981,000	1,304,000
Net loan and lease activity, excluding sales and purchases	(3,680,000)	(3,951,000)	(3,187,000)
Purchases of premises and equipment	(194,000)	(120,000)	(93,000)
Proceeds from sales of other real estate	38,000	50,000	36,000
Purchases of loans and leases	(405,000)	(411,000)	(334,000)
Cash Provided by (Used in) Investing Activities, Discontinued Operations	0	(480,000)	0
Other, net	17,000	2,000	10,000
Net cash provided by (used in) investing activities	(4,866,000)	(3,445,000)	(4,929,000)
Financing activities
Increase (decrease) in deposits	1,433,000	(292,000)	3,644,000
Increase (decrease) in short-term borrowings	1,371,000	1,900,000	(1,819,000)
Sale of deposits	0	0	(48,000)
Net proceeds from issuance of long-term debt	1,816,000	2,128,000	3,232,000
Maturity/redemption of long-term debt	(948,000)	(1,275,000)	(1,037,000)
Dividends paid on preferred stock	(76,000)	(54,000)	(32,000)
Dividends paid on common stock	(349,000)	(245,000)	(193,000)
Repurchases of common stock	(260,000)	0	(252,000)
Proceeds from stock options exercised	11,000	17,000	19,000
Net proceeds from issuance of preferred stock	0	585,000	0
Proceeds from issuance of manditorily reedemable preferred stock	75,000	0	0
Payments Related to Tax Withholding for Share-based Compensation	(26,000)	0	0
Other, net	0	4,000	8,000
Net cash provided by (used) financing activities	3,047,000	2,768,000	3,522,000
Increase (decrease) in cash and cash equivalents	135,000	538,000	(374,000)
Cash and cash equivalents at beginning of period	1,385,000	847,000	1,221,000
Cash and cash equivalents at end of period	1,520,000	1,385,000	847,000
Supplemental disclosures:
Interest paid	409,000	241,000	150,000
Income taxes paid	84,000	5,000	154,000
Non-cash activities:
Common stock issued to acquire FirstMerit	0	2,767,000	0
Preferred stock issued to acquire FirstMerit	0	104,000	0
Loans transferred to held-for-sale from portfolio	660,000	3,437,000	1,727,000
Loans transferred to portfolio from held-for-sale	12,000	482,000	278,000
Transfer of loans to OREO	29,000	$ 79,000	25,000
Transfer of securities to held-to-maturity from available-for-sale	$ 993,000		$ 3,000,000

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES Nature of Operations — Huntington Bancshares Incorporated (Huntington or the Company) is a multi-state diversified regional bank holding company organized under Maryland law in 1966 and headquartered in Columbus, Ohio. Through its subsidiaries, including its bank subsidiary, The Huntington National Bank (the Bank), Huntington is engaged in providing full-service commercial, small business, consumer banking services, mortgage banking services, automobile financing, recreational vehicle and marine financing, equipment leasing, investment management, trust services, brokerage services, customized insurance programs, and other financial products and services. Huntington’s banking offices are located in Ohio, Illinois, Michigan, Pennsylvania, Indiana, West Virginia, Wisconsin and Kentucky. Select financial services and other activities are also conducted in various other states. International banking services are available through the headquarters office in Columbus, Ohio. Basis of Presentation — The Consolidated Financial Statements include the accounts of Huntington and its majority-owned subsidiaries and are presented in accordance with GAAP. All intercompany transactions and balances have been eliminated in consolidation. Companies in which Huntington holds more than a 50% voting equity interest, or a controlling financial interest, or are a VIE in which Huntington has the power to direct the activities of an entity that most significantly impact the entity’s economic performance and has an obligation to absorb losses or the right to receive benefits from the VIE which could potentially be significant to the VIE are consolidated. VIEs are legal entities with insubstantial equity, whose equity investors lack the ability to make decisions about the entity’s activities, or whose equity investors do not have the obligation to absorb losses or the right to receive the residual returns of the entity if they occur. VIEs in which Huntington does not hold the power to direct the activities of the entity that most significantly impact the entity’s economic performance or does not have an obligation to absorb losses or the right to receive benefits from the VIE which could potentially be significant to the VIE are not consolidated. For consolidated entities where Huntington holds less than a 100% interest, Huntington recognizes non-controlling interest (included in shareholders’ equity) for the equity held by others and non-controlling profit or loss (included in noninterest expense) for the portion of the entity’s earnings attributable to other’s interests. Investments in companies that are not consolidated are accounted for using the equity method when Huntington has the ability to exert significant influence. Those investments in nonmarketable securities for which Huntington does not have the ability to exert significant influence are generally accounted for using the cost method. Investments in private investment partnerships that are accounted for under the equity method or the cost method are included in Accrued income and other assets and Huntington’s proportional interest in the equity investments’ earnings are included in other noninterest income. Investment interests accounted for under the cost and equity methods are periodically evaluated for impairment. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that significantly affect amounts reported in the Consolidated Financial Statements. Huntington utilizes processes that involve the use of significant estimates and the judgments of management in determining the amount of its allowance for credit losses, income taxes, deferred tax, and contingent liabilities, as well as fair value measurements of investment securities, derivatives, goodwill, other intangible assets, pension assets and liabilities, short-term borrowings, mortgage servicing rights, and loans held for sale. As with any estimate, actual results could differ from those estimates. For statements of cash flows purposes, cash and cash equivalents are defined as the sum of Cash and due from banks, which includes amounts on deposit with the Federal Reserve and Federal funds sold and securities purchased under resale agreements. Certain prior period amounts have been reclassified to conform to the current year’s presentation. Resale and Repurchase Agreements — Securities purchased under agreements to resell and securities sold under agreements to repurchase are treated as collateralized financing transactions and are recorded at the amounts at which the securities were acquired or sold plus accrued interest. The fair value of collateral either received from or provided to a third-party is continually monitored and additional collateral is obtained or requested to be returned to Huntington in accordance with the agreement. Securities — Securities purchased with the intention of recognizing short-term profits or which are actively bought and sold are classified as trading account securities and reported at fair value. The unrealized gains or losses on trading account securities are recorded in other noninterest income, except for gains and losses on trading account securities used to economically hedge the fair value of MSRs, which are included in mortgage banking income. Debt securities purchased in which Huntington has the positive intent and ability to hold to their maturity are classified as held-to-maturity securities. Held-to-maturity securities are recorded at amortized cost. All other debt and equity securities are classified as available-for-sale and other securities. Unrealized gains or losses on available-for-sale and other securities are reported as a separate component of accumulated OCI in the Consolidated Statements of Changes in Shareholders’ Equity. Credit-related declines in the value of debt securities that are considered OTTI are recorded in noninterest income. Huntington evaluates its investment securities portfolio on a quarterly basis for indicators of OTTI. Huntington assesses whether OTTI has occurred when the fair value of a debt security is less than the amortized cost basis at the balance sheet date. Management reviews the amount of unrealized loss, the length of time the security has been in an unrealized loss position, the credit rating history, market trends of similar security classes, time remaining to maturity, and the source of both interest and principal payments to identify securities which could potentially be impaired. For those debt securities that Huntington intends to sell or is more likely than not required to sell, before the recovery of their amortized cost bases, the difference between fair value and amortized cost is considered to be OTTI and is recognized in noninterest income. For those debt securities that Huntington does not intend to sell or is not more likely than not required to sell, prior to expected recovery of amortized cost bases, the credit portion of the OTTI is recognized in noninterest income while the noncredit portion is recognized on OCI. In determining the credit portion, Huntington uses a discounted cash flow analysis, which includes evaluating the timing and amount of the expected cash flows. Non-credit-related OTTI results from other factors, including increased liquidity spreads and higher interest rates. Presentation of OTTI is made in the Consolidated Statements of Income on a gross basis with a reduction for the amount of OTTI recognized in OCI. Securities transactions are recognized on the trade date (the date the order to buy or sell is executed). The carrying value plus any related accumulated OCI balance of sold securities is used to compute realized gains and losses. Interest and dividends on securities, including amortization of premiums and accretion of discounts using the effective interest method over the period to maturity, are included in interest income. Nonmarketable equity securities include stock acquired for regulatory purposes, such as FHLB stock and FRB stock. These securities are accounted for at cost, evaluated for impairment, and included in available-for-sale and other securities. Loans and Leases — Loans and direct financing leases for which Huntington has the intent and ability to hold for the foreseeable future, or until maturity or payoff, are classified in the Consolidated Balance Sheets as loans and leases. Except for purchase credit impaired loans and loans for which the fair value option has been elected, loans and leases are carried at the principal amount outstanding, net of charge-offs, unamortized deferred loan origination fees and costs, premiums and discounts, and unearned income. Direct financing leases are reported at the aggregate of lease payments receivable and estimated residual values, net of unearned and deferred income. Interest income is accrued as earned using the interest method based on unpaid principal balances. Huntington defers the fees it receives from the origination of loans and leases, as well as the direct costs of those activities. Huntington also acquires loans at a premium and at a discount to their contractual values. Except for purchased credit impaired loans, Huntington amortizes loan discounts, premiums, and net loan origination fees and costs over the contractual lives of the related loans using the effective interest method. Troubled debt restructurings are loans for which the original contractual terms have been modified to provide a concession to a borrower experiencing financial difficulties. Loan modifications are considered TDRs when the concessions provided are not available to the borrower through either normal channels or other sources. However, not all loan modifications are TDRs. Modifications resulting in troubled debt restructurings may include changes to one or more terms of the loan, including but not limited to, a change in interest rate, an extension of the repayment period, a reduction in payment amount, and partial forgiveness or deferment of principal or accrued interest. Residual values on leased equipment are evaluated quarterly for impairment. Impairment of the residual values of direct financing leases determined to be other than temporary is recognized by writing the leases down to fair value with a charge to other noninterest expense. Leased equipment residual value impairment will arise if the expected fair value is less than the carrying amount, net of estimated amounts reimbursable by the lessee. Future declines in the expected residual value of the leased equipment would result in expected losses of the leased equipment. For leased equipment, the residual component of a direct financing lease represents the estimated fair value of the leased equipment at the end of the lease term. Huntington uses industry data, historical experience, and independent appraisals to establish these residual value estimates. Additional information regarding product life cycle, product upgrades, as well as insight into competing products are obtained through relationships with industry contacts and are factored into residual value estimates where applicable. Loans Held for Sale — Loans in which Huntington does not have the intent and ability to hold for the foreseeable future are classified as loans held for sale. Loans held for sale (excluding loans originated or acquired with the intent to sell, which are carried at fair value) are carried at the lower of cost or fair value less cost to sell. The fair value option is generally elected for mortgage loans held for sale to facilitate hedging of the loans. The fair value of such loans is estimated based on the inputs that include prices of mortgage backed securities adjusted for other variables such as, interest rates, expected credit defaults and market discount rates. The adjusted value reflects the price we expect to receive from the sale of such loans. Allowance for Credit Losses — Huntington maintains two reserves, both of which reflect management’s judgment regarding the appropriate level necessary to absorb credit losses inherent in our loan and lease portfolio: the ALLL and the AULC. Combined, these reserves comprise the total ACL. The determination of the ACL requires significant estimates, including the timing and amounts of expected future cash flows on impaired loans and leases, consideration of current economic conditions, and historical loss experience pertaining to pools of homogeneous loans and leases, all of which may be susceptible to change. The appropriateness of the ACL is based on management’s current judgments about the credit quality of the loan portfolio. These judgments consider on-going evaluations of the loan and lease portfolio, including such factors as the differing economic risks associated with each loan category, the financial condition of specific borrowers, the level of delinquent loans, the value of any collateral and, where applicable, the existence of any guarantees or other documented support. Further, management evaluates the impact of changes in interest rates and overall economic conditions on the ability of borrowers to meet their financial obligations when quantifying our exposure to credit losses and assessing the appropriateness of our ACL at each reporting date. In addition to general economic conditions and the other factors described above, additional factors also considered include: the impact of increasing or decreasing commercial real estate values and the development of new or expanded Commercial business segments. The ALLL consists of two components: (1) the transaction reserve, which includes a loan level allocation, specific reserves related to loans considered to be impaired, and loans involved in troubled debt restructurings, and (2) the general reserve. The transaction reserve component includes both (1) an estimate of loss based on pools of commercial and consumer loans and leases with similar characteristics and (2) an estimate of loss based on an impairment review of each impaired C&I and CRE loan where obligor balance is greater than $1 million . For the C&I and CRE portfolios, the estimate of loss based on pools of loans and leases with similar characteristics is made by applying a PD factor and a LGD factor to each individual loan based on a regularly updated loan grade, using a standardized loan grading system. The PD factor and an LGD factor are determined for each loan grade using statistical models based on historical performance data. The PD factor considers on-going reviews of the financial performance of the specific borrower, including cash flow, debt-service coverage ratio, earnings power, debt level, and equity position, in conjunction with an assessment of the borrower’s industry and future prospects. The LGD factor considers analysis of the type of collateral and the relative LTV ratio. These reserve factors are developed based on credit migration models that track historical movements of loans between loan ratings over time and a combination of long-term average loss experience of our own portfolio and external industry data. In the case of more homogeneous portfolios, such as automobile loans, home equity loans, and residential mortgage loans, the determination of the transaction reserve also incorporates PD and LGD factors. The estimate of loss is based on pools of loans and leases with similar characteristics. The PD factor considers current credit scores unless the account is delinquent, in which case a higher PD factor is used driven by the associated delinquency status. The credit score provides a basis for understanding the borrower’s past and current payment performance, and this information is used to estimate expected losses over the emergence period. The performance of first-lien loans ahead of our junior-lien loans is available to use as part of our updated score process. The LGD factor considers analysis of the type of collateral and the relative LTV ratio. Credit scores, models, analyses, and other factors used to determine both the PD and LGD factors are updated frequently to capture the recent behavioral characteristics of the subject portfolios, as well as any changes in loss mitigation or credit origination strategies, and adjustments to the reserve factors are made as required. The general reserve consists of various risk-profile reserve components. The risk-profile component considers items unique to our structure, policies, processes, and portfolio composition, as well as qualitative measurements and assessments of the loan portfolios including, but not limited to, concentrations, portfolio composition, industry comparisons, and internal review functions. The estimate for the AULC is determined using the same procedures and methodologies as used for the ALLL. The loss factors used in the AULC are the same as the loss factors used in the ALLL while also considering a historical utilization of unused commitments. The AULC is recorded in Accrued expenses and other liabilities in the Consolidated Balance Sheets. Nonaccrual and Past Due Loans — Loans are considered past due when the contractual amounts due with respect to principal and interest are not received within 30 days of the contractual due date. Any loan in any portfolio may be placed on nonaccrual status prior to the policies described below when collection of principal or interest is in doubt. When a borrower with debt is discharged in a Chapter 7 bankruptcy and not reaffirmed by the borrower, the loan is determined to be collateral dependent and placed on nonaccrual status, unless there is a co-borrower. All classes within the C&I and CRE portfolios (except for purchased credit-impaired loans) are placed on nonaccrual status at 90 -days past due. First-lien home equity loans are placed on nonaccrual status at 150 -days past due. Junior-lien home equity loans are placed on nonaccrual status at the earlier of 120 -days past due or when the related first-lien loan has been identified as nonaccrual. Automobile, RV and marine finance and other consumer loans are placed on non-accrual if not charged off when the loan is 120 -days past due. Residential mortgage loans are placed on nonaccrual status at 150 -days past due, with the exception of residential mortgages guaranteed by government agencies which continue to accrue interest at the rate guaranteed by the government agency. Huntington is reimbursed from the government agency for reasonable expenses incurred in servicing loans. For all classes within all loan portfolios, when a loan is placed on nonaccrual status, any accrued interest income is reversed with current year accruals charged to interest income, and prior year amounts charged-off as a credit loss. For all classes within all loan portfolios, cash receipts on NALs are applied against principal until the loan or lease has been collected in full, including the charged-off portion, after which time any additional cash receipts are recognized as interest income. However, for secured non-reaffirmed debt in a Chapter 7 bankruptcy, payments are applied to principal and interest when the borrower has demonstrated a capacity to continue payment of the debt and collection of the debt is reasonably assured. For unsecured non-reaffirmed debt in a Chapter 7 bankruptcy where the carrying value has been fully charged-off, payments are recorded as loan recoveries. Regarding all classes within the C&I and CRE portfolios, the determination of a borrower’s ability to make the required principal and interest payments is based on an examination of the borrower’s current financial statements, industry, management capabilities, and other qualitative measures. For all classes within the consumer loan portfolio, the determination of a borrower’s ability to make the required principal and interest payments is based on multiple factors, including number of days past due and, in some instances, an evaluation of the borrower’s financial condition. When, in management’s judgment, the borrower’s ability to make required principal and interest payments resumes and collectability is no longer in doubt, supported by sustained repayment history, the loan is returned to accrual status. For these loans that have been returned to accrual status, cash receipts are applied according to the contractual terms of the loan. Charge-off of Uncollectible Loans — Any loan in any portfolio may be charged-off prior to the policies described below if a loss confirming event has occurred. Loss confirming events include, but are not limited to, bankruptcy (unsecured), continued delinquency, foreclosure, or receipt of an asset valuation indicating a collateral deficiency and that asset is the sole source of repayment. Additionally, discharged, collateral dependent non-reaffirmed debt in Chapter 7 bankruptcy filings will result in a charge-off to estimated collateral value, less anticipated selling costs. C&I and CRE loans are either charged-off or written down to net realizable value at 90 -days past due. Automobile, RV and marine finance and other consumer loans are generally charged-off at 120 -days past due. First-lien and junior-lien home equity loans are charged-off to the estimated fair value of the collateral, less anticipated selling costs, at 150 -days past due and 120 -days past due, respectively. Residential mortgages are charged-off to the estimated fair value of the collateral at 150 -days past due. Impaired Loans — For all classes within the C&I and CRE portfolios, all loans with an obligor balance of $1 million or greater are evaluated on a quarterly basis for impairment. Except for TDRs, consumer loans within any class are generally not individually evaluated on a regular basis for impairment. All TDRs, regardless of the outstanding balance amount, are also considered to be impaired. Loans acquired with evidence of deterioration in credit quality since origination for which it is probable at acquisition that all contractually required payments will not be collected are also considered to be impaired. Once a loan has been identified for an assessment of impairment, the loan is considered impaired when, based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. This determination requires significant judgment and use of estimates, and the eventual outcome may differ significantly from those estimates. When a loan in any class has been determined to be impaired, the amount of the impairment is measured using the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, the observable market price of the loan, or the fair value of the collateral, less anticipated selling costs, if the loan is collateral dependent. A specific reserve is established as a component of the ALLL when a loan has been determined to be impaired. Subsequent to the initial measurement of impairment, if there is a significant change to the impaired loan’s expected future cash flows, or if actual cash flows are significantly different from the cash flows previously estimated, Huntington recalculates the impairment and appropriately adjusts the specific reserve. Similarly, if Huntington measures impairment based on the observable market price of an impaired loan or the fair value of the collateral of an impaired collateral dependent loan, Huntington will adjust the specific reserve. When a loan within any class is impaired, the accrual of interest income is discontinued unless the receipt of principal and interest is no longer in doubt. Interest income on TDRs is accrued when all principal and interest is expected to be collected under the post-modification terms. Cash receipts on nonaccruing impaired loans within any class are generally applied entirely against principal until the loan has been collected in full (including any portion charged-off) or the loan is deemed current, after which time any additional cash receipts are recognized as interest income. Cash receipts on accruing impaired loans within any class are applied in the same manner as accruing loans that are not considered impaired. Purchased Credit-Impaired Loans — Purchased loans with evidence of deterioration in credit quality since origination, for which it is probable at acquisition that we will be unable to collect all contractually required payments, are considered to be credit impaired. Purchased credit-impaired loans are initially recorded at fair value, which is estimated by discounting the cash flows expected to be collected at the acquisition date. Because the estimate of expected cash flows reflects an estimate of future credit losses expected to be incurred over the life of the loans, an allowance for credit losses is not recorded at the acquisition date. The excess of cash flows expected at acquisition over the estimated fair value, referred to as the accretable yield, is recognized in interest income over the remaining life of the loan, or pool of loans, on a level-yield basis. The difference between the contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable difference. A subsequent decrease in the estimate of cash flows expected to be received on purchased credit-impaired loans generally results in the recognition of an allowance for credit losses. Subsequent increases in cash flows result in reversal of any nonaccretable difference (or allowance for loan and lease losses to the extent one has been recorded) with a positive impact on interest income subsequently recognized. The measurement of cash flows involves assumptions and judgments for interest rates, prepayments, default rates, loss severity, and collateral values. All of these factors are inherently subjective and significant changes in the cash flow estimates over the life of the loan can result. Transfers of Financial Assets and Securitizations — Transfers of financial assets in which we have surrendered control over the transferred assets are accounted for as sales. In assessing whether control has been surrendered, we consider whether the transferee would be a consolidated affiliate, the existence and extent of any continuing involvement in the transferred financial assets, and the impact of all arrangements or agreements made contemporaneously with, or in contemplation of, the transfer, even if they were not entered into at the time of transfer. Control is generally considered to have been surrendered when (i) the transferred assets have been legally isolated from us or any of our consolidated affiliates, even in bankruptcy or other receivership, (ii) the transferee (or, if the transferee is an entity whose sole purpose is to engage in securitization or asset-backed financing that is constrained from pledging or exchanging the assets it receives, each third-party holder of its beneficial interests) has the right to pledge or exchange the assets (or beneficial interests) it received without any constraints that provide more than a trivial benefit to us, and (iii) neither we nor our consolidated affiliates and agents have (a) both the right and obligation under any agreement to repurchase or redeem the transferred assets before their maturity, (b) the unilateral ability to cause the holder to return specific financial assets that also provides us with a more-than-trivial benefit (other than through a cleanup call) or (c) an agreement that permits the transferee to require us to repurchase the transferred assets at a price so favorable that it is probable that it will require us to repurchase them. If the sale criteria are met, the transferred financial assets are removed from our balance sheet and a gain or loss on sale is recognized. If the sale criteria are not met, the transfer is recorded as a secured borrowing in which the assets remain on our balance sheet and the proceeds from the transaction are recognized as a liability. For the majority of financial asset transfers, it is clear whether or not we have surrendered control. For other transfers, such as in connection with complex transactions or where we have continuing involvement, we generally obtain a legal opinion as to whether the transfer results in a true sale by law. From time to time we securitize certain automobile loans. Gains and losses on the loans and leases sold and servicing rights associated with loan and lease sales are determined when the related loans or leases are sold to either a securitization trust or third-party. For loan or lease sales with servicing retained, a servicing asset is recorded at fair value for the right to service the loans sold. Derivative Financial Instruments — A variety of derivative financial instruments, principally interest rate swaps, caps, floors, and collars, are used in asset and liability management activities to protect against the risk of adverse price or interest rate movements. These instruments provide flexibility in adjusting Huntington’s sensitivity to changes in interest rates without exposure to loss of principal and higher funding requirements. Huntington also uses derivatives, principally loan sale commitments, in hedging its mortgage loan interest rate lock commitments and its mortgage loans held for sale. Mortgage loan sale commitments and the related interest rate lock commitments are carried at fair value on the Consolidated Balance Sheets with changes in fair value reflected in mortgage banking income. Huntington also uses certain derivative financial instruments to offset changes in value of its MSRs. These derivatives consist primarily of forward interest rate agreements and forward mortgage contracts. The derivative instruments used are not designated as qualifying hedges. Accordingly, such derivatives are recorded at fair value with changes in fair value reflected in mortgage banking income. Derivative financial instruments are recorded in the Consolidated Balance Sheets as either an asset or a liability (in accrued income and other assets or accrued expenses and other liabilities, respectively) and measured at fair value. On the date a derivative contract is entered into, we designate it as either: • a qualifying hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge); • a qualifying hedge of the variability of cash flows to be received or paid related to a recognized asset liability or forecasted transaction (cash flow hedge); or • a trading instrument or a non-qualifying (economic) hedge. Changes in the fair value of a derivative that has been designated and qualifies as a fair value hedge, along with the changes in the fair value of the hedged asset or liability that is attributable to the hedged risk, are recorded in current period earnings. Changes in the fair value of a derivative that has been designated and qualifies as a cash flow hedge, to the extent effective as a hedge, are recorded in accumulated other comprehensive income, net of income taxes, and reclassified into earnings in the period during which the hedged item affects earnings. Ineffectiveness in the hedging relationship is reflected in current period earnings. Changes in the fair value of derivatives held for trading purposes or which do not qualify for hedge accounting are reported in current period earnings. For those derivatives to which hedge accounting is applied, Huntington formally documents the hedging relationship and the risk management objective and strategy for undertaking the hedge. This documentation identifies the hedging instrument, the hedged item or transaction, the nature of the risk being hedged, and, unless the hedge meets all of the criteria to assume there is no ineffectiveness, the method that will be used to assess the effectiveness of the hedging instrument and how ineffectiveness will be measured. The methods utilized to assess retrospective hedge effectiveness, as well as the frequency of testing, vary based on the type of item being hedged and the designated hedge period. For specifically designated fair value hedges of certain fixed-rate debt, Huntington utilizes the short-cut method when certain criteria are met. For other fair value hedges of fixed-rate debt, including certificates of deposit, Huntington utilizes the regression method to evaluate hedge effectiveness on a quarterly basis. For fair value hedges of portfolio loans, the regression method is used to evaluate effectiveness on a daily basis. For cash flow hedges, the regression method is applied on a quarterly

ACCOUNTING STANDARDS UPDATE

ACCOUNTING STANDARDS UPDATE	12 Months Ended
	Dec. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
ACCOUNTING STANDARDS UPDATE	ACCOUNTING STANDARDS UPDATE Standard Summary of guidance Effects on financial statements ASU 2014-09 - Revenue from Contracts with Customers (Topic 606): Issued May 2014 - Topic 606 supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. - Requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. - Also requires additional qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers - Guidance sets forth a five step approach for revenue recognition. - Effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Management adopted the new guidance on January 1, 2018 using the modified retrospective approach. - Management's analysis includes: (a) Identification of all revenue streams included in the financial statements; (b) Determination of scope exclusions to identify ‘in-scope’ revenue streams; (c) Determination of size, timing, and amount of revenue recognition for in-scope items; (d) Identification of contracts for further analysis; and (e) Completion of review of certain contracts to evaluate the potential impact of the new guidance. - Key revenue streams identified include service charges, credit card and payment processing fees, trust services fees, insurance income, brokerage services, and mortgage banking income. - The Update did not have a significant impact on Huntington’s Consolidated Financial Statements. ASU 2016-01 - Recognition and Measurement of Financial Assets and Financial Liabilities. Issued January 2016 - Improvements to GAAP disclosures including requiring an entity to: (a) Measure its equity investments with changes in the fair value recognized in the income statement. (b) Present separately in OCI the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments (i.e., FVO liability). (c) Use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. (d) Assess deferred tax assets related to a net unrealized loss on AFS securities in combination with the entity’s other deferred tax assets. - Effective for the fiscal period beginning after December 15, 2017, including interim periods within those fiscal years. - Amendments are applied as a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. - The amendment did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2016-02 - Leases. Issued February 2016 - New lease accounting model for lessors and lessees. For lessees, virtually all leases will be required to be recognized on the balance sheet by recording a right-of-use asset and lease liability. Subsequent accounting for leases varies depending on whether the lease is classified as an operating lease or a finance lease. - Accounting applied by a lessor is largely unchanged from that applied under the existing guidance. - Requires additional qualitative and quantitative disclosures with the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. - Effective for the fiscal period beginning after December 15, 2018, with early application permitted. - Management intends to adopt the guidance on January 1, 2019, and has formed a working group comprised of associates from different disciplines, including Procurement, Real Estate, and Credit Administration, to evaluate the impact of the standard where Huntington is a lessee or lessor, as well as any impact to borrower’s financial statements. - Management is currently assessing the impact of the new guidance on Huntington's Consolidated Financial Statements, including working with associates engaged in the procurement of goods and services used in the entity’s operations, and reviewing contractual arrangements for embedded leases in an effort to identify Huntington’s full lease population. - Huntington will recognize right-of-use assets and lease liabilities for virtually all of its operating lease commitments. Standard Summary of guidance Effects on financial statements ASU 2016-13 - Financial Instruments - Credit Losses. Issued June 2016 - Eliminates the probable recognition threshold for credit losses on financial assets measured at amortized cost. - Requires those financial assets to be presented at the net amount expected to be collected (i.e., net of expected credit losses). - Measurement of expected credit losses should be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amount. - Effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018. - Adoption will be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. - Management intends to adopt the guidance on January 1, 2020 and has formed a working group comprised of teams from different disciplines including credit and finance to evaluate the requirements of the new standard and the impact it will have on our processes. - The early stages of this evaluation include a review of existing credit models to identify areas where existing credit models used to comply with other regulatory requirements may be leveraged and areas where new impairment models may be required. ASU 2016-15 - Classification of Certain Cash Receipts and Cash Payments. Issued August 2016 - Clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. - Provides consistent principles for evaluating the classification of cash payments and receipts in the statement of cash flows to reduce diversity in practice with respect to several types of cash flows. - Effective using a retrospective transition approach for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-04 - Simplifying the Test for Goodwill Impairment. Issued January 2017 - Simplifies the goodwill impairment test by eliminating Step 2 of the goodwill impairment process, which requires an entity to determine the implied fair value of its goodwill by assigning fair value to all its assets and liabilities. - Entities will instead recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. - Entities will still have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. - Effective for annual and interim goodwill tests performed in fiscal years beginning after December 15, 2019. Early adoption is permitted. - The amendment is not expected to have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-07 - Improving the Presentation of Net Periodic Pension Cost and Periodic Postretirement Benefit Cost. Issued March 2017 - Requires that an employer report the service cost component of the pension cost and postretirement benefit cost in the same line items as other compensation costs arising from services rendered by the pertinent employees during the period. - Other components of the net benefit cost should be presented or disclosed separately in the income statement from the service cost component. - Effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-09 - Stock Compensation Modification Accounting. Issued May 2017 - Reduces the current diversity in practice and provides explicit guidance pertaining to the provisions of modification accounting. - Clarifies that an entity should account for effects of modification unless the fair value, vesting conditions and the classification of the modified award are the same as the original awards immediately before the original award is modified. - Effective prospectively for annual periods and interim periods within those annual periods, beginning after December 15, 2017. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. Standard Summary of guidance Effects on financial statements ASU 2017-12 - Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities. Issued August 2017 - Aligns the entity’s risk management activities and financial reporting for hedging relationships. - Requires an entity to present the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is reported. - Refines measurement techniques for hedges of benchmark interest rate risk. - Eliminates the separate measurement and reporting of hedge ineffectiveness. - Allows stated amount of assets in a closed portfolio to be fair value hedged by excluding proportion of hedged item related to prepayments, defaults and other events. - Eases hedge effectiveness testing including an option to perform qualitative testing. - Effective for annual periods and interim periods within those annual periods, beginning after December 15, 2018. For cash flow and net investment hedges, cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness should be recognized in AOCI with a corresponding adjustment to retained earnings. Earlier application is permitted. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220) Issued Feb 2018 - Allows an entity to elect a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. - The amount of that reclassification should include the effect of changes of tax rate on the deferred tax amount, any related valuation allowance and other income tax effects on the items in AOCI. - Requires an entity to state if an election to reclassify the tax effect to retained earnings is made along with the description of other income tax effects that are reclassified from AOCI. - Effective for fiscal years beginning after Dec 15, 2018 and interim periods within those fiscal years with earl y adoption permitted. - Huntington has elected to reclassify $93 million from AOCI to retained earnings in the current period.

ACQUISITION OF FIRSTMERIT CORPO

ACQUISITION OF FIRSTMERIT CORPORATION	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
ACQUISITION OF FIRSTMERIT CORPORATION	ACQUISITION OF FIRSTMERIT CORPORATION On August 16, 2016, Huntington completed its acquisition of FirstMerit Corporation in a stock and cash transaction valued at approximately $3.7 billion . FirstMerit Corporation was a diversified financial services company headquartered in Akron, Ohio, with operations in Ohio, Michigan, Wisconsin, Illinois and Pennsylvania. Post-merger, Huntington now operates across an eight -state Midwestern footprint. The merger resulted in a combined company with a larger market presence and more diversified loan portfolio, as well as a larger core deposit funding base and economies of scale associated with a larger financial institution. Under the terms of the agreement, shareholders of FirstMerit Corporation received 1.72 shares of Huntington common stock, and $5.00 in cash, for each share of FirstMerit Corporation common stock. The aggregate purchase price was $3.7 billion , including $0.8 billion of cash, $2.8 billion of common stock, and $0.1 billion of preferred stock. Huntington issued 285 million shares of common stock that had a total fair value of $2.8 billion based on the closing market price of $9.68 per share on August 15, 2016. The acquisition of FirstMerit constituted a business combination. The FirstMerit merger has been accounted for using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed, and consideration exchanged were recorded at estimated fair value on the acquisition date. The determination of estimated fair values required management to make certain estimates about discount rates, future expected cash flows, market conditions, and other future events that are highly subjective in nature and may require adjustments. As of December 31, 2016, Management completed its review of information relating to events or circumstances existing at the acquisition date.

LOANS AND LEASES AND ALLOWANCE

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES	LOANS / LEASES AND ALLOWANCE FOR CREDIT LOSSES Loans and leases which Huntington has the intent and ability to hold for the foreseeable future, or until maturity or payoff, are classified in the Consolidated Balance Sheets as loans and leases. Except for loans which are either accounted for at fair value or purchased credit-impaired, loans are carried at the principal amount outstanding, net of unamortized premiums and discounts and deferred loan fees and costs , which resulted in a net balance of $334 million and $120 million , at December 31, 2017 and 2016 , respectively. Loan and Lease Portfolio Composition The following table provides a detailed listing of Huntington’s loan and lease portfolio at December 31, 2017 and December 31, 2016 . At December 31, (dollar amounts in millions) 2017 2016 Loans and leases: Commercial and industrial $ 28,107 $ 28,059 Commercial real estate 7,225 7,301 Automobile 12,100 10,969 Home equity 10,099 10,106 Residential mortgage 9,026 7,725 RV and marine finance 2,438 1,846 Other consumer 1,122 956 Loans and leases 70,117 66,962 Allowance for loan and lease losses (691 ) (638 ) Net loans and leases $ 69,426 $ 66,324 Direct Financing Leases Huntington’s loan and lease portfolio includes lease financing receivables consisting of direct financing leases on equipment, which are included in C&I loans. Net investments in lease financing receivables by category at December 31, 2017 and 2016 were as follows: At December 31, (dollar amounts in millions) 2017 2016 Commercial and industrial: Lease payments receivable $ 1,645 $ 1,881 Estimated residual value of leased assets 755 798 Gross investment in commercial lease financing receivables 2,400 2,679 Deferred origination costs 18 13 Deferred fees (225 ) (254 ) Total net investment in commercial lease financing receivables $ 2,193 $ 2,438 The future lease rental payments due from customers on direct financing leases at December 31, 2017 , totaled $1.7 billion and were due as follows: $0.6 billion in 2018 , $0.4 billion in 2019 , $0.3 billion in 2020 , $0.1 billion in 2021 , $0.1 billion in 2022 , and $0.2 billion thereafter. Purchased Credit-Impaired Loans The following table presents a rollforward of the accretable yield for purchased credit impaired loans for the year ended December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Balance, beginning of period $ 37 $ — Impact of acquisition/purchase on August 16, 2016 — 18 Accretion (18 ) (5 ) Reclassification from nonaccretable difference 14 24 Balance at December 31, $ 33 $ 37 The following table reflects the ending and unpaid balances of the purchased credit-impaired loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 (dollar amounts in millions) Ending Unpaid Principal Ending Unpaid Principal Commercial and industrial $ 39 $ 61 $ 68 $ 100 Commercial real estate 2 15 34 56 Total $ 41 $ 76 $ 102 $ 156 Nonaccrual and Past Due Loans The following table presents NALs by loan class at December 31, 2017 and 2016 : December 31, (dollar amounts in millions) 2017 2016 Commercial and industrial $ 161 $ 234 Commercial real estate 29 20 Automobile 6 6 Home equity 68 72 Residential mortgage 84 91 RV and marine finance 1 — Other consumer — — Total nonaccrual loans $ 349 $ 423 The amount of interest that would have been recorded under the original terms for total NAL loans was $21 million , $24 million , and $20 million for 2017 , 2016 , and 2015 , respectively. The total amount of interest recorded to interest income for these loans was $18 million , $17 million , and $10 million in 2017 , 2016 , and 2015 , respectively. The following table presents an aging analysis of loans and leases, including past due loans and leases, by loan class at December 31, 2017 and 2016 (1): December 31, 2017 Past Due Purchased Credit Impaired Loans Accounted for Under the Fair Value Option Total Loans 90 or (dollar amounts in millions) 30-59 60-89 90 or Total Current Commercial and industrial $ 35 $ 14 $ 65 $ 114 $ 27,954 $ 39 $ — $ 28,107 $ 9 (2) Commercial real estate 10 1 11 22 7,201 2 — 7,225 3 Automobile 89 18 10 117 11,982 — 1 12,100 7 Home equity 49 19 60 128 9,969 — 2 10,099 18 Residential mortgage 129 48 118 295 8,642 — 89 9,026 72 RV and marine finance 11 3 2 16 2,421 — 1 2,438 1 Other consumer 12 5 5 22 1,100 — — 1,122 5 Total loans and leases $ 335 $ 108 $ 271 $ 714 $ 69,269 $ 41 $ 93 $ 70,117 $ 115 December 31, 2016 Past Due Loans Accounted for Under the Fair Value Option Total Loans 90 or (dollar amounts in millions) 30-59 60-89 90 or Total Current Purchased Commercial and industrial $ 42 $ 20 $ 74 $ 136 $ 27,855 68 — $ 28,059 $ 18 (2) Commercial real estate 21 3 30 54 7,213 34 — 7,301 17 Automobile 76 17 10 103 10,864 — 2 10,969 10 Home equity 39 24 53 116 9,987 — 3 10,106 12 Residential mortgage 122 37 117 276 7,374 — 75 7,725 67 RV and marine finance 10 2 2 14 1,830 — 2 1,846 1 Other consumer 11 6 3 20 936 — — 956 4 Total loans and leases $ 321 $ 109 $ 289 $ 719 $ 66,059 $ 102 $ 82 $ 66,962 $ 129 (1) NALs are included in this aging analysis based on the loan’s past due status. (2) Amounts include Huntington Technology Finance administrative lease delinquencies. Allowance for Credit Losses The following table presents ALLL and AULC activity by portfolio segment for the years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) Commercial Consumer Total Year ended December 31, 2017: ALLL balance, beginning of period $ 451 $ 187 $ 638 Loan charge-offs (72 ) (180 ) (252 ) Recoveries of loans previously charged-off 41 52 93 Provision for loan and lease losses 62 150 212 Allowance for loans sold or transferred to loans held for sale — — — ALLL balance, end of period $ 482 $ 209 $ 691 AULC balance, beginning of period $ 87 $ 11 $ 98 Provision (reduction in allowance) for unfunded loan commitments and letters of credit (3 ) (8 ) (11 ) AULC recorded at acquisition — — — AULC balance, end of period $ 84 $ 3 $ 87 ACL balance, end of period $ 566 $ 212 $ 778 Year ended December 31, 2016: ALLL balance, beginning of period $ 399 $ 199 $ 598 Loan charge-offs (92 ) (135 ) (227 ) Recoveries of loans previously charged-off 73 45 118 Provision for loan and lease losses 85 84 169 Allowance for loans sold or transferred to loans held for sale (14 ) (6 ) (20 ) ALLL balance, end of period $ 451 $ 187 $ 638 AULC balance, beginning of period $ 64 $ 8 $ 72 Provision (reduction in allowance) for unfunded loan commitments and letters of credit 19 3 22 AULC recorded at acquisition 4 — 4 AULC balance, end of period $ 87 $ 11 $ 98 ACL balance, end of period $ 538 $ 198 $ 736 Year ended December 31, 2015: ALLL balance, beginning of period $ 390 $ 215 $ 605 Loan charge-offs (98 ) (120 ) (218 ) Recoveries of loans previously charged-off 86 44 130 Provision for loan and lease losses 21 68 89 Allowance for loans sold or transferred to loans held for sale — (8 ) (8 ) ALLL balance, end of period $ 399 $ 199 $ 598 AULC balance, beginning of period $ 55 $ 6 $ 61 Provision (reduction in allowance) for unfunded loan commitments and letters of credit 9 2 11 AULC recorded at acquisition — — — AULC balance, end of period $ 64 $ 8 $ 72 ACL balance, end of period $ 463 $ 207 $ 670 Credit Quality Indicators To facilitate the monitoring of credit quality for C&I and CRE loans, and for purposes of determining an appropriate ACL level for these loans, Huntington utilizes the following internally defined categories of credit grades: • Pass - Higher quality loans that do not fit any of the other categories described below. • OLEM - The credit risk may be relatively minor yet represents a risk given certain specific circumstances. If the potential weaknesses are not monitored or mitigated, the loan may weaken or the collateral may be inadequate to protect Huntington’s position in the future. For these reasons, Huntington considers the loans to be potential problem loans. • Substandard - Inadequately protected loans by the borrower’s ability to repay, equity, and/or the collateral pledged to secure the loan. These loans have identified weaknesses that could hinder normal repayment or collection of the debt. It is likely Huntington will sustain some loss if any identified weaknesses are not mitigated. • Doubtful - Loans that have all of the weaknesses inherent in those loans classified as Substandard, with the added elements of the full collection of the loan is improbable and that the possibility of loss is high. The categories above, which are derived from standard regulatory rating definitions, are assigned upon initial approval of the loan or lease and subsequently updated as appropriate. Commercial loans categorized as OLEM, Substandard, or Doubtful are considered Criticized loans. Commercial loans categorized as Substandard or Doubtful are both considered Classified loans. For all classes within consumer loan portfolios, each loan is assigned a specific PD factor that is primarily based on the borrower’s most recent credit bureau score, which Huntington updates quarterly. A credit bureau score is a credit score developed by FICO based on data provided by the credit bureaus. The credit bureau score is widely accepted as the standard measure of consumer credit risk used by lenders, regulators, rating agencies, and consumers. The higher the credit bureau score, the higher likelihood of repayment and therefore, an indicator of higher credit quality. Huntington assesses the risk in the loan portfolio by utilizing numerous risk characteristics. The classifications described above, and also presented in the table below, represent one of those characteristics that are closely monitored in the overall credit risk management processes. The following table presents each loan and lease class by credit quality indicator at December 31, 2017 and 2016 : December 31, 2017 Credit Risk Profile by UCS Classification (dollar amounts in millions) Pass OLEM Substandard Doubtful Total Commercial and industrial $ 26,268 $ 694 $ 1,116 $ 29 $ 28,107 Commercial real estate 6,909 200 115 1 7,225 Credit Risk Profile by FICO Score (1), (2) 750+ 650-749 <650 Other (3) Total Automobile 6,102 4,312 1,390 295 12,099 Home equity 6,352 3,024 617 104 10,097 Residential mortgage 5,697 2,581 605 54 8,937 RV and marine finance 1,433 863 96 45 2,437 Other consumer 428 540 143 11 1,122 December 31, 2016 Credit Risk Profile by UCS Classification (dollar amounts in millions) Pass OLEM Substandard Doubtful Total Commercial and industrial $ 26,212 $ 810 $ 1,029 $ 8 $ 28,059 Commercial real estate 7,042 97 159 3 7,301 Credit Risk Profile by FICO Score (1), (2) 750+ 650-749 <650 Other (3) Total Automobile 5,369 4,044 1,298 256 $ 10,967 Home equity 6,280 2,891 638 294 10,103 Residential mortgage 4,663 2,285 615 87 7,650 RV and marine finance 1,064 644 73 64 1,845 Other consumer 347 456 133 20 956 (1) Excludes loans accounted for under the fair value option. (2) Reflects updated customer credit scores. (3) Reflects deferred fees and costs, loans in process, etc. Impaired Loans For all classes within the C&I and CRE portfolios, all loans with an obligor balance of $1 million or greater are evaluated on a quarterly basis for impairment. Generally, consumer loans within any class and commercial loans less than $1 million are not individually evaluated on a regular basis for impairment. All TDRs, regardless of the outstanding balance amount, are also considered to be impaired. Loans acquired with evidence of deterioration of credit quality since origination, for which it is probable at acquisition that all contractually required payments will not be collected, are also considered to be impaired. Once a loan has been identified for an assessment of impairment, the loan is considered impaired when, based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. The following tables present the balance of the ALLL attributable to loans by portfolio segment individually and collectively evaluated for impairment and the related loan and lease balance for the years ended December 31, 2017 and 2016 : (dollar amounts in millions) Commercial Consumer Total ALLL at December 31, 2017: Portion of ALLL balance: Attributable to purchased credit-impaired loans $ — $ — $ — Attributable to loans individually evaluated for impairment $ 32 $ 9 $ 41 Attributable to loans collectively evaluated for impairment 450 200 650 Total ALLL balance $ 482 $ 209 $ 691 Loan and Lease Ending Balances at December 31, 2017: (1) Portion of loan and lease ending balance: Attributable to purchased credit-impaired loans $ 41 $ — $ 41 Individually evaluated for impairment 607 616 1,223 Collectively evaluated for impairment 34,684 34,076 68,760 Total loans and leases evaluated for impairment $ 35,332 $ 34,692 $ 70,024 (1) Excludes loans accounted for under the fair value option. (dollar amounts in millions) Commercial Consumer Total ALLL at December 31, 2016: Portion of ALLL balance: Attributable to purchased credit-impaired loans $ — $ — $ — Attributable to loans individually evaluated for impairment 11 11 22 Attributable to loans collectively evaluated for impairment 440 176 616 Total ALLL balance: $ 451 $ 187 $ 638 Loan and Lease Ending Balances at December 31, 2016: (1) Portion of loan and lease ending balances: Attributable to purchased credit-impaired loans $ 102 $ — $ 102 Individually evaluated for impairment 416 458 874 Collectively evaluated for impairment 34,842 31,062 65,904 Total loans and leases evaluated for impairment $ 35,360 $ 31,520 $ 66,880 (1) Excludes loans accounted for under the fair value option. The following tables present by class the ending, unpaid principal balance, and the related ALLL, along with the average balance and interest income recognized only for impaired loans and leases and purchased credit-impaired loans for the years ended December 31, 2017 and 2016 (1) (2): Year Ended December 31, 2017 December 31, 2017 (dollar amounts in millions) Ending Balance Unpaid Principal Balance (6) Related Allowance Average Balance Interest Income Recognized With no related allowance recorded: Commercial and industrial $ 284 $ 311 $ — $ 206 $ 12 Commercial real estate 56 81 — 64 8 Automobile — — — — — Home equity — — — — — Residential mortgage — — — — — RV and marine finance — — — — — Other consumer — — — — — With an allowance recorded: Commercial and industrial 257 280 29 292 16 Commercial real estate 51 51 3 52 2 Automobile 36 40 2 33 2 Home equity 334 385 14 329 15 Residential mortgage 308 338 4 325 12 RV and marine finance 2 3 — 1 — Other consumer 8 8 2 5 — Total Commercial and industrial (3) 541 591 29 498 28 Commercial real estate (4) 107 132 3 116 10 Automobile (2) 36 40 2 33 2 Home equity (5) 334 385 14 329 15 Residential mortgage (5) 308 338 4 325 12 RV and marine finance (2) 2 3 — 1 — Other consumer (2) 8 8 2 5 — Year Ended December 31, 2016 December 31, 2016 (dollar amounts in millions) Ending Balance Unpaid Principal Balance (6) Related Allowance Average Balance Interest Income Recognized With no related allowance recorded: Commercial and industrial $ 300 $ 359 $ — $ 293 $ 9 Commercial real estate 89 126 — 73 4 Automobile — — — — — Home equity — — — — — Residential mortgage — — — — — RV and marine finance — — — — — Other consumer — — — — — With an allowance recorded: Commercial and industrial 406 448 22 302 8 Commercial real estate 97 108 3 69 3 Automobile 31 31 2 32 2 Home equity 319 353 15 278 13 Residential mortgage 328 363 13 348 12 RV and marine finance — — — — — Other consumer 4 4 — 4 — Total Commercial and industrial (3) 706 807 22 595 17 Commercial real estate (4) 186 234 3 142 7 Automobile (2) 31 31 2 32 2 Home equity (5) 319 353 15 278 13 Residential mortgage (5) 328 363 13 348 12 RV and marine finance (2) — — — — — Other consumer (2) 4 4 — 4 — (1) These tables do not include loans fully charged-off. (2) All automobile, RV and marine finance and other consumer impaired loans included in these tables are considered impaired due to their status as a TDR. (3) At December 31, 2017 and December 31, 2016 , commercial and industrial loans of $382 million and $317 million , respectively, were considered impaired due to their status as a TDR. (4) At December 31, 2017 and December 31, 2016 , commercial real estate loans of $93 million and $82 million , respectively, were considered impaired due to their status as a TDR. (5) Includes home equity and residential mortgages considered to be collateral dependent due to their non-accrual status as well as home equity and mortgage loans considered impaired due to their status as a TDR. (6) The differences between the ending balance and unpaid principal balance amounts represent partial charge-offs. TDR Loans The amount of interest that would have been recorded under the original terms for total accruing TDR loans was $49 million , $49 million , and $46 million for 2017 , 2016 , and 2015 , respectively. The total amount of actual interest recorded to interest income for these loans was $45 million , $40 million , and $41 million for 2017 , 2016 , and 2015 , respectively. TDR Concession Types The Company’s standards relating to loan modifications consider, among other factors, minimum verified income requirements, cash flow analyses, and collateral valuations. Each potential loan modification is reviewed individually and the terms of the loan are modified to meet a borrower’s specific circumstances at a point in time. All commercial TDRs are reviewed and approved by our SAD. The types of concessions provided to borrowers include: • Interest rate reduction: A reduction of the stated interest rate to a nonmarket rate for the remaining original life of the debt. • Amortization or maturity date change beyond what the collateral supports, including any of the following: • Lengthens the amortization period of the amortized principal beyond market terms. This concession reduces the minimum monthly payment and could increase the amount of the balloon payment at the end of the term of the loan. Principal is generally not forgiven. • Reduces the amount of loan principal to be amortized and increases the amount of the balloon payment at the end of the term of the loan. This concession also reduces the minimum monthly payment. Principal is generally not forgiven. • Extends the maturity date or dates of the debt beyond what the collateral supports. This concession generally applies to loans without a balloon payment at the end of the term of the loan. • Chapter 7 bankruptcy: A bankruptcy court’s discharge of a borrower’s debt is considered a concession when the borrower does not reaffirm the discharged debt. • Other: A concession that is not categorized as one of the concessions described above. These concessions include, but are not limited to: principal forgiveness, collateral concessions, covenant concessions, and reduction of accrued interest. Principal forgiveness may result from any TDR modification of any concession type. However, the aggregate amount of principal forgiven as a result of loans modified as TDRs during the years ended December 31, 2017 and 2016 , was not significant. Following is a description of TDRs by the different loan types: Commercial loan TDRs – Commercial accruing TDRs often result from loans receiving a concession with terms that are not considered a market transaction to Huntington. The TDR remains in accruing status as long as the customer is less than 90 -days past due on payments per the restructured loan terms and no loss is expected. Commercial nonaccrual TDRs result from either: (1) an accruing commercial TDR being placed on nonaccrual status, or (2) a workout where an existing commercial NAL is restructured and a concession is given. At times, these workouts restructure the NAL so that two or more new notes are created. The primary note is underwritten based upon our normal underwriting standards and is sized so projected cash flows are sufficient to repay contractual principal and interest. The terms on the secondary note(s) vary by situation, and may include notes that defer principal and interest payments until after the primary note is repaid. Creating two or more notes often allows the borrower to continue a project and allows Huntington to right-size a loan based upon the current expectations for a borrower’s or project’s performance. Our strategy involving TDR borrowers includes working with these borrowers to allow them to refinance elsewhere, as well as allow them time to improve their financial position and remain a Huntington customer through refinancing their notes according to market terms and conditions in the future. A subsequent refinancing or modification of a loan may occur when either the loan matures according to the terms of the TDR-modified agreement or the borrower requests a change to the loan agreements. At that time, the loan is evaluated to determine if the borrower is creditworthy. It is subjected to the normal underwriting standards and processes for other similar credit extensions, both new and existing. The refinanced note is evaluated to determine if it is considered a new loan or a continuation of the prior loan. A new loan is considered for removal of the TDR designation, whereas a continuation of the prior note requires a continuation of the TDR designation. In order for a TDR designation to be removed, the borrower must no longer be experiencing financial difficulties and the terms of the refinanced loan must not represent a concession. Consumer loan TDRs – Residential mortgage TDRs represent loan modifications associated with traditional first-lien mortgage loans in which a concession has been provided to the borrower. The primary concessions given to residential mortgage borrowers are amortization or maturity date changes and interest rate reductions. Residential mortgages identified as TDRs involve borrowers unable to refinance their mortgages through the Company’s normal mortgage origination channels or through other independent sources. Some, but not all, of the loans may be delinquent. The Company may make similar interest rate, term, and principal concessions for Automobile, Home Equity, RV and Marine Finance and Other Consumer loan TDRs. TDR Impact on Credit Quality Huntington’s ALLL is largely determined by updated risk ratings assigned to commercial loans, updated borrower credit scores on consumer loans, and borrower delinquency history in both the commercial and consumer portfolios. These updated risk ratings and credit scores consider the default history of the borrower, including payment redefaults. As such, the provision for credit losses is impacted primarily by changes in borrower payment performance rather than the TDR classification. TDRs can be classified as either accrual or nonaccrual loans. Nonaccrual TDRs are included in NALs whereas accruing TDRs are excluded from NALs as it is probable that all contractual principal and interest due under the restructured terms will be collected. The Company's TDRs may include multiple concessions and the disclosure classifications are presented based on the primary concession provided to the borrower. The majority of the concessions for the C&I and CRE portfolios are the extension of the maturity date, but could also include an increase in the interest rate. In these instances, the primary concession is the maturity date extension. TDR concessions may also result in the reduction of the ALLL within the C&I and CRE portfolios. This reduction is derived from payments and the resulting application of the reserve calculation within the ALLL. The transaction reserve for non-TDR C&I and CRE loans is calculated based upon several estimated probability factors, such as PD and LGD. Upon the occurrence of a TDR in the C&I and CRE portfolios, the reserve is measured based on discounted expected cash flows or collateral value, less anticipated selling costs, of the modified loan in accordance with ASC 310-10. The resulting TDR ALLL calculation often results in a lower ALLL amount because (1) the discounted expected cash flows or collateral value, less anticipated selling costs, indicate a lower estimated loss, (2) if the modification includes a rate increase, the discounting of the cash flows on the modified loan, using the pre-modification interest rate, exceeds the carrying value of the loan, or (3) payments may occur as part of the modification. Alternatively, the ALLL for C&I and CRE loans may increase as a result of the modification, as the discounted cash flow analysis may indicate additional reserves are required. TDR concessions on consumer loans may increase the ALLL. The concessions made to these borrowers often include interest rate reductions, and therefore, the TDR ALLL calculation results in a greater ALLL compared with the non-TDR calculation as the reserve is measured based on the estimation of the discounted expected cash flows or collateral value, less anticipated selling costs, on the modified loan in accordance with ASC 310-10. The resulting TDR ALLL calculation often results in a higher ALLL amount because (1) the discounted expected cash flows or collateral value, less anticipated selling costs, indicate a higher estimated loss or, (2) due to the rate decrease, the discounting of the cash flows on the modified loan, using the pre-modification interest rate, indicates a reduction in the present value of expected cash flows or collateral value, less anticipated selling costs. However, in certain instances, the ALLL may decrease as a result of payments made in connection with the modification. Commercial loan TDRs – In instances where the bank substantiates that it will collect its outstanding balance in full, the note is considered for return to accrual status upon the borrower showing a sustained period of repayment performance for a six -month period of time. This six -month period could extend before or after the restructure date. If a charge-off was taken as part of the restructuring, any interest or principal payments received on that note are applied to first reduce the bank’s outstanding book balance and then to recoveries of charged-off principal, unpaid interest, and/or fee expenses while the TDR is in nonaccrual status. Consumer loan TDRs – Modified consumer loans identified as TDRs are aggregated into pools for analysis. Cash flows and weighted average interest rates are used to calculate impairment at the pooled-loan level. Once the loans are aggregated into the pool, they continue to be classified as TDRs until contractually repaid or charged-off. Residential mortgage loans not guaranteed by a U.S. government agency such as the FHA, VA, and the USDA, including TDR loans, are reported as accrual or nonaccrual based upon delinquency status. Nonaccrual TDRs are those that are greater than 150 -days contractually past due. Loans guaranteed by U.S. government organizations continue to accrue interest on guaranteed rates upon delinquency. The following table presents by class and by the reason for the modification the number of contracts, post-modification outstanding balance, and the financial effects of the modification for the years ended December 31, 2017 and 2016 : New Troubled Debt Restructurings During The Year Ended (1) December 31, 2017 December 31, 2016 (dollar amounts in millions) Number of Contracts Post-modification Outstanding Balance (2) Financial effects of modification (3) Number of Contracts Post-modification Outstanding Balance (2) Financial effects of modification (3) Commercial and industrial: Interest rate reduction 9 $ 1 $ — 4 $ — $ — Amortization or maturity date change 1,034 600 (9 ) 872 490 (9 ) Other 4 — — 20 3 — Total Commercial and industrial 1,047 601 (9 ) 896 493 (9 ) Commercial real estate: Interest rate reduction 3 — — 2 — — Amortization or maturity date change 106 122 (1 ) 111 69 (2 ) Other 2 — — 4 — — Total commercial real estate: 111 122 (1 ) 117 69 (2 ) Automobile: Interest rate reduction 31 — — 17 — — Amortization or maturity date change 1,727 15 1 1,593 15 1 Chapter 7 bankruptcy 983 8 — 1,059 8 — Other — — — — — — Total Automobile 2,741 23 1 2,669 23 1 Home equity: Interest rate reduction 36 2 — 55 3 — Amortization or maturity date change 517 33 (4 ) 578 32 (4 ) Chapter 7 bankruptcy 299 11 2 282 10 4 Other 70 4 — — — — Total Home equity 922 50 (2 ) 915 45 — Residential mortgage: Interest rate reduction 3 — — 13 1 — Amortization or maturity date change 349 40 (2 ) 363 39 (2 ) Chapter 7 bankruptcy 79 7 — 62 6 — Other 22 2 — 4 1 — Total Residential mortgage 453 49 (2 ) 442 47 (2 ) RV and marine finance: Interest rate reduction 1 — — — — — Amortization or maturity date change 42 1 — — — — Chapter 7 bankruptcy 88 1 — — — — Other — — — — — — Total RV and marine finance 131 2 — — — — Other consumer: Interest rate reduction 19 — — — — — Amortization or maturity date change 1,312 6 — 6 1 — Chapter 7 bankruptcy 9 — — 8 — — Other — — — — — — Total Other consumer 1,340 6 — 14 1 — Total new troubled debt restructurings 6,745 $ 853 $ (13 ) 5,053 $ 678 $ (12 ) (1) TDRs may include multiple concessions and the disclosure classifications are based on the primary concession provided to the borrower. (2) Post-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of a restructuring are not significant. (3) Amounts represent the financial impact via provision (recovery) for loan and lease losses as a result of the modification. Pledged Loans and Leases The Bank has access to the Federal Reserve’s discount window and advances from the FHLB of Cincinnati. As of December 31, 2017 and 2016 , these borrowings and advances are secured by $31.7 billion and $19.7 billion , respectively of loans and securities.

AVAILABLE-FOR-SALE AND OTHER SE

AVAILABLE-FOR-SALE AND OTHER SECURITIES	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
AVAILABLE-FOR-SALE AND OTHER SECURITIES	AVAILABLE-FOR-SALE AND OTHER SECURITIES Contractual maturities of available-for-sale and other securities as of December 31, 2017 and 2016 were: 2017 2016 (dollar amounts in millions) Amortized Cost Fair Value Amortized Cost Fair Value Under 1 year $ 111 $ 111 $ 224 $ 222 After 1 year through 5 years 1,333 1,327 1,147 1,150 After 5 years through 10 years 2,088 2,083 1,957 1,962 After 10 years 11,595 11,348 11,885 11,665 Other securities: Nonmarketable equity securities 581 581 548 548 Mutual funds 18 18 15 15 Marketable equity securities 1 1 1 1 Total available-for-sale and other securities $ 15,727 $ 15,469 $ 15,777 $ 15,563 Other securities at December 31, 2017 and 2016 include nonmarketable equity securities of $287 million and $249 million of stock issued by the FHLB of Cincinnati and $293 million and $299 million of FRB stock, respectively. Nonmarketable equity securities are recorded at amortized cost. Other securities also include mutual funds and marketable equity securities. The following tables provide amortized cost, fair value, and gross unrealized gains and losses recognized in OCI by investment category at December 31, 2017 and 2016 : Unrealized (dollar amounts in millions) Amortized Cost Gross Gains Gross Losses Fair Value December 31, 2017 U.S. Treasury $ 5 $ — $ — $ 5 Federal agencies: Residential CMO 6,661 1 (178 ) 6,484 Residential MBS 1,371 1 (5 ) 1,367 Commercial MBS 2,539 — (52 ) 2,487 Other agencies 69 1 — 70 Total U.S. Treasury, Federal agency, and other agency securities 10,645 3 (235 ) 10,413 Municipal securities 3,892 21 (35 ) 3,878 Asset-backed securities 482 1 (16 ) 467 Corporate debt 106 3 — 109 Other securities 602 — — 602 Total available-for-sale and other securities $ 15,727 $ 28 $ (286 ) $ 15,469 Unrealized (dollar amounts in millions) Amortized Gross Gross Fair Value December 31, 2016 U.S. Treasury $ 6 $ — $ — $ 6 Federal agencies: Residential CMO 6,955 6 (151 ) 6,810 Residential MBS 196 5 (1 ) 200 Commercial MBS 3,700 2 (39 ) 3,663 Other agencies 73 — — 73 Total U.S. Treasury, Federal agency, and other agency securities 10,930 13 (191 ) 10,752 Municipal securities 3,260 29 (39 ) 3,250 Asset-backed securities 824 2 (32 ) 794 Corporate debt 195 4 — 199 Other securities 568 — — 568 Total available-for-sale and other securities $ 15,777 $ 48 $ (262 ) $ 15,563 The following tables provide detail on investment securities with unrealized losses aggregated by investment category and the length of time the individual securities have been in a continuous loss position at December 31, 2017 and 2016 : Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 Federal agencies: Residential CMO $ 1,660 $ (19 ) $ 4,520 $ (159 ) $ 6,180 $ (178 ) Residential MBS 1,078 (5 ) 11 — 1,089 (5 ) Commercial MBS 960 (15 ) 1,527 (37 ) 2,487 (52 ) Other agencies 39 — — — 39 — Total Federal agency, and other agency securities 3,737 (39 ) 6,058 (196 ) 9,795 (235 ) Municipal securities 1,681 (21 ) 497 (14 ) 2,178 (35 ) Asset-backed securities 127 (1 ) 173 (15 ) 300 (16 ) Corporate debt — — — — — — Other securities — — — — — — Total temporarily impaired securities $ 5,545 $ (61 ) $ 6,728 $ (225 ) $ 12,273 $ (286 ) Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2016 Federal agencies: Residential CMO $ 5,858 $ (150 ) $ 21 $ (1 ) $ 5,879 $ (151 ) Residential MBS 31 (1 ) — — 31 (1 ) Commercial MBS 3,019 (39 ) 21 — 3,040 (39 ) Other agencies 1 — — — 1 — Total Federal agency, and other agency securities 8,909 (190 ) 42 (1 ) 8,951 (191 ) Municipal securities 1,412 (29 ) 272 (10 ) 1,684 (39 ) Asset-backed securities 361 (3 ) 179 (29 ) 540 (32 ) Corporate debt 4 — — — 4 — Other securities 1 — 2 — 3 — Total temporarily impaired securities $ 10,687 $ (222 ) $ 495 $ (40 ) $ 11,182 $ (262 ) At December 31, 2017 , the carrying value of investment securities pledged to secure public and trust deposits, trading account liabilities, U.S. Treasury demand notes, and security repurchase agreements totaled $6.1 billion . There were no securities of a single issuer, which are not governmental or government-sponsored, that exceeded 10% of shareholders’ equity at December 31, 2017 . The following table is a summary of realized securities gains and losses for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Gross gains on sales of securities $ 10 $ 23 $ 7 Gross (losses) on sales of securities (10 ) (21 ) (4 ) Net gain (loss) on sales of securities $ — $ 2 $ 3 OTTI recognized in earnings (4 ) (2 ) (2 ) Net securities gains (losses) $ (4 ) $ — $ 1 Security Impairment Huntington evaluates the available-for-sale securities portfolio on a quarterly basis for impairment and conducts a comprehensive security-level assessment on all available-for-sale securities. Impairment exists when the present value of the expected cash flows are not sufficient to recover the entire amortized cost basis at the balance sheet date. Under these circumstances, any credit impairment would be recognized in earnings. During 2017, Huntington changed its intent from able and willing to hold for two CDO securities which were subsequently sold. Related to this change in intent, Huntington recognized $4 million of OTTI on these two securities. For all other securities, Huntington does not intend to sell, nor does it believe it will be required to sell these securities until the amortized cost is recovered, which may be at maturity. The highest risk segment in our investment portfolio is the trust preferred CDO securities which are in the asset-backed securities portfolio. This portfolio is in run off, and the Company has not purchased this type of security since 2005. The fair values of the CDO assets have been impacted by various market conditions. The unrealized losses are primarily the result of wider liquidity spreads on asset-backed securities and the longer expected average lives of the trust-preferred CDO securities, due to changes in the expectations of when the underlying securities will be repaid. The following table summarizes the Company's CDO securities portfolio, which are included in asset-backed securities, at December 31, 2017 and 2016 . Collateralized Debt Obligation Securities (dollar amounts in millions) Par Value Amortized Cost Fair Value Unrealized Loss (1) MM Comm III 4 4 4 — Tropic III 31 31 20 (11 ) Total at December 31, 2017 $ 35 $ 35 $ 24 $ (11 ) Total at December 31, 2016 $ 137 $ 101 $ 76 $ (25 ) (1) One of the two remaining securities in the portfolio has been in a continuous loss position for 12 months or longer. For the periods ended December 31, 2017 , 2016 , and 2015 , the following table summarizes by security type, the total OTTI losses recognized in the Consolidated Statements of Income for securities evaluated for impairment as described above: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Available-for-sale and other securities: Collateralized Debt Obligations $ (4 ) $ — $ (2 ) Municipal Securities — (2 ) — Total available-for-sale and other securities $ (4 ) $ (2 ) $ (2 ) The following table rolls forward the OTTI recognized in earnings on debt securities held by Huntington for the years ended December 31, 2017 , and 2016 as follows: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Balance, beginning of year $ 12 $ 18 $ 31 Reductions from sales (15 ) (8 ) (15 ) Credit losses not previously recognized 4 2 — Additional credit losses — — 2 Balance, end of year $ 1 $ 12 $ 18

HELD-TO-MATURITY SECURITIES

HELD-TO-MATURITY SECURITIES	12 Months Ended
	Dec. 31, 2017
Held-to-maturity Securities [Abstract]
HELD-TO-MATURITY SECURITIES	HELD-TO-MATURITY SECURITIES These are debt securities that Huntington has the intent and ability to hold until maturity. The debt securities are carried at amortized cost and adjusted for amortization of premiums and accretion of discounts using the interest method. During 2017 and 2016, Huntington transferred federal agencies, mortgage-backed securities and other agency securities totaling $1.0 billion and $2.9 billion , respectively from the available-for-sale securities portfolio to the held-to-maturity securities portfolio. At the time of the transfer, $14 million of unrealized net losses and $58 million of unrealized net gains were recognized in OCI, respectively. The amounts in OCI will be recognized in earnings over the remaining life of the securities as an offset to the adjustment of yield in a manner consistent with the amortization of the premium on the same transferred securities, resulting in an immaterial impact on net income. Listed below are the contractual maturities of held-to-maturity securities at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 (dollar amounts in millions) Amortized Cost Fair Value Amortized Cost Fair Value Federal agencies: Residential CMO: 1 year or less $ — $ — $ — $ — After 1 year through 5 years — — — — After 5 years through 10 years — — — — After 10 years 3,714 3,657 4,189 4,163 Total Residential CMO 3,714 3,657 4,189 4,163 Residential MBS: 1 year or less $ — $ — $ — $ — After 1 year through 5 years — — — — After 5 years through 10 years 28 28 15 15 After 10 years 1,021 1,016 83 86 Total Residential MBS 1,049 1,044 98 101 Commercial MBS: 1 year or less $ — $ — $ — $ — After 1 year through 5 years 38 37 — — After 5 years through 10 years 1 1 26 25 After 10 years 3,752 3,698 2,885 2,891 Total Commercial MBS 3,791 3,736 2,911 2,916 Other agencies: 1 year or less — — — — After 1 year through 5 years 7 8 — — After 5 years through 10 years 362 360 399 399 After 10 years 163 161 204 202 Total other agencies 532 529 603 601 Total Federal agencies and other agencies 9,086 8,966 7,801 7,781 Municipal securities: 1 year or less — — — — After 1 year through 5 years — — — — After 5 years through 10 years — — — — After 10 years 5 5 6 6 Total Municipal securities 5 5 6 6 Total held-to-maturity securities $ 9,091 $ 8,971 $ 7,807 $ 7,787 The following table provides amortized cost, gross unrealized gains and losses, and fair value by investment category at December 31, 2017 and 2016 : Unrealized (dollar amounts in millions) Amortized Cost Gross Gains Gross Losses Fair Value December 31, 2017 Federal agencies: Residential CMO $ 3,714 $ 1 $ (58 ) $ 3,657 Residential MBS 1,049 2 (7 ) 1,044 Commercial MBS 3,791 — (55 ) 3,736 Other agencies 532 1 (4 ) 529 Total Federal agencies and other agencies 9,086 4 (124 ) 8,966 Municipal securities 5 — — 5 Total held-to-maturity securities $ 9,091 $ 4 $ (124 ) $ 8,971 Unrealized (dollar amounts in millions) Amortized Gross Gross Fair Value December 31, 2016 Federal agencies: Residential CMO $ 4,189 $ 7 $ (33 ) $ 4,163 Residential MBS 98 3 — 101 Commercial MBS 2,911 10 (5 ) 2,916 Other agencies 603 2 (4 ) 601 Total Federal agencies and other agencies 7,801 22 (42 ) 7,781 Municipal securities 6 — — 6 Total held-to-maturity securities $ 7,807 $ 22 $ (42 ) $ 7,787 The following tables provide detail on HTM securities with unrealized losses aggregated by investment category and the length of time the individual securities have been in a continuous loss position at December 31, 2017 and 2016 : Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2017 Federal agencies: Residential CMO $ 2,369 $ (26 ) $ 1,019 $ (32 ) $ 3,388 $ (58 ) Residential MBS 974 (7 ) — — 974 (7 ) Commercial MBS 3,456 (49 ) 253 (6 ) 3,709 (55 ) Other agencies 249 (2 ) 139 (2 ) 388 (4 ) Total Federal agencies and other agencies 7,048 (84 ) 1,411 (40 ) 8,459 (124 ) Municipal securities — — 5 — 5 — Total temporarily impaired securities $ 7,048 $ (84 ) $ 1,416 $ (40 ) $ 8,464 $ (124 ) Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2016 Federal agencies: Residential CMO $ 2,483 $ (26 ) $ 186 $ (7 ) $ 2,669 $ (33 ) Residential MBS 20 — — — 20 — Commercial MBS 352 (5 ) — — 352 (5 ) Other agencies 414 (4 ) — — 414 (4 ) Total Federal agencies and other agencies 3,269 (35 ) 186 (7 ) 3,455 (42 ) Municipal securities 6 — — — 6 — Total temporarily impaired securities $ 3,275 $ (35 ) $ 186 $ (7 ) $ 3,461 $ (42 ) Security Impairment Huntington evaluates the held-to-maturity securities portfolio on a quarterly basis for impairment. Impairment would exist when the present value of the expected cash flows is not sufficient to recover the entire amortized cost basis at the balance sheet date. Under these circumstances, any impairment would be recognized in earnings. As of December 31, 2017 and 2016 , the Company evaluated held-to-maturity securities with unrealized losses for impairment and concluded no OTTI is required.

LOAN SALES AND SECURITIZATIONS

LOAN SALES AND SECURITIZATIONS	12 Months Ended
	Dec. 31, 2017
Transfers and Servicing [Abstract]
LOAN SALES AND SECURITIZATIONS	LOAN SALES AND SECURITIZATIONS Residential Mortgage Portfolio The following table summarizes activity relating to residential mortgage loans sold with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Residential mortgage loans sold with servicing retained $ 3,985 $ 3,632 $ 3,323 Pretax gains resulting from above loan sales (1) 99 97 83 (1) Recorded in mortgage banking income. The following table summarizes the changes in MSRs recorded using the amortization method for the years ended December 31, 2017 and 2016 : (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 172 $ 143 New servicing assets created 44 38 Servicing assets acquired — 15 Impairment recovery (charge) 1 2 Amortization and other (26 ) (26 ) Carrying value, end of year $ 191 $ 172 Fair value, end of year $ 191 $ 173 Weighted-average life (years) 7.1 7.2 MSRs do not trade in an active, open market with readily observable prices. While sales of MSRs occur, the precise terms and conditions are typically not readily available. Therefore, the fair value of MSRs is estimated using a discounted future cash flow model. The model considers portfolio characteristics, contractually specified servicing fees and assumptions related to prepayments, delinquency rates, late charges, other ancillary revenues, costs to service, and other economic factors. Changes in the assumptions used may have a significant impact on the valuation of MSRs. MSR values are very sensitive to movements in interest rates as expected future net servicing income depends on the projected outstanding principal balances of the underlying loans, which can be greatly impacted by the level of prepayments. Huntington economically hedges the value of certain MSRs against changes in value attributable to changes in interest rates using a combination of derivative instruments and trading securities. For MSRs under the amortization method, a summary of key assumptions and the sensitivity of the MSR value to changes in these assumptions at December 31, 2017 , and 2016 follows: December 31, 2017 December 31, 2016 Decline in fair value due to Decline in fair value due to (dollar amounts in millions) Actual 10% adverse change 20% adverse change Actual 10% adverse change 20% adverse change Constant prepayment rate (annualized) 8.30 % $ (5 ) $ (10 ) 7.80 % $ (5 ) $ (9 ) Spread over forward interest rate swap rates 1,049 bps (7 ) (13 ) 1,173 bps (5 ) (10 ) Additionally, Huntington has MSRs recorded using the fair value method of $11 million and $14 million at December 31, 2017 and 2016 , respectively. The change in fair value representing time decay, payoffs and changes in valuation inputs and assumptions for the years ended December 31, 2017 and 2016 was $3 million and $4 million , respectively. Total servicing, late and other ancillary fees included in mortgage banking income was $56 million , $50 million , and $47 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. The unpaid principal balance of residential mortgage loans serviced for third parties was $19.8 billion , $18.9 billion , and $16.2 billion at December 31, 2017 , 2016 , and 2015 , respectively. Automobile Loans The following table summarizes activity relating to automobile loans securitized with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 (1) 2016 2015 UPB of automobile loans securitized with servicing retained $ — 1,500 750 Net proceeds received in loan securitizations — 1,552 780 Servicing asset recognized in loan securitizations (2) — 15 11 Pretax gains resulting from above loan securitizations (3) — 6 5 (1) Huntington did not sell or securitize any automobile loans in 2017. (2) Recorded in servicing rights. (3) Recorded in gain on sale of loans. Huntington has retained servicing responsibilities on sold automobile loans and receives annual servicing fees and other ancillary fees on the outstanding loan balances. Automobile loan servicing rights are accounted for using the amortization method. A servicing asset is established at fair value at the time of the sale. The servicing asset is then amortized against servicing income. Impairment, if any, is recognized when carrying value exceeds the fair value as determined by calculating the present value of expected net future cash flows. The primary risk characteristic for measuring servicing assets is payoff rates of the underlying loan pools. Valuation calculations rely on the predicted payoff assumption and, if actual payoffs are faster than expected, then future value would be impaired. Changes in the carrying value of automobile loan servicing rights for the years ended December 31, 2017 , and 2016 , and the fair value at the end of each period were as follows: (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 18 $ 9 New servicing assets created — 15 Amortization and other (10 ) (6 ) Carrying value, end of year $ 8 $ 18 Fair value, end of year $ 9 $ 18 Weighted-average life (years) 3.5 4.2 Servicing income was $18 million , $9 million , and $5 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. The unpaid principal balance of automobile loans serviced for third parties was $1.0 billion , $1.7 billion , and $0.9 billion at December 31, 2017 , 2016 , and 2015 , respectively. Small Business Association (SBA) Portfolio The following table summarizes activity relating to SBA loans sold with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 SBA loans sold with servicing retained $ 413 $ 270 $ 233 Pretax gains resulting from above loan sales (1) 32 21 19 (1) Recorded in gain on sale of loans. Huntington has retained servicing responsibilities on sold SBA loans and receives annual servicing fees on the outstanding loan balances. SBA loan servicing rights are accounted for using the amortization method. A servicing asset is established at fair value at the time of the sale using a discounted future cash flow model. The servicing asset is then amortized against servicing income. Impairment, if any, is recognized when carrying value exceeds the fair value as determined by calculating the present value of expected net future cash flows. The following tables summarize the changes in the carrying value of the servicing asset for the years ended December 31, 2017 , and 2016 : (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 21 $ 20 New servicing assets created 14 9 Amortization and other (8 ) (8 ) Carrying value, end of year $ 27 $ 21 Fair value, end of year $ 30 $ 24 Weighted-average life (years) 3.3 3.3 Servicing income was $11 million , $9 million , and $8 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. The unpaid principal balance of SBA loans serviced for third parties was $1.4 billion , $1.1 billion and $1.0 billion at December 31, 2017 , 2016 , and 2015 , respectively.

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS Business segments are based on segment leadership structure, which reflects how segment performance is monitored and assessed. We have four major business segments: Consumer and Business Banking , Commercial Banking , Vehicle Finance , and Regional Banking and The Huntington Private Client Group (RBHPCG) . The Treasury / Other function includes technology and operations, other unallocated assets, liabilities, revenue, and expense. A rollforward of goodwill by business segment for the years ended December 31, 2017 and 2016 , is presented in the table below: Consumer & Business Commercial Vehicle Treasury/ Huntington (dollar amounts in millions) Banking Banking Finance RBHPCG Other Consolidated Balance, January 1, 2016 $ 368 $ 215 $ — $ 89 $ 5 $ 677 Goodwill acquired during the period 1,030 238 — 53 — 1,321 Adjustments — — — — (5 ) (5 ) Balance, December 31, 2016 1,398 453 — 142 — 1,993 Adjustments — (28 ) — 28 — — Balance, December 31, 2017 $ 1,398 $ 425 $ — $ 170 $ — $ 1,993 Huntington announced a change in its executive leadership team, which became effective at the end of 2017. As a result, Commercial Real Estate is now included as an operating unit in the Commercial Banking segment. During the 2017 second quarter, the previously reported Home Lending segment was included as an operating unit within the Consumer and Business Banking segment. Additionally, the Insurance operating unit previously included in Commercial Banking was realigned to RBHPCG during second quarter. As a result, Huntington reclassified a net $28 million of goodwill from the Commercial Banking segment to the RBHPCG segment. On August 16, 2016, Huntington completed its acquisition of FirstMerit in a stock and cash transaction valued at approximately $3.7 billion . In connection with the acquisition, the Company recorded $1.3 billion of goodwill, $310 million core deposit intangible asset and $95 million of other intangible assets. Huntington allocated goodwill recognized in the acquisition of FirstMerit to its existing operating segments. The allocation was performed using the ‘with and without’ approach, where an entity calculates the fair value of each segment before and after the acquisition, with the difference attributable to the fair value acquired via the acquisition. This method is most appropriate when multiple segments are expected to benefit from synergies realized in an acquisition. The results of the allocation are presented in the table above. For additional information on the acquisition, see Note 3 Acquisition of FirstMerit Corporation. During the 2016 third quarter, Huntington reclassified $5 million of goodwill in the Treasury / Other segment related to a held for sale disposal group. Goodwill is not amortized but is evaluated for impairment on an annual basis at October 1 of each year or whenever events or changes in circumstances indicate the carrying value may not be recoverable. No impairment was recorded in 2017 or 2016 . At December 31, 2017 and 2016 , Huntington’s other intangible assets consisted of the following: (dollar amounts in millions) Gross Accumulated Net December 31, 2017 Core deposit intangible $ 325 $ (61 ) $ 264 Customer relationship 190 (108 ) 82 Total other intangible assets $ 515 $ (169 ) $ 346 December 31, 2016 Core deposit intangible $ 325 $ (27 ) $ 298 Customer relationship 195 (1) (91 ) 104 Total other intangible assets $ 520 $ (118 ) $ 402 (1) During the 2016 third quarter, certain commercial merchant relationships, which resulted in an intangible of $14 million , were contributed to a joint venture in which Huntington holds a minority interest. The estimated amortization expense of other intangible assets for the next five years is as follows: (dollar amounts in millions) Amortization Expense 2018 $ 53 2019 50 2020 42 2021 40 2022 38

PREMISES AND EQUIPMENT

PREMISES AND EQUIPMENT	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
PREMISES AND EQUIPMENT	PREMISES AND EQUIPMENT Premises and equipment were comprised of the following at December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Land and land improvements $ 193 $ 199 Buildings 563 523 Leasehold improvements 240 265 Equipment 746 722 Total premises and equipment 1,742 1,709 Less accumulated depreciation and amortization (878 ) (893 ) Net premises and equipment $ 864 $ 816 Depreciation and amortization charged to expense and rental income credited to net occupancy expense for the three years ended December 31, 2017 , 2016 , and 2015 were: (dollar amounts in millions) 2017 2016 2015 Total depreciation and amortization of premises and equipment $ 123 $ 126 $ 86 Rental income credited to occupancy expense 14 13 13

SHORT-TERM BORROWINGS

SHORT-TERM BORROWINGS	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
SHORT-TERM BORROWINGS	SHORT-TERM BORROWINGS Borrowings with original maturities of one year or less are classified as short-term and were comprised of the following at December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Federal funds purchased and securities sold under agreements to repurchase $ 1,318 $ 1,248 Federal Home Loan Bank advances 3,725 2,425 Other borrowings 13 20 Total short-term borrowings $ 5,056 $ 3,693 Other borrowings consist of borrowings from the U.S. Treasury and other notes payable.

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2017
Debt Instruments [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT Huntington’s long-term debt consisted of the following: At December 31, (dollar amounts in millions) 2017 2016 The Parent Company: Senior Notes: 3.19% Huntington Bancshares Incorporated medium-term notes due 2021 $ 969 $ 973 2.33% Huntington Bancshares Incorporated senior note due 2022 953 954 2.64% Huntington Bancshares Incorporated senior note due 2018 399 399 Subordinated Notes: 7.00% Huntington Bancshares Incorporated subordinated notes due 2020 312 320 3.55% Huntington Bancshares Incorporated subordinated notes due 2023 245 248 Sky Financial Capital Trust IV 3.09% junior subordinated debentures due 2036 (1) 74 74 Sky Financial Capital Trust III 3.09% junior subordinated debentures due 2036 (1) 72 72 Huntington Capital I Trust Preferred 2.39% junior subordinated debentures due 2027 (2) 69 69 Huntington Capital II Trust Preferred 2.32% junior subordinated debentures due 2028 (3) 31 32 Camco Financial Statutory Trust I 3.02% due 2037 (4) 4 4 Total notes issued by the parent 3,128 3,145 The Bank: Senior Notes: 2.24% Huntington National Bank senior notes due 2018 844 844 2.10% Huntington National Bank senior notes due 2018 748 747 2.47% Huntington National Bank senior notes due 2020 694 — 2.55% Huntington National Bank senior notes due 2022 685 — 2.43% Huntington National Bank senior notes due 2020 498 498 2.23% Huntington National Bank senior note due 2019 497 500 1.75% Huntington National Bank senior notes due 2018 496 500 2.97% Huntington National Bank senior notes due 2020 492 495 2.20% Huntington National Bank senior notes due 2020 (5) 300 — 5.04% Huntington National Bank medium-term notes due 2018 35 36 2.23% Huntington National Bank senior note due 2017 — 499 1.42% Huntington National Bank senior notes due 2017 (6) — 250 Subordinated Notes: 3.86% Huntington National Bank subordinated notes due 2026 238 239 6.67% Huntington National Bank subordinated notes due 2018 129 132 5.45% Huntington National Bank subordinated notes due 2019 77 81 Total notes issued by the bank 5,733 4,821 FHLB Advances: 3.51% weighted average rate, varying maturities greater than one year 7 8 Other: Huntington Technology Finance nonrecourse debt, 3.63% effective interest rate, varying maturities 263 278 3.57% Huntington Preferred Capital II - Class F securities (7) 75 — Huntington Technology Finance ABS Trust 2014 1.70% due 2020 — 57 Total other 338 335 Total long-term debt $ 9,206 $ 8,309 (1) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.400% . (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70% (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625% . (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.33% . (5) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.51% (6) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.425% . (7) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.880% . Amounts above are net of unamortized discounts and adjustments related to hedging with derivative financial instruments. The derivative instruments, principally interest rate swaps, are used to hedge the fair values of certain fixed-rate debt by converting the debt to a variable rate. See Note 18 for more information regarding such financial instruments. In March 2017, the Bank issued $0.7 billion of senior notes at 99.994% of face value. The senior notes mature on March 10, 2020 and have a fixed coupon rate of 2.375% . The senior notes may be redeemed one month prior to the maturity date at 100% of principal plus accrued and unpaid interest. Also, in March 2017, the Bank issued $0.3 billion of senior notes at 100% of face value. The senior notes mature on March 10, 2020 and have a variable coupon rate of three month LIBOR + 51 basis points. In August 2017, the Bank issued $0.7 billion of senior notes at 99.762% of face value. The senior notes mature on August 7, 2022 and have a fixed coupon rate of 2.50% . The senior notes may be redeemed one month prior to the maturity date at 100% of principal plus accrued and unpaid interest. In August 2016, FirstMerit Parent Company and Bank subordinated debt with a fair value totaling $520 million was acquired by Huntington as part of the acquisition. In August 2016, Huntington issued $1.0 billion of senior notes at 99.849% of face value. The senior notes mature on January 14, 2022 and have a fixed coupon rate of 2.3% . In March 2016, Huntington issued $1.0 billion of senior notes at 99.803% of face value. The senior notes mature on March 14, 2021 and have a fixed coupon rate of 3.15% . Long-term debt maturities for the next five years and thereafter are as follows: (dollar amounts in millions) 2018 2019 2020 2021 2022 Thereafter Total The Parent Company: Senior notes $ 400 $ — $ — $ 1,000 $ 1,000 $ — $ 2,400 Subordinated notes — — 300 — — 504 804 The Bank: Senior notes 2,135 500 2,000 — 700 — 5,335 Subordinated notes 125 76 — — — 325 526 FHLB Advances 1 — 2 — — 4 7 Other 27 43 95 48 50 — 263 Total $ 2,688 $ 619 $ 2,397 $ 1,048 $ 1,750 $ 833 $ 9,335 These maturities are based upon the par values of the long-term debt. The terms of the long-term debt obligations contain various restrictive covenants including limitations on the acquisition of additional debt in excess of specified levels, dividend payments, and the disposition of subsidiaries. As of December 31, 2017 , Huntington was in compliance with all such covenants.

OTHER COMPREHENSIVE INCOME

OTHER COMPREHENSIVE INCOME	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
OTHER COMPREHENSIVE INCOME	OTHER COMPREHENSIVE INCOME The components of Huntington’s OCI in the three years ended December 31, 2017 , 2016 , and 2015 , were as follows: 2017 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 4 $ (2 ) $ 2 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (87 ) 31 (56 ) Less: Reclassification adjustment for net losses (gains) included in net income 26 (9 ) 17 Net change in unrealized holding gains (losses) on available-for-sale debt securities (57 ) 20 (37 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities 1 (1 ) — Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period 3 (1 ) 2 Less: Reclassification adjustment for net (gains) losses included in net income 1 — 1 Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 4 (1 ) 3 Net change in pension and other post-retirement obligations — — — Total other comprehensive income (loss) $ (52 ) $ 18 $ (34 ) 2016 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 1 $ — $ 1 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (203 ) 70 (133 ) Less: Reclassification adjustment for net losses (gains) included in net income (107 ) 38 (69 ) Net change in unrealized holding gains (losses) on available-for-sale debt securities (309 ) 108 (201 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities — — — Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period 2 (1 ) 1 Less: Reclassification adjustment for net (gains) losses included in net income — — — Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 2 (1 ) 1 Net change in pension and other post-retirement obligations 38 (13 ) 25 Total other comprehensive income (loss) $ (269 ) $ 94 $ (175 ) 2015 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 20 $ (7 ) $ 13 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (26 ) 9 (17 ) Less: Reclassification adjustment for net gains (losses) included in net income (4 ) 1 (3 ) Net change in unrealized holding gains (losses) on available-for-sale debt securities (10 ) 3 (7 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities — — — Unrealized gains and losses on derivatives used in cash flow hedging relationships arising during the period 13 (4 ) 9 Less: Reclassification adjustment for net losses (gains) losses included in net income (1 ) — (1 ) Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 12 (4 ) 8 Defined benefit pension items (8 ) 3 (5 ) Net change in pension and post-retirement obligations (8 ) 3 (5 ) Total other comprehensive income (loss) $ (6 ) $ 2 $ (4 ) Activity in accumulated OCI for the two years ended December 31, were as follows: (dollar amounts in millions) Unrealized gains (losses) on debt securities (1) Unrealized gains (losses) on equity securities Unrealized gains (losses) on cash flow hedging derivatives Unrealized gains (losses) for pension and other post-retirement obligations Total December 31, 2015 $ 8 $ — $ (4 ) $ (230 ) $ (226 ) Other comprehensive income before reclassifications (132 ) — 1 — (131 ) Amounts reclassified from accumulated OCI to earnings (69 ) — — 25 (44 ) Period change (201 ) — 1 25 (175 ) December 31, 2016 (193 ) — (3 ) (205 ) (401 ) Other comprehensive income before reclassifications (54 ) — 2 (10 ) (62 ) Amounts reclassified from accumulated OCI to earnings 17 — 1 10 28 Period change (37 ) — 3 — (34 ) TCJA, Reclassification from accumulated OCI to retained earnings (48 ) — — (45 ) (93 ) December 31, 2017 $ (278 ) $ — $ — $ (250 ) $ (528 ) (1) Amount at December 31, 2017 includes $95 million of net unrealized losses on securities transferred from the available-for-sale securities portfolio to the held-to-maturity securities portfolio. The net unrealized losses will be recognized in earnings over the remaining life of the security using the effective interest method. The following table presents the reclassification adjustments out of accumulated OCI included in net income and the impacted line items as listed on the Consolidated Statements of Income for the years ended December 31, 2017 and 2016 : Reclassifications out of accumulated OCI Accumulated OCI components Amounts reclassified from accumulated OCI Location of net gain (loss) reclassified from accumulated OCI into earnings (dollar amounts in millions) 2017 2016 Gains (losses) on debt securities: Amortization of unrealized gains (losses) $ (8 ) $ 91 Interest income—held-to-maturity securities—taxable Realized gain (loss) on sale of securities (14 ) 18 Noninterest income—net gains (losses) on sale of securities OTTI recorded (4 ) (2 ) Noninterest income—net gains (losses) on sale of securities Total before tax (26 ) 107 Tax (expense) benefit 9 (38 ) Net of tax $ (17 ) $ 69 Gains (losses) on cash flow hedging relationships: Interest rate contracts $ (1 ) $ — Interest and fee income—loans and leases Interest rate contracts — — Noninterest expense—other income Total before tax (1 ) — Tax (expense) benefit — — Net of tax $ (1 ) $ — Amortization of defined benefit pension and post-retirement items: Actuarial gains (losses) $ (18 ) $ (40 ) Noninterest expense—personnel costs Net periodic benefit costs 2 2 Noninterest expense—personnel costs Total before tax (16 ) (38 ) Tax (expense) benefit 6 13 Net of tax $ (10 ) $ (25 )

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' EQUITY	SHAREHOLDERS’ EQUITY The following is a summary of Huntington's non-cumulative perpetual preferred stock outstanding as of December 31, 2017 . (dollar amounts in millions, except per share amounts) Series Description Issuance Date Total Shares Outstanding Carrying Amount Dividend Rate Earliest Redemption Date Series A Non-cumulative, non-voting, perpetual, convertible 11/14/2008 362,506 363 8.50 % N/A Series B Non-cumulative, non-voting, perpetual 12/28/2011 35,500 23 3-mo. LIBOR + 270 bps 1/15/2017 Series D Non-cumulative, non-voting perpetual 3/21/2016 400,000 386 6.25 % 7/15/2021 Series D Non-cumulative, non-voting perpetual 5/5/2016 200,000 199 6.25 % 7/15/2021 Series C Non-cumulative, non-voting perpetual 8/16/2016 100,000 100 5.875 % 1/15/2022 Total 1,098,006 1,071 Each series of preferred stock has a liquidation value and redemption price per share of $1,000 , plus any declared and unpaid dividends. All preferred stock, with the exception of Series A, has no stated maturity and redemption is solely at the option of the Company. Under current rules, any redemption of the preferred stock is subject to prior approval of the FRB. Preferred Series A Stock issued and outstanding Each share of the Series A Preferred Stock is non-voting and may be converted at any time, at the option of the holder, into 83.668 shares of common stock of Huntington, which represents an approximate initial conversion price of $11.95 per share of common stock. Since April 15, 2013, at the option of Huntington, the Series A Preferred Stock is subject to conversion into Huntington’s common stock at the prevailing conversion rate if the closing price of Huntington’s common stock exceeds 130% of the conversion price for 20 trading days during any 30 consecutive trading-day period. To exercise this right, a notice of mandatory conversion or issuance of a press release must be published by Huntington with the conversion date being no later than 20 days after providing the notice of conversion. Preferred Series B Stock issued and outstanding Dividends on the Preferred B Stock will be non-cumulative and payable quarterly in arrears, when, as and if authorized by the Company's board of directors or a duly authorized committee of the board and declared by the Company, at a floating rate equal to three-month LIBOR plus a spread of 2.70% per year on the liquidation preference of $1,000 per share, equivalent to $25 per depositary share. The dividend payment dates will be the fifteenth day of each January, April, July and October, commencing on January 15, 2012, or the next business day if any such day is not a business day. The Preferred B Stock is perpetual and has no maturity date. Huntington may redeem the Preferred B Stock at its option, (i) in whole or in part, from time to time, on any dividend payment date on or after January 15, 2017 or (ii) in whole but not in part, within 90 days following a regulatory capital treatment event, in each case, at a redemption price equal to $1,000 per share (equivalent to $25 per depositary share), plus any declared and unpaid dividends and, in the case of a redemption following a regulatory capital treatment event, the pro-rated portion of dividends, whether or not declared, for the dividend period in which the such redemption occurs. If Huntington redeems the Preferred B Stock, the depositary will redeem a proportional number of depositary shares. Neither the holders of Preferred B Stock nor holders of depositary shares will have the right to require the redemption or repurchase of the Preferred B Stock. Any redemption of the Preferred B Stock is subject to Huntington's receipt of any required prior approval by the Board of Governors of the Federal Reserve System. Preferred Series C Stock issued and outstanding Dividends on the Preferred C Stock will be non-cumulative and payable quarterly in arrears, when, as and if authorized by the Company's board of directors or a duly authorized committee of the board and declared by the Company, at an annual rate of 5.875% per year on the liquidation preference of $1,000 per share, equivalent to $25 per depositary share. The dividend payment dates will be the fifteenth day of each January, April, July and October, commencing on October 15, 2016, or the next business day if any such day is not a business day. The Preferred C Stock is perpetual and has no maturity date. Huntington may redeem the Preferred C Stock at its option, (i) in whole or in part, from time to time, on any dividend payment date on or after October 15, 2021 or (ii) in whole but not in part, within 90 days following a regulatory capital treatment event, in each case, at a redemption price equal to $1,000 per share (equivalent to $25 per depositary share), plus any declared and unpaid dividends, without regard to any undeclared dividends, on the Series C Preferred Stock prior to the date fixed for redemption. If Huntington redeems the Preferred C Stock, the depositary will redeem a proportional number of depositary shares. Neither the holders of Preferred C Stock nor holders of depositary shares will have the right to require the redemption or repurchase of the Preferred C Stock or the depositary shares. Any redemption of the Preferred C Stock is subject to Huntington's receipt of any required prior approval by the Board of Governors of the Federal Reserve System. Preferred Series D Stock issued and outstanding Dividends on the Preferred D Stock will be non-cumulative and payable quarterly in arrears, when, as and if authorized by the Company's board of directors or a duly authorized committee of the board and declared by the Company, at an annual rate of 6.25% per year on the liquidation preference of $1,000 per share, equivalent to $25 per depositary share. The dividend payment dates will be the fifteenth day of each January, April, July and October, commencing on July 15, 2016, or the next business day if any such day is not a business day. The Preferred D Stock is perpetual and has no maturity date. Huntington may redeem the Preferred D Stock at its option, (i) in whole or in part, from time to time, on any dividend payment date on or after April 15, 2021 or (ii) in whole but not in part, within 90 days following a regulatory capital treatment event, in each case, at a redemption price equal to $1,000 per share (equivalent to $25 per depositary share), plus any declared and unpaid dividends and, in the case of a redemption following a regulatory capital treatment event, the prorated portion of dividends, whether or not declared, for the dividend period in which such redemption occurs. Notwithstanding the foregoing, pursuant to a commitment Huntington made to the Federal Reserve, for at least five years after the date of the issuance of depositary shares offered by the prospectus supplement, Huntington will not redeem or repurchase the Preferred D Stock, whether issued on March 21, 2016 or on the date of the issuance of the depositary shares offered by the prospectus supplement. If Huntington redeems the Preferred D Stock, the depositary will redeem a proportional number of depositary shares. Neither the holders of Preferred D Stock nor holders of depositary shares will have the right to require the redemption or repurchase of the Preferred D Stock or the depositary shares. Any redemption of the Preferred D Stock is subject to Huntington's receipt of any required prior approval by the Board of Governors of the Federal Reserve System. 2017 Share Repurchase Program During 2017, Huntington repurchased a total of 19.4 million shares of common stock at a weighted average share price of $13.38 . 2017 Comprehensive Capital Analysis and Review (CCAR) On June 28, 2017, Huntington was notified by the Federal Reserve that it had no objection to Huntington's proposed capital actions included in Huntington's capital plan submitted in the 2017 CCAR. These actions included a 38% increase in quarterly dividend per common share to $0.11 , starting in the fourth quarter of 2017, the repurchase of up to $308 million of common stock over the next four quarters (July 1, 2017 through June 30, 2018), subject to authorization by the Board of Directors, and maintaining dividends on the outstanding classes of preferred stock and trust preferred securities.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share is the amount of earnings (adjusted for dividends declared on preferred stock) available to each share of common stock outstanding during the reporting period. Diluted earnings per share is the amount of earnings available to each share of common stock outstanding during the reporting period adjusted to include the effect of potentially dilutive common shares. Potentially dilutive common shares include incremental shares issued for stock options, restricted stock units and awards, distributions from deferred compensation plans, and the conversion of the Company’s convertible preferred stock (See Note 13 ). Potentially dilutive common shares are excluded from the computation of diluted earnings per share in periods in which the effect would be antidilutive. For diluted earnings per share, net income available to common shares can be affected by the conversion of the Company’s convertible preferred stock. Where the effect of this conversion would be dilutive, net income available to common shareholders is adjusted by the associated preferred dividends and deemed dividend. The 2017 total diluted average common shares issued and outstanding was impacted by using the if-converted method. The calculation of basic and diluted earnings per share for each of the three years ended December 31 was as follows: Year Ended December 31, (dollar amounts in millions, except per share amounts) 2017 2016 2015 Basic earnings per common share: Net income $ 1,186 $ 712 $ 693 Preferred stock dividends (76 ) (65 ) (32 ) Net income available to common shareholders $ 1,110 $ 647 $ 661 Average common shares issued and outstanding (000) 1,084,686 904,438 803,412 Basic earnings per common share $ 1.02 $ 0.72 $ 0.82 Diluted earnings per common share: Net income available to common shareholders $ 1,110 $ 647 $ 661 Effect of assumed preferred stock conversion 31 — — Net income applicable to diluted earnings per share $ 1,141 $ 647 $ 661 Average common shares issued and outstanding (000) 1,084,686 904,438 803,412 Dilutive potential common shares Stock options and restricted stock units and awards 17,883 11,728 11,633 Shares held in deferred compensation plans 3,160 2,486 1,912 Other 30,457 138 172 Dilutive potential common shares 51,500 14,352 13,717 Total diluted average common shares issued and outstanding (000) 1,136,186 918,790 817,129 Diluted earnings per common share $ 1.00 $ 0.70 $ 0.81 Approximately 1.0 million , 3.1 million , and 1.6 million options to purchase shares of common stock outstanding at the end of December 31, 2017 , 2016 , and 2015 , respectively, were not included in the computation of diluted earnings per share because the effect would be antidilutive.

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION Huntington sponsors nonqualified and incentive share based compensation plans. These plans provide for the granting of stock options and other awards to officers, directors, and other employees. Compensation costs are included in personnel costs on the Consolidated Statements of Income. Stock options and awards are granted at the closing market price on the date of the grant. Options granted typically vest ratably over four years or when other conditions are met. Stock options, which represented a portion of the grant values, have no intrinsic value until the stock price increases. Options granted on or after May 1, 2015 have a contractual term of ten years . All options granted on or before April 30, 2015 have a contractual term of seven years . 2015 Long-Term Incentive Plan In 2015, shareholders approved the Huntington Bancshares Incorporated 2015 Long-Term Incentive Plan (the 2015 Plan). Shares remaining under the 2012 Long-Term Incentive Plan have been incorporated into the 2015 Plan. Accordingly, the total number of shares authorized for awards under the 2015 Plan is 30 million shares. At December 31, 2017 , 8 million shares from the Plan were available for future grants. Huntington issues shares to fulfill stock option exercises and restricted stock unit and award vesting from available authorized common shares. At December 31, 2017 , Huntington believes there are adequate authorized common shares to satisfy anticipated stock option exercises and restricted stock unit and award vesting in 2018 . The following table presents total share-based compensation expense and related tax benefit for the three years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) 2017 2016 2015 Share-based compensation expense $ 92 $ 66 $ 51 Tax benefit 32 22 18 Huntington uses the Black-Scholes option pricing model to value options in determining the share-based compensation expense. Forfeitures are estimated at the date of grant based on historical rates, and updated as necessary, and reduce the compensation expense recognized. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the date of grant. The expected dividend yield is based on the dividend rate and stock price at the date of the grant. Expected volatility is based on the estimated volatility of Huntington’s stock over the expected term of the option. The following table presents the weighted average assumptions used in the option-pricing model at the grant date for options granted in the three years ended December 31, 2017 , 2016 , and 2015 : 2017 2016 2015 Assumptions Risk-free interest rate 2.04 % 1.63 % 2.13 % Expected dividend yield 3.31 3.18 2.57 Expected volatility of Huntington’s common stock 29.5 30.0 29.0 Expected option term (years) 6.5 6.5 6.5 Weighted-average grant date fair value per share $ 2.81 $ 2.17 $ 2.57 Huntington’s stock option activity and related information for the year ended December 31, 2017 , was as follows: (dollar amounts in millions, except per share and options amounts) Options (in thousands) Weighted- Weighted- Aggregate Outstanding at January 1, 2017 14,874 $ 7.50 Granted 1,486 13.09 Exercised (2,372 ) 6.72 Forfeited/expired (70 ) 11.17 Outstanding at December 31, 2017 13,918 $ 8.21 3.5 $ 88 Expected to vest (1) 3,508 $ 11.33 8.0 $ 11 Exercisable at December 31, 2017 10,311 $ 7.11 1.9 $ 77 (1) The number of options expected to vest includes an estimate of 99 thousand shares expected to be forfeited. The aggregate intrinsic value represents the amount by which the fair value of underlying stock exceeds the “in-the-money” option exercise price. For the years ended December 31, 2017 , 2016 , and 2015 , cash received for the exercises of stock options was $11 million , $14 million and $26 million , respectively. The tax benefit realized for the tax deductions from option exercises totaled $5 million , $3 million and $7 million in 2017, 2016, and 2015, respectively. Huntington also grants restricted stock, restricted stock units, performance share awards, and other stock-based awards. Restricted stock units and awards are issued at no cost to the recipient, and can be settled only in shares at the end of the vesting period. Restricted stock awards provide the holder with full voting rights and cash dividends during the vesting period. Restricted stock units do not provide the holder with voting rights or cash dividends during the vesting period, but do accrue a dividend equivalent that is paid upon vesting, and are subject to certain service restrictions. Performance share awards are payable contingent upon Huntington achieving certain predefined performance objectives over the three -year measurement period. The fair value of these awards reflects the closing market price of Huntington's common stock on the grant date. The following table summarizes the status of Huntington’s restricted stock units and performance share awards as of December 31, 2017 , and activity for the year ended December 31, 2017 : Restricted Stock Awards Restricted Stock Units Performance Share Awards (amounts in thousands, except per share amounts) Quantity Weighted- Average Grant Date Fair Value Per Share Quantity Weighted- Average Grant Date Fair Value Per Share Quantity Weighted- Average Grant Date Fair Value Per Share Nonvested at January 1, 2017 (000) 656 $ 9.68 14,733 $ 9.61 3,307 $ 9.63 Granted — — 6,232 13.45 1,278 12.18 Assumed — — — — — — Vested (174 ) 9.68 (4,267 ) 8.72 (1,550 ) 9.00 Forfeited (34 ) 9.68 (539 ) 10.91 (17 ) 11.07 Nonvested at December 31, 2017 (000) 448 $ 9.68 16,159 $ 11.26 3,018 $ 10.67 The weighted-average grant date fair value of nonvested shares granted for the years ended December 31, 2017 , 2016 , and 2015 were $11.13 , $9.59 , and $10.86 , respectively. The total fair value of awards vested during the years ended December 31, 2017 , 2016 , and 2015 was $53 million , $31 million , and $30 million , respectively. As of December 31, 2017 , the total unrecognized compensation cost related to nonvested awards was $93 million with a weighted-average expense recognition period of 2.3 years .

BENEFIT PLANS

BENEFIT PLANS	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
BENEFIT PLANS	BENEFIT PLANS Huntington sponsors the Plan, a non-contributory defined benefit pension plan covering substantially all employees hired or rehired prior to January 1, 2010. The Plan, which was modified in 2013 and no longer accrues service benefits to participants, provides benefits based upon length of service and compensation levels. The funding policy of Huntington is to contribute an annual amount that is at least equal to the minimum funding requirements but not more than the amount deductible under the Internal Revenue Code. There were no required minimum contributions during 2017. At December 31, 2017 Huntington and FirstMerit pension plans merged into a single legal entity, combining the respective plans' obligations and assets. As such, a single set of assumptions were selected for the merged entity, reflecting timing of cash flows, funded status, investment allocation, and any other relevant considerations, on a combined basis. In addition, Huntington has an unfunded defined benefit post-retirement plan that provides certain healthcare and life insurance benefits to retired employees who have attained the age of 55 and have at least 10 years of vesting service under this plan. For any employee retiring on or after January 1, 1993, post-retirement healthcare benefits are based upon the employee’s number of months of service and are limited to the actual cost of coverage. Life insurance benefits are a percentage of the employee’s base salary at the time of retirement, with a maximum of $50,000 of coverage. The employer paid portion of the post-retirement health and life insurance plan was eliminated for employees retiring on and after March 1, 2010. Eligible employees retiring on and after March 1, 2010, who elect retiree medical coverage, will pay the full cost of this coverage. Huntington does not provide any employer paid life insurance to employees retiring on and after March 1, 2010. Eligible employees will be able to convert or port their existing life insurance at their own expense under the same terms that are available to all terminated employees. On January 1, 2015, Huntington terminated the company sponsored retiree health care plan for Medicare eligible retirees and their dependents. Instead, Huntington will partner with a third-party to assist the retirees and their dependents in selecting individual policies from a variety of carriers on a private exchange. This plan amendment resulted in a measurement of the liability at the approval date. The result of the measurement was a $5 million reduction of the liability and increase in AOCI. It will also result in a reduction of expense over the estimated life of plan participants. Huntington executed a life insurance buyout for the remaining life insurance benefits of FirstMerit retired participants. The buyout was executed in December 2017 for $4 million and is being reflected as a settlement in the projected benefit obligation at the end of the year. The following table shows the weighted-average assumptions used to determine the benefit obligation at December 31, 2017 and 2016 , and the net periodic benefit cost for the years then ended: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 Weighted-average assumptions used to determine benefit obligations Discount rate 3.73 % 4.38 % 3.34 % 3.64 % Rate of compensation increase N/A N/A N/A N/A Weighted-average assumptions used to determine net periodic benefit cost Discount rate 4.38 4.54 3.64 3.81 Expected return on plan assets 6.50 6.75 N/A N/A Rate of compensation increase N/A N/A N/A N/A N/A—Not Applicable The expected long-term rate of return on plan assets is an assumption reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the projected benefit obligation. The expected long-term rate of return is established at the beginning of the plan year based upon historical returns and projected returns on the underlying mix of invested assets. The following table reconciles the beginning and ending balances of the benefit obligation of the Plan and the post-retirement benefit plan with the amounts recognized in the consolidated balance sheets at December 31: Pension Benefits Post-Retirement Benefits (dollar amounts in millions) 2017 2016 2017 2016 Projected benefit obligation at beginning of measurement year $ 851 $ 1,084 $ 14 $ 15 Changes due to: Service cost 3 5 — — Interest cost 30 30 — — Benefits paid (27 ) (20 ) (2 ) (1 ) Settlements (31 ) (203 ) (4 ) — Plan amendments — — (2 ) — Actuarial assumptions and gains and losses 74 (45 ) 1 — Total changes 49 (233 ) (7 ) (1 ) Projected benefit obligation at end of measurement year $ 900 $ 851 $ 7 $ 14 The following table reconciles the beginning and ending balances of the fair value of Plan assets at the December 31, 2017 and 2016 measurement dates: Pension Benefits (dollar amounts in millions) 2017 2016 Fair value of plan assets at beginning of measurement year $ 841 $ 874 Changes due to: Actual return on plan assets 118 37 Employer Contributions — 150 Settlements (29 ) (199 ) Benefits paid (27 ) (21 ) Total changes 62 (33 ) Fair value of plan assets at end of measurement year $ 903 $ 841 Huntington’s accumulated benefit obligation under the Plan was $900 million and $851 million at December 31, 2017 and 2016 . As of December 31, 2017 , the difference between the accumulated benefit obligation and the fair value of Huntington's plan assets was $3 million and is recorded in noncurrent liabilities. The following table shows the components of net periodic benefit costs recognized in the three years ended December 31, 2017 : Pension Benefits Post-Retirement Benefits (dollar amounts in millions) 2017 2016 2015 2017 2016 2015 Service cost $ 3 $ 5 $ 2 $ — $ — $ — Interest cost 30 30 32 — — — Expected return on plan assets (55 ) (45 ) (44 ) — — — Amortization of prior service credit — — — (2 ) (2 ) (2 ) Amortization of (gain) / loss 7 7 8 — — — Settlements 11 (8 ) 12 — — (3 ) Benefit costs $ (4 ) $ (11 ) $ 10 $ (2 ) $ (2 ) $ (5 ) Included in benefit costs are $2 million , $2 million , and $4 million of plan expenses that were recognized in the three years ended December 31, 2017 , 2016 , and 2015 . It is Huntington’s policy to recognize settlement gains and losses as incurred. Assuming no cash contributions are made to the Plan during 2018 , Huntington expects net periodic pension benefit, excluding any expense of settlements, to approximate $9 million for 2018 . The post-retirement medical and life subsidy was eliminated for anyone who retires on or after March 1, 2010. As such, there were no incremental net periodic post-retirement benefits costs associated with this plan. The estimated transition obligation, prior service credit, and net actuarial loss for the plans that will be amortized from OCI into net periodic benefit cost over the next fiscal year is zero , $2 million , and a $8 million benefit, respectively. At December 31, 2017 and 2016 , The Huntington National Bank, as trustee, held all Plan assets. The Plan assets consisted of investments in a variety of corporate and government fixed income investments, money market funds, and mutual funds as follows: Fair Value (dollar amounts in millions) 2017 2016 Cash equivalents: Mutual Funds-money market $ 14 2 % $ 21 3 % U.S. Treasury bills 5 1 — — Fixed income: Corporate obligations 293 32 218 26 U.S. Government obligations 216 24 165 19 Mutual funds-fixed income — — 51 6 U.S. Government Agencies 23 3 10 1 Equities: Mutual funds-equities 118 13 150 18 Common stock 158 17 182 22 Preferred stock 5 1 5 1 Exchange Traded Funds 58 6 28 3 Limited Partnerships 13 1 11 1 Fair value of plan assets $ 903 100 % $ 841 100 % Investments of the Plan are accounted for at cost on the trade date and are reported at fair value. The valuation methodologies used to measure the fair value of pension plan assets vary depending on the type of asset. For an explanation of the fair value hierarchy, refer to Note 1 “Significant Accounting Policies” under the heading “Fair Value Measurements”. At December 31, 2017 , cash equivalent money market funds and U.S. Treasury bills are valued at the closing price reported from an actively traded exchange and are classified as Level 1. Mutual funds are valued at quoted market prices that represent the net asset value of shares held by the Plan at year-end. The mutual funds held by the Plan are actively traded and are classified as Level 1. Corporate obligations, U.S. government obligations, and U.S. government securities are valued using unadjusted quoted prices from active markets for similar assets are classified as Level 2. Common and preferred stock are valued using the year-end closing price as determined by a national securities exchange and are classified as Level 1. The investment in the limited partnerships is reported at net asset value per share as determined by the general partners of each limited partnership, based on their proportionate share of the partnership’s fair value as recorded in the partnership’s audited financial statements. In general, investments of the Plan are exposed to various risks such as interest rate risk, credit risk, and overall market volatility. Due to the level of risk associated with certain investments, it is reasonably possible changes in the values of investments will occur in the near term and such changes could materially affect the amounts reported in the Plan assets. The investment objective of the Plan is to maximize the return on Plan assets over a long-time period, while meeting the Plan obligations. At December 31, 2017 , Plan assets were invested 3% in cash and cash equivalents, 38% in equity investments, and 59% in bonds, with an average duration of 13.7 years on bond investments. The estimated life of benefit obligations was 13.5 years . Although it may fluctuate with market conditions, Huntington has targeted a long-term allocation of Plan assets of 20% to 50% in equity investments and 80% to 50% in bond investments. The allocation of Plan assets between equity investments and fixed income investments will change from time to time with the allocation to fixed income investments increasing as the funding level increases. At December 31, 2017 , the following table shows when benefit payments were expected to be paid: (dollar amounts in millions) Pension Benefits Post-Retirement Benefits 2018 $ 50 $ 1 2019 49 1 2020 48 1 2021 47 1 2022 47 1 2023 through 2027 233 2 Although not required, a cash contribution can be made to the Plan up to the maximum deductible limit in the plan year. Anticipated contributions for 2018 to the post-retirement benefit plan are zero . The 2018 healthcare cost trend rate is projected to be 6.6% for participants. This rate is assumed to decrease gradually until it reaches 4.5% in the year 2028 and remain at that level thereafter. Huntington updated the immediate healthcare cost trend rate assumption based on current market data and Huntington’s claims experience. This trend rate is expected to decline over time to a trend level consistent with medical inflation and long-term economic assumptions. Huntington also sponsors other nonqualified retirement plans, the most significant being the SERP and the SRIP. The SERP provides certain former officers and directors, and the SRIP provides certain current and former officers and directors of Huntington and its subsidiaries with defined pension benefits in excess of limits imposed by federal tax law. At December 31, 2017 and 2016 , Huntington has an accrued pension liability of $35 million and $33 million , respectively, associated with these plans. Pension expense for the plans was $1 million , $1 million , and $1 million in 2017 , 2016 , and 2015 , respectively. The following table presents the amounts recognized in the Consolidated Balance Sheets at December 31, 2017 and 2016 , for all defined benefit plans: (dollar amounts in millions) 2017 2016 Noncurrent liabilities $ 78 $ 189 The following tables present the amounts recognized in OCI as of December 31, 2017 , 2016 , and 2015 , and the changes in accumulated OCI for the years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) 2017 2016 2015 Net actuarial loss $ (264 ) $ (217 ) $ (244 ) Prior service cost 14 12 14 Defined benefit pension plans $ (250 ) $ (205 ) $ (230 ) 2017 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (316 ) $ 111 $ (205 ) Net actuarial (loss) gain: Amounts arising during the year (16 ) 6 (10 ) Amortization included in net periodic benefit costs 18 (7 ) 11 TCJA, Reclassification from accumulated OCI to retained earnings (47 ) Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) TCJA, Reclassification from accumulated OCI to retained earnings 2 Balance, end of year $ (316 ) $ 111 $ (250 ) 2016 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (354 ) $ 124 $ (230 ) Net actuarial (loss) gain: Amounts arising during the year 38 (13 ) 25 Amortization included in net periodic benefit costs 2 (1 ) 1 Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) Balance, end of year $ (316 ) $ 111 $ (205 ) 2015 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (347 ) $ 121 $ (226 ) Net actuarial (loss) gain: Amounts arising during the year (25 ) 9 (16 ) Amortization included in net periodic benefit costs 20 (7 ) 13 Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) Balance, end of year $ (354 ) $ 124 $ (230 ) Huntington has a defined contribution plan that is available to eligible employees. Huntington matches participant contributions, up to the first 4% of base pay contributed to the Plan. For 2016 , a discretionary profit-sharing contribution equal to 1% of eligible participants’ annual base pay was awarded. For 2017, the discretionary profit-sharing targets were not met. The following table shows the costs of providing the defined contribution plan: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Defined contribution plan $ 35 $ 36 $ 32 The following table shows the number of shares, market value, and dividends received on shares of Huntington stock held by the defined contribution plan: December 31, (dollar amounts in millions, except share amounts) 2017 2016 Shares in Huntington common stock (000) 13,566 11,748 Market value of Huntington common stock $ 198 $ 162 Dividends received on shares of Huntington stock 4 4

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES On December 22, 2017, the U.S. government enacted the TCJA, a comprehensive tax legislation which, among other things, reduced the federal income tax rate for C corporations from 35% to 21% effective on January 1, 2018. The TCJA makes broad and complex changes to the Internal Revenue Code which will impact the Company, including reduction of the U.S. corporate income tax rate as well as introduction of business-related exclusions, deductions and credits. The effects of the TCJA have been recorded in the fourth quarter 2017 and its impact to the Company’s Consolidated Financial Statements are included and described within this footnote. The Company’s deferred federal and state income tax and related valuation accounts represents the estimated impact of temporary differences between how we recognize our assets and liabilities under GAAP and how such assets and liabilities are recognized under federal and state tax law. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities as measured by the enacted tax rates which will be in effect when these differences reverse. As a result of the reduction in the U.S. corporate income tax rate from 35% to 21% under the TCJA, the Company revalued its ending net deferred tax liabilities at December 31, 2017. The Company recognized a $123 million tax benefit in the Company’s Consolidated Statement of Income for the year ended December 31, 2017 as a result of the TCJA, of which the benefit recorded is primarily attributable to the revaluation of net deferred tax liabilities. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state, city, and foreign jurisdictions. Federal income tax audits have been completed for tax years through 2009. The IRS is currently examining our 2010 and 2011 consolidated federal income tax returns. While the statute of limitations remains open for tax years 2012 through 2016, the IRS has advised that tax years 2012 through 2014 will not be audited, and plans to begin the examination of the 2015 federal income tax return during the 2018 first quarter. Various state and other jurisdictions remain open to examination, including Ohio, Kentucky, Indiana, Michigan, Pennsylvania, West Virginia, Wisconsin, and Illinois. Huntington accounts for uncertainties in income taxes in accordance with ASC 740, Income Taxes. At December 31, 2017 , Huntington had gross unrecognized tax benefits of $50 million in income tax liability related to uncertain tax positions. Due to the complexities of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from the current estimate of the tax liabilities. It is reasonably possible that the liability for gross unrecognized tax benefits could decrease by $50 million during the next 12 months due to the completion of tax authority examinations. The following table provides a reconciliation of the beginning and ending amounts of gross unrecognized tax benefits: (dollar amounts in millions) 2017 2016 Unrecognized tax benefits at beginning of year $ 24 $ 23 Gross increases for tax positions taken during current period — 1 Gross increases for tax positions taken during prior years 26 — Unrecognized tax benefits at end of year $ 50 $ 24 Any interest and penalties on income tax assessments or income tax refunds are recognized in the Consolidated Statements of Income as a component of provision for income taxes. Huntington recognized interest expense of less than one million dollars for each of the years ended December 31, 2017 , 2016 and 2015 . Total interest accrued was less than one million at December 31, 2017 and 2016 . All of the gross unrecognized tax benefits would impact the Company’s effective tax rate if recognized. The following is a summary of the provision (benefit) for income taxes: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Current tax provision (benefit) Federal $ 41 $ 40 $ 146 State (1 ) 3 6 Total current tax provision (benefit) 40 43 152 Deferred tax provision (benefit) Federal 151 161 67 State 17 4 2 Total deferred tax provision (benefit) 168 165 69 Provision (benefit) for income taxes $ 208 $ 208 $ 221 The following is a reconciliation for provision for income taxes: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Provision for income taxes computed at the statutory rate $ 488 $ 322 $ 320 Increases (decreases): Tax-exempt income (31 ) (27 ) (21 ) Tax-exempt bank owned life insurance income (23 ) (20 ) (18 ) General business credits (71 ) (64 ) (48 ) Capital loss (67 ) (46 ) (46 ) Impact from TCJA (123 ) — — Affordable housing investment amortization, net of tax benefits 46 37 32 State income taxes, net 11 5 5 Stock based compensation (13 ) (4 ) — Other (9 ) 5 (3 ) Provision (benefit) for income taxes $ 208 $ 208 $ 221 The significant components of deferred tax assets and liabilities at December 31, were as follows: At December 31, (dollar amounts in millions) 2017 (1) 2016 (2) Deferred tax assets: Allowances for credit losses $ 162 $ 255 Tax credit carryforward 153 76 Fair value adjustments 142 217 Net operating and other loss carryforward 108 141 Accrued expense/prepaid 17 64 Market discount 10 8 Pension and other employee benefits — 35 Partnership investments 7 23 Other assets 6 11 Total deferred tax assets 605 830 Deferred tax liabilities: Lease financing 249 325 Loan origination costs 116 138 Deferred dividend income 77 — Purchase accounting adjustments 68 74 Operating assets 53 54 Mortgage servicing rights 39 51 Securities adjustments 6 56 Pension and other employee benefits 5 — Other liabilities 18 9 Total deferred tax liabilities 631 707 Net deferred tax (liability) asset before valuation allowance (26 ) 123 Valuation allowance (6 ) (5 ) Net deferred tax (liability) asset $ (32 ) $ 118 (1) 2017 balances reflect federal statutory tax rate 21% . (2) 2016 balances reflect federal statutory tax rate 35% . At December 31, 2017 , Huntington’s net deferred tax asset related to loss and other carryforwards was $261 million . This was comprised of federal net operating loss carryforwards of $65 million , which will begin expiring in 2023 , $42 million of state net operating loss carryforwards, which will begin expiring in 2018 , an alternative minimum tax credit carryforward of $121 million , which will be fully utilized or refunded by 2022, a general business credit carryforward of $32 million , which will begin expiring in 2037 , and a charitable contribution carryforward of $1 million , which will begin expiring in 2020 . In prior periods, Huntington established a valuation allowance against deferred tax assets for state deferred tax assets, and state net operating loss carryforwards. The state valuation allowance was based on the uncertainty of forecasted state taxable income expected in applicable jurisdictions in order to utilize the state deferred tax assets and state net operating loss carryforwards. Based on current analysis of both positive and negative evidence and projected forecasted taxable income within applicable jurisdictions, the Company believes that it is more likely than not, portions of the state deferred tax assets and state net operating loss carryforwards will be realized. As a result of this analysis, the state valuation allowance was $6 million at December 31, 2017 compared to $5 million at December 31, 2016 . At December 31, 2017 , retained earnings included approximately $12 million of base year reserves of acquired thrift institutions, for which no deferred federal income tax liability has been recognized. Under current law, if these bad debt reserves are used for purposes other than to absorb bad debt losses, they will be subject to federal income tax at the current corporate rate. The amount of unrecognized deferred tax liability relating to the cumulative bad debt deduction was approximately $3 million at December 31, 2017 .

FAIR VALUES OF ASSETS AND LIABI

FAIR VALUES OF ASSETS AND LIABILITIES	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
FAIR VALUES OF ASSETS AND LIABILITIES	FAIR VALUES OF ASSETS AND LIABILITIES Following is a description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy. Loans held for sale Huntington has elected to apply the fair value option for mortgage loans originated with the intent to sell which are included in loans held for sale. Mortgage loans held for sale are classified as Level 2 and are estimated using security prices for similar product types. Loans held for investment Certain mortgage loans originated with the intent to sell have been reclassified to mortgage loans held for investment. These loans continue to be measured at fair value. The fair value is determined using fair value of similar mortgage-backed securities adjusted for loan specific variables. Huntington elected the fair value option for consumer loans with deteriorated credit quality acquired from FirstMerit in accordance with ASC 825 to allow for operational efficiencies not normally associated with purchased credit impaired loans. The consumer loans are classified as Level 3. The key assumption used to determine the fair value of the consumer loans is discounted cash flows. Available-for-sale securities and trading account securities Securities accounted for at fair value include both the available-for-sale and trading portfolios. Huntington uses prices obtained from third-party pricing services and recent trades to determine the fair value of securities. AFS and trading securities are classified as Level 1 using quoted market prices (unadjusted) in active markets for identical securities that Huntington has the ability to access at the measurement date. Less than 1% of the positions in these portfolios are Level 1, and consist of U.S. Treasury securities and money market mutual funds. When quoted market prices are not available, fair values are classified as Level 2 using quoted prices for similar assets in active markets, quoted prices of identical or similar assets in markets that are not active, and inputs that are observable for the asset, either directly or indirectly, for substantially the full term of the financial instrument. 78% of the positions in these portfolios are Level 2, and consist of U.S. Government and agency debt securities, agency mortgage backed securities, asset-backed securities other than the CDO-preferred securities portfolio, certain municipal securities and other securities. For Level 2 securities Huntington uses various methods and techniques to corroborate prices obtained from the pricing service, including references to dealer or other market quotes, and by reviewing valuations of comparable instruments. If relevant market prices are limited or unavailable, valuations may require significant management judgment or estimation to determine fair value, in which case the fair values are classified as Level 3. 21% of our positions are Level 3, and consist of CDO-preferred securities and municipal securities. A significant change in the unobservable inputs for these securities may result in a significant change in the ending fair value measurement of these securities. The municipal securities portion that is classified as Level 3 uses significant estimates to determine the fair value of these securities which results in greater subjectivity. The fair value is determined by utilizing third-party valuation services. The third-party service provider reviews credit worthiness, prevailing market rates, analysis of similar securities, and projected cash flows. The third-party service provider also incorporates industry and general economic conditions into their analysis. Huntington evaluates the analysis provided for reasonableness. The CDO-preferred securities portfolios are classified as Level 3 and as such use significant estimates to determine the fair value of these securities which results in greater subjectivity. The CDO-preferred securities portfolio are subjected to a quarterly review of the projected cash flows. These reviews are supported with analysis from independent third parties, and are used as a basis for impairment analysis. MSRs MSRs do not trade in an active market with readily observable prices. Accordingly, the fair value of these assets is classified as Level 3. Huntington determines the fair value of MSRs using an income approach model based upon the month-end interest rate curve and prepayment assumptions. The model utilizes assumptions to estimate future net servicing income cash flows, including estimates of time decay, payoffs, and changes in valuation inputs and assumptions. Servicing brokers and other sources of information (e.g. discussion with other mortgage servicers and industry surveys) are used to obtain information on market practice and assumptions. On at least a quarterly basis, third-party marks are obtained from at least one servicing broker. Huntington reviews the valuation assumptions against this market data for reasonableness and adjusts the assumptions if deemed appropriate. Any recommended change in assumptions and/or inputs are presented for review to the Mortgage Price Risk Subcommittee for final approval. Derivative assets and liabilities Derivatives classified as Level 2 consist of foreign exchange and commodity contracts, which are valued using exchange traded swaps and futures market data. In addition, Level 2 includes interest rate contracts, which are valued using a discounted cash flow method that incorporates current market interest rates. Level 2 also includes exchange traded options and forward commitments to deliver mortgage-backed securities, which are valued using quoted prices. Derivatives classified as Level 3 consist of interest rate lock agreements related to mortgage loan commitments. The determination of fair value includes assumptions related to the likelihood that a commitment will ultimately result in a closed loan, which is a significant unobservable assumption. A significant increase or decrease in the external market price would result in a significantly higher or lower fair value measurement. Assets and Liabilities measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and 2016 are summarized below: Fair Value Measurements at Reporting Date Using Netting Adjustments (1) December 31, 2017 (dollar amounts in millions) Level 1 Level 2 Level 3 Assets Loans held for sale $ — $ 413 $ — $ — $ 413 Loans held for investment — 55 38 — 93 Trading account securities: Other securities 83 3 — — 86 83 3 — — 86 Available-for-sale and other securities: U.S. Treasury securities 5 — — — 5 Residential CMOs — 6,484 — — 6,484 Residential MBS 1,367 1,367 Commercial MBS 2,487 2,487 Other agencies — 70 — — 70 Municipal securities — 711 3,167 — 3,878 Asset-backed securities — 443 24 — 467 Corporate debt — 109 — — 109 Other securities 20 1 — — 21 25 11,672 3,191 — 14,888 MSRs — — 11 — 11 Derivative assets — 316 6 (190 ) 132 Liabilities Derivative liabilities — 326 5 (245 ) 86 Short-term borrowings — — — — — Fair Value Measurements at Reporting Date Using Netting Adjustments (1) December 31, 2016 (dollar amounts in millions) Level 1 Level 2 Level 3 Assets Loans held for sale $ — $ 438 $ — $ — $ 438 Loans held for investment — 34 48 — 82 Trading account securities: Municipal securities — 1 — — 1 Other securities 132 — — — 132 132 1 — — 133 Available-for-sale and other securities: U.S. Treasury securities 6 — — — 6 Residential CMOs — 6,810 — — 6,810 Residential MBS 200 200 Commercial MBS 3,663 3,663 Other agencies — 73 — — 73 Municipal securities — 452 2,798 — 3,250 Asset-backed securities — 718 76 — 794 Corporate debt — 199 — — 199 Other securities 16 4 — — 20 22 12,119 2,874 — 15,015 MSRs — — 14 — 14 Derivative assets — 414 6 (182 ) 238 Liabilities Derivative liabilities — 363 8 (272 ) 99 Short-term borrowings — — — — — (1) Amounts represent the impact of legally enforceable master netting agreements that allow the Company to settle positive and negative positions and cash collateral held or placed with the same counterparties. The tables below present a rollforward of the balance sheet amounts for the years ended December 31, 2017 , 2016 , and 2015 for financial instruments measured on a recurring basis and classified as Level 3. The classification of an item as Level 3 is based on the significance of the unobservable inputs to the overall fair value measurement. However, Level 3 measurements may also include observable components of value that can be validated externally. Accordingly, the gains and losses in the table below include changes in fair value due in part to observable factors that are part of the valuation methodology. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (15 ) — — — Total gains/losses for the period: Included in earnings (3 ) 16 (2 ) (5 ) 1 Included in OCI — — (8 ) 14 — Purchases/originations — — 787 — — Sales — — — (60 ) — Repayments — — — — (11 ) Settlements — — (408 ) (1 ) — Closing balance $ 11 $ (1 ) $ 3,167 $ 24 $ 38 Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date $ (3 ) $ — $ — $ (4 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 18 $ 6 $ 2,095 $ 100 $ 2 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (7 ) — — — Total gains/losses for the period: Included in earnings (4 ) (1 ) 7 (2 ) (2 ) Included in OCI — — (28 ) 6 — Purchases/originations — — 1,399 — 56 Sales — — (37 ) (25 ) — Repayments — — — — (8 ) Settlements — — (638 ) (3 ) — Closing balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (4 ) $ (1 ) $ (33 ) $ 4 $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Private label CMO Asset- backed securities Loans held for investment Balance, beginning of year $ 23 $ 3 $ 1,418 $ 30 $ 83 $ 10 Transfers into Level 3 — — — — — — Transfers out of Level 3 (1) — (2 ) — — — — Total gains/losses for the period: Included in earnings (5 ) 5 — — (3 ) — Included in OCI — — (4 ) 2 25 — Purchases/originations — — 1,002 — — — Sales — — (10 ) (30 ) — — Repayments — — — — — (8 ) Settlements — — (311 ) (2 ) (5 ) — Balance, end of year $ 18 $ 6 $ 2,095 $ — $ 100 $ 2 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (5 ) $ 5 $ — $ — $ (3 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. The tables below summarize the classification of gains and losses due to changes in fair value, recorded in earnings for Level 3 assets and liabilities for the years ended December 31, 2017 , 2016 , and 2015 : Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income $ (3 ) $ 16 $ — $ — $ — Securities gains (losses) — — — (5 ) — Interest and fee income — — (2 ) — — Noninterest income — — — — 1 Total $ (3 ) $ 16 $ (2 ) $ (5 ) $ 1 Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income $ (4 ) $ (1 ) $ — $ — $ — Securities gains (losses) — — 1 (2 ) — Interest and fee income — — — — — Noninterest income — — 6 — (2 ) Total $ (4 ) $ (1 ) $ 7 $ (2 ) $ (2 ) Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income (loss) $ (5 ) $ 5 $ — $ — $ — Securities gains (losses) — — — (3 ) — Interest and fee income — — — — — Noninterest income — — — — — Total $ (5 ) $ 5 $ — $ (3 ) $ — Assets and liabilities under the fair value option The following table presents the fair value and aggregate principal balance of certain assets and liabilities under the fair value option: December 31, 2017 Total Loans Loans that are 90 or more days past due (dollar amounts in millions) Fair value Aggregate Difference Fair value Aggregate Difference Assets Loans held for sale $ 413 $ 400 $ 13 $ 1 $ 1 $ — Loans held for investment 93 102 (9 ) 10 11 (1 ) December 31, 2016 Total Loans Loans that are 90 or more days past due (dollar amounts in millions) Fair value Aggregate Difference Fair value Aggregate Difference Assets Loans held for sale $ 438 $ 434 $ 4 $ — $ — $ — Loans held for investment 82 92 $ (10 ) 8 11 $ (3 ) The following tables present the net gains (losses) from fair value changes, including net gains (losses) associated with instrument specific credit risk for the years ended December 31, 2017 , 2016 , and 2015 : Net gains (losses) from fair value changes Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Assets Loans held for sale $ 8 $ 7 $ (2 ) Loans held for investment — — (1 ) Assets and Liabilities measured at fair value on a nonrecurring basis Certain assets and liabilities may be required to be measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. These assets and liabilities are not measured at fair value on an ongoing basis; however, they are subject to fair value adjustments in certain circumstances, such as when there is evidence of impairment. For the year ended December 31, 2017 , assets measured at fair value on a nonrecurring basis were as follows: Fair Value Measurements Using (dollar amounts in millions) Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total MSRs $ 190 $ — $ — $ 190 $ 1 Impaired loans 36 — — 36 (5 ) Other real estate owned 33 — — 33 (2 ) MSRs accounted for under the amortization method are subject to nonrecurring fair value measurement when the fair value is lower than the carrying amount. Periodically, Huntington records nonrecurring adjustments of collateral-dependent loans measured for impairment when establishing the ALLL. Such amounts are generally based on the fair value of the underlying collateral supporting the loan. Appraisals are generally obtained to support the fair value of the collateral and incorporate measures such as recent sales prices for comparable properties and cost of construction. In cases where the carrying value exceeds the fair value of the collateral less cost to sell, an impairment charge is recognized. Other real estate owned properties are included in accrued income and other assets and valued based on appraisals and third-party price opinions. The appraisals supporting the fair value of the collateral to recognize loan impairment or unrealized loss on other real estate owned properties may not have been obtained as of December 31, 2017 . Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis The table below presents quantitative information about the significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis at December 31, 2017 : Quantitative Information about Level 3 Fair Value Measurements at December 31, 2017 (dollar amounts in millions) Fair Value Valuation Technique Significant Unobservable Input Range (Weighted Average) Measured at fair value on a recurring basis: MSRs $ 11 Discounted cash flow Constant prepayment rate 8% - 33% (12%) Spread over forward interest rate 8% - 10% (8%) Derivative assets 6 Consensus Pricing Net market price -5% - 20% (2%) Estimated Pull through % 3% - 100% (75%) Derivative liabilities 5 Discounted cash flow Estimated conversion factor 165% Estimated growth rate of Visa Class A shares 7% Discount rate 3% Timing of the resolution of the litigation 12/31/2017 - 06/30/2020 Municipal securities 3,167 Discounted cash flow Discount rate 0% - 10% (4%) Cumulative default 0% - 64% (3%) Loss given default 5% - 90% (24%) Asset-backed securities 24 Discounted cash flow Discount rate 7% - 7% (7%) Cumulative prepayment rate 0% - 72% (7%) Cumulative default 3% - 53% (7%) Loss given default 90% - 100% (98%) Cure given deferral 50% - 50% (50%) Loans held for investment 38 Discounted cash flow Discount rate 7% - 18% (8%) Constant prepayment rate 2% - 22% (9%) Measured at fair value on a nonrecurring basis: MSRs 190 Discounted cash flow Constant prepayment rate 6% - 21% (8%) Spread over forward interest rate 2% - 20% (10%) Impaired loans 36 Appraisal value NA NA Other real estate owned 33 Appraisal value NA NA The following provides a general description of the impact of a change in an unobservable input on the fair value measurement and the interrelationship between unobservable inputs, where relevant/significant. Interrelationships may also exist between observable and unobservable inputs. Such relationships have not been included in the discussion below. A significant change in the unobservable inputs may result in a significant change in the ending fair value measurement of Level 3 instruments. In general, prepayment rates increase when market interest rates decline and decrease when market interest rates rise and higher prepayment rates generally resulting in lower fair values for MSR assets asset-backed securities. Credit loss estimates, such as probability of default, constant default, cumulative default, loss given default, cure given deferral, and loss severity, are driven by the ability of the borrowers to pay their loans and the value of the underlying collateral and are impacted by changes in macroeconomic conditions, typically increasing when economic conditions worsen and decreasing when conditions improve. An increase in the estimated prepayment rate typically results in a decrease in estimated credit losses and vice versa. Higher credit loss estimates generally result in lower fair values. Credit spreads generally increase when liquidity risks and market volatility increase and decrease when liquidity conditions and market volatility improve. Discount rates and spread over forward interest rate swap rates typically increase when market interest rates increase and/or credit and liquidity risks increase and decrease when market interest rates decline and/or credit and liquidity conditions improve. Higher discount rates and credit spreads generally result in lower fair market values. Net market price and pull through percentages generally increase when market interest rates increase and decline when market interest rates decline. Higher net market price and pull through percentages generally result in higher fair values. Fair values of financial instruments The following table provides the carrying amounts and estimated fair values of Huntington’s financial instruments that are carried either at fair value or cost at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 Carrying Fair Carrying Fair (dollar amounts in millions) Amount Value Amount Value Financial Assets: Cash and short-term assets $ 1,567 $ 1,567 $ 1,443 $ 1,443 Trading account securities 86 86 133 133 Loans held for sale 488 491 513 516 Available-for-sale and other securities 15,469 15,469 15,563 15,563 Held-to-maturity securities 9,091 8,971 7,807 7,787 Net loans and direct financing leases 69,426 69,146 66,324 66,295 Derivatives 132 132 238 238 Financial Liabilities: Deposits 77,041 77,010 75,608 76,161 Short-term borrowings 5,056 5,056 3,693 3,693 Long-term debt 9,206 9,402 8,309 8,387 Derivatives 86 86 98 98 The following table presents the level in the fair value hierarchy for the estimated fair values of Huntington’s financial instruments at fair value at December 31, 2017 and December 31, 2016 : Estimated Fair Value Measurements at Reporting Date Using December 31, 2017 (dollar amounts in millions) Level 1 Level 2 Level 3 Financial Assets: Trading account securities $ 83 $ 3 $ 86 Loans held for sale — 413 78 491 Available-for-sale and other securities 25 11,672 3,191 14,888 Held-to-maturity securities — 8,971 — 8,971 Net loans and direct financing leases — — 69,146 69,146 Financial Liabilities: Deposits — 73,975 3,035 77,010 Short-term borrowings — — 5,056 5,056 Long-term debt — 8,944 458 9,402 Estimated Fair Value Measurements at Reporting Date Using December 31, 2016 (dollar amounts in millions) Level 1 Level 2 Level 3 Financial Assets: Held-to-maturity securities $ — $ 7,787 $ — $ 7,787 Net loans and direct financing leases — — 66,295 66,295 Financial Liabilities: Deposits — 72,319 3,842 76,161 Short-term borrowings 1 — 3,692 3,693 Long-term debt — 7,980 407 8,387 The short-term nature of certain assets and liabilities result in their carrying value approximating fair value. These include trading account securities, customers’ acceptance liabilities, short-term borrowings, bank acceptances outstanding, FHLB advances, and cash and short-term assets, which include cash and due from banks, interest-bearing deposits in banks, and federal funds sold and securities purchased under resale agreements. Loan commitments and letters-of-credit generally have short-term, variable-rate features and contain clauses that limit Huntington’s exposure to changes in customer credit quality. Accordingly, their carrying values, which are immaterial at the respective balance sheet dates, are reasonable estimates of fair value. Certain assets, the most significant being operating lease assets, bank owned life insurance, and premises and equipment, do not meet the definition of a financial instrument and are excluded from this disclosure. Similarly, mortgage and nonmortgage servicing rights, deposit base, and other customer relationship intangibles are not considered financial instruments and are not included above. Accordingly, this fair value information is not intended to, and does not, represent Huntington’s underlying value. Many of the assets and liabilities subject to the disclosure requirements are not actively traded, requiring fair values to be estimated by Management. These estimations necessarily involve the use of judgment about a wide variety of factors, including but not limited to, relevancy of market prices of comparable instruments, expected future cash flows, and appropriate discount rates. The following methods and assumptions were used by Huntington to estimate the fair value of the remaining classes of financial instruments: Held-to-maturity securities Fair values are determined by using models that are based on security-specific details, as well as relevant industry and economic factors. The most significant of these inputs are quoted market prices, and interest rate spreads on relevant benchmark securities. Loans and Direct Financing Leases Variable-rate loans that reprice frequently are based on carrying amounts, as adjusted for estimated credit losses. The fair values for other loans and leases are estimated using discounted cash flow analyses and employ discount rates based on current interest rates offered for loans and leases for similar terms. The rates take into account the position of the yield curve, as well as an adjustment for prepayment risk, operating costs, and profit. This value is also reduced by an estimate of expected losses and the credit risk associated in the loan and lease portfolio. The valuation of the loan portfolio reflected discounts that Huntington believed are consistent with transactions occurring in the marketplace. Deposits Demand deposits, savings accounts, and money market deposits are, by definition, equal to the amount payable on demand. The fair values of fixed-rate time deposits are estimated by discounting cash flows using interest rates currently being offered on certificates with similar maturities. Debt Long-term debt is based upon quoted market prices, which are inclusive of Huntington’s credit risk. In the absence of quoted market prices, discounted cash flows using market rates for similar debt with the same maturities are used in the determination of fair value.

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	DERIVATIVE FINANCIAL INSTRUMENTS Derivative financial instruments are recorded in the Consolidated Balance Sheets as either an asset or a liability (in accrued income and other assets or accrued expenses and other liabilities, respectively) and measured at fair value. Derivative financial instruments can be designated as accounting hedges under GAAP. Designating a derivative as an accounting hedge allows Huntington to recognize gains and losses, less any ineffectiveness, in the income statement within the same period that the hedged item affects earnings. Gains and losses on derivatives that are not designated to an effective hedge relationship under GAAP immediately impact earnings within the period they occur. The following table presents the fair values of all derivative instruments included in the Consolidated Balance Sheets at December 31, 2017 and December 31, 2016 . Amounts in the table below are presented gross without the impact of any net collateral arrangements. December 31, 2017 December 31, 2016 (dollar amounts in millions) Asset Liability Asset Liability Derivatives designated as Hedging Instruments Interest rate contracts $ 22 $ 121 $ 46 $ 100 Derivatives not designated as Hedging Instruments Interest rate contracts (1) 187 100 233 141 Foreign exchange contracts 18 18 23 20 Commodities contracts 92 87 108 104 Equity contracts 3 5 10 6 Total Contracts $ 322 $ 331 $ 420 $ 371 (1) Includes derivative assets and liabilities used in mortgage banking activities. Derivatives used in Asset and Liability Management Activities Huntington engages in balance sheet hedging activity, principally for asset liability management purposes, to convert fixed rate assets or liabilities into floating rate or vice versa. Balance sheet hedging activity is arranged to receive hedge accounting treatment and is classified as either fair value or cash flow hedges. Fair value hedges are purchased to convert deposits and subordinated and other long-term debt from fixed-rate obligations to floating rate. Cash flow hedges are also used to convert floating rate loans made to customers into fixed rate loans. The following table presents the gross notional values of derivatives used in Huntington’s asset and liability management activities at December 31, 2017 and December 31, 2016 , identified by the underlying interest rate-sensitive instruments: December 31, 2017 (dollar amounts in millions) Fair Value Hedges Cash Flow Hedges Total Instruments associated with: Loans $ — $ — $ — Subordinated notes 950 — 950 Long-term debt 7,425 — 7,425 Total notional value at December 31, 2017 $ 8,375 $ — $ 8,375 December 31, 2016 (dollar amounts in millions) Fair Value Hedges Cash Flow Hedges Total Instruments associated with: Loans $ — $ 3,325 $ 3,325 Subordinated notes 950 — 950 Long-term debt 6,525 — 6,525 Total notional value at December 31, 2016 $ 7,475 $ 3,325 $ 10,800 The following table presents additional information about the interest rate swaps used in Huntington’s asset and liability management activities at December 31, 2017 and December 31, 2016 : December 31, 2017 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ — 0 $ — — % — % Liability conversion swaps Receive fixed—generic 8,375 2.5 (99 ) 1.56 1.44 Total swap portfolio at December 31, 2017 $ 8,375 2.5 $ (99 ) 1.56 % 1.44 % December 31, 2016 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ 3,325 0.6 $ (2 ) 1.04 % 0.91 % Liability conversion swaps Receive fixed—generic 7,475 3.1 (52 ) 1.49 0.88 Total swap portfolio at December 31, 2016 $ 10,800 2.3 $ (54 ) 1.35 % 0.89 % These derivative financial instruments were entered into for the purpose of managing the interest rate risk of assets and liabilities. Consequently, net amounts receivable or payable on contracts hedging either interest earning assets or interest bearing liabilities were accrued as an adjustment to either interest income or interest expense. The net amounts resulted in an increase to net interest income of $23 million , $72 million , and $108 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively. Fair Value Hedges The changes in fair value of the fair value hedges are, to the extent that the hedging relationship is effective, recorded through earnings and offset against changes in the fair value of the hedged item. The following table presents the change in fair value for derivatives designated as fair value hedges as well as the offsetting change in fair value on the hedged item: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Interest rate contracts Change in fair value of interest rate swaps hedging deposits (1) $ — $ — $ (1 ) Change in fair value of hedged deposits (1) — — 1 Change in fair value of interest rate swaps hedging subordinated notes (2) (14 ) (48 ) (8 ) Change in fair value of hedged subordinated notes (2) 17 45 8 Change in fair value of interest rate swaps hedging long-term debt (2) (39 ) (74 ) 4 Change in fair value of hedged other long-term debt (2) 37 67 (4 ) (1) Effective portion of the hedging relationship is recognized in Interest expense—deposits in the Consolidated Statements of Income. Any resulting ineffective portion of the hedging relationship is recognized in noninterest income in the Consolidated Statements of Income. (2) Effective portion of the hedging relationship is recognized in Interest expense—subordinated notes and other long-term debt in the Consolidated Statements of Income. Any resulting ineffective portion of the hedging relationship is recognized in noninterest income in the Consolidated Statements of Income. Cash Flow Hedges The following table presents the gains and (losses) recognized in OCI and the location in the Consolidated Statements of Income of gains and (losses) reclassified from OCI into earnings for derivatives designated as effective cash flow hedges: Derivatives in cash flow hedging relationships Amount of gain or (loss) recognized in OCI on derivatives (effective portion) Location of gain or (loss) reclassified from accumulated OCI into earnings (effective portion) Amount of (gain) or loss reclassified from accumulated OCI into earnings (effective portion) (pre-tax) (dollar amounts in millions) 2017 2016 2015 2017 2016 2015 Interest rate contracts Loans $ 2 $ 1 $ 9 Interest and fee income—loans and leases $ 1 $ — $ (1 ) Total $ 2 $ 1 $ 9 $ 1 $ — $ (1 ) Gains and losses on swaps related to loans are recorded in interest income and interest expense, respectively. To the extent these derivatives are effective in offsetting the variability of the hedged cash flows, changes in the derivatives’ fair value will not be included in current earnings but are reported as a component of OCI in the Consolidated Statements of Changes in Shareholders’ Equity. These changes in fair value will be included in earnings of future periods when earnings are also affected by the changes in the hedged cash flows. To the extent these derivatives are not effective, changes in their fair values are immediately included in noninterest income. Derivatives used in mortgage banking activities Mortgage loan origination hedging activity Huntington’s mortgage origination hedging activity is related to the hedging of the mortgage pricing commitments to customers and the secondary sale to third parties. The value of a newly originated mortgage is not firm until the interest rate is committed or locked. The interest rate lock commitments are derivative positions offset by forward commitments to sell loans. Huntington uses two types of mortgage-backed securities in its forward commitments to sell loans. The first type of forward commitment is a “To Be Announced” (or TBA), the second is a “Specified Pool” mortgage-backed security. Huntington uses these derivatives to hedge the value of mortgage-backed securities until they are sold. The following table summarizes the derivative assets and liabilities used in mortgage banking activities: Derivatives used in mortgage banking activities December 31, 2017 December 31, 2016 (dollar amounts in millions) Asset Liability Asset Liability Interest rate lock agreements $ 6 $ — $ 6 $ 2 Forward trades and options 1 — 13 1 Total derivatives used in mortgage banking activities $ 7 $ — $ 19 $ 3 MSR hedging activity Huntington’s MSR economic hedging activity uses derivatives to manage the value of the MSR asset and to mitigate the various types of risk inherent in the MSR asset, including risks related to duration, basis, convexity, volatility, and yield curve. The hedging instruments include forward commitments, interest rate swaps, and options on interest rate swaps. The total notional value of these derivative financial instruments at December 31, 2017 and 2016 , was $188 million and $308 million , respectively. The total notional amount at December 31, 2017 corresponds to trading liabilities with a fair value of $3 million . Net trading gains (losses) related to MSR hedging for the years ended December 31, 2017 , 2016 , and 2015 , were less than $1 million , $(1) million , and $(2) million , respectively. These amounts are included in mortgage banking income in the Consolidated Statements of Income. Derivatives used in customer related activities Various derivative financial instruments are offered to enable customers to meet their financing and investing objectives and for their risk management purposes. Derivative financial instruments used in trading activities consisted of commodity, interest rate, and foreign exchange contracts. The derivative contracts grant the option holder the right to buy or sell an underlying financial instrument for a predetermined price before the contract expires. Huntington may enter into offsetting third-party contracts with approved, reputable counterparties with substantially matching terms and currencies in order to economically hedge significant exposure related to derivatives used in trading activities. The interest rate risk of customer derivatives is mitigated by entering into similar derivatives having offsetting terms with other counterparties. The credit risk to these customers is evaluated and included in the calculation of fair value. Foreign currency derivatives help the customer hedge risk and reduce exposure to fluctuations in exchange rates. Transactions are primarily in liquid currencies with Canadian dollars and Euros comprising a majority of all transactions. The net fair values of these derivative financial instruments, for which the gross amounts are included in accrued income and other assets or accrued expenses and other liabilities at December 31, 2017 and December 31, 2016 , were $88 million and $80 million , respectively. The total notional values of derivative financial instruments used by Huntington on behalf of customers, including offsetting derivatives, were $22 billion and $21 billion at December 31, 2017 and December 31, 2016 , respectively. Huntington’s credit risks from interest rate swaps used for trading purposes were $119 million and $196 million at the same dates, respectively. Visa ® related Swap In connection with the sale of Huntington’s Class B Visa ® shares, Huntington entered into a swap agreement with the purchaser of the shares. The swap agreement adjusts for dilution in the conversion ratio of Class B shares resulting from changes in the Visa ® litigation. In connection with the FirstMerit acquisition, Huntington acquired an additional Visa ® related swap agreement. At December 31, 2017 , the combined fair value of the swap liabilities of $5 million is an estimate of the exposure liability based upon Huntington’s assessment of the potential Visa ® litigation losses and timing of the litigation settlement. Financial assets and liabilities that are offset in the Consolidated Balance Sheets All derivatives are carried on the Consolidated Balance Sheets at fair value. Derivative balances are presented on a net basis taking into consideration the effects of legally enforceable master netting agreements. Collateral agreements are regularly entered into as part of the underlying derivative agreements with Huntington’s counterparties to mitigate counterparty credit risk. Cash collateral exchanged with counterparties is also netted against the applicable derivative fair values. Huntington enters into derivative transactions with two primary groups: broker-dealers and banks, and Huntington’s customers. Different methods are utilized for managing counterparty credit exposure and credit risk for each of these groups. Huntington enters into transactions with broker-dealers and banks for various risk management purposes. These types of transactions generally are high dollar volume. Huntington enters into bilateral collateral and master netting agreements with these counterparties, and routinely exchange cash and high quality securities collateral with these counterparties. Huntington enters into transactions with customers to meet their financing, investing, payment and risk management needs. These types of transactions generally are low dollar volume. Huntington generally enters into master netting agreements with customer counterparties, however collateral is generally not exchanged with customer counterparties. At December 31, 2017 and December 31, 2016 , aggregate credit risk associated with these derivatives, net of collateral that has been pledged by the counterparty, was $30 million and $26 million , respectively. The credit risk associated with interest rate swaps is calculated after considering master netting agreements with broker-dealers and banks. At December 31, 2017 , Huntington pledged $122 million of investment securities and cash collateral to counterparties, while other counterparties pledged $75 million of investment securities and cash collateral to Huntington to satisfy collateral netting agreements. In the event of credit downgrades, Huntington could be required to provide additional collateral. The following tables present the gross amounts of these assets and liabilities with any offsets to arrive at the net amounts recognized in the Consolidated Balance Sheets at December 31, 2017 and December 31, 2016 : Offsetting of Financial Assets and Derivative Assets Gross amounts offset in the consolidated balance sheets Net amounts of assets presented in the consolidated balance sheets Gross amounts not offset in the consolidated balance sheets (dollar amounts in millions) Gross amounts of recognized assets Financial instruments Cash collateral received Net amount December 31, 2017 Derivatives $ 322 $ (190 ) $ 132 $ (11 ) $ (18 ) $ 103 December 31, 2016 Derivatives 420 (182 ) 238 (34 ) (5 ) 199 Offsetting of Financial Liabilities and Derivative Liabilities Gross amounts offset in the consolidated balance sheets Net amounts of assets presented in the consolidated balance sheets Gross amounts not offset in the consolidated balance sheets (dollar amounts in millions) Gross amounts of recognized liabilities Financial instruments Cash collateral delivered Net amount December 31, 2017 Derivatives $ 331 $ (245 ) $ 86 $ — $ (21 ) $ 65 December 31, 2016 Derivatives 371 (272 ) 99 (8 ) (24 ) 67

VIEs

VIEs	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
VIEs	Consolidated VIEs Certain loan and lease securitization trusts are consolidated at December 31, 2016. During the 2017 fourth quarter, Huntington canceled the Series 2014A Trust. As a result, any remaining assets at the time of the cancellation were no longer part of the trust. The following table present the carrying amount and classification of the consolidated trusts’ assets and liabilities that were included in the Consolidated Balance Sheet at December 31, 2016 : December 31, 2016 Huntington Technology Other Consolidated VIEs Total (dollar amounts in millions) Series 2014A Assets: Cash $ 2 $ — $ 2 Net loans and leases 70 — 70 Accrued income and other assets — — — Total assets $ 72 $ — $ 72 Liabilities: Other long-term debt $ 57 $ — $ 57 Accrued interest and other liabilities — — — Total liabilities 57 — 57 Equity: Beneficial Interest owned by third party $ 14 — 14 Total liabilities and equity $ 71 $ — $ 71 The loans and leases were designated to repay the securitized notes. Huntington services the loans and leases and uses the proceeds from principal and interest payments to pay the securitized notes during the amortization period. Huntington has not provided financial or other support that was not previously contractually required. Unconsolidated VIEs The following tables provide a summary of the assets and liabilities included in Huntington’s Consolidated Financial Statements, as well as the maximum exposure to losses, associated with its interests related to unconsolidated VIEs for which Huntington holds an interest, but is not the primary beneficiary, to the VIE at December 31, 2017 , and 2016 : December 31, 2017 (dollar amounts in millions) Total Assets Total Liabilities Maximum Exposure to Loss 2016-1 Automobile Trust $ 7 $ — $ 7 2015-1 Automobile Trust 1 — 1 Trust Preferred Securities 14 252 — Affordable Housing Tax Credit Partnerships 636 335 636 Other Investments 117 53 117 Total $ 775 $ 640 $ 761 December 31, 2016 (dollar amounts in millions) Total Assets Total Liabilities Maximum Exposure to Loss 2016-1 Automobile Trust $ 15 $ — $ 15 2015-1 Automobile Trust 2 — 2 Trust Preferred Securities 14 253 — Affordable Housing Tax Credit Partnerships 577 293 577 Other Investments 79 42 79 Total $ 687 $ 588 $ 673 Automobile Securitizations The following table provides a summary of automobile transfers to trusts in separate securitization transactions. (dollar amounts in millions) Year Amount Transferred 2016-1 Automobile Trust 2016 $ 1,500 2015-1 Automobile Trust 2015 750 The securitizations and the resulting sale of all underlying securities qualified for sale accounting. Huntington has concluded that it is not the primary beneficiary of these trusts because it has neither the obligation to absorb losses of the entities that could potentially be significant to the VIEs nor the right to receive benefits from the entities that could potentially be significant to the VIEs. Huntington is not required and does not currently intend to provide any additional financial support to the trusts. Investors and creditors only have recourse to the assets held by the trusts. The interest Huntington holds in the VIEs relates to servicing rights which are included within accrued income and other assets of Huntington’s Consolidated Balance Sheets. The maximum exposure to loss is equal to the carrying value of the servicing asset. See Note 7 for more information. Trust-Preferred Securities Huntington has certain wholly-owned trusts whose assets, liabilities, equity, income, and expenses are not included within Huntington’s Consolidated Financial Statements. These trusts have been formed for the sole purpose of issuing trust-preferred securities, from which the proceeds are then invested in Huntington junior subordinated debentures, which are reflected in Huntington’s Consolidated Balance Sheet as subordinated notes. The trust securities are the obligations of the trusts, and as such, are not consolidated within Huntington’s Consolidated Financial Statements. A list of trust-preferred securities outstanding at December 31, 2017 follows: (dollar amounts in millions) Rate Principal amount of subordinated note/ debenture issued to trust (1) Investment in unconsolidated subsidiary Huntington Capital I 2.39 % (2) $ 70 $ 6 Huntington Capital II 2.32 (3) 32 3 Sky Financial Capital Trust III 3.09 (4) 72 2 Sky Financial Capital Trust IV 3.09 (4) 74 2 Camco Financial Trust 3.02 (5) 4 1 Total $ 252 $ 14 (1) Represents the principal amount of debentures issued to each trust, including unamortized original issue discount. (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70 %. (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625 %. (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.40 %. (5) Variable effective rate at December 31, 2017 , based on three month LIBOR + 1.33 %. Each issue of the junior subordinated debentures has an interest rate equal to the corresponding trust securities distribution rate. Huntington has the right to defer payment of interest on the debentures at any time, or from time-to-time for a period not exceeding five years provided that no extension period may extend beyond the stated maturity of the related debentures. During any such extension period, distributions to the trust securities will also be deferred and Huntington’s ability to pay dividends on its common stock will be restricted. Periodic cash payments and payments upon liquidation or redemption with respect to trust securities are guaranteed by Huntington to the extent of funds held by the trusts. The guarantee ranks subordinate and junior in right of payment to all indebtedness of the Company to the same extent as the junior subordinated debt. The guarantee does not place a limitation on the amount of additional indebtedness that may be incurred by Huntington. Affordable Housing Tax Credit Partnerships Huntington makes certain equity investments in various limited partnerships that sponsor affordable housing projects utilizing the Low Income Housing Tax Credit (LIHTC) pursuant to Section 42 of the Internal Revenue Code. The purpose of these investments is to achieve a satisfactory return on capital, to facilitate the sale of additional affordable housing product offerings, and to assist in achieving goals associated with the Community Reinvestment Act. The primary activities of the limited partnerships include the identification, development, and operation of multi-family housing that is leased to qualifying residential tenants. Generally, these types of investments are funded through a combination of debt and equity. Huntington uses the proportional amortization method to account for a majority of its investments in these entities. These investments are included in accrued income and other assets. Investments that do not meet the requirements of the proportional amortization method are recognized using the equity method. Investment losses related to these investments are included in noninterest income in the Consolidated Statements of Income. The following table presents the balances of Huntington’s affordable housing tax credit investments and related unfunded commitments at December 31, 2017 and 2016 . (dollar amounts in millions) December 31, December 31, Affordable housing tax credit investments $ 996 $ 877 Less: amortization (360 ) (300 ) Net affordable housing tax credit investments $ 636 $ 577 Unfunded commitments $ 335 $ 293 The following table presents other information relating to Huntington’s affordable housing tax credit investments for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Tax credits and other tax benefits recognized $ 91 $ 80 $ 60 Proportional amortization method Tax credit amortization expense included in provision for income taxes (1) 70 53 43 Equity method Tax credit investment losses included in noninterest income — 1 — (1) Includes an adjustment of $4 million tax related to the TCJA for the year ended December 31, 2017. There were no material sales of affordable housing tax credit investments in 2017 , 2016 or 2015 . Huntington recognized immaterial impairment losses for the years ended December 31, 2017 , 2016 and 2015 . The impairment losses recognized related to the fair value of the tax credit investments that were less than carrying value. Other Investments Other investments determined to be VIE’s include investments in New Market Tax Credit Investments, Historic Tax Credit Investments, Small Business Investment Companies, Rural Business Investment Companies, certain equity method investments and other miscellaneous investments.

COMMITMENTS AND CONTINGENT LIAB

COMMITMENTS AND CONTINGENT LIABILITIES	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENT LIABILITIES	COMMITMENTS AND CONTINGENT LIABILITIES Commitments to extend credit In the ordinary course of business, Huntington makes various commitments to extend credit that are not reflected in the Consolidated Financial Statements. The contract amounts of these financial agreements at December 31, 2017 , and December 31, 2016 were as follows: At December 31, (dollar amounts in millions) 2017 2016 Contract amount represents credit risk Commitments to extend credit: Commercial $ 16,219 $ 15,190 Consumer 13,384 12,236 Commercial real estate 1,366 1,698 Standby letters of credit 510 637 Commercial letters-of-credit 21 5 Commitments to extend credit generally have fixed expiration dates, are variable-rate, and contain clauses that permit Huntington to terminate or otherwise renegotiate the contracts in the event of a significant deterioration in the customer’s credit quality. These arrangements normally require the payment of a fee by the customer, the pricing of which is based on prevailing market conditions, credit quality, probability of funding, and other relevant factors. Since many of these commitments are expected to expire without being drawn upon, the contract amounts are not necessarily indicative of future cash requirements. The interest rate risk arising from these financial instruments is insignificant as a result of their predominantly short-term, variable-rate nature. Standby letters-of-credit are conditional commitments issued to guarantee the performance of a customer to a third-party. These guarantees are primarily issued to support public and private borrowing arrangements, including commercial paper, bond financing, and similar transactions. Most of these arrangements mature within two years. The carrying amount of deferred revenue associated with these guarantees was $10 million and $8 million at December 31, 2017 and December 31, 2016 , respectively. Commercial letters-of-credit represent short-term, self-liquidating instruments that facilitate customer trade transactions and generally have maturities of no longer than 90 days . The goods or cargo being traded normally secures these instruments. Commitments to sell loans Activity related to our mortgage origination activity supports the hedging of the mortgage pricing commitments to customers and the secondary sale to third parties. At December 31, 2017 and 2016 , Huntington had commitments to sell residential real estate loans of $0.7 billion and $0.8 billion , respectively. These contracts mature in less than one year . Litigation and Regulatory Matters In the ordinary course of business, Huntington is routinely a defendant in or party to pending and threatened legal and regulatory actions and proceedings. In view of the inherent difficulty of predicting the outcome of such matters, particularly where the claimants seek very large or indeterminate damages or where the matters present novel legal theories or involve a large number of parties, Huntington generally cannot predict what the eventual outcome of the pending matters will be, what the timing of the ultimate resolution of these matters will be, or what the eventual loss, fines or penalties related to each matter may be. Huntington establishes an accrued liability when those matters present loss contingencies that are both probable and estimable. In such cases, there may be an exposure to loss in excess of any amounts accrued. Huntington thereafter continues to monitor the matter for further developments that could affect the amount of the accrued liability that has been previously established. For certain matters, Huntington is able to estimate a range of possible loss. In cases in which Huntington possesses information to estimate a range of possible loss, that estimate is aggregated and disclosed below. There may be other matters for which a loss is probable or reasonably possible but such an estimate of the range of possible loss may not be possible. For those matters where an estimate of the range of possible loss is possible, management currently estimates the aggregate range of possible loss is $0 to $55 million at December 31, 2017 in excess of the accrued liability (if any) related to those matters. This estimated range of possible loss is based upon currently available information and is subject to significant judgment and a variety of assumptions, and known and unknown uncertainties. The matters underlying the estimated range will change from time to time, and actual results may vary significantly from the current estimate. The estimated range of possible loss does not represent Huntington’s maximum loss exposure. Information is provided below regarding the nature of all of these contingencies and, where specified, the amount of the claim associated with these loss contingencies. Based on current knowledge, management does not believe that loss contingencies arising from pending matters, including the matters described herein, will have a material adverse effect on the consolidated financial position of Huntington. Further, management believes that amounts previously accrued are adequate to address Huntington’s contingent liabilities. However, in light of the inherent uncertainties involved in these matters, some of which are beyond Huntington’s control, and the large or indeterminate damages sought in some of these matters, an adverse outcome in one or more of these matters could be material to Huntington’s results of operations for any particular reporting period. Meoli v. The Huntington National Bank (Cyberco Litigation). The Bank has been named a defendant in a lawsuit arising from the Bank’s commercial lending, depository, and equipment leasing relationships with Cyberco Holdings, Inc. (Cyberco). Cyberco allegedly defrauded equipment lessors and financial institutions, including Huntington, in financing the purchase of computer equipment from Teleservices Group, Inc. (Teleservices), which itself later proved to be a shell corporation. Bankruptcy proceedings for both Cyberco and Teleservices ensued. In an adversary proceeding brought by the bankruptcy trustee for Teleservices in the U.S. District Court for the Western District of Michigan on September 28, 2015, judgment was rendered against Huntington in the amount of $72 million plus costs and pre- and post-judgment interest. Huntington appealed the judgment to the U.S. Sixth Circuit Court of Appeals, which, on February 8, 2017, reversed the judgment in part and remanded the case for further proceedings. After further briefing in the bankruptcy court on liability and the appropriate calculation of damages, the parties have reached an agreement in principle with the bankruptcy trustee on January 31, 2018 to settle the matter. Notice of the settlement must be provided to all parties-in-interest to the bankruptcy proceedings. A hearing in the bankruptcy court is scheduled for March, 19, 2018 to address any objections to the settlement and obtain bankruptcy court approval. Powell v. The Huntington National Bank. The Bank is a defendant in a putative class action filed on October 15, 2013 alleging Huntington charged late fees on mortgage loans in a method that violated West Virginia law and the loan documents. Plaintiffs seek statutory civil penalties, compensatory damages and attorney’s fees. Huntington filed a motion for summary judgment on the plaintiffs’ claims, which was granted by the U.S. District Court for the Southern District of West Virginia on December 28, 2016. Plaintiffs appealed to the U.S. Fourth Circuit Court of Appeals. Oral arguments were held on October 25, 2017. The parties reached an agreement in principle on February 1, 2018 to settle the matter. The parties are in the process of finalizing a written settlement agreement. Commitments under Operating Lease Obligations At December 31, 2017 , Huntington and its subsidiaries were obligated under noncancelable leases for land, buildings, and equipment. Many of these leases contain renewal options and certain leases provide options to purchase the leased property during or at the expiration of the lease period at specified prices. Some leases contain escalation clauses calling for rentals to be adjusted for increased real estate taxes and other operating expenses or proportionately adjusted for increases in the consumer or other price indices. The future minimum rental payments required under operating leases that have initial or remaining noncancelable lease terms in excess of one year as of December 31, 2017 , were as follows: $59 million in 2018 , $55 million in 2019 , $53 million in 2020 , $38 million in 2021 , $34 million in 2022 , and $135 million thereafter. At December 31, 2017 , total minimum lease payments have not been reduced by minimum sublease rentals of $6 million due in the future under noncancelable subleases. At December 31, 2017 , the future minimum sublease rental payments that Huntington expects to receive were as follows: $2 million in 2018 , $2 million in 2019 , $1 million in 2020 , $0 million 2021 , $0 million in 2022 , and $0 million thereafter. The rental expense for all operating leases was $76 million , $65 million , and $58 million for 2017 , 2016 , and 2015 , respectively. Huntington had no material obligations under capital leases.

OTHER REGULATORY MATTERS

OTHER REGULATORY MATTERS	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
OTHER REGULATORY MATTERS	OTHER REGULATORY MATTERS Huntington and the Bank are subject to certain risk-based capital and leverage ratio requirements adopted by the Federal Reserve, for Huntington, and the OCC, for the Bank, to implement the U.S. Basel III capital rules. These quantitative calculations are minimums, and the Federal Reserve and OCC may determine that a banking organization, based on its size, complexity or risk profile, must maintain a higher level of capital in order to operate in a safe and sound manner. Under the U.S. Basel III capital rules, Huntington’s and the Bank’s assets, exposures and certain off-balance sheet items are subject to risk weights used to determine the institutions’ risk-weighted assets. These risk-weighted assets are used to calculate the following minimum capital ratios for Huntington and the Bank: • Tier 1 Leverage Ratio , equal to the ratio of Tier 1 capital to quarterly average assets (net of goodwill, certain other intangible assets and certain other deductions). The Bank’s minimum Tier 1 leverage ratio requirement is 4%. • CET1 Risk-Based Capital Ratio , equal to the ratio of CET1 capital to risk-weighted assets. CET1 capital primarily includes common shareholders’ equity subject to certain regulatory adjustments and deductions, including with respect to goodwill, intangible assets, certain deferred tax assets and AOCI. Certain of these adjustments and deductions are subject to phase-in periods that began on January 1, 2015 and ended on January 1, 2018. Together with the FDIC, the Federal Reserve and OCC have issued proposed rules that would simplify the capital treatment of certain capital deductions and adjustments. The final phase-in period for these capital deductions and adjustments has been indefinitely delayed. The minimum CET1 risk-based capital ratio requirement for Huntington and the Bank is 4.5%. • Tier 1 Risk-Based Capital Ratio , equal to the ratio of Tier 1 capital to risk-weighted assets. Tier 1 capital is primarily comprised of CET1 capital, perpetual preferred stock and certain qualifying capital instruments. The minimum Tier 1 risk-based capital ratio requirement for Huntington and the Bank is 6%. • Total Risk-Based Capital Ratio , equal to the ratio of total capital, including CET1 capital, Tier 1 capital and Tier 2 capital, to risk-weighted assets. Tier 2 capital primarily includes qualifying subordinated debt and qualifying ALLL. Tier 2 capital also includes, among other things, certain trust preferred securities. The minimum total risk-based capital ratio requirement for Huntington and the Bank is 8%. To be well-capitalized, the Bank must maintain the following capital ratios: CET1 Risk-Based Capital Ratio of 6.5% or greater; Tier 1 Risk-Based Capital Ratio of 8.0% or greater; Total Risk-Based Capital Ratio of 10.0% or greater; and Tier 1 Leverage Ratio of 5.0% or greater. Failure to be well-capitalized or to meet minimum capital requirements could result in certain mandatory and possible additional discretionary actions by regulators that, if undertaken, could have an adverse material effect on our operations or financial condition. Failure to be well-capitalized or to meet minimum capital requirements could also result in restrictions on Huntington’s or the Bank’s ability to pay dividends or otherwise distribute capital or to receive regulatory approval of applications. In addition to meeting the minimum capital requirements, under the U.S. Basel III capital rules Huntington and the Bank must also maintain the required Capital Conservation Buffer to avoid becoming subject to restrictions on capital distributions and certain discretionary bonus payments to management. The Capital Conservation Buffer is calculated as a ratio of CET1 capital to risk-weighted assets, and it effectively increases the required minimum risk-based capital ratios. The Capital Conservation Buffer requirement is being phased in over a three-year period that began on January 1, 2016. When the phase-in period is complete on January 1, 2019, the Capital Conservation Buffer will be 2.5%. Throughout 2017, the required Capital Conservation Buffer was 1.25%, and the required Capital Conservation Buffer throughout 2018 will be 1.875%. As of December 31, 2017 , Huntington’s and the Bank’s regulatory capital ratios were above the well-capitalized standards and met the then-applicable Capital Conservation Buffer. Please refer to the table below for a summary of Huntington’s and the Bank’s regulatory capital ratios as of December 31, 2017, calculated using the regulatory capital methodology applicable to us during 2017. Minimum Minimum December 31, Regulatory Ratio+Capital Well- 2017 2016 Capital Conservation Capitalized Basel III (dollar amounts in millions) Ratios Buffer Minimums Ratio Amount Ratio Amount Tier 1 leverage Consolidated 4.00 % N/A N/A 9.09 % $ 9,110 8.70 % $ 8,547 Bank 4.00 N/A 5.00 % 9.70 9,727 9.29 9,086 CET 1 risk-based capital Consolidated 4.50 5.75 % N/A 10.01 8,041 9.56 7,486 Bank 4.50 5.75 6.50 11.02 8,856 10.42 8,153 Tier 1 risk-based capital Consolidated 6.00 7.25 6.00 11.34 9,110 10.92 8,547 Bank 6.00 7.25 8.00 12.10 9,727 11.61 9,086 Total risk-based capital Consolidated 8.00 9.25 10.00 13.39 10,757 13.05 10,215 Bank 8.00 9.25 10.00 14.33 11,517 13.83 10,818 Huntington and its subsidiaries are also subject to various regulatory requirements that impose restrictions on cash, debt, and dividends. The Bank is required to maintain cash reserves based on the level of certain of its deposits. This reserve requirement may be met by holding cash in banking offices or on deposit at the FRB. During 2017 and 2016 , the average balances of these deposits were $0.4 billion and $0.3 billion , respectively. Under current Federal Reserve regulations, the Bank is limited as to the amount and type of loans it may make to the parent company and nonbank subsidiaries. At December 31, 2017 , the Bank could lend $1.1 billion to a single affiliate, subject to the qualifying collateral requirements defined in the regulations. Dividends from the Bank are one of the major sources of funds for the Company. These funds aid the Company in the payment of dividends to shareholders, expenses, and other obligations. Payment of dividends and/or return of capital to the parent company is subject to various legal and regulatory limitations. During 2017 , the Bank paid dividends and returned capital of $723.7 million to the holding company. Also, there are statutory and regulatory limitations on the ability of national banks to pay dividends or make other capital distributions.

PARENT COMPANY FINANCIAL STATEM

PARENT COMPANY FINANCIAL STATEMENTS	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
PARENT COMPANY FINANCIAL STATEMENTS	PARENT-ONLY FINANCIAL STATEMENTS The parent-only financial statements, which include transactions with subsidiaries, are as follows: Balance Sheets December 31, (dollar amounts in millions) 2017 2016 Assets Cash and due from banks $ 1,618 $ 1,753 Due from The Huntington National Bank 798 730 Due from non-bank subsidiaries 58 45 Investment in The Huntington National Bank 11,696 10,668 Investment in non-bank subsidiaries 111 500 Accrued interest receivable and other assets 252 321 Total assets $ 14,533 $ 14,017 Liabilities and shareholders’ equity Long-term borrowings $ 3,128 $ 3,145 Dividends payable, accrued expenses, and other liabilities 591 564 Total liabilities 3,719 3,709 Shareholders’ equity (1) 10,814 10,308 Total liabilities and shareholders’ equity $ 14,533 $ 14,017 (1) See Consolidated Statements of Changes in Shareholders’ Equity. Statements of Income Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Income Dividends from The Huntington National Bank $ 298 $ 188 $ 822 Non-bank subsidiaries 14 11 39 Interest from The Huntington National Bank 20 14 6 Non-bank subsidiaries 2 3 2 Other 4 — 5 Total income 338 216 874 Expense Personnel costs 19 12 5 Interest on borrowings 91 59 17 Other 115 123 93 Total expense 225 194 115 Income (loss) before income taxes and equity in undistributed net income of subsidiaries 113 22 759 Provision (benefit) for income taxes (56 ) (56 ) (110 ) Income (loss) before equity in undistributed net income of subsidiaries 169 78 869 Increase (decrease) in undistributed net income (loss) of: The Huntington National Bank 1,015 629 (161 ) Non-bank subsidiaries 2 5 (15 ) Net income $ 1,186 $ 712 $ 693 Other comprehensive income (loss) (1) (34 ) (175 ) (4 ) Comprehensive income $ 1,152 $ 537 $ 689 (1) See Consolidated Statements of Comprehensive Income for other comprehensive income (loss) detail. Statements of Cash Flows Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Operating activities Net income $ 1,186 $ 712 $ 693 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed net income of subsidiaries (997 ) (634 ) 176 Depreciation and amortization 4 (1 ) 1 Loss on sales of securities available-for-sale — — — Other, net (37 ) (24 ) (45 ) Net cash (used for) provided by operating activities 156 53 825 Investing activities Repayments from subsidiaries 442 464 495 Advances to subsidiaries (29 ) (1,758 ) (612 ) Proceeds from sale of securities available-for-sale 1 (2 ) — Cash paid for acquisitions, net of cash received — (133 ) — Proceeds from business divestitures — — 9 Net cash (used for) provided by investing activities 414 (1,429 ) (108 ) Financing activities Proceeds from issuance of long-term borrowings — 1,990 — Payment of borrowings — (65 ) — Dividends paid on stock (425 ) (299 ) (225 ) Net proceeds from issuance of preferred stock — 585 — Repurchases of common stock (260 ) — (252 ) Other, net (20 ) 1 14 Net cash provided by (used for) financing activities (705 ) 2,212 (463 ) Increase (decrease) in cash and due from banks (135 ) 836 254 Cash and due from banks at beginning of year 1,753 917 663 Cash and due from banks at end of year $ 1,618 $ 1,753 $ 917 Supplemental disclosure: Interest paid $ 90 $ 36 $ 17

SEGMENT REPORTING

SEGMENT REPORTING	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING Huntington's business segments are based on the internally-aligned segment leadership structure, which is how management monitors results and assesses performance. The Company has four major business segments: Consumer and Business Banking , Commercial Banking , Vehicle Finance , Regional Banking and The Huntington Private Client Group (RBHPCG) . The Treasury / Other function includes technology and operations, other unallocated assets, liabilities, revenue, and expense. Business segment results are determined based upon Huntington's management reporting system, which assigns balance sheet and income statement items to each of the business segments. The process is designed around the organizational and management structure and, accordingly, the results derived are not necessarily comparable with similar information published by other financial institutions. Additionally, because of the interrelationships of the various segments, the information presented is not indicative of how the segments would perform if they operated as independent entities. Revenue is recorded in the business segment responsible for the related product or service. Fee sharing is recorded to allocate portions of such revenue to other business segments involved in selling to, or providing service to customers. Results of operations for the business segments reflect these fee sharing allocations. The management accounting process that develops the business segment reporting utilizes various estimates and allocation methodologies to measure the performance of the business segments. Expenses are allocated to business segments using a two-phase approach. The first phase consists of measuring and assigning unit costs (activity-based costs) to activities related to product origination and servicing. These activity-based costs are then extended, based on volumes, with the resulting amount allocated to business segments that own the related products. The second phase consists of the allocation of overhead costs to all four business segments from Treasury / Other . Huntington utilizes a full-allocation methodology, where all Treasury / Other expenses, except reported Significant Items, and a small amount of other residual unallocated expenses, are allocated to the four business segments. The management accounting policies and processes utilized in compiling segment financial information are highly subjective and, unlike financial accounting, are not based on authoritative guidance similar to GAAP. As a result, reported segment results are not necessarily comparable with similar information reported by other financial institutions. Furthermore, changes in management structure or allocation methodologies and procedures result in changes in reported segment financial data. Accordingly, certain amounts have been reclassified to conform to the current period presentation. Huntington uses an active and centralized FTP methodology to attribute appropriate net interest income to the business segments. The intent of the FTP methodology is to transfer interest rate risk from the business segments by providing matched duration funding of assets and liabilities. The result is to centralize the financial impact, management, and reporting of interest rate risk in the Treasury / Other function where it can be centrally monitored and managed. The Treasury / Other function charges (credits) an internal cost of funds for assets held in (or pays for funding provided by) each business segment. The FTP rate is based on prevailing market interest rates for comparable duration assets (or liabilities). A new methodology for establishing FTP rates was adopted in 2017, therefore, prior period amounts have been restated to reflect the new methodology. Huntington announced a change in the executive leadership team, which became effective at the end of 2017. As a result, Commercial Real Estate is now included as an operating unit in the Commercial Banking segment. During the 2017 second quarter, the previously reported Home Lending segment was included as an operating unit in the Consumer and Business Banking segment. Additionally, the Insurance operating unit previously included in Commercial Banking was realigned to RBHPCG during the second quarter. Prior period results have been reclassified to conform to the current period presentation. Consumer and Business Banking - The Consumer and Business Banking segment, including Home Lending, provides a wide array of financial products and services to consumer and small business customers including but not limited to checking accounts, savings accounts, money market accounts, certificates of deposit, mortgage loans, consumer loans, credit cards, and small business loans and investment products. Other financial services available to consumer and small business customers include insurance, interest rate risk protection, foreign exchange, and treasury management. Business Banking is defined as serving companies with revenues up to $20 million. Home Lending supports origination and servicing of consumer loans and mortgages for customers who are generally located in our primary banking markets across all segments. Commercial Banking - Through a relationship banking model, this segment provides a wide array of products and services to the middle market, large corporate, real estate and government public sector customers located primarily within our geographic footprint. The segment is divided into six business units: Middle Market, Specialty Banking, Asset Finance, Capital Markets/ Institutional Corporate Banking, Commercial Real Estate and Treasury Management. Vehicle Finance - Our products and services include providing financing to consumers for the purchase of automobiles, light-duty trucks, recreational vehicles and marine craft at franchised and other select dealerships, and providing financing to franchised dealerships for the acquisition of new and used inventory. Products and services are delivered through highly specialized relationship-focused bankers and product partners. Regional Banking and The Huntington Private Client Group - The core business of The Huntington Private Client Group is The Huntington Private Bank, which consists of Private Banking, Wealth & Investment Management, and Retirement Plan Services. The Huntington Private Bank provides high net-worth customers with deposit, lending (including specialized lending options), and banking services. The Huntington Private Bank also delivers wealth management and legacy planning through investment and portfolio management, fiduciary administration, and trust services. This group also provides retirement plan services to corporate businesses. The Huntington Private Client Group provides corporate trust services and institutional and mutual fund custody services. Listed below is certain financial information reconciled to Huntington’s December 31, 2017 , December 31, 2016 , and December 31, 2015 , reported results by business segment: Income Statements (dollar amounts in millions) Consumer & Business Banking Commercial Banking Vehicle Finance RBHPCG Treasury / Other Huntington Consolidated 2017 Net interest income $ 1,555 $ 899 $ 424 $ 184 $ (60 ) $ 3,002 Provision (benefit) for credit losses 110 28 63 — — 201 Noninterest income 735 278 14 188 92 1,307 Noninterest expense 1,647 474 150 243 200 2,714 Provision (benefit) for income taxes 187 236 79 45 (339 ) 208 Net income (loss) $ 346 $ 439 $ 146 $ 84 $ 171 $ 1,186 2016 Net interest income $ 1,224 $ 725 $ 345 $ 152 $ (77 ) $ 2,369 Provision (benefit) for credit losses 68 79 47 (3 ) — 191 Noninterest income 650 244 14 177 65 1,150 Noninterest expense 1,338 398 118 229 325 2,408 Provision (benefit) for income taxes 164 172 68 36 (232 ) 208 Net income (loss) $ 304 $ 320 $ 126 $ 67 $ (105 ) $ 712 2015 Net interest income $ 995 $ 560 $ 262 $ 125 $ 9 $ 1,951 Provision (benefit) for credit losses 45 16 39 — — 100 Noninterest income 566 214 13 174 72 1,039 Noninterest expense 1,192 343 93 241 107 1,976 Provision (benefit) for income taxes 113 145 50 21 (108 ) 221 Net income (loss) $ 211 $ 270 $ 93 $ 37 $ 82 $ 693 Assets at December 31, Deposits at December 31, (dollar amounts in millions) 2017 2016 2017 2016 Consumer & Business Banking $ 26,220 $ 25,333 $ 45,643 $ 45,356 Commercial Banking 32,118 31,566 21,235 19,597 Vehicle Finance 17,865 16,132 358 349 RBHPCG 5,821 5,328 6,057 6,214 Treasury / Other 22,161 21,355 3,748 4,092 Total $ 104,185 $ 99,714 $ 77,041 $ 75,608

QUARTERLY RESULTS OF OPERATIONS

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY RESULTS OF OPERATIONS (UNAUDITED)	QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) The following is a summary of the quarterly results of operations, for the years ended December 31, 2017 and 2016 : Three Months Ended December 31, September 30, June 30, March 31, (dollar amounts in millions, except per share data) 2017 2017 2017 2017 Interest income $ 894 $ 873 $ 846 $ 820 Interest expense 124 115 101 91 Net interest income 770 758 745 729 Provision for credit losses 65 43 25 68 Noninterest income 340 330 325 312 Noninterest expense 633 680 694 707 Income before income taxes 412 365 351 266 Provision (benefit) for income taxes (20 ) 90 79 59 Net income 432 275 272 207 Dividends on preferred shares 19 19 19 19 Net income applicable to common shares $ 413 $ 256 $ 253 $ 188 Net income per common share — Basic $ 0.38 $ 0.24 $ 0.23 $ 0.17 Net income per common share — Diluted 0.37 0.23 0.23 0.17 Three Months Ended December 31, September 30, June 30, March 31, (dollar amounts in millions, except per share data) 2016 2016 2016 2016 Interest income $ 815 $ 694 $ 566 $ 557 Interest expense 80 69 60 54 Net interest income 735 625 506 503 Provision for credit losses 75 63 25 28 Noninterest income 334 303 271 242 Noninterest expense 681 713 523 491 Income before income taxes 313 152 229 226 Provision (benefit) for income taxes 74 25 54 55 Net income 239 127 175 171 Dividends on preferred shares 19 18 20 8 Net income applicable to common shares $ 220 $ 109 $ 155 $ 163 Net income per common share — Basic $ 0.20 $ 0.12 $ 0.19 $ 0.21 Net income per common share — Diluted 0.20 0.11 0.19 0.20

SIGNIFICANT ACCOUNTING POLICI34

SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation — The Consolidated Financial Statements include the accounts of Huntington and its majority-owned subsidiaries and are presented in accordance with GAAP. All intercompany transactions and balances have been eliminated in consolidation. Companies in which Huntington holds more than a 50% voting equity interest, or a controlling financial interest, or are a VIE in which Huntington has the power to direct the activities of an entity that most significantly impact the entity’s economic performance and has an obligation to absorb losses or the right to receive benefits from the VIE which could potentially be significant to the VIE are consolidated. VIEs are legal entities with insubstantial equity, whose equity investors lack the ability to make decisions about the entity’s activities, or whose equity investors do not have the obligation to absorb losses or the right to receive the residual returns of the entity if they occur. VIEs in which Huntington does not hold the power to direct the activities of the entity that most significantly impact the entity’s economic performance or does not have an obligation to absorb losses or the right to receive benefits from the VIE which could potentially be significant to the VIE are not consolidated. For consolidated entities where Huntington holds less than a 100% interest, Huntington recognizes non-controlling interest (included in shareholders’ equity) for the equity held by others and non-controlling profit or loss (included in noninterest expense) for the portion of the entity’s earnings attributable to other’s interests. Investments in companies that are not consolidated are accounted for using the equity method when Huntington has the ability to exert significant influence. Those investments in nonmarketable securities for which Huntington does not have the ability to exert significant influence are generally accounted for using the cost method. Investments in private investment partnerships that are accounted for under the equity method or the cost method are included in Accrued income and other assets and Huntington’s proportional interest in the equity investments’ earnings are included in other noninterest income. Investment interests accounted for under the cost and equity methods are periodically evaluated for impairment. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that significantly affect amounts reported in the Consolidated Financial Statements. Huntington utilizes processes that involve the use of significant estimates and the judgments of management in determining the amount of its allowance for credit losses, income taxes, deferred tax, and contingent liabilities, as well as fair value measurements of investment securities, derivatives, goodwill, other intangible assets, pension assets and liabilities, short-term borrowings, mortgage servicing rights, and loans held for sale. As with any estimate, actual results could differ from those estimates. For statements of cash flows purposes, cash and cash equivalents are defined as the sum of Cash and due from banks, which includes amounts on deposit with the Federal Reserve and Federal funds sold and securities purchased under resale agreements. Certain prior period amounts have been reclassified to conform to the current year’s presentation.
Resale and Repurchase Agreements	Resale and Repurchase Agreements — Securities purchased under agreements to resell and securities sold under agreements to repurchase are treated as collateralized financing transactions and are recorded at the amounts at which the securities were acquired or sold plus accrued interest. The fair value of collateral either received from or provided to a third-party is continually monitored and additional collateral is obtained or requested to be returned to Huntington in accordance with the agreement.
Securities	Securities — Securities purchased with the intention of recognizing short-term profits or which are actively bought and sold are classified as trading account securities and reported at fair value. The unrealized gains or losses on trading account securities are recorded in other noninterest income, except for gains and losses on trading account securities used to economically hedge the fair value of MSRs, which are included in mortgage banking income. Debt securities purchased in which Huntington has the positive intent and ability to hold to their maturity are classified as held-to-maturity securities. Held-to-maturity securities are recorded at amortized cost. All other debt and equity securities are classified as available-for-sale and other securities. Unrealized gains or losses on available-for-sale and other securities are reported as a separate component of accumulated OCI in the Consolidated Statements of Changes in Shareholders’ Equity. Credit-related declines in the value of debt securities that are considered OTTI are recorded in noninterest income. Huntington evaluates its investment securities portfolio on a quarterly basis for indicators of OTTI. Huntington assesses whether OTTI has occurred when the fair value of a debt security is less than the amortized cost basis at the balance sheet date. Management reviews the amount of unrealized loss, the length of time the security has been in an unrealized loss position, the credit rating history, market trends of similar security classes, time remaining to maturity, and the source of both interest and principal payments to identify securities which could potentially be impaired. For those debt securities that Huntington intends to sell or is more likely than not required to sell, before the recovery of their amortized cost bases, the difference between fair value and amortized cost is considered to be OTTI and is recognized in noninterest income. For those debt securities that Huntington does not intend to sell or is not more likely than not required to sell, prior to expected recovery of amortized cost bases, the credit portion of the OTTI is recognized in noninterest income while the noncredit portion is recognized on OCI. In determining the credit portion, Huntington uses a discounted cash flow analysis, which includes evaluating the timing and amount of the expected cash flows. Non-credit-related OTTI results from other factors, including increased liquidity spreads and higher interest rates. Presentation of OTTI is made in the Consolidated Statements of Income on a gross basis with a reduction for the amount of OTTI recognized in OCI. Securities transactions are recognized on the trade date (the date the order to buy or sell is executed). The carrying value plus any related accumulated OCI balance of sold securities is used to compute realized gains and losses. Interest and dividends on securities, including amortization of premiums and accretion of discounts using the effective interest method over the period to maturity, are included in interest income. Nonmarketable equity securities include stock acquired for regulatory purposes, such as FHLB stock and FRB stock. These securities are accounted for at cost, evaluated for impairment, and included in available-for-sale and other securities.
Loans and Leases	Loans and Leases — Loans and direct financing leases for which Huntington has the intent and ability to hold for the foreseeable future, or until maturity or payoff, are classified in the Consolidated Balance Sheets as loans and leases. Except for purchase credit impaired loans and loans for which the fair value option has been elected, loans and leases are carried at the principal amount outstanding, net of charge-offs, unamortized deferred loan origination fees and costs, premiums and discounts, and unearned income. Direct financing leases are reported at the aggregate of lease payments receivable and estimated residual values, net of unearned and deferred income. Interest income is accrued as earned using the interest method based on unpaid principal balances. Huntington defers the fees it receives from the origination of loans and leases, as well as the direct costs of those activities. Huntington also acquires loans at a premium and at a discount to their contractual values. Except for purchased credit impaired loans, Huntington amortizes loan discounts, premiums, and net loan origination fees and costs over the contractual lives of the related loans using the effective interest method. Troubled debt restructurings are loans for which the original contractual terms have been modified to provide a concession to a borrower experiencing financial difficulties. Loan modifications are considered TDRs when the concessions provided are not available to the borrower through either normal channels or other sources. However, not all loan modifications are TDRs. Modifications resulting in troubled debt restructurings may include changes to one or more terms of the loan, including but not limited to, a change in interest rate, an extension of the repayment period, a reduction in payment amount, and partial forgiveness or deferment of principal or accrued interest. Residual values on leased equipment are evaluated quarterly for impairment. Impairment of the residual values of direct financing leases determined to be other than temporary is recognized by writing the leases down to fair value with a charge to other noninterest expense. Leased equipment residual value impairment will arise if the expected fair value is less than the carrying amount, net of estimated amounts reimbursable by the lessee. Future declines in the expected residual value of the leased equipment would result in expected losses of the leased equipment. For leased equipment, the residual component of a direct financing lease represents the estimated fair value of the leased equipment at the end of the lease term. Huntington uses industry data, historical experience, and independent appraisals to establish these residual value estimates. Additional information regarding product life cycle, product upgrades, as well as insight into competing products are obtained through relationships with industry contacts and are factored into residual value estimates where applicable.
Loans Held for Sale	Loans Held for Sale — Loans in which Huntington does not have the intent and ability to hold for the foreseeable future are classified as loans held for sale. Loans held for sale (excluding loans originated or acquired with the intent to sell, which are carried at fair value) are carried at the lower of cost or fair value less cost to sell. The fair value option is generally elected for mortgage loans held for sale to facilitate hedging of the loans. The fair value of such loans is estimated based on the inputs that include prices of mortgage backed securities adjusted for other variables such as, interest rates, expected credit defaults and market discount rates. The adjusted value reflects the price we expect to receive from the sale of such loans.
Allowance for Credit Losses	Allowance for Credit Losses — Huntington maintains two reserves, both of which reflect management’s judgment regarding the appropriate level necessary to absorb credit losses inherent in our loan and lease portfolio: the ALLL and the AULC. Combined, these reserves comprise the total ACL. The determination of the ACL requires significant estimates, including the timing and amounts of expected future cash flows on impaired loans and leases, consideration of current economic conditions, and historical loss experience pertaining to pools of homogeneous loans and leases, all of which may be susceptible to change. The appropriateness of the ACL is based on management’s current judgments about the credit quality of the loan portfolio. These judgments consider on-going evaluations of the loan and lease portfolio, including such factors as the differing economic risks associated with each loan category, the financial condition of specific borrowers, the level of delinquent loans, the value of any collateral and, where applicable, the existence of any guarantees or other documented support. Further, management evaluates the impact of changes in interest rates and overall economic conditions on the ability of borrowers to meet their financial obligations when quantifying our exposure to credit losses and assessing the appropriateness of our ACL at each reporting date. In addition to general economic conditions and the other factors described above, additional factors also considered include: the impact of increasing or decreasing commercial real estate values and the development of new or expanded Commercial business segments. The ALLL consists of two components: (1) the transaction reserve, which includes a loan level allocation, specific reserves related to loans considered to be impaired, and loans involved in troubled debt restructurings, and (2) the general reserve. The transaction reserve component includes both (1) an estimate of loss based on pools of commercial and consumer loans and leases with similar characteristics and (2) an estimate of loss based on an impairment review of each impaired C&I and CRE loan where obligor balance is greater than $1 million . For the C&I and CRE portfolios, the estimate of loss based on pools of loans and leases with similar characteristics is made by applying a PD factor and a LGD factor to each individual loan based on a regularly updated loan grade, using a standardized loan grading system. The PD factor and an LGD factor are determined for each loan grade using statistical models based on historical performance data. The PD factor considers on-going reviews of the financial performance of the specific borrower, including cash flow, debt-service coverage ratio, earnings power, debt level, and equity position, in conjunction with an assessment of the borrower’s industry and future prospects. The LGD factor considers analysis of the type of collateral and the relative LTV ratio. These reserve factors are developed based on credit migration models that track historical movements of loans between loan ratings over time and a combination of long-term average loss experience of our own portfolio and external industry data. In the case of more homogeneous portfolios, such as automobile loans, home equity loans, and residential mortgage loans, the determination of the transaction reserve also incorporates PD and LGD factors. The estimate of loss is based on pools of loans and leases with similar characteristics. The PD factor considers current credit scores unless the account is delinquent, in which case a higher PD factor is used driven by the associated delinquency status. The credit score provides a basis for understanding the borrower’s past and current payment performance, and this information is used to estimate expected losses over the emergence period. The performance of first-lien loans ahead of our junior-lien loans is available to use as part of our updated score process. The LGD factor considers analysis of the type of collateral and the relative LTV ratio. Credit scores, models, analyses, and other factors used to determine both the PD and LGD factors are updated frequently to capture the recent behavioral characteristics of the subject portfolios, as well as any changes in loss mitigation or credit origination strategies, and adjustments to the reserve factors are made as required. The general reserve consists of various risk-profile reserve components. The risk-profile component considers items unique to our structure, policies, processes, and portfolio composition, as well as qualitative measurements and assessments of the loan portfolios including, but not limited to, concentrations, portfolio composition, industry comparisons, and internal review functions. The estimate for the AULC is determined using the same procedures and methodologies as used for the ALLL. The loss factors used in the AULC are the same as the loss factors used in the ALLL while also considering a historical utilization of unused commitments. The AULC is recorded in Accrued expenses and other liabilities in the Consolidated Balance Sheets.
Nonaccrual and Past Due Loans	Nonaccrual and Past Due Loans — Loans are considered past due when the contractual amounts due with respect to principal and interest are not received within 30 days of the contractual due date. Any loan in any portfolio may be placed on nonaccrual status prior to the policies described below when collection of principal or interest is in doubt. When a borrower with debt is discharged in a Chapter 7 bankruptcy and not reaffirmed by the borrower, the loan is determined to be collateral dependent and placed on nonaccrual status, unless there is a co-borrower. All classes within the C&I and CRE portfolios (except for purchased credit-impaired loans) are placed on nonaccrual status at 90 -days past due. First-lien home equity loans are placed on nonaccrual status at 150 -days past due. Junior-lien home equity loans are placed on nonaccrual status at the earlier of 120 -days past due or when the related first-lien loan has been identified as nonaccrual. Automobile, RV and marine finance and other consumer loans are placed on non-accrual if not charged off when the loan is 120 -days past due. Residential mortgage loans are placed on nonaccrual status at 150 -days past due, with the exception of residential mortgages guaranteed by government agencies which continue to accrue interest at the rate guaranteed by the government agency. Huntington is reimbursed from the government agency for reasonable expenses incurred in servicing loans. For all classes within all loan portfolios, when a loan is placed on nonaccrual status, any accrued interest income is reversed with current year accruals charged to interest income, and prior year amounts charged-off as a credit loss. For all classes within all loan portfolios, cash receipts on NALs are applied against principal until the loan or lease has been collected in full, including the charged-off portion, after which time any additional cash receipts are recognized as interest income. However, for secured non-reaffirmed debt in a Chapter 7 bankruptcy, payments are applied to principal and interest when the borrower has demonstrated a capacity to continue payment of the debt and collection of the debt is reasonably assured. For unsecured non-reaffirmed debt in a Chapter 7 bankruptcy where the carrying value has been fully charged-off, payments are recorded as loan recoveries. Regarding all classes within the C&I and CRE portfolios, the determination of a borrower’s ability to make the required principal and interest payments is based on an examination of the borrower’s current financial statements, industry, management capabilities, and other qualitative measures. For all classes within the consumer loan portfolio, the determination of a borrower’s ability to make the required principal and interest payments is based on multiple factors, including number of days past due and, in some instances, an evaluation of the borrower’s financial condition. When, in management’s judgment, the borrower’s ability to make required principal and interest payments resumes and collectability is no longer in doubt, supported by sustained repayment history, the loan is returned to accrual status. For these loans that have been returned to accrual status, cash receipts are applied according to the contractual terms of the loan.
Charge-off of Uncollectible Loans	Charge-off of Uncollectible Loans — Any loan in any portfolio may be charged-off prior to the policies described below if a loss confirming event has occurred. Loss confirming events include, but are not limited to, bankruptcy (unsecured), continued delinquency, foreclosure, or receipt of an asset valuation indicating a collateral deficiency and that asset is the sole source of repayment. Additionally, discharged, collateral dependent non-reaffirmed debt in Chapter 7 bankruptcy filings will result in a charge-off to estimated collateral value, less anticipated selling costs. C&I and CRE loans are either charged-off or written down to net realizable value at 90 -days past due. Automobile, RV and marine finance and other consumer loans are generally charged-off at 120 -days past due. First-lien and junior-lien home equity loans are charged-off to the estimated fair value of the collateral, less anticipated selling costs, at 150 -days past due and 120 -days past due, respectively. Residential mortgages are charged-off to the estimated fair value of the collateral at 150 -days past due.
Impaired Loans	Impaired Loans — For all classes within the C&I and CRE portfolios, all loans with an obligor balance of $1 million or greater are evaluated on a quarterly basis for impairment. Except for TDRs, consumer loans within any class are generally not individually evaluated on a regular basis for impairment. All TDRs, regardless of the outstanding balance amount, are also considered to be impaired. Loans acquired with evidence of deterioration in credit quality since origination for which it is probable at acquisition that all contractually required payments will not be collected are also considered to be impaired. Once a loan has been identified for an assessment of impairment, the loan is considered impaired when, based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. This determination requires significant judgment and use of estimates, and the eventual outcome may differ significantly from those estimates. When a loan in any class has been determined to be impaired, the amount of the impairment is measured using the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, the observable market price of the loan, or the fair value of the collateral, less anticipated selling costs, if the loan is collateral dependent. A specific reserve is established as a component of the ALLL when a loan has been determined to be impaired. Subsequent to the initial measurement of impairment, if there is a significant change to the impaired loan’s expected future cash flows, or if actual cash flows are significantly different from the cash flows previously estimated, Huntington recalculates the impairment and appropriately adjusts the specific reserve. Similarly, if Huntington measures impairment based on the observable market price of an impaired loan or the fair value of the collateral of an impaired collateral dependent loan, Huntington will adjust the specific reserve. When a loan within any class is impaired, the accrual of interest income is discontinued unless the receipt of principal and interest is no longer in doubt. Interest income on TDRs is accrued when all principal and interest is expected to be collected under the post-modification terms. Cash receipts on nonaccruing impaired loans within any class are generally applied entirely against principal until the loan has been collected in full (including any portion charged-off) or the loan is deemed current, after which time any additional cash receipts are recognized as interest income. Cash receipts on accruing impaired loans within any class are applied in the same manner as accruing loans that are not considered impaired. Purchased Credit-Impaired Loans — Purchased loans with evidence of deterioration in credit quality since origination, for which it is probable at acquisition that we will be unable to collect all contractually required payments, are considered to be credit impaired. Purchased credit-impaired loans are initially recorded at fair value, which is estimated by discounting the cash flows expected to be collected at the acquisition date. Because the estimate of expected cash flows reflects an estimate of future credit losses expected to be incurred over the life of the loans, an allowance for credit losses is not recorded at the acquisition date. The excess of cash flows expected at acquisition over the estimated fair value, referred to as the accretable yield, is recognized in interest income over the remaining life of the loan, or pool of loans, on a level-yield basis. The difference between the contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable difference. A subsequent decrease in the estimate of cash flows expected to be received on purchased credit-impaired loans generally results in the recognition of an allowance for credit losses. Subsequent increases in cash flows result in reversal of any nonaccretable difference (or allowance for loan and lease losses to the extent one has been recorded) with a positive impact on interest income subsequently recognized. The measurement of cash flows involves assumptions and judgments for interest rates, prepayments, default rates, loss severity, and collateral values. All of these factors are inherently subjective and significant changes in the cash flow estimates over the life of the loan can result.
Transfers of Financial Assets and Securitizations	Transfers of Financial Assets and Securitizations — Transfers of financial assets in which we have surrendered control over the transferred assets are accounted for as sales. In assessing whether control has been surrendered, we consider whether the transferee would be a consolidated affiliate, the existence and extent of any continuing involvement in the transferred financial assets, and the impact of all arrangements or agreements made contemporaneously with, or in contemplation of, the transfer, even if they were not entered into at the time of transfer. Control is generally considered to have been surrendered when (i) the transferred assets have been legally isolated from us or any of our consolidated affiliates, even in bankruptcy or other receivership, (ii) the transferee (or, if the transferee is an entity whose sole purpose is to engage in securitization or asset-backed financing that is constrained from pledging or exchanging the assets it receives, each third-party holder of its beneficial interests) has the right to pledge or exchange the assets (or beneficial interests) it received without any constraints that provide more than a trivial benefit to us, and (iii) neither we nor our consolidated affiliates and agents have (a) both the right and obligation under any agreement to repurchase or redeem the transferred assets before their maturity, (b) the unilateral ability to cause the holder to return specific financial assets that also provides us with a more-than-trivial benefit (other than through a cleanup call) or (c) an agreement that permits the transferee to require us to repurchase the transferred assets at a price so favorable that it is probable that it will require us to repurchase them. If the sale criteria are met, the transferred financial assets are removed from our balance sheet and a gain or loss on sale is recognized. If the sale criteria are not met, the transfer is recorded as a secured borrowing in which the assets remain on our balance sheet and the proceeds from the transaction are recognized as a liability. For the majority of financial asset transfers, it is clear whether or not we have surrendered control. For other transfers, such as in connection with complex transactions or where we have continuing involvement, we generally obtain a legal opinion as to whether the transfer results in a true sale by law. From time to time we securitize certain automobile loans. Gains and losses on the loans and leases sold and servicing rights associated with loan and lease sales are determined when the related loans or leases are sold to either a securitization trust or third-party. For loan or lease sales with servicing retained, a servicing asset is recorded at fair value for the right to service the loans sold.
Derivative Financial Instruments	Derivative Financial Instruments — A variety of derivative financial instruments, principally interest rate swaps, caps, floors, and collars, are used in asset and liability management activities to protect against the risk of adverse price or interest rate movements. These instruments provide flexibility in adjusting Huntington’s sensitivity to changes in interest rates without exposure to loss of principal and higher funding requirements. Huntington also uses derivatives, principally loan sale commitments, in hedging its mortgage loan interest rate lock commitments and its mortgage loans held for sale. Mortgage loan sale commitments and the related interest rate lock commitments are carried at fair value on the Consolidated Balance Sheets with changes in fair value reflected in mortgage banking income. Huntington also uses certain derivative financial instruments to offset changes in value of its MSRs. These derivatives consist primarily of forward interest rate agreements and forward mortgage contracts. The derivative instruments used are not designated as qualifying hedges. Accordingly, such derivatives are recorded at fair value with changes in fair value reflected in mortgage banking income. Derivative financial instruments are recorded in the Consolidated Balance Sheets as either an asset or a liability (in accrued income and other assets or accrued expenses and other liabilities, respectively) and measured at fair value. On the date a derivative contract is entered into, we designate it as either: • a qualifying hedge of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge); • a qualifying hedge of the variability of cash flows to be received or paid related to a recognized asset liability or forecasted transaction (cash flow hedge); or • a trading instrument or a non-qualifying (economic) hedge. Changes in the fair value of a derivative that has been designated and qualifies as a fair value hedge, along with the changes in the fair value of the hedged asset or liability that is attributable to the hedged risk, are recorded in current period earnings. Changes in the fair value of a derivative that has been designated and qualifies as a cash flow hedge, to the extent effective as a hedge, are recorded in accumulated other comprehensive income, net of income taxes, and reclassified into earnings in the period during which the hedged item affects earnings. Ineffectiveness in the hedging relationship is reflected in current period earnings. Changes in the fair value of derivatives held for trading purposes or which do not qualify for hedge accounting are reported in current period earnings. For those derivatives to which hedge accounting is applied, Huntington formally documents the hedging relationship and the risk management objective and strategy for undertaking the hedge. This documentation identifies the hedging instrument, the hedged item or transaction, the nature of the risk being hedged, and, unless the hedge meets all of the criteria to assume there is no ineffectiveness, the method that will be used to assess the effectiveness of the hedging instrument and how ineffectiveness will be measured. The methods utilized to assess retrospective hedge effectiveness, as well as the frequency of testing, vary based on the type of item being hedged and the designated hedge period. For specifically designated fair value hedges of certain fixed-rate debt, Huntington utilizes the short-cut method when certain criteria are met. For other fair value hedges of fixed-rate debt, including certificates of deposit, Huntington utilizes the regression method to evaluate hedge effectiveness on a quarterly basis. For fair value hedges of portfolio loans, the regression method is used to evaluate effectiveness on a daily basis. For cash flow hedges, the regression method is applied on a quarterly basis. Hedge accounting is discontinued prospectively when: • the derivative is no longer effective or expected to be effective in offsetting changes in the fair value or cash flows of a hedged item (including firm commitments or forecasted transactions); • the derivative expires or is sold, terminated, or exercised; • the forecasted transaction is no longer probable of occurring; • the hedged firm commitment no longer meets the definition of a firm commitment; or • the designation of the derivative as a hedging instrument is removed. When hedge accounting is discontinued because it is determined that the derivative no longer qualifies as an effective fair value or cash flow hedge, the derivative will continue to be carried on the balance sheet at fair value. In the case of a discontinued fair value hedge of a recognized asset or liability, as long as the hedged item continues to exist on the balance sheet, the hedged item will no longer be adjusted for changes in fair value. The basis adjustment that had previously been recorded to the hedged item during the period from the hedge designation date to the hedge discontinuation date is recognized as an adjustment to the yield of the hedged item over the remaining life of the hedged item. In the case of a discontinued cash flow hedge of a recognized asset or liability, as long as the hedged item continues to exist on the balance sheet, the effective portion of the changes in fair value of the hedging derivative will no longer be recorded to other comprehensive income. The balance applicable to the discontinued hedging relationship will be recognized in earnings over the remaining life of the hedged item as an adjustment to yield. If the discontinued hedged item was a forecasted transaction that is not expected to occur, any amounts recorded on the balance sheet related to the hedged item, including any amounts recorded in accumulated other comprehensive income, are immediately reclassified to current period earnings. In the case of either a fair value hedge or a cash flow hedge, if the previously hedged item is sold or extinguished, the basis adjustment to the underlying asset or liability or any remaining unamortized AOCI balance will be recognized in the current period earnings. In all other situations in which hedge accounting is discontinued, the derivative will be carried at fair value on the consolidated balance sheets, with changes in its fair value recognized in current period earnings unless re-designated as a qualifying hedge. Like other financial instruments, derivatives contain an element of credit risk, which is the possibility that Huntington will incur a loss because the counterparty fails to meet its contractual obligations. Notional values of interest rate swaps and other off-balance sheet financial instruments significantly exceed the credit risk associated with these instruments and represent contractual balances on which calculations of amounts to be exchanged are based. Credit exposure is limited to the sum of the aggregate fair value of positions that have become favorable to Huntington, including any accrued interest receivable due from counterparties. Potential credit losses are mitigated through careful evaluation of counterparty credit standing, selection of counterparties from a limited group of high quality institutions, collateral agreements, and other contract provisions. Huntington considers the value of collateral held and collateral provided in determining the net carrying value of derivatives. Huntington offsets the fair value amounts recognized for derivative instruments and the fair value for the right to reclaim cash collateral or the obligation to return cash collateral arising from derivative instrument(s) recognized at fair value executed with the same counterparty under a master netting arrangement.
Repossessed Collateral	Repossessed Collateral — Repossessed collateral, also referred to as OREO, is comprised principally of commercial and residential real estate properties obtained in partial or total satisfaction of loan obligations, and is carried at fair value. Collateral obtained in satisfaction of a loan is recorded at the estimated fair value less anticipated selling costs based upon the property’s appraised value at the date of foreclosure, with any difference between the fair value of the property and the carrying value of the loan recorded as a charge-off. If the fair value is higher than the carrying amount of the loan the excess is recognized first as a recovery and then as noninterest income. Subsequent declines in value are reported as adjustments to the carrying amount and are recorded in noninterest expense. Gains or losses resulting from the sale of collateral are recognized in noninterest expense at the date of sale.
Collateral	Collateral — We pledge assets as collateral as required for various transactions including security repurchase agreements, public deposits, loan notes, derivative financial instruments, short-term borrowings and long-term borrowings. Assets that have been pledged as collateral, including those that can be sold or repledged by the secured party, continue to be reported on our Consolidated Balance Sheets. We also accept collateral, primarily as part of various transactions including derivative and security resale agreements. Collateral accepted by us, including collateral that we can sell or repledge, is excluded from our Consolidated Balance Sheets. The market value of collateral we have accepted or pledged is regularly monitored and additional collateral is obtained or provided as necessary to ensure appropriate collateral coverage in these transactions.
Premises and Equipment	Premises and Equipment — Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is computed principally by the straight-line method over the estimated useful lives of the related assets. Buildings and building improvements are depreciated over an average of 30 to 40 years and 10 to 30 years, respectively. Land improvements and furniture and fixtures are depreciated over an average of 5 to 20 years, while equipment is depreciated over a range of 3 to 10 years. Leasehold improvements are amortized over the lesser of the asset’s useful life or the lease term, including any renewal periods for which renewal is reasonably assured. Maintenance and repairs are charged to expense as incurred, while improvements that extend the useful life of an asset are capitalized and depreciated over the remaining useful life. Premises and equipment is evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable.
Mortgage Servicing Rights	Mortgage Servicing Rights — Huntington recognizes the rights to service mortgage loans as separate assets, which are included in Servicing Rights in the Consolidated Balance Sheets when purchased, or when servicing is contractually separated from the underlying mortgage loans by sale or securitization of the loans with servicing rights retained. For loan sales with servicing retained, a servicing asset is recorded on the day of the sale at fair value for the right to service the loans sold. To determine the fair value of a MSR, Huntington uses an option adjusted spread cash flow analysis incorporating market implied forward interest rates to estimate the future direction of mortgage and market interest rates. The forward rates utilized are derived from the current yield curve for U.S. dollar interest rate swaps and are consistent with pricing of capital markets instruments. The current and projected mortgage interest rate influences the prepayment rate and, therefore, the timing and magnitude of the cash flows associated with the MSR. Servicing revenues on mortgage loans are included in mortgage banking income. At the time of initial capitalization, MSRs may be grouped into servicing classes based on the availability of market inputs used in determining fair value and the method used for managing the risks of the servicing assets. MSR assets are recorded using the fair value method or the amortization method. The election of the fair value or amortization method is made at the time each servicing class is established. All newly created MSRs since 2009 were recorded using the amortization method. Any change in the fair value of MSRs carried under the fair value method, as well as amortization and impairment of MSRs under the amortization method, during the period is recorded in mortgage banking income, which is reflected in the Consolidated Statements of Income. Huntington economically hedges the value of certain MSRs using derivative instruments and trading securities. Changes in fair value of these derivatives and trading securities are reported as a component of mortgage banking income.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets — Under the acquisition method of accounting, the net assets of entities acquired by Huntington are recorded at their estimated fair value at the date of acquisition. The excess cost of the acquisition over the fair value of net assets acquired is recorded as goodwill. Other intangible assets with finite useful lives are amortized either on an accelerated or straight-line basis over their estimated useful lives. Goodwill is evaluated for impairment on an annual basis at October 1 st of each year or whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Other intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable.
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits — Huntington recognizes the funded status of the postretirement benefit plans on the Consolidated Balance Sheets. Net postretirement benefit cost charged to current earnings related to these plans is predominantly based on various actuarial assumptions regarding expected future experience. Certain employees are participants in various defined contribution and other non-qualified supplemental retirement plans. Contributions to defined contribution plans are charged to current earnings. In addition, we maintain a 401(k) plan covering substantially all employees. Employer contributions to the plan, which are charged to current earnings, are based on employee contributions.
Share-Based Compensation	Share-Based Compensation — Huntington uses the fair value based method of accounting for awards of HBAN stock granted to employees under various share-based compensation plans. Share-based compensation costs are recognized prospectively for all new awards granted under these plans. Compensation expense relating to stock options is calculated using a methodology that is based on the underlying assumptions of the Black-Scholes option pricing model and is charged to expense over the requisite service period (e.g. vesting period). Compensation expense relating to restricted stock awards is based upon the fair value of the awards on the date of grant and is charged to earnings over the requisite service period (e.g., vesting period) of the award.
Stock Repurchases	Stock Repurchases — Acquisitions of Huntington stock are recorded at cost. The re-issuance of shares is recorded at weighted-average cost.
Income Taxes	Income Taxes — Income taxes are accounted for under the asset and liability method. Accordingly, deferred tax assets and liabilities are recognized for the future book and tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are determined using enacted tax rates expected to apply in the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income at the time of enactment of such change in tax rates. In the fourth quarter 2017, the TCJA was signed into law which requires the deferred tax assets and liabilities to be revalued using the 21% federal tax rate enacted. The effect was recorded in the fourth quarter tax provision. Any interest or penalties due for payment of income taxes are included in the provision for income taxes. To the extent we do not consider it more likely than not that a deferred tax asset will be recovered, a valuation allowance is recorded. All positive and negative evidence is reviewed when determining how much of a valuation allowance is recognized on a quarterly basis. In determining the requirements for a valuation allowance, sources of possible taxable income are evaluated including future reversals of existing taxable temporary differences, future taxable income exclusive of reversing temporary differences and carryforwards, taxable income in appropriate carryback years, and tax-planning strategies. Huntington applies a more likely than not recognition threshold for all tax uncertainties.
Bank Owned Life Insurance	Bank Owned Life Insurance — Huntington’s bank owned life insurance policies are recorded at their cash surrender value. Huntington recognizes tax-exempt income from the periodic increases in the cash surrender value of these policies and from death benefits. A portion of the cash surrender value is supported by holdings in separate accounts. Book value protection for the separate accounts is provided by the insurance carriers and a highly rated major bank.
Fair Value Measurements	Fair Value Measurements — The Company records or discloses certain of its assets and liabilities at fair value. 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. Fair value measurements are classified within one of three levels in a valuation hierarchy based upon the observability of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows: • Level 1 – inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2 – inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 – inputs to the valuation methodology are unobservable and significant to the fair value measurement. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.
Segment Results	Segment Results — Accounting policies for the business segments are the same as those used in the preparation of the Consolidated Financial Statements with respect to activities specifically attributable to each business segment. However, the preparation of business segment results requires management to establish methodologies to allocate funding costs and benefits, expenses, and other financial elements to each business segment, which are described in Note 24 .
Accounting Standards Update	Standard Summary of guidance Effects on financial statements ASU 2014-09 - Revenue from Contracts with Customers (Topic 606): Issued May 2014 - Topic 606 supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. - Requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. - Also requires additional qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers - Guidance sets forth a five step approach for revenue recognition. - Effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Management adopted the new guidance on January 1, 2018 using the modified retrospective approach. - Management's analysis includes: (a) Identification of all revenue streams included in the financial statements; (b) Determination of scope exclusions to identify ‘in-scope’ revenue streams; (c) Determination of size, timing, and amount of revenue recognition for in-scope items; (d) Identification of contracts for further analysis; and (e) Completion of review of certain contracts to evaluate the potential impact of the new guidance. - Key revenue streams identified include service charges, credit card and payment processing fees, trust services fees, insurance income, brokerage services, and mortgage banking income. - The Update did not have a significant impact on Huntington’s Consolidated Financial Statements. ASU 2016-01 - Recognition and Measurement of Financial Assets and Financial Liabilities. Issued January 2016 - Improvements to GAAP disclosures including requiring an entity to: (a) Measure its equity investments with changes in the fair value recognized in the income statement. (b) Present separately in OCI the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments (i.e., FVO liability). (c) Use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. (d) Assess deferred tax assets related to a net unrealized loss on AFS securities in combination with the entity’s other deferred tax assets. - Effective for the fiscal period beginning after December 15, 2017, including interim periods within those fiscal years. - Amendments are applied as a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. - The amendment did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2016-02 - Leases. Issued February 2016 - New lease accounting model for lessors and lessees. For lessees, virtually all leases will be required to be recognized on the balance sheet by recording a right-of-use asset and lease liability. Subsequent accounting for leases varies depending on whether the lease is classified as an operating lease or a finance lease. - Accounting applied by a lessor is largely unchanged from that applied under the existing guidance. - Requires additional qualitative and quantitative disclosures with the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. - Effective for the fiscal period beginning after December 15, 2018, with early application permitted. - Management intends to adopt the guidance on January 1, 2019, and has formed a working group comprised of associates from different disciplines, including Procurement, Real Estate, and Credit Administration, to evaluate the impact of the standard where Huntington is a lessee or lessor, as well as any impact to borrower’s financial statements. - Management is currently assessing the impact of the new guidance on Huntington's Consolidated Financial Statements, including working with associates engaged in the procurement of goods and services used in the entity’s operations, and reviewing contractual arrangements for embedded leases in an effort to identify Huntington’s full lease population. - Huntington will recognize right-of-use assets and lease liabilities for virtually all of its operating lease commitments. Standard Summary of guidance Effects on financial statements ASU 2016-13 - Financial Instruments - Credit Losses. Issued June 2016 - Eliminates the probable recognition threshold for credit losses on financial assets measured at amortized cost. - Requires those financial assets to be presented at the net amount expected to be collected (i.e., net of expected credit losses). - Measurement of expected credit losses should be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectibility of the reported amount. - Effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018. - Adoption will be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. - Management intends to adopt the guidance on January 1, 2020 and has formed a working group comprised of teams from different disciplines including credit and finance to evaluate the requirements of the new standard and the impact it will have on our processes. - The early stages of this evaluation include a review of existing credit models to identify areas where existing credit models used to comply with other regulatory requirements may be leveraged and areas where new impairment models may be required. ASU 2016-15 - Classification of Certain Cash Receipts and Cash Payments. Issued August 2016 - Clarifies guidance on the classification of certain cash receipts and payments in the statement of cash flows. - Provides consistent principles for evaluating the classification of cash payments and receipts in the statement of cash flows to reduce diversity in practice with respect to several types of cash flows. - Effective using a retrospective transition approach for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-04 - Simplifying the Test for Goodwill Impairment. Issued January 2017 - Simplifies the goodwill impairment test by eliminating Step 2 of the goodwill impairment process, which requires an entity to determine the implied fair value of its goodwill by assigning fair value to all its assets and liabilities. - Entities will instead recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. - Entities will still have the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. - Effective for annual and interim goodwill tests performed in fiscal years beginning after December 15, 2019. Early adoption is permitted. - The amendment is not expected to have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-07 - Improving the Presentation of Net Periodic Pension Cost and Periodic Postretirement Benefit Cost. Issued March 2017 - Requires that an employer report the service cost component of the pension cost and postretirement benefit cost in the same line items as other compensation costs arising from services rendered by the pertinent employees during the period. - Other components of the net benefit cost should be presented or disclosed separately in the income statement from the service cost component. - Effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2017-09 - Stock Compensation Modification Accounting. Issued May 2017 - Reduces the current diversity in practice and provides explicit guidance pertaining to the provisions of modification accounting. - Clarifies that an entity should account for effects of modification unless the fair value, vesting conditions and the classification of the modified award are the same as the original awards immediately before the original award is modified. - Effective prospectively for annual periods and interim periods within those annual periods, beginning after December 15, 2017. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. Standard Summary of guidance Effects on financial statements ASU 2017-12 - Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities. Issued August 2017 - Aligns the entity’s risk management activities and financial reporting for hedging relationships. - Requires an entity to present the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is reported. - Refines measurement techniques for hedges of benchmark interest rate risk. - Eliminates the separate measurement and reporting of hedge ineffectiveness. - Allows stated amount of assets in a closed portfolio to be fair value hedged by excluding proportion of hedged item related to prepayments, defaults and other events. - Eases hedge effectiveness testing including an option to perform qualitative testing. - Effective for annual periods and interim periods within those annual periods, beginning after December 15, 2018. For cash flow and net investment hedges, cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness should be recognized in AOCI with a corresponding adjustment to retained earnings. Earlier application is permitted. - Huntington adopted the new guidance on January 1, 2018. The Update did not have a significant impact on Huntington's Consolidated Financial Statements. ASU 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220) Issued Feb 2018 - Allows an entity to elect a reclassification from accumulated other comprehensive income (AOCI) to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. - The amount of that reclassification should include the effect of changes of tax rate on the deferred tax amount, any related valuation allowance and other income tax effects on the items in AOCI. - Requires an entity to state if an election to reclassify the tax effect to retained earnings is made along with the description of other income tax effects that are reclassified from AOCI. - Effective for fiscal years beginning after Dec 15, 2018 and interim periods within those fiscal years with earl y adoption permitted. - Huntington has elected to reclassify $93 million from AOCI to retained earnings in the current period.
Consolidated VIEs	Consolidated VIEs Certain loan and lease securitization trusts are consolidated at December 31, 2016. During the 2017 fourth quarter, Huntington canceled the Series 2014A Trust. As a result, any remaining assets at the time of the cancellation were no longer part of the trust.

ACQUISITION OF FIRSTMERIT COR35

ACQUISITION OF FIRSTMERIT CORPORATION (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition
Business Acquisition, Pro Forma Information

LOANS AND LEASES AND ALLOWANC36

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Asset and liability derivatives included in accrued income and other assets [Table Text Block]	December 31, 2017 December 31, 2016 (dollar amounts in millions) Asset Liability Asset Liability Derivatives designated as Hedging Instruments Interest rate contracts $ 22 $ 121 $ 46 $ 100 Derivatives not designated as Hedging Instruments Interest rate contracts (1) 187 100 233 141 Foreign exchange contracts 18 18 23 20 Commodities contracts 92 87 108 104 Equity contracts 3 5 10 6 Total Contracts $ 322 $ 331 $ 420 $ 371 .
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period
Schedule of financing receivable portfolio segments
Lease financing receivables	Net investments in lease financing receivables by category at December 31, 2017 and 2016 were as follows: At December 31, (dollar amounts in millions) 2017 2016 Commercial and industrial: Lease payments receivable $ 1,645 $ 1,881 Estimated residual value of leased assets 755 798 Gross investment in commercial lease financing receivables 2,400 2,679 Deferred origination costs 18 13 Deferred fees (225 ) (254 ) Total net investment in commercial lease financing receivables $ 2,193 $ 2,438
Loans acquired with deteriorated credit quality	The following table presents a rollforward of the accretable yield for purchased credit impaired loans for the year ended December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Balance, beginning of period $ 37 $ — Impact of acquisition/purchase on August 16, 2016 — 18 Accretion (18 ) (5 ) Reclassification from nonaccretable difference 14 24 Balance at December 31, $ 33 $ 37 The following table reflects the ending and unpaid balances of the purchased credit-impaired loans at December 31, 2017 and 2016 : December 31, 2017 December 31, 2016 (dollar amounts in millions) Ending Unpaid Principal Ending Unpaid Principal Commercial and industrial $ 39 $ 61 $ 68 $ 100 Commercial real estate 2 15 34 56 Total $ 41 $ 76 $ 102 $ 156
Loan Purchases and Sales	Loan
Nonaccrual loans by loan class	The following table presents NALs by loan class at December 31, 2017 and 2016 : December 31, (dollar amounts in millions) 2017 2016 Commercial and industrial $ 161 $ 234 Commercial real estate 29 20 Automobile 6 6 Home equity 68 72 Residential mortgage 84 91 RV and marine finance 1 — Other consumer — — Total nonaccrual loans $ 349 $ 423
Aging analysis of loans and leases	The following table presents an aging analysis of loans and leases, including past due loans and leases, by loan class at December 31, 2017 and 2016 (1): December 31, 2017 Past Due Purchased Credit Impaired Loans Accounted for Under the Fair Value Option Total Loans 90 or (dollar amounts in millions) 30-59 60-89 90 or Total Current Commercial and industrial $ 35 $ 14 $ 65 $ 114 $ 27,954 $ 39 $ — $ 28,107 $ 9 (2) Commercial real estate 10 1 11 22 7,201 2 — 7,225 3 Automobile 89 18 10 117 11,982 — 1 12,100 7 Home equity 49 19 60 128 9,969 — 2 10,099 18 Residential mortgage 129 48 118 295 8,642 — 89 9,026 72 RV and marine finance 11 3 2 16 2,421 — 1 2,438 1 Other consumer 12 5 5 22 1,100 — — 1,122 5 Total loans and leases $ 335 $ 108 $ 271 $ 714 $ 69,269 $ 41 $ 93 $ 70,117 $ 115 December 31, 2016 Past Due Loans Accounted for Under the Fair Value Option Total Loans 90 or (dollar amounts in millions) 30-59 60-89 90 or Total Current Purchased Commercial and industrial $ 42 $ 20 $ 74 $ 136 $ 27,855 68 — $ 28,059 $ 18 (2) Commercial real estate 21 3 30 54 7,213 34 — 7,301 17 Automobile 76 17 10 103 10,864 — 2 10,969 10 Home equity 39 24 53 116 9,987 — 3 10,106 12 Residential mortgage 122 37 117 276 7,374 — 75 7,725 67 RV and marine finance 10 2 2 14 1,830 — 2 1,846 1 Other consumer 11 6 3 20 936 — — 956 4 Total loans and leases $ 321 $ 109 $ 289 $ 719 $ 66,059 $ 102 $ 82 $ 66,962 $ 129 (1) NALs are included in this aging analysis based on the loan’s past due status. (2) Amounts include Huntington Technology Finance administrative lease delinquencies.
ALLL and AULC activity by portfolio segment	The following table presents ALLL and AULC activity by portfolio segment for the years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) Commercial Consumer Total Year ended December 31, 2017: ALLL balance, beginning of period $ 451 $ 187 $ 638 Loan charge-offs (72 ) (180 ) (252 ) Recoveries of loans previously charged-off 41 52 93 Provision for loan and lease losses 62 150 212 Allowance for loans sold or transferred to loans held for sale — — — ALLL balance, end of period $ 482 $ 209 $ 691 AULC balance, beginning of period $ 87 $ 11 $ 98 Provision (reduction in allowance) for unfunded loan commitments and letters of credit (3 ) (8 ) (11 ) AULC recorded at acquisition — — — AULC balance, end of period $ 84 $ 3 $ 87 ACL balance, end of period $ 566 $ 212 $ 778 Year ended December 31, 2016: ALLL balance, beginning of period $ 399 $ 199 $ 598 Loan charge-offs (92 ) (135 ) (227 ) Recoveries of loans previously charged-off 73 45 118 Provision for loan and lease losses 85 84 169 Allowance for loans sold or transferred to loans held for sale (14 ) (6 ) (20 ) ALLL balance, end of period $ 451 $ 187 $ 638 AULC balance, beginning of period $ 64 $ 8 $ 72 Provision (reduction in allowance) for unfunded loan commitments and letters of credit 19 3 22 AULC recorded at acquisition 4 — 4 AULC balance, end of period $ 87 $ 11 $ 98 ACL balance, end of period $ 538 $ 198 $ 736 Year ended December 31, 2015: ALLL balance, beginning of period $ 390 $ 215 $ 605 Loan charge-offs (98 ) (120 ) (218 ) Recoveries of loans previously charged-off 86 44 130 Provision for loan and lease losses 21 68 89 Allowance for loans sold or transferred to loans held for sale — (8 ) (8 ) ALLL balance, end of period $ 399 $ 199 $ 598 AULC balance, beginning of period $ 55 $ 6 $ 61 Provision (reduction in allowance) for unfunded loan commitments and letters of credit 9 2 11 AULC recorded at acquisition — — — AULC balance, end of period $ 64 $ 8 $ 72 ACL balance, end of period $ 463 $ 207 $ 670
Loan and lease balances by credit quality indicator	The following table presents each loan and lease class by credit quality indicator at December 31, 2017 and 2016 : December 31, 2017 Credit Risk Profile by UCS Classification (dollar amounts in millions) Pass OLEM Substandard Doubtful Total Commercial and industrial $ 26,268 $ 694 $ 1,116 $ 29 $ 28,107 Commercial real estate 6,909 200 115 1 7,225 Credit Risk Profile by FICO Score (1), (2) 750+ 650-749 <650 Other (3) Total Automobile 6,102 4,312 1,390 295 12,099 Home equity 6,352 3,024 617 104 10,097 Residential mortgage 5,697 2,581 605 54 8,937 RV and marine finance 1,433 863 96 45 2,437 Other consumer 428 540 143 11 1,122 December 31, 2016 Credit Risk Profile by UCS Classification (dollar amounts in millions) Pass OLEM Substandard Doubtful Total Commercial and industrial $ 26,212 $ 810 $ 1,029 $ 8 $ 28,059 Commercial real estate 7,042 97 159 3 7,301 Credit Risk Profile by FICO Score (1), (2) 750+ 650-749 <650 Other (3) Total Automobile 5,369 4,044 1,298 256 $ 10,967 Home equity 6,280 2,891 638 294 10,103 Residential mortgage 4,663 2,285 615 87 7,650 RV and marine finance 1,064 644 73 64 1,845 Other consumer 347 456 133 20 956 (1) Excludes loans accounted for under the fair value option. (2) Reflects updated customer credit scores. (3) Reflects deferred fees and costs, loans in process, etc.
Summarized data for impaired loans and the related ALLL by portfolio segment	The following tables present the balance of the ALLL attributable to loans by portfolio segment individually and collectively evaluated for impairment and the related loan and lease balance for the years ended December 31, 2017 and 2016 : (dollar amounts in millions) Commercial Consumer Total ALLL at December 31, 2017: Portion of ALLL balance: Attributable to purchased credit-impaired loans $ — $ — $ — Attributable to loans individually evaluated for impairment $ 32 $ 9 $ 41 Attributable to loans collectively evaluated for impairment 450 200 650 Total ALLL balance $ 482 $ 209 $ 691 Loan and Lease Ending Balances at December 31, 2017: (1) Portion of loan and lease ending balance: Attributable to purchased credit-impaired loans $ 41 $ — $ 41 Individually evaluated for impairment 607 616 1,223 Collectively evaluated for impairment 34,684 34,076 68,760 Total loans and leases evaluated for impairment $ 35,332 $ 34,692 $ 70,024 (1) Excludes loans accounted for under the fair value option. (dollar amounts in millions) Commercial Consumer Total ALLL at December 31, 2016: Portion of ALLL balance: Attributable to purchased credit-impaired loans $ — $ — $ — Attributable to loans individually evaluated for impairment 11 11 22 Attributable to loans collectively evaluated for impairment 440 176 616 Total ALLL balance: $ 451 $ 187 $ 638 Loan and Lease Ending Balances at December 31, 2016: (1) Portion of loan and lease ending balances: Attributable to purchased credit-impaired loans $ 102 $ — $ 102 Individually evaluated for impairment 416 458 874 Collectively evaluated for impairment 34,842 31,062 65,904 Total loans and leases evaluated for impairment $ 35,360 $ 31,520 $ 66,880
Detailed impaired loan information by class	The following tables present by class the ending, unpaid principal balance, and the related ALLL, along with the average balance and interest income recognized only for impaired loans and leases and purchased credit-impaired loans for the years ended December 31, 2017 and 2016 (1) (2): Year Ended December 31, 2017 December 31, 2017 (dollar amounts in millions) Ending Balance Unpaid Principal Balance (6) Related Allowance Average Balance Interest Income Recognized With no related allowance recorded: Commercial and industrial $ 284 $ 311 $ — $ 206 $ 12 Commercial real estate 56 81 — 64 8 Automobile — — — — — Home equity — — — — — Residential mortgage — — — — — RV and marine finance — — — — — Other consumer — — — — — With an allowance recorded: Commercial and industrial 257 280 29 292 16 Commercial real estate 51 51 3 52 2 Automobile 36 40 2 33 2 Home equity 334 385 14 329 15 Residential mortgage 308 338 4 325 12 RV and marine finance 2 3 — 1 — Other consumer 8 8 2 5 — Total Commercial and industrial (3) 541 591 29 498 28 Commercial real estate (4) 107 132 3 116 10 Automobile (2) 36 40 2 33 2 Home equity (5) 334 385 14 329 15 Residential mortgage (5) 308 338 4 325 12 RV and marine finance (2) 2 3 — 1 — Other consumer (2) 8 8 2 5 — Year Ended December 31, 2016 December 31, 2016 (dollar amounts in millions) Ending Balance Unpaid Principal Balance (6) Related Allowance Average Balance Interest Income Recognized With no related allowance recorded: Commercial and industrial $ 300 $ 359 $ — $ 293 $ 9 Commercial real estate 89 126 — 73 4 Automobile — — — — — Home equity — — — — — Residential mortgage — — — — — RV and marine finance — — — — — Other consumer — — — — — With an allowance recorded: Commercial and industrial 406 448 22 302 8 Commercial real estate 97 108 3 69 3 Automobile 31 31 2 32 2 Home equity 319 353 15 278 13 Residential mortgage 328 363 13 348 12 RV and marine finance — — — — — Other consumer 4 4 — 4 — Total Commercial and industrial (3) 706 807 22 595 17 Commercial real estate (4) 186 234 3 142 7 Automobile (2) 31 31 2 32 2 Home equity (5) 319 353 15 278 13 Residential mortgage (5) 328 363 13 348 12 RV and marine finance (2) — — — — — Other consumer (2) 4 4 — 4 — (1) These tables do not include loans fully charged-off. (2) All automobile, RV and marine finance and other consumer impaired loans included in these tables are considered impaired due to their status as a TDR. (3) At December 31, 2017 and December 31, 2016 , commercial and industrial loans of $382 million and $317 million , respectively, were considered impaired due to their status as a TDR. (4) At December 31, 2017 and December 31, 2016 , commercial real estate loans of $93 million and $82 million , respectively, were considered impaired due to their status as a TDR. (5) Includes home equity and residential mortgages considered to be collateral dependent due to their non-accrual status as well as home equity and mortgage loans considered impaired due to their status as a TDR. (6)
Detailed troubled debt restructuring information by class	The following table presents by class and by the reason for the modification the number of contracts, post-modification outstanding balance, and the financial effects of the modification for the years ended December 31, 2017 and 2016 : New Troubled Debt Restructurings During The Year Ended (1) December 31, 2017 December 31, 2016 (dollar amounts in millions) Number of Contracts Post-modification Outstanding Balance (2) Financial effects of modification (3) Number of Contracts Post-modification Outstanding Balance (2) Financial effects of modification (3) Commercial and industrial: Interest rate reduction 9 $ 1 $ — 4 $ — $ — Amortization or maturity date change 1,034 600 (9 ) 872 490 (9 ) Other 4 — — 20 3 — Total Commercial and industrial 1,047 601 (9 ) 896 493 (9 ) Commercial real estate: Interest rate reduction 3 — — 2 — — Amortization or maturity date change 106 122 (1 ) 111 69 (2 ) Other 2 — — 4 — — Total commercial real estate: 111 122 (1 ) 117 69 (2 ) Automobile: Interest rate reduction 31 — — 17 — — Amortization or maturity date change 1,727 15 1 1,593 15 1 Chapter 7 bankruptcy 983 8 — 1,059 8 — Other — — — — — — Total Automobile 2,741 23 1 2,669 23 1 Home equity: Interest rate reduction 36 2 — 55 3 — Amortization or maturity date change 517 33 (4 ) 578 32 (4 ) Chapter 7 bankruptcy 299 11 2 282 10 4 Other 70 4 — — — — Total Home equity 922 50 (2 ) 915 45 — Residential mortgage: Interest rate reduction 3 — — 13 1 — Amortization or maturity date change 349 40 (2 ) 363 39 (2 ) Chapter 7 bankruptcy 79 7 — 62 6 — Other 22 2 — 4 1 — Total Residential mortgage 453 49 (2 ) 442 47 (2 ) RV and marine finance: Interest rate reduction 1 — — — — — Amortization or maturity date change 42 1 — — — — Chapter 7 bankruptcy 88 1 — — — — Other — — — — — — Total RV and marine finance 131 2 — — — — Other consumer: Interest rate reduction 19 — — — — — Amortization or maturity date change 1,312 6 — 6 1 — Chapter 7 bankruptcy 9 — — 8 — — Other — — — — — — Total Other consumer 1,340 6 — 14 1 — Total new troubled debt restructurings 6,745 $ 853 $ (13 ) 5,053 $ 678 $ (12 ) (1) TDRs may include multiple concessions and the disclosure classifications are based on the primary concession provided to the borrower. (2) Post-modification balances approximate pre-modification balances. The aggregate amount of charge-offs as a result of a restructuring are not significant. (3) Amounts represent the financial impact via provision (recovery) for loan and lease losses as a result of the modification.

AVAILABLE-FOR-SALE AND OTHER 37

AVAILABLE-FOR-SALE AND OTHER SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Contractual maturities of investment securities	Contractual maturities of available-for-sale and other securities as of December 31, 2017 and 2016 were: 2017 2016 (dollar amounts in millions) Amortized Cost Fair Value Amortized Cost Fair Value Under 1 year $ 111 $ 111 $ 224 $ 222 After 1 year through 5 years 1,333 1,327 1,147 1,150 After 5 years through 10 years 2,088 2,083 1,957 1,962 After 10 years 11,595 11,348 11,885 11,665 Other securities: Nonmarketable equity securities 581 581 548 548 Mutual funds 18 18 15 15 Marketable equity securities 1 1 1 1 Total available-for-sale and other securities $ 15,727 $ 15,469 $ 15,777 $ 15,563
Amortized cost, fair value, and gross unrealized gain and losses recognized in accumulated other comprehensive income	The following tables provide amortized cost, fair value, and gross unrealized gains and losses recognized in OCI by investment category at December 31, 2017 and 2016 : Unrealized (dollar amounts in millions) Amortized Cost Gross Gains Gross Losses Fair Value December 31, 2017 U.S. Treasury $ 5 $ — $ — $ 5 Federal agencies: Residential CMO 6,661 1 (178 ) 6,484 Residential MBS 1,371 1 (5 ) 1,367 Commercial MBS 2,539 — (52 ) 2,487 Other agencies 69 1 — 70 Total U.S. Treasury, Federal agency, and other agency securities 10,645 3 (235 ) 10,413 Municipal securities 3,892 21 (35 ) 3,878 Asset-backed securities 482 1 (16 ) 467 Corporate debt 106 3 — 109 Other securities 602 — — 602 Total available-for-sale and other securities $ 15,727 $ 28 $ (286 ) $ 15,469 Unrealized (dollar amounts in millions) Amortized Gross Gross Fair Value December 31, 2016 U.S. Treasury $ 6 $ — $ — $ 6 Federal agencies: Residential CMO 6,955 6 (151 ) 6,810 Residential MBS 196 5 (1 ) 200 Commercial MBS 3,700 2 (39 ) 3,663 Other agencies 73 — — 73 Total U.S. Treasury, Federal agency, and other agency securities 10,930 13 (191 ) 10,752 Municipal securities 3,260 29 (39 ) 3,250 Asset-backed securities 824 2 (32 ) 794 Corporate debt 195 4 — 199 Other securities 568 — — 568 Total available-for-sale and other securities $ 15,777 $ 48 $ (262 ) $ 15,563
Available for sale securities in an unrealized loss position	The following tables provide detail on investment securities with unrealized losses aggregated by investment category and the length of time the individual securities have been in a continuous loss position at December 31, 2017 and 2016 : Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 Federal agencies: Residential CMO $ 1,660 $ (19 ) $ 4,520 $ (159 ) $ 6,180 $ (178 ) Residential MBS 1,078 (5 ) 11 — 1,089 (5 ) Commercial MBS 960 (15 ) 1,527 (37 ) 2,487 (52 ) Other agencies 39 — — — 39 — Total Federal agency, and other agency securities 3,737 (39 ) 6,058 (196 ) 9,795 (235 ) Municipal securities 1,681 (21 ) 497 (14 ) 2,178 (35 ) Asset-backed securities 127 (1 ) 173 (15 ) 300 (16 ) Corporate debt — — — — — — Other securities — — — — — — Total temporarily impaired securities $ 5,545 $ (61 ) $ 6,728 $ (225 ) $ 12,273 $ (286 ) Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2016 Federal agencies: Residential CMO $ 5,858 $ (150 ) $ 21 $ (1 ) $ 5,879 $ (151 ) Residential MBS 31 (1 ) — — 31 (1 ) Commercial MBS 3,019 (39 ) 21 — 3,040 (39 ) Other agencies 1 — — — 1 — Total Federal agency, and other agency securities 8,909 (190 ) 42 (1 ) 8,951 (191 ) Municipal securities 1,412 (29 ) 272 (10 ) 1,684 (39 ) Asset-backed securities 361 (3 ) 179 (29 ) 540 (32 ) Corporate debt 4 — — — 4 — Other securities 1 — 2 — 3 — Total temporarily impaired securities $ 10,687 $ (222 ) $ 495 $ (40 ) $ 11,182 $ (262 )
Realized securities gains and losses	The following table is a summary of realized securities gains and losses for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Gross gains on sales of securities $ 10 $ 23 $ 7 Gross (losses) on sales of securities (10 ) (21 ) (4 ) Net gain (loss) on sales of securities $ — $ 2 $ 3 OTTI recognized in earnings (4 ) (2 ) (2 ) Net securities gains (losses) $ (4 ) $ — $ 1
Credit ratings on selected investment securities	The following table summarizes the Company's CDO securities portfolio, which are included in asset-backed securities, at December 31, 2017 and 2016 . Collateralized Debt Obligation Securities (dollar amounts in millions) Par Value Amortized Cost Fair Value Unrealized Loss (1) MM Comm III 4 4 4 — Tropic III 31 31 20 (11 ) Total at December 31, 2017 $ 35 $ 35 $ 24 $ (11 ) Total at December 31, 2016 $ 137 $ 101 $ 76 $ (25 ) (1) One of the two remaining securities in the portfolio has been in a continuous loss position for 12 months or longer.
OTTI recognized in earnings	For the periods ended December 31, 2017 , 2016 , and 2015 , the following table summarizes by security type, the total OTTI losses recognized in the Consolidated Statements of Income for securities evaluated for impairment as described above: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Available-for-sale and other securities: Collateralized Debt Obligations $ (4 ) $ — $ (2 ) Municipal Securities — (2 ) — Total available-for-sale and other securities $ (4 ) $ (2 ) $ (2 ) The following table rolls forward the OTTI recognized in earnings on debt securities held by Huntington for the years ended December 31, 2017 , and 2016 as follows: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Balance, beginning of year $ 12 $ 18 $ 31 Reductions from sales (15 ) (8 ) (15 ) Credit losses not previously recognized 4 2 — Additional credit losses — — 2 Balance, end of year $ 1 $ 12 $ 18

HELD-TO-MATURITY SECURITIES (Ta

HELD-TO-MATURITY SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Held-to-maturity Securities [Abstract]
Contractual maturities of held-to-maturity securities	Listed below are the contractual maturities of held-to-maturity securities at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 (dollar amounts in millions) Amortized Cost Fair Value Amortized Cost Fair Value Federal agencies: Residential CMO: 1 year or less $ — $ — $ — $ — After 1 year through 5 years — — — — After 5 years through 10 years — — — — After 10 years 3,714 3,657 4,189 4,163 Total Residential CMO 3,714 3,657 4,189 4,163 Residential MBS: 1 year or less $ — $ — $ — $ — After 1 year through 5 years — — — — After 5 years through 10 years 28 28 15 15 After 10 years 1,021 1,016 83 86 Total Residential MBS 1,049 1,044 98 101 Commercial MBS: 1 year or less $ — $ — $ — $ — After 1 year through 5 years 38 37 — — After 5 years through 10 years 1 1 26 25 After 10 years 3,752 3,698 2,885 2,891 Total Commercial MBS 3,791 3,736 2,911 2,916 Other agencies: 1 year or less — — — — After 1 year through 5 years 7 8 — — After 5 years through 10 years 362 360 399 399 After 10 years 163 161 204 202 Total other agencies 532 529 603 601 Total Federal agencies and other agencies 9,086 8,966 7,801 7,781 Municipal securities: 1 year or less — — — — After 1 year through 5 years — — — — After 5 years through 10 years — — — — After 10 years 5 5 6 6 Total Municipal securities 5 5 6 6 Total held-to-maturity securities $ 9,091 $ 8,971 $ 7,807 $ 7,787
Amortized cost, gross unrealized gains and losses, and fair value by investment category	The following table provides amortized cost, gross unrealized gains and losses, and fair value by investment category at December 31, 2017 and 2016 : Unrealized (dollar amounts in millions) Amortized Cost Gross Gains Gross Losses Fair Value December 31, 2017 Federal agencies: Residential CMO $ 3,714 $ 1 $ (58 ) $ 3,657 Residential MBS 1,049 2 (7 ) 1,044 Commercial MBS 3,791 — (55 ) 3,736 Other agencies 532 1 (4 ) 529 Total Federal agencies and other agencies 9,086 4 (124 ) 8,966 Municipal securities 5 — — 5 Total held-to-maturity securities $ 9,091 $ 4 $ (124 ) $ 8,971 Unrealized (dollar amounts in millions) Amortized Gross Gross Fair Value December 31, 2016 Federal agencies: Residential CMO $ 4,189 $ 7 $ (33 ) $ 4,163 Residential MBS 98 3 — 101 Commercial MBS 2,911 10 (5 ) 2,916 Other agencies 603 2 (4 ) 601 Total Federal agencies and other agencies 7,801 22 (42 ) 7,781 Municipal securities 6 — — 6 Total held-to-maturity securities $ 7,807 $ 22 $ (42 ) $ 7,787
Investment securities in an unrealized loss position	The following tables provide detail on HTM securities with unrealized losses aggregated by investment category and the length of time the individual securities have been in a continuous loss position at December 31, 2017 and 2016 : Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2017 Federal agencies: Residential CMO $ 2,369 $ (26 ) $ 1,019 $ (32 ) $ 3,388 $ (58 ) Residential MBS 974 (7 ) — — 974 (7 ) Commercial MBS 3,456 (49 ) 253 (6 ) 3,709 (55 ) Other agencies 249 (2 ) 139 (2 ) 388 (4 ) Total Federal agencies and other agencies 7,048 (84 ) 1,411 (40 ) 8,459 (124 ) Municipal securities — — 5 — 5 — Total temporarily impaired securities $ 7,048 $ (84 ) $ 1,416 $ (40 ) $ 8,464 $ (124 ) Less than 12 Months Over 12 Months Total (dollar amounts in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2016 Federal agencies: Residential CMO $ 2,483 $ (26 ) $ 186 $ (7 ) $ 2,669 $ (33 ) Residential MBS 20 — — — 20 — Commercial MBS 352 (5 ) — — 352 (5 ) Other agencies 414 (4 ) — — 414 (4 ) Total Federal agencies and other agencies 3,269 (35 ) 186 (7 ) 3,455 (42 ) Municipal securities 6 — — — 6 — Total temporarily impaired securities $ 3,275 $ (35 ) $ 186 $ (7 ) $ 3,461 $ (42 )

LOAN SALES AND SECURITIZATIONS

LOAN SALES AND SECURITIZATIONS (Tables)	12 Months Ended
	Dec. 31, 2017
Transfers and Servicing [Abstract]
Schedule of activity relating to loans securitized sold with servicing rights	The following table summarizes activity relating to SBA loans sold with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 SBA loans sold with servicing retained $ 413 $ 270 $ 233 Pretax gains resulting from above loan sales (1) 32 21 19 (1) Recorded in gain on sale of loans. The following table summarizes activity relating to residential mortgage loans sold with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Residential mortgage loans sold with servicing retained $ 3,985 $ 3,632 $ 3,323 Pretax gains resulting from above loan sales (1) 99 97 83 (1) Recorded in mortgage banking income. The following table summarizes activity relating to automobile loans securitized with servicing retained for the years ended December 31, 2017 , 2016 , and 2015 : Year Ended December 31, (dollar amounts in millions) 2017 (1) 2016 2015 UPB of automobile loans securitized with servicing retained $ — 1,500 750 Net proceeds received in loan securitizations — 1,552 780 Servicing asset recognized in loan securitizations (2) — 15 11 Pretax gains resulting from above loan securitizations (3) — 6 5 (1) Huntington did not sell or securitize any automobile loans in 2017. (2) Recorded in servicing rights. (3) Recorded in gain on sale of loans
Servicing asset at fair value	The following table summarizes the changes in MSRs recorded using the amortization method for the years ended December 31, 2017 and 2016 :
Servicing asset at amortized cost	The following tables summarize the changes in the carrying value of the servicing asset for the years ended December 31, 2017 , and 2016 : (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 21 $ 20 New servicing assets created 14 9 Amortization and other (8 ) (8 ) Carrying value, end of year $ 27 $ 21 Fair value, end of year $ 30 $ 24 Weighted-average life (years) 3.3 3.3 Changes in the carrying value of automobile loan servicing rights for the years ended December 31, 2017 , and 2016 , and the fair value at the end of each period were as follows: (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 18 $ 9 New servicing assets created — 15 Amortization and other (10 ) (6 ) Carrying value, end of year $ 8 $ 18 Fair value, end of year $ 9 $ 18 Weighted-average life (years) 3.5 4.2 (dollar amounts in millions) 2017 2016 Carrying value, beginning of year $ 172 $ 143 New servicing assets created 44 38 Servicing assets acquired — 15 Impairment recovery (charge) 1 2 Amortization and other (26 ) (26 ) Carrying value, end of year $ 191 $ 172 Fair value, end of year $ 191 $ 173 Weighted-average life (years) 7.1 7.2
Summary of key assumptions and the sensitivity analysis of servicing rights	For MSRs under the amortization method, a summary of key assumptions and the sensitivity of the MSR value to changes in these assumptions at December 31, 2017 , and 2016 follows: December 31, 2017 December 31, 2016 Decline in fair value due to Decline in fair value due to (dollar amounts in millions) Actual 10% adverse change 20% adverse change Actual 10% adverse change 20% adverse change Constant prepayment rate (annualized) 8.30 % $ (5 ) $ (10 ) 7.80 % $ (5 ) $ (9 ) Spread over forward interest rate swap rates 1,049 bps (7 ) (13 ) 1,173 bps (5 ) (10 )

GOODWILL AND OTHER INTANGIBLE40

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill by business segment	A rollforward of goodwill by business segment for the years ended December 31, 2017 and 2016 , is presented in the table below: Consumer & Business Commercial Vehicle Treasury/ Huntington (dollar amounts in millions) Banking Banking Finance RBHPCG Other Consolidated Balance, January 1, 2016 $ 368 $ 215 $ — $ 89 $ 5 $ 677 Goodwill acquired during the period 1,030 238 — 53 — 1,321 Adjustments — — — — (5 ) (5 ) Balance, December 31, 2016 1,398 453 — 142 — 1,993 Adjustments — (28 ) — 28 — — Balance, December 31, 2017 $ 1,398 $ 425 $ — $ 170 $ — $ 1,993
Summary of other intangible assets	At December 31, 2017 and 2016 , Huntington’s other intangible assets consisted of the following: (dollar amounts in millions) Gross Accumulated Net December 31, 2017 Core deposit intangible $ 325 $ (61 ) $ 264 Customer relationship 190 (108 ) 82 Total other intangible assets $ 515 $ (169 ) $ 346 December 31, 2016 Core deposit intangible $ 325 $ (27 ) $ 298 Customer relationship 195 (1) (91 ) 104 Total other intangible assets $ 520 $ (118 ) $ 402
Estimated amortization expense of other intangible assets	The estimated amortization expense of other intangible assets for the next five years is as follows: (dollar amounts in millions) Amortization Expense 2018 $ 53 2019 50 2020 42 2021 40 2022 38

PREMISES AND EQUIPMENT (Tables)

PREMISES AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	Premises and equipment were comprised of the following at December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Land and land improvements $ 193 $ 199 Buildings 563 523 Leasehold improvements 240 265 Equipment 746 722 Total premises and equipment 1,742 1,709 Less accumulated depreciation and amortization (878 ) (893 ) Net premises and equipment $ 864 $ 816
Depreciation and amortization charged to expense and rental income credited to net occupancy expense	Depreciation and amortization charged to expense and rental income credited to net occupancy expense for the three years ended December 31, 2017 , 2016 , and 2015 were: (dollar amounts in millions) 2017 2016 2015 Total depreciation and amortization of premises and equipment $ 123 $ 126 $ 86 Rental income credited to occupancy expense 14 13 13

SHORT-TERM BORROWINGS (Tables)

SHORT-TERM BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Short-term Debt	Borrowings with original maturities of one year or less are classified as short-term and were comprised of the following at December 31, 2017 and 2016 : At December 31, (dollar amounts in millions) 2017 2016 Federal funds purchased and securities sold under agreements to repurchase $ 1,318 $ 1,248 Federal Home Loan Bank advances 3,725 2,425 Other borrowings 13 20 Total short-term borrowings $ 5,056 $ 3,693

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Instruments [Abstract]
Schedule of Long-Term Debt	Huntington’s long-term debt consisted of the following: At December 31, (dollar amounts in millions) 2017 2016 The Parent Company: Senior Notes: 3.19% Huntington Bancshares Incorporated medium-term notes due 2021 $ 969 $ 973 2.33% Huntington Bancshares Incorporated senior note due 2022 953 954 2.64% Huntington Bancshares Incorporated senior note due 2018 399 399 Subordinated Notes: 7.00% Huntington Bancshares Incorporated subordinated notes due 2020 312 320 3.55% Huntington Bancshares Incorporated subordinated notes due 2023 245 248 Sky Financial Capital Trust IV 3.09% junior subordinated debentures due 2036 (1) 74 74 Sky Financial Capital Trust III 3.09% junior subordinated debentures due 2036 (1) 72 72 Huntington Capital I Trust Preferred 2.39% junior subordinated debentures due 2027 (2) 69 69 Huntington Capital II Trust Preferred 2.32% junior subordinated debentures due 2028 (3) 31 32 Camco Financial Statutory Trust I 3.02% due 2037 (4) 4 4 Total notes issued by the parent 3,128 3,145 The Bank: Senior Notes: 2.24% Huntington National Bank senior notes due 2018 844 844 2.10% Huntington National Bank senior notes due 2018 748 747 2.47% Huntington National Bank senior notes due 2020 694 — 2.55% Huntington National Bank senior notes due 2022 685 — 2.43% Huntington National Bank senior notes due 2020 498 498 2.23% Huntington National Bank senior note due 2019 497 500 1.75% Huntington National Bank senior notes due 2018 496 500 2.97% Huntington National Bank senior notes due 2020 492 495 2.20% Huntington National Bank senior notes due 2020 (5) 300 — 5.04% Huntington National Bank medium-term notes due 2018 35 36 2.23% Huntington National Bank senior note due 2017 — 499 1.42% Huntington National Bank senior notes due 2017 (6) — 250 Subordinated Notes: 3.86% Huntington National Bank subordinated notes due 2026 238 239 6.67% Huntington National Bank subordinated notes due 2018 129 132 5.45% Huntington National Bank subordinated notes due 2019 77 81 Total notes issued by the bank 5,733 4,821 FHLB Advances: 3.51% weighted average rate, varying maturities greater than one year 7 8 Other: Huntington Technology Finance nonrecourse debt, 3.63% effective interest rate, varying maturities 263 278 3.57% Huntington Preferred Capital II - Class F securities (7) 75 — Huntington Technology Finance ABS Trust 2014 1.70% due 2020 — 57 Total other 338 335 Total long-term debt $ 9,206 $ 8,309 (1) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.400% . (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70% (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625% . (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.33% . (5) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.51% (6) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.425% . (7) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.880% . The trust securities are the obligations of the trusts, and as such, are not consolidated within Huntington’s Consolidated Financial Statements. A list of trust-preferred securities outstanding at December 31, 2017 follows: (dollar amounts in millions) Rate Principal amount of subordinated note/ debenture issued to trust (1) Investment in unconsolidated subsidiary Huntington Capital I 2.39 % (2) $ 70 $ 6 Huntington Capital II 2.32 (3) 32 3 Sky Financial Capital Trust III 3.09 (4) 72 2 Sky Financial Capital Trust IV 3.09 (4) 74 2 Camco Financial Trust 3.02 (5) 4 1 Total $ 252 $ 14 (1) Represents the principal amount of debentures issued to each trust, including unamortized original issue discount. (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70 %. (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625 %. (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.40 %. (5) Variable effective rate at December 31, 2017 , based on three month LIBOR + 1.33 %.
Schedule of Maturities of Long-term Debt	Long-term debt maturities for the next five years and thereafter are as follows: (dollar amounts in millions) 2018 2019 2020 2021 2022 Thereafter Total The Parent Company: Senior notes $ 400 $ — $ — $ 1,000 $ 1,000 $ — $ 2,400 Subordinated notes — — 300 — — 504 804 The Bank: Senior notes 2,135 500 2,000 — 700 — 5,335 Subordinated notes 125 76 — — — 325 526 FHLB Advances 1 — 2 — — 4 7 Other 27 43 95 48 50 — 263 Total $ 2,688 $ 619 $ 2,397 $ 1,048 $ 1,750 $ 833 $ 9,335

OTHER COMPREHENSIVE INCOME (Tab

OTHER COMPREHENSIVE INCOME (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Components of Accumulated Other Comprehensive Income	The components of Huntington’s OCI in the three years ended December 31, 2017 , 2016 , and 2015 , were as follows: 2017 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 4 $ (2 ) $ 2 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (87 ) 31 (56 ) Less: Reclassification adjustment for net losses (gains) included in net income 26 (9 ) 17 Net change in unrealized holding gains (losses) on available-for-sale debt securities (57 ) 20 (37 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities 1 (1 ) — Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period 3 (1 ) 2 Less: Reclassification adjustment for net (gains) losses included in net income 1 — 1 Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 4 (1 ) 3 Net change in pension and other post-retirement obligations — — — Total other comprehensive income (loss) $ (52 ) $ 18 $ (34 ) 2016 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 1 $ — $ 1 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (203 ) 70 (133 ) Less: Reclassification adjustment for net losses (gains) included in net income (107 ) 38 (69 ) Net change in unrealized holding gains (losses) on available-for-sale debt securities (309 ) 108 (201 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities — — — Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period 2 (1 ) 1 Less: Reclassification adjustment for net (gains) losses included in net income — — — Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 2 (1 ) 1 Net change in pension and other post-retirement obligations 38 (13 ) 25 Total other comprehensive income (loss) $ (269 ) $ 94 $ (175 ) 2015 Tax (expense) (dollar amounts in millions) Pretax Benefit After-tax Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold $ 20 $ (7 ) $ 13 Unrealized holding gains (losses) on available-for-sale debt securities arising during the period (26 ) 9 (17 ) Less: Reclassification adjustment for net gains (losses) included in net income (4 ) 1 (3 ) Net change in unrealized holding gains (losses) on available-for-sale debt securities (10 ) 3 (7 ) Net change in unrealized holding gains (losses) on available-for-sale equity securities — — — Unrealized gains and losses on derivatives used in cash flow hedging relationships arising during the period 13 (4 ) 9 Less: Reclassification adjustment for net losses (gains) losses included in net income (1 ) — (1 ) Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships 12 (4 ) 8 Defined benefit pension items (8 ) 3 (5 ) Net change in pension and post-retirement obligations (8 ) 3 (5 ) Total other comprehensive income (loss) $ (6 ) $ 2 $ (4 )
Activity in Accumulated Other Comprehensive Income	Activity in accumulated OCI for the two years ended December 31, were as follows: (dollar amounts in millions) Unrealized gains (losses) on debt securities (1) Unrealized gains (losses) on equity securities Unrealized gains (losses) on cash flow hedging derivatives Unrealized gains (losses) for pension and other post-retirement obligations Total December 31, 2015 $ 8 $ — $ (4 ) $ (230 ) $ (226 ) Other comprehensive income before reclassifications (132 ) — 1 — (131 ) Amounts reclassified from accumulated OCI to earnings (69 ) — — 25 (44 ) Period change (201 ) — 1 25 (175 ) December 31, 2016 (193 ) — (3 ) (205 ) (401 ) Other comprehensive income before reclassifications (54 ) — 2 (10 ) (62 ) Amounts reclassified from accumulated OCI to earnings 17 — 1 10 28 Period change (37 ) — 3 — (34 ) TCJA, Reclassification from accumulated OCI to retained earnings (48 ) — — (45 ) (93 ) December 31, 2017 $ (278 ) $ — $ — $ (250 ) $ (528 ) (1) Amount at December 31, 2017 includes $95 million of net unrealized losses on securities transferred from the available-for-sale securities portfolio to the held-to-maturity securities portfolio. The net unrealized losses will be recognized in earnings over the remaining life of the security using the effective interest method.
Reclassification Out Of Accumulated OCI	The following table presents the reclassification adjustments out of accumulated OCI included in net income and the impacted line items as listed on the Consolidated Statements of Income for the years ended December 31, 2017 and 2016 : Reclassifications out of accumulated OCI Accumulated OCI components Amounts reclassified from accumulated OCI Location of net gain (loss) reclassified from accumulated OCI into earnings (dollar amounts in millions) 2017 2016 Gains (losses) on debt securities: Amortization of unrealized gains (losses) $ (8 ) $ 91 Interest income—held-to-maturity securities—taxable Realized gain (loss) on sale of securities (14 ) 18 Noninterest income—net gains (losses) on sale of securities OTTI recorded (4 ) (2 ) Noninterest income—net gains (losses) on sale of securities Total before tax (26 ) 107 Tax (expense) benefit 9 (38 ) Net of tax $ (17 ) $ 69 Gains (losses) on cash flow hedging relationships: Interest rate contracts $ (1 ) $ — Interest and fee income—loans and leases Interest rate contracts — — Noninterest expense—other income Total before tax (1 ) — Tax (expense) benefit — — Net of tax $ (1 ) $ — Amortization of defined benefit pension and post-retirement items: Actuarial gains (losses) $ (18 ) $ (40 ) Noninterest expense—personnel costs Net periodic benefit costs 2 2 Noninterest expense—personnel costs Total before tax (16 ) (38 ) Tax (expense) benefit 6 13 Net of tax $ (10 ) $ (25 )

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Basic and diluted earnings loss per share	The calculation of basic and diluted earnings per share for each of the three years ended December 31 was as follows: Year Ended December 31, (dollar amounts in millions, except per share amounts) 2017 2016 2015 Basic earnings per common share: Net income $ 1,186 $ 712 $ 693 Preferred stock dividends (76 ) (65 ) (32 ) Net income available to common shareholders $ 1,110 $ 647 $ 661 Average common shares issued and outstanding (000) 1,084,686 904,438 803,412 Basic earnings per common share $ 1.02 $ 0.72 $ 0.82 Diluted earnings per common share: Net income available to common shareholders $ 1,110 $ 647 $ 661 Effect of assumed preferred stock conversion 31 — — Net income applicable to diluted earnings per share $ 1,141 $ 647 $ 661 Average common shares issued and outstanding (000) 1,084,686 904,438 803,412 Dilutive potential common shares Stock options and restricted stock units and awards 17,883 11,728 11,633 Shares held in deferred compensation plans 3,160 2,486 1,912 Other 30,457 138 172 Dilutive potential common shares 51,500 14,352 13,717 Total diluted average common shares issued and outstanding (000) 1,136,186 918,790 817,129 Diluted earnings per common share $ 1.00 $ 0.70 $ 0.81

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share based compensation expense and related tax benefit	The following table presents total share-based compensation expense and related tax benefit for the three years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) 2017 2016 2015 Share-based compensation expense $ 92 $ 66 $ 51 Tax benefit 32 22 18
Weighted average assumptions used in the option pricing model	The following table presents the weighted average assumptions used in the option-pricing model at the grant date for options granted in the three years ended December 31, 2017 , 2016 , and 2015 : 2017 2016 2015 Assumptions Risk-free interest rate 2.04 % 1.63 % 2.13 % Expected dividend yield 3.31 3.18 2.57 Expected volatility of Huntington’s common stock 29.5 30.0 29.0 Expected option term (years) 6.5 6.5 6.5 Weighted-average grant date fair value per share $ 2.81 $ 2.17 $ 2.57
Stock option activity and related information	Huntington’s stock option activity and related information for the year ended December 31, 2017 , was as follows: (dollar amounts in millions, except per share and options amounts) Options (in thousands) Weighted- Weighted- Aggregate Outstanding at January 1, 2017 14,874 $ 7.50 Granted 1,486 13.09 Exercised (2,372 ) 6.72 Forfeited/expired (70 ) 11.17 Outstanding at December 31, 2017 13,918 $ 8.21 3.5 $ 88 Expected to vest (1) 3,508 $ 11.33 8.0 $ 11 Exercisable at December 31, 2017 10,311 $ 7.11 1.9 $ 77 (1) The number of options expected to vest includes an estimate of 99 thousand shares expected to be forfeited.
Schedule of restricted stock, restricted stock units, and performance shares	The following table summarizes the status of Huntington’s restricted stock units and performance share awards as of December 31, 2017 , and activity for the year ended December 31, 2017 : Restricted Stock Awards Restricted Stock Units Performance Share Awards (amounts in thousands, except per share amounts) Quantity Weighted- Average Grant Date Fair Value Per Share Quantity Weighted- Average Grant Date Fair Value Per Share Quantity Weighted- Average Grant Date Fair Value Per Share Nonvested at January 1, 2017 (000) 656 $ 9.68 14,733 $ 9.61 3,307 $ 9.63 Granted — — 6,232 13.45 1,278 12.18 Assumed — — — — — — Vested (174 ) 9.68 (4,267 ) 8.72 (1,550 ) 9.00 Forfeited (34 ) 9.68 (539 ) 10.91 (17 ) 11.07 Nonvested at December 31, 2017 (000) 448 $ 9.68 16,159 $ 11.26 3,018 $ 10.67

BENEFIT PLANS (Tables)

BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of weighted-average assumptions used	The following table shows the weighted-average assumptions used to determine the benefit obligation at December 31, 2017 and 2016 , and the net periodic benefit cost for the years then ended: Pension Benefits Post-Retirement Benefits 2017 2016 2017 2016 Weighted-average assumptions used to determine benefit obligations Discount rate 3.73 % 4.38 % 3.34 % 3.64 % Rate of compensation increase N/A N/A N/A N/A Weighted-average assumptions used to determine net periodic benefit cost Discount rate 4.38 4.54 3.64 3.81 Expected return on plan assets 6.50 6.75 N/A N/A Rate of compensation increase N/A N/A N/A N/A N/A—Not Applicable
Schedule of changes in projected benefit obligation	The following table reconciles the beginning and ending balances of the benefit obligation of the Plan and the post-retirement benefit plan with the amounts recognized in the consolidated balance sheets at December 31: Pension Benefits Post-Retirement Benefits (dollar amounts in millions) 2017 2016 2017 2016 Projected benefit obligation at beginning of measurement year $ 851 $ 1,084 $ 14 $ 15 Changes due to: Service cost 3 5 — — Interest cost 30 30 — — Benefits paid (27 ) (20 ) (2 ) (1 ) Settlements (31 ) (203 ) (4 ) — Plan amendments — — (2 ) — Actuarial assumptions and gains and losses 74 (45 ) 1 — Total changes 49 (233 ) (7 ) (1 ) Projected benefit obligation at end of measurement year $ 900 $ 851 $ 7 $ 14
Schedule of changes in fair value of plan assets	The following table reconciles the beginning and ending balances of the fair value of Plan assets at the December 31, 2017 and 2016 measurement dates: Pension Benefits (dollar amounts in millions) 2017 2016 Fair value of plan assets at beginning of measurement year $ 841 $ 874 Changes due to: Actual return on plan assets 118 37 Employer Contributions — 150 Settlements (29 ) (199 ) Benefits paid (27 ) (21 ) Total changes 62 (33 ) Fair value of plan assets at end of measurement year $ 903 $ 841
Schedule of net periodic benefit costs	The following table shows the components of net periodic benefit costs recognized in the three years ended December 31, 2017 : Pension Benefits Post-Retirement Benefits (dollar amounts in millions) 2017 2016 2015 2017 2016 2015 Service cost $ 3 $ 5 $ 2 $ — $ — $ — Interest cost 30 30 32 — — — Expected return on plan assets (55 ) (45 ) (44 ) — — — Amortization of prior service credit — — — (2 ) (2 ) (2 ) Amortization of (gain) / loss 7 7 8 — — — Settlements 11 (8 ) 12 — — (3 ) Benefit costs $ (4 ) $ (11 ) $ 10 $ (2 ) $ (2 ) $ (5 )
Schedule of allocation of plan assets	At December 31, 2017 and 2016 , The Huntington National Bank, as trustee, held all Plan assets. The Plan assets consisted of investments in a variety of corporate and government fixed income investments, money market funds, and mutual funds as follows: Fair Value (dollar amounts in millions) 2017 2016 Cash equivalents: Mutual Funds-money market $ 14 2 % $ 21 3 % U.S. Treasury bills 5 1 — — Fixed income: Corporate obligations 293 32 218 26 U.S. Government obligations 216 24 165 19 Mutual funds-fixed income — — 51 6 U.S. Government Agencies 23 3 10 1 Equities: Mutual funds-equities 118 13 150 18 Common stock 158 17 182 22 Preferred stock 5 1 5 1 Exchange Traded Funds 58 6 28 3 Limited Partnerships 13 1 11 1 Fair value of plan assets $ 903 100 % $ 841 100 %
Schedule of expected benefit payments	At December 31, 2017 , the following table shows when benefit payments were expected to be paid: (dollar amounts in millions) Pension Benefits Post-Retirement Benefits 2018 $ 50 $ 1 2019 49 1 2020 48 1 2021 47 1 2022 47 1 2023 through 2027 233 2
Schedule of amounts recognized in balance sheet	The following table presents the amounts recognized in the Consolidated Balance Sheets at December 31, 2017 and 2016 , for all defined benefit plans: (dollar amounts in millions) 2017 2016 Noncurrent liabilities $ 78 $ 189
Schedule of amounts recognized in OCI	The following tables present the amounts recognized in OCI as of December 31, 2017 , 2016 , and 2015 , and the changes in accumulated OCI for the years ended December 31, 2017 , 2016 , and 2015 : (dollar amounts in millions) 2017 2016 2015 Net actuarial loss $ (264 ) $ (217 ) $ (244 ) Prior service cost 14 12 14 Defined benefit pension plans $ (250 ) $ (205 ) $ (230 ) 2017 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (316 ) $ 111 $ (205 ) Net actuarial (loss) gain: Amounts arising during the year (16 ) 6 (10 ) Amortization included in net periodic benefit costs 18 (7 ) 11 TCJA, Reclassification from accumulated OCI to retained earnings (47 ) Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) TCJA, Reclassification from accumulated OCI to retained earnings 2 Balance, end of year $ (316 ) $ 111 $ (250 ) 2016 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (354 ) $ 124 $ (230 ) Net actuarial (loss) gain: Amounts arising during the year 38 (13 ) 25 Amortization included in net periodic benefit costs 2 (1 ) 1 Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) Balance, end of year $ (316 ) $ 111 $ (205 ) 2015 (dollar amounts in millions) Pretax Tax (expense) Benefit After-tax Balance, beginning of year $ (347 ) $ 121 $ (226 ) Net actuarial (loss) gain: Amounts arising during the year (25 ) 9 (16 ) Amortization included in net periodic benefit costs 20 (7 ) 13 Prior service cost: Amounts arising during the year — — — Amortization included in net periodic benefit costs (2 ) 1 (1 ) Balance, end of year $ (354 ) $ 124 $ (230 )
Defined contribution plan disclosures	The following table shows the costs of providing the defined contribution plan: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Defined contribution plan $ 35 $ 36 $ 32
Schedule of Huntington stock statistics for defined contribution plan	The following table shows the number of shares, market value, and dividends received on shares of Huntington stock held by the defined contribution plan: December 31, (dollar amounts in millions, except share amounts) 2017 2016 Shares in Huntington common stock (000) 13,566 11,748 Market value of Huntington common stock $ 198 $ 162 Dividends received on shares of Huntington stock 4 4

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Reconciliation of gross unrecognized tax benefits	The following table provides a reconciliation of the beginning and ending amounts of gross unrecognized tax benefits: (dollar amounts in millions) 2017 2016 Unrecognized tax benefits at beginning of year $ 24 $ 23 Gross increases for tax positions taken during current period — 1 Gross increases for tax positions taken during prior years 26 — Unrecognized tax benefits at end of year $ 50 $ 24
Summary of provision (benefit) for income taxes	The following is a summary of the provision (benefit) for income taxes: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Current tax provision (benefit) Federal $ 41 $ 40 $ 146 State (1 ) 3 6 Total current tax provision (benefit) 40 43 152 Deferred tax provision (benefit) Federal 151 161 67 State 17 4 2 Total deferred tax provision (benefit) 168 165 69 Provision (benefit) for income taxes $ 208 $ 208 $ 221
Reconcilement of provision (benefit) for income taxes	The following is a reconciliation for provision for income taxes: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Provision for income taxes computed at the statutory rate $ 488 $ 322 $ 320 Increases (decreases): Tax-exempt income (31 ) (27 ) (21 ) Tax-exempt bank owned life insurance income (23 ) (20 ) (18 ) General business credits (71 ) (64 ) (48 ) Capital loss (67 ) (46 ) (46 ) Impact from TCJA (123 ) — — Affordable housing investment amortization, net of tax benefits 46 37 32 State income taxes, net 11 5 5 Stock based compensation (13 ) (4 ) — Other (9 ) 5 (3 ) Provision (benefit) for income taxes $ 208 $ 208 $ 221
Significant components of deferred tax assets and liabilities	The significant components of deferred tax assets and liabilities at December 31, were as follows: At December 31, (dollar amounts in millions) 2017 (1) 2016 (2) Deferred tax assets: Allowances for credit losses $ 162 $ 255 Tax credit carryforward 153 76 Fair value adjustments 142 217 Net operating and other loss carryforward 108 141 Accrued expense/prepaid 17 64 Market discount 10 8 Pension and other employee benefits — 35 Partnership investments 7 23 Other assets 6 11 Total deferred tax assets 605 830 Deferred tax liabilities: Lease financing 249 325 Loan origination costs 116 138 Deferred dividend income 77 — Purchase accounting adjustments 68 74 Operating assets 53 54 Mortgage servicing rights 39 51 Securities adjustments 6 56 Pension and other employee benefits 5 — Other liabilities 18 9 Total deferred tax liabilities 631 707 Net deferred tax (liability) asset before valuation allowance (26 ) 123 Valuation allowance (6 ) (5 ) Net deferred tax (liability) asset $ (32 ) $ 118 (1) 2017 balances reflect federal statutory tax rate 21% . (2) 2016 balances reflect federal statutory tax rate 35% .

FAIR VALUES OF ASSETS AND LIA49

FAIR VALUES OF ASSETS AND LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis	Assets and liabilities measured at fair value on a recurring basis at December 31, 2017 and 2016 are summarized below: Fair Value Measurements at Reporting Date Using Netting Adjustments (1) December 31, 2017 (dollar amounts in millions) Level 1 Level 2 Level 3 Assets Loans held for sale $ — $ 413 $ — $ — $ 413 Loans held for investment — 55 38 — 93 Trading account securities: Other securities 83 3 — — 86 83 3 — — 86 Available-for-sale and other securities: U.S. Treasury securities 5 — — — 5 Residential CMOs — 6,484 — — 6,484 Residential MBS 1,367 1,367 Commercial MBS 2,487 2,487 Other agencies — 70 — — 70 Municipal securities — 711 3,167 — 3,878 Asset-backed securities — 443 24 — 467 Corporate debt — 109 — — 109 Other securities 20 1 — — 21 25 11,672 3,191 — 14,888 MSRs — — 11 — 11 Derivative assets — 316 6 (190 ) 132 Liabilities Derivative liabilities — 326 5 (245 ) 86 Short-term borrowings — — — — — Fair Value Measurements at Reporting Date Using Netting Adjustments (1) December 31, 2016 (dollar amounts in millions) Level 1 Level 2 Level 3 Assets Loans held for sale $ — $ 438 $ — $ — $ 438 Loans held for investment — 34 48 — 82 Trading account securities: Municipal securities — 1 — — 1 Other securities 132 — — — 132 132 1 — — 133 Available-for-sale and other securities: U.S. Treasury securities 6 — — — 6 Residential CMOs — 6,810 — — 6,810 Residential MBS 200 200 Commercial MBS 3,663 3,663 Other agencies — 73 — — 73 Municipal securities — 452 2,798 — 3,250 Asset-backed securities — 718 76 — 794 Corporate debt — 199 — — 199 Other securities 16 4 — — 20 22 12,119 2,874 — 15,015 MSRs — — 14 — 14 Derivative assets — 414 6 (182 ) 238 Liabilities Derivative liabilities — 363 8 (272 ) 99 Short-term borrowings — — — — — (1) Amounts represent the impact of legally enforceable master netting agreements that allow the Company to settle positive and negative positions and cash collateral held or placed with the same counterparties.
Roll forward of derivatives measured on a recurring basis and classified as Level 3	The tables below present a rollforward of the balance sheet amounts for the years ended December 31, 2017 , 2016 , and 2015 for financial instruments measured on a recurring basis and classified as Level 3. The classification of an item as Level 3 is based on the significance of the unobservable inputs to the overall fair value measurement. However, Level 3 measurements may also include observable components of value that can be validated externally. Accordingly, the gains and losses in the table below include changes in fair value due in part to observable factors that are part of the valuation methodology. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (15 ) — — — Total gains/losses for the period: Included in earnings (3 ) 16 (2 ) (5 ) 1 Included in OCI — — (8 ) 14 — Purchases/originations — — 787 — — Sales — — — (60 ) — Repayments — — — — (11 ) Settlements — — (408 ) (1 ) — Closing balance $ 11 $ (1 ) $ 3,167 $ 24 $ 38 Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date $ (3 ) $ — $ — $ (4 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 18 $ 6 $ 2,095 $ 100 $ 2 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (7 ) — — — Total gains/losses for the period: Included in earnings (4 ) (1 ) 7 (2 ) (2 ) Included in OCI — — (28 ) 6 — Purchases/originations — — 1,399 — 56 Sales — — (37 ) (25 ) — Repayments — — — — (8 ) Settlements — — (638 ) (3 ) — Closing balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (4 ) $ (1 ) $ (33 ) $ 4 $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Private label CMO Asset- backed securities Loans held for investment Balance, beginning of year $ 23 $ 3 $ 1,418 $ 30 $ 83 $ 10 Transfers into Level 3 — — — — — — Transfers out of Level 3 (1) — (2 ) — — — — Total gains/losses for the period: Included in earnings (5 ) 5 — — (3 ) — Included in OCI — — (4 ) 2 25 — Purchases/originations — — 1,002 — — — Sales — — (10 ) (30 ) — — Repayments — — — — — (8 ) Settlements — — (311 ) (2 ) (5 ) — Balance, end of year $ 18 $ 6 $ 2,095 $ — $ 100 $ 2 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (5 ) $ 5 $ — $ — $ (3 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2.
Roll forward of assets measured on a recurring basis and classified as Level 3	Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (15 ) — — — Total gains/losses for the period: Included in earnings (3 ) 16 (2 ) (5 ) 1 Included in OCI — — (8 ) 14 — Purchases/originations — — 787 — — Sales — — — (60 ) — Repayments — — — — (11 ) Settlements — — (408 ) (1 ) — Closing balance $ 11 $ (1 ) $ 3,167 $ 24 $ 38 Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date $ (3 ) $ — $ — $ (4 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Opening balance $ 18 $ 6 $ 2,095 $ 100 $ 2 Transfers into Level 3 — — — — — Transfers out of Level 3 (1) — (7 ) — — — Total gains/losses for the period: Included in earnings (4 ) (1 ) 7 (2 ) (2 ) Included in OCI — — (28 ) 6 — Purchases/originations — — 1,399 — 56 Sales — — (37 ) (25 ) — Repayments — — — — (8 ) Settlements — — (638 ) (3 ) — Closing balance $ 14 $ (2 ) $ 2,798 $ 76 $ 48 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (4 ) $ (1 ) $ (33 ) $ 4 $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2. Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Private label CMO Asset- backed securities Loans held for investment Balance, beginning of year $ 23 $ 3 $ 1,418 $ 30 $ 83 $ 10 Transfers into Level 3 — — — — — — Transfers out of Level 3 (1) — (2 ) — — — — Total gains/losses for the period: Included in earnings (5 ) 5 — — (3 ) — Included in OCI — — (4 ) 2 25 — Purchases/originations — — 1,002 — — — Sales — — (10 ) (30 ) — — Repayments — — — — — (8 ) Settlements — — (311 ) (2 ) (5 ) — Balance, end of year $ 18 $ 6 $ 2,095 $ — $ 100 $ 2 Change in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at end of the reporting date $ (5 ) $ 5 $ — $ — $ (3 ) $ — (1) Transfers out of Level 3 represent the settlement value of the derivative instruments (i.e. interest rate lock agreements) that is transferred to loans held for sale, which is classified as Level 2.
Classification of gains and losses due to changes in fair value, recorded in earnings for Level 3 assets and liabilities	The tables below summarize the classification of gains and losses due to changes in fair value, recorded in earnings for Level 3 assets and liabilities for the years ended December 31, 2017 , 2016 , and 2015 : Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income $ (3 ) $ 16 $ — $ — $ — Securities gains (losses) — — — (5 ) — Interest and fee income — — (2 ) — — Noninterest income — — — — 1 Total $ (3 ) $ 16 $ (2 ) $ (5 ) $ 1 Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income $ (4 ) $ (1 ) $ — $ — $ — Securities gains (losses) — — 1 (2 ) — Interest and fee income — — — — — Noninterest income — — 6 — (2 ) Total $ (4 ) $ (1 ) $ 7 $ (2 ) $ (2 ) Level 3 Fair Value Measurements Available-for-sale securities (dollar amounts in millions) MSRs Derivative instruments Municipal securities Asset- backed securities Loans held for investment Classification of gains and losses in earnings: Mortgage banking income (loss) $ (5 ) $ 5 $ — $ — $ — Securities gains (losses) — — — (3 ) — Interest and fee income — — — — — Noninterest income — — — — — Total $ (5 ) $ 5 $ — $ (3 ) $ —
Assets and liabilities under the fair value option	The following table presents the fair value and aggregate principal balance of certain assets and liabilities under the fair value option: December 31, 2017 Total Loans Loans that are 90 or more days past due (dollar amounts in millions) Fair value Aggregate Difference Fair value Aggregate Difference Assets Loans held for sale $ 413 $ 400 $ 13 $ 1 $ 1 $ — Loans held for investment 93 102 (9 ) 10 11 (1 ) December 31, 2016 Total Loans Loans that are 90 or more days past due (dollar amounts in millions) Fair value Aggregate Difference Fair value Aggregate Difference Assets Loans held for sale $ 438 $ 434 $ 4 $ — $ — $ — Loans held for investment 82 92 $ (10 ) 8 11 $ (3 ) The following tables present the net gains (losses) from fair value changes, including net gains (losses) associated with instrument specific credit risk for the years ended December 31, 2017 , 2016 , and 2015 : Net gains (losses) from fair value changes Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Assets Loans held for sale $ 8 $ 7 $ (2 ) Loans held for investment — — (1 )
Assets measured at fair value on a nonrecurring basis	For the year ended December 31, 2017 , assets measured at fair value on a nonrecurring basis were as follows: Fair Value Measurements Using (dollar amounts in millions) Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Total MSRs $ 190 $ — $ — $ 190 $ 1 Impaired loans 36 — — 36 (5 ) Other real estate owned 33 — — 33 (2 )
Quantitative information about significant unobservable level 3 fair value measurement inputs	The table below presents quantitative information about the significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis at December 31, 2017 : Quantitative Information about Level 3 Fair Value Measurements at December 31, 2017 (dollar amounts in millions) Fair Value Valuation Technique Significant Unobservable Input Range (Weighted Average) Measured at fair value on a recurring basis: MSRs $ 11 Discounted cash flow Constant prepayment rate 8% - 33% (12%) Spread over forward interest rate 8% - 10% (8%) Derivative assets 6 Consensus Pricing Net market price -5% - 20% (2%) Estimated Pull through % 3% - 100% (75%) Derivative liabilities 5 Discounted cash flow Estimated conversion factor 165% Estimated growth rate of Visa Class A shares 7% Discount rate 3% Timing of the resolution of the litigation 12/31/2017 - 06/30/2020 Municipal securities 3,167 Discounted cash flow Discount rate 0% - 10% (4%) Cumulative default 0% - 64% (3%) Loss given default 5% - 90% (24%) Asset-backed securities 24 Discounted cash flow Discount rate 7% - 7% (7%) Cumulative prepayment rate 0% - 72% (7%) Cumulative default 3% - 53% (7%) Loss given default 90% - 100% (98%) Cure given deferral 50% - 50% (50%) Loans held for investment 38 Discounted cash flow Discount rate 7% - 18% (8%) Constant prepayment rate 2% - 22% (9%) Measured at fair value on a nonrecurring basis: MSRs 190 Discounted cash flow Constant prepayment rate 6% - 21% (8%) Spread over forward interest rate 2% - 20% (10%) Impaired loans 36 Appraisal value NA NA Other real estate owned 33 Appraisal value NA NA
Fair value by balance sheet grouping	The following table provides the carrying amounts and estimated fair values of Huntington’s financial instruments that are carried either at fair value or cost at December 31, 2017 and December 31, 2016 : December 31, 2017 December 31, 2016 Carrying Fair Carrying Fair (dollar amounts in millions) Amount Value Amount Value Financial Assets: Cash and short-term assets $ 1,567 $ 1,567 $ 1,443 $ 1,443 Trading account securities 86 86 133 133 Loans held for sale 488 491 513 516 Available-for-sale and other securities 15,469 15,469 15,563 15,563 Held-to-maturity securities 9,091 8,971 7,807 7,787 Net loans and direct financing leases 69,426 69,146 66,324 66,295 Derivatives 132 132 238 238 Financial Liabilities: Deposits 77,041 77,010 75,608 76,161 Short-term borrowings 5,056 5,056 3,693 3,693 Long-term debt 9,206 9,402 8,309 8,387 Derivatives 86 86 98 98 The following table presents the level in the fair value hierarchy for the estimated fair values of Huntington’s financial instruments at fair value at December 31, 2017 and December 31, 2016 : Estimated Fair Value Measurements at Reporting Date Using December 31, 2017 (dollar amounts in millions) Level 1 Level 2 Level 3 Financial Assets: Trading account securities $ 83 $ 3 $ 86 Loans held for sale — 413 78 491 Available-for-sale and other securities 25 11,672 3,191 14,888 Held-to-maturity securities — 8,971 — 8,971 Net loans and direct financing leases — — 69,146 69,146 Financial Liabilities: Deposits — 73,975 3,035 77,010 Short-term borrowings — — 5,056 5,056 Long-term debt — 8,944 458 9,402 Estimated Fair Value Measurements at Reporting Date Using December 31, 2016 (dollar amounts in millions) Level 1 Level 2 Level 3 Financial Assets: Held-to-maturity securities $ — $ 7,787 $ — $ 7,787 Net loans and direct financing leases — — 66,295 66,295 Financial Liabilities: Deposits — 72,319 3,842 76,161 Short-term borrowings 1 — 3,692 3,693 Long-term debt — 7,980 407 8,387

DERIVATIVE FINANCIAL INSTRUME50

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross notional values of derivatives used in asset and liability management activities	The following table presents the gross notional values of derivatives used in Huntington’s asset and liability management activities at December 31, 2017 and December 31, 2016 , identified by the underlying interest rate-sensitive instruments: December 31, 2017 (dollar amounts in millions) Fair Value Hedges Cash Flow Hedges Total Instruments associated with: Loans $ — $ — $ — Subordinated notes 950 — 950 Long-term debt 7,425 — 7,425 Total notional value at December 31, 2017 $ 8,375 $ — $ 8,375 December 31, 2016 (dollar amounts in millions) Fair Value Hedges Cash Flow Hedges Total Instruments associated with: Loans $ — $ 3,325 $ 3,325 Subordinated notes 950 — 950 Long-term debt 6,525 — 6,525 Total notional value at December 31, 2016 $ 7,475 $ 3,325 $ 10,800
Additional information about the interest rate swaps used in asset and liability management activities	The following table presents additional information about the interest rate swaps used in Huntington’s asset and liability management activities at December 31, 2017 and December 31, 2016 : December 31, 2017 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ — 0 $ — — % — % Liability conversion swaps Receive fixed—generic 8,375 2.5 (99 ) 1.56 1.44 Total swap portfolio at December 31, 2017 $ 8,375 2.5 $ (99 ) 1.56 % 1.44 % December 31, 2016 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ 3,325 0.6 $ (2 ) 1.04 % 0.91 % Liability conversion swaps Receive fixed—generic 7,475 3.1 (52 ) 1.49 0.88 Total swap portfolio at December 31, 2016 $ 10,800 2.3 $ (54 ) 1.35 % 0.89 %
Asset and liability derivatives included in accrued income and other assets	December 31, 2017 December 31, 2016 (dollar amounts in millions) Asset Liability Asset Liability Derivatives designated as Hedging Instruments Interest rate contracts $ 22 $ 121 $ 46 $ 100 Derivatives not designated as Hedging Instruments Interest rate contracts (1) 187 100 233 141 Foreign exchange contracts 18 18 23 20 Commodities contracts 92 87 108 104 Equity contracts 3 5 10 6 Total Contracts $ 322 $ 331 $ 420 $ 371 .
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	The following table presents the change in fair value for derivatives designated as fair value hedges as well as the offsetting change in fair value on the hedged item: Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Interest rate contracts Change in fair value of interest rate swaps hedging deposits (1) $ — $ — $ (1 ) Change in fair value of hedged deposits (1) — — 1 Change in fair value of interest rate swaps hedging subordinated notes (2) (14 ) (48 ) (8 ) Change in fair value of hedged subordinated notes (2) 17 45 8 Change in fair value of interest rate swaps hedging long-term debt (2) (39 ) (74 ) 4 Change in fair value of hedged other long-term debt (2) 37 67 (4 ) (1) Effective portion of the hedging relationship is recognized in Interest expense—deposits in the Consolidated Statements of Income. Any resulting ineffective portion of the hedging relationship is recognized in noninterest income in the Consolidated Statements of Income. (2) Effective portion of the hedging relationship is recognized in Interest expense—subordinated notes and other long-term debt in the Consolidated Statements of Income. Any resulting ineffective portion of the hedging relationship is recognized in noninterest income in the Consolidated Statements of Income.
Gains and (losses) recognized in other comprehensive income (loss) (OCI) for derivatives designated as effective cash flow hedges	The following table presents the gains and (losses) recognized in OCI and the location in the Consolidated Statements of Income of gains and (losses) reclassified from OCI into earnings for derivatives designated as effective cash flow hedges: Derivatives in cash flow hedging relationships Amount of gain or (loss) recognized in OCI on derivatives (effective portion) Location of gain or (loss) reclassified from accumulated OCI into earnings (effective portion) Amount of (gain) or loss reclassified from accumulated OCI into earnings (effective portion) (pre-tax) (dollar amounts in millions) 2017 2016 2015 2017 2016 2015 Interest rate contracts Loans $ 2 $ 1 $ 9 Interest and fee income—loans and leases $ 1 $ — $ (1 ) Total $ 2 $ 1 $ 9 $ 1 $ — $ (1 )
Gains and (losses) recognized in noninterest income on the ineffective portion on interest rate contracts for derivatives designated as fair value and cash flow hedges	.
Offsetting of financial assets and derivatives assets	The following tables present the gross amounts of these assets and liabilities with any offsets to arrive at the net amounts recognized in the Consolidated Balance Sheets at December 31, 2017 and December 31, 2016 : Offsetting of Financial Assets and Derivative Assets Gross amounts offset in the consolidated balance sheets Net amounts of assets presented in the consolidated balance sheets Gross amounts not offset in the consolidated balance sheets (dollar amounts in millions) Gross amounts of recognized assets Financial instruments Cash collateral received Net amount December 31, 2017 Derivatives $ 322 $ (190 ) $ 132 $ (11 ) $ (18 ) $ 103 December 31, 2016 Derivatives 420 (182 ) 238 (34 ) (5 ) 199
Offsetting of financial liabilities and derivative liabilities	Offsetting of Financial Liabilities and Derivative Liabilities Gross amounts offset in the consolidated balance sheets Net amounts of assets presented in the consolidated balance sheets Gross amounts not offset in the consolidated balance sheets (dollar amounts in millions) Gross amounts of recognized liabilities Financial instruments Cash collateral delivered Net amount December 31, 2017 Derivatives $ 331 $ (245 ) $ 86 $ — $ (21 ) $ 65 December 31, 2016 Derivatives 371 (272 ) 99 (8 ) (24 ) 67
Derivative assets and liabilities used in mortgage banking activities	The following table summarizes the derivative assets and liabilities used in mortgage banking activities: Derivatives used in mortgage banking activities December 31, 2017 December 31, 2016 (dollar amounts in millions) Asset Liability Asset Liability Interest rate lock agreements $ 6 $ — $ 6 $ 2 Forward trades and options 1 — 13 1 Total derivatives used in mortgage banking activities $ 7 $ — $ 19 $ 3

VIEs (Tables)

VIEs (Tables)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Carrying amount and classification of the trusts assets and liabilities	The following tables provide a summary of the assets and liabilities included in Huntington’s Consolidated Financial Statements, as well as the maximum exposure to losses, associated with its interests related to unconsolidated VIEs for which Huntington holds an interest, but is not the primary beneficiary, to the VIE at December 31, 2017 , and 2016 : December 31, 2017 (dollar amounts in millions) Total Assets Total Liabilities Maximum Exposure to Loss 2016-1 Automobile Trust $ 7 $ — $ 7 2015-1 Automobile Trust 1 — 1 Trust Preferred Securities 14 252 — Affordable Housing Tax Credit Partnerships 636 335 636 Other Investments 117 53 117 Total $ 775 $ 640 $ 761 December 31, 2016 (dollar amounts in millions) Total Assets Total Liabilities Maximum Exposure to Loss 2016-1 Automobile Trust $ 15 $ — $ 15 2015-1 Automobile Trust 2 — 2 Trust Preferred Securities 14 253 — Affordable Housing Tax Credit Partnerships 577 293 577 Other Investments 79 42 79 Total $ 687 $ 588 $ 673 The following table present the carrying amount and classification of the consolidated trusts’ assets and liabilities that were included in the Consolidated Balance Sheet at December 31, 2016 : December 31, 2016 Huntington Technology Other Consolidated VIEs Total (dollar amounts in millions) Series 2014A Assets: Cash $ 2 $ — $ 2 Net loans and leases 70 — 70 Accrued income and other assets — — — Total assets $ 72 $ — $ 72 Liabilities: Other long-term debt $ 57 $ — $ 57 Accrued interest and other liabilities — — — Total liabilities 57 — 57 Equity: Beneficial Interest owned by third party $ 14 — 14 Total liabilities and equity $ 71 $ — $ 71
Summary of outstanding trust preferred securities	Huntington’s long-term debt consisted of the following: At December 31, (dollar amounts in millions) 2017 2016 The Parent Company: Senior Notes: 3.19% Huntington Bancshares Incorporated medium-term notes due 2021 $ 969 $ 973 2.33% Huntington Bancshares Incorporated senior note due 2022 953 954 2.64% Huntington Bancshares Incorporated senior note due 2018 399 399 Subordinated Notes: 7.00% Huntington Bancshares Incorporated subordinated notes due 2020 312 320 3.55% Huntington Bancshares Incorporated subordinated notes due 2023 245 248 Sky Financial Capital Trust IV 3.09% junior subordinated debentures due 2036 (1) 74 74 Sky Financial Capital Trust III 3.09% junior subordinated debentures due 2036 (1) 72 72 Huntington Capital I Trust Preferred 2.39% junior subordinated debentures due 2027 (2) 69 69 Huntington Capital II Trust Preferred 2.32% junior subordinated debentures due 2028 (3) 31 32 Camco Financial Statutory Trust I 3.02% due 2037 (4) 4 4 Total notes issued by the parent 3,128 3,145 The Bank: Senior Notes: 2.24% Huntington National Bank senior notes due 2018 844 844 2.10% Huntington National Bank senior notes due 2018 748 747 2.47% Huntington National Bank senior notes due 2020 694 — 2.55% Huntington National Bank senior notes due 2022 685 — 2.43% Huntington National Bank senior notes due 2020 498 498 2.23% Huntington National Bank senior note due 2019 497 500 1.75% Huntington National Bank senior notes due 2018 496 500 2.97% Huntington National Bank senior notes due 2020 492 495 2.20% Huntington National Bank senior notes due 2020 (5) 300 — 5.04% Huntington National Bank medium-term notes due 2018 35 36 2.23% Huntington National Bank senior note due 2017 — 499 1.42% Huntington National Bank senior notes due 2017 (6) — 250 Subordinated Notes: 3.86% Huntington National Bank subordinated notes due 2026 238 239 6.67% Huntington National Bank subordinated notes due 2018 129 132 5.45% Huntington National Bank subordinated notes due 2019 77 81 Total notes issued by the bank 5,733 4,821 FHLB Advances: 3.51% weighted average rate, varying maturities greater than one year 7 8 Other: Huntington Technology Finance nonrecourse debt, 3.63% effective interest rate, varying maturities 263 278 3.57% Huntington Preferred Capital II - Class F securities (7) 75 — Huntington Technology Finance ABS Trust 2014 1.70% due 2020 — 57 Total other 338 335 Total long-term debt $ 9,206 $ 8,309 (1) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.400% . (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70% (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625% . (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.33% . (5) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.51% (6) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.425% . (7) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.880% . The trust securities are the obligations of the trusts, and as such, are not consolidated within Huntington’s Consolidated Financial Statements. A list of trust-preferred securities outstanding at December 31, 2017 follows: (dollar amounts in millions) Rate Principal amount of subordinated note/ debenture issued to trust (1) Investment in unconsolidated subsidiary Huntington Capital I 2.39 % (2) $ 70 $ 6 Huntington Capital II 2.32 (3) 32 3 Sky Financial Capital Trust III 3.09 (4) 72 2 Sky Financial Capital Trust IV 3.09 (4) 74 2 Camco Financial Trust 3.02 (5) 4 1 Total $ 252 $ 14 (1) Represents the principal amount of debentures issued to each trust, including unamortized original issue discount. (2) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.70 %. (3) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 0.625 %. (4) Variable effective rate at December 31, 2017 , based on three-month LIBOR + 1.40 %. (5) Variable effective rate at December 31, 2017 , based on three month LIBOR + 1.33 %.

COMMITMENTS AND CONTINGENT LI52

COMMITMENTS AND CONTINGENT LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Contract amounts of various commitments to extend credit	The contract amounts of these financial agreements at December 31, 2017 , and December 31, 2016 were as follows: At December 31, (dollar amounts in millions) 2017 2016 Contract amount represents credit risk Commitments to extend credit: Commercial $ 16,219 $ 15,190 Consumer 13,384 12,236 Commercial real estate 1,366 1,698 Standby letters of credit 510 637 Commercial letters-of-credit 21 5

OTHER REGULATORY MATTERS (Table

OTHER REGULATORY MATTERS (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Period-end capital amounts and capital ratios	Minimum Minimum December 31, Regulatory Ratio+Capital Well- 2017 2016 Capital Conservation Capitalized Basel III (dollar amounts in millions) Ratios Buffer Minimums Ratio Amount Ratio Amount Tier 1 leverage Consolidated 4.00 % N/A N/A 9.09 % $ 9,110 8.70 % $ 8,547 Bank 4.00 N/A 5.00 % 9.70 9,727 9.29 9,086 CET 1 risk-based capital Consolidated 4.50 5.75 % N/A 10.01 8,041 9.56 7,486 Bank 4.50 5.75 6.50 11.02 8,856 10.42 8,153 Tier 1 risk-based capital Consolidated 6.00 7.25 6.00 11.34 9,110 10.92 8,547 Bank 6.00 7.25 8.00 12.10 9,727 11.61 9,086 Total risk-based capital Consolidated 8.00 9.25 10.00 13.39 10,757 13.05 10,215 Bank 8.00 9.25 10.00 14.33 11,517 13.83 10,818

PARENT COMPANY FINANCIAL STAT54

PARENT COMPANY FINANCIAL STATEMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Balance Sheets	The parent-only financial statements, which include transactions with subsidiaries, are as follows: Balance Sheets December 31, (dollar amounts in millions) 2017 2016 Assets Cash and due from banks $ 1,618 $ 1,753 Due from The Huntington National Bank 798 730 Due from non-bank subsidiaries 58 45 Investment in The Huntington National Bank 11,696 10,668 Investment in non-bank subsidiaries 111 500 Accrued interest receivable and other assets 252 321 Total assets $ 14,533 $ 14,017 Liabilities and shareholders’ equity Long-term borrowings $ 3,128 $ 3,145 Dividends payable, accrued expenses, and other liabilities 591 564 Total liabilities 3,719 3,709 Shareholders’ equity (1) 10,814 10,308 Total liabilities and shareholders’ equity $ 14,533 $ 14,017 (1) See Consolidated Statements of Changes in Shareholders’ Equity.
Statements of Income	Statements of Income Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Income Dividends from The Huntington National Bank $ 298 $ 188 $ 822 Non-bank subsidiaries 14 11 39 Interest from The Huntington National Bank 20 14 6 Non-bank subsidiaries 2 3 2 Other 4 — 5 Total income 338 216 874 Expense Personnel costs 19 12 5 Interest on borrowings 91 59 17 Other 115 123 93 Total expense 225 194 115 Income (loss) before income taxes and equity in undistributed net income of subsidiaries 113 22 759 Provision (benefit) for income taxes (56 ) (56 ) (110 ) Income (loss) before equity in undistributed net income of subsidiaries 169 78 869 Increase (decrease) in undistributed net income (loss) of: The Huntington National Bank 1,015 629 (161 ) Non-bank subsidiaries 2 5 (15 ) Net income $ 1,186 $ 712 $ 693 Other comprehensive income (loss) (1) (34 ) (175 ) (4 ) Comprehensive income $ 1,152 $ 537 $ 689 (1) See Consolidated Statements of Comprehensive Income for other comprehensive income (loss) detail.
Statements of Cash Flows	Statements of Cash Flows Year Ended December 31, (dollar amounts in millions) 2017 2016 2015 Operating activities Net income $ 1,186 $ 712 $ 693 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed net income of subsidiaries (997 ) (634 ) 176 Depreciation and amortization 4 (1 ) 1 Loss on sales of securities available-for-sale — — — Other, net (37 ) (24 ) (45 ) Net cash (used for) provided by operating activities 156 53 825 Investing activities Repayments from subsidiaries 442 464 495 Advances to subsidiaries (29 ) (1,758 ) (612 ) Proceeds from sale of securities available-for-sale 1 (2 ) — Cash paid for acquisitions, net of cash received — (133 ) — Proceeds from business divestitures — — 9 Net cash (used for) provided by investing activities 414 (1,429 ) (108 ) Financing activities Proceeds from issuance of long-term borrowings — 1,990 — Payment of borrowings — (65 ) — Dividends paid on stock (425 ) (299 ) (225 ) Net proceeds from issuance of preferred stock — 585 — Repurchases of common stock (260 ) — (252 ) Other, net (20 ) 1 14 Net cash provided by (used for) financing activities (705 ) 2,212 (463 ) Increase (decrease) in cash and due from banks (135 ) 836 254 Cash and due from banks at beginning of year 1,753 917 663 Cash and due from banks at end of year $ 1,618 $ 1,753 $ 917 Supplemental disclosure: Interest paid $ 90 $ 36 $ 17

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Business Segment Financial Information	Listed below is certain financial information reconciled to Huntington’s December 31, 2017 , December 31, 2016 , and December 31, 2015 , reported results by business segment: Income Statements (dollar amounts in millions) Consumer & Business Banking Commercial Banking Vehicle Finance RBHPCG Treasury / Other Huntington Consolidated 2017 Net interest income $ 1,555 $ 899 $ 424 $ 184 $ (60 ) $ 3,002 Provision (benefit) for credit losses 110 28 63 — — 201 Noninterest income 735 278 14 188 92 1,307 Noninterest expense 1,647 474 150 243 200 2,714 Provision (benefit) for income taxes 187 236 79 45 (339 ) 208 Net income (loss) $ 346 $ 439 $ 146 $ 84 $ 171 $ 1,186 2016 Net interest income $ 1,224 $ 725 $ 345 $ 152 $ (77 ) $ 2,369 Provision (benefit) for credit losses 68 79 47 (3 ) — 191 Noninterest income 650 244 14 177 65 1,150 Noninterest expense 1,338 398 118 229 325 2,408 Provision (benefit) for income taxes 164 172 68 36 (232 ) 208 Net income (loss) $ 304 $ 320 $ 126 $ 67 $ (105 ) $ 712 2015 Net interest income $ 995 $ 560 $ 262 $ 125 $ 9 $ 1,951 Provision (benefit) for credit losses 45 16 39 — — 100 Noninterest income 566 214 13 174 72 1,039 Noninterest expense 1,192 343 93 241 107 1,976 Provision (benefit) for income taxes 113 145 50 21 (108 ) 221 Net income (loss) $ 211 $ 270 $ 93 $ 37 $ 82 $ 693
Segment Disclosure of Assets and Deposits	Assets at December 31, Deposits at December 31, (dollar amounts in millions) 2017 2016 2017 2016 Consumer & Business Banking $ 26,220 $ 25,333 $ 45,643 $ 45,356 Commercial Banking 32,118 31,566 21,235 19,597 Vehicle Finance 17,865 16,132 358 349 RBHPCG 5,821 5,328 6,057 6,214 Treasury / Other 22,161 21,355 3,748 4,092 Total $ 104,185 $ 99,714 $ 77,041 $ 75,608

QUARTERLY RESULTS OF OPERATIO56

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly results of operations	The following is a summary of the quarterly results of operations, for the years ended December 31, 2017 and 2016 : Three Months Ended December 31, September 30, June 30, March 31, (dollar amounts in millions, except per share data) 2017 2017 2017 2017 Interest income $ 894 $ 873 $ 846 $ 820 Interest expense 124 115 101 91 Net interest income 770 758 745 729 Provision for credit losses 65 43 25 68 Noninterest income 340 330 325 312 Noninterest expense 633 680 694 707 Income before income taxes 412 365 351 266 Provision (benefit) for income taxes (20 ) 90 79 59 Net income 432 275 272 207 Dividends on preferred shares 19 19 19 19 Net income applicable to common shares $ 413 $ 256 $ 253 $ 188 Net income per common share — Basic $ 0.38 $ 0.24 $ 0.23 $ 0.17 Net income per common share — Diluted 0.37 0.23 0.23 0.17 Three Months Ended December 31, September 30, June 30, March 31, (dollar amounts in millions, except per share data) 2016 2016 2016 2016 Interest income $ 815 $ 694 $ 566 $ 557 Interest expense 80 69 60 54 Net interest income 735 625 506 503 Provision for credit losses 75 63 25 28 Noninterest income 334 303 271 242 Noninterest expense 681 713 523 491 Income before income taxes 313 152 229 226 Provision (benefit) for income taxes 74 25 54 55 Net income 239 127 175 171 Dividends on preferred shares 19 18 20 8 Net income applicable to common shares $ 220 $ 109 $ 155 $ 163 Net income per common share — Basic $ 0.20 $ 0.12 $ 0.19 $ 0.21 Net income per common share — Diluted 0.20 0.11 0.19 0.20

SIGNIFICANT ACCOUNTING POLICI57

SIGNIFICANT ACCOUNTING POLICIES - Loans and Leases (Details)	12 Months Ended
	Dec. 31, 2017USD ($)reservecomponent
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance number of reserves | reserve	2
Allowance number of components of reserve | component	2
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold period past due for nonperforming status	90 days
Threshold past due for write-off	90 days
Threshold outstanding balance for quarterly impairment evaluation	$ 1,000,000
CRE
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold period past due for nonperforming status	90 days
Threshold past due for write-off	90 days
Threshold outstanding balance for quarterly impairment evaluation	$ 1,000,000
Home Equity | First-lien home equity loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold period past due for nonperforming status	150 days
Threshold past due for write-off	150 days
Home Equity | Junior-lien home equity loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold past due for write-off	120 days
Automobile
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold past due for write-off	120 days
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold past due for write-off	120 days
Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold period past due for nonperforming status	150 days
Threshold past due for write-off	150 days

SIGNIFICANT ACCOUNTING POLICI58

SIGNIFICANT ACCOUNTING POLICIES - Property, Plant, and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	30 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	40 years
Building Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	10 years
Building Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	30 years
Land Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	5 years
Land Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	20 years
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	10 years
Furniture and Fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	5 years
Furniture and Fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	20 years

ACQUISITION OF FIRSTMERIT COR59

ACQUISITION OF FIRSTMERIT CORPORATION - Narrative (Details) $ / shares in Units, $ in Thousands, shares in Millions	Aug. 16, 2016USD ($)$ / sharesshares	Dec. 31, 2017USD ($)state	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)state	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Aug. 15, 2016$ / shares
Business Acquisition [Line Items]
Goodwill		$ 1,993,000				$ 1,993,000				$ 1,993,000	$ 1,993,000	$ 677,000
Number of States in which Entity Operates | state		8								8
Share Price | $ / shares													$ 9.68
Net Income (Loss) Attributable to Parent		$ 432,000	$ 275,000	$ 272,000	$ 207,000	$ 239,000	$ 127,000	$ 175,000	$ 171,000	$ 1,186,000	$ 712,000	$ 693,000
FirstMerit Bank
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	$ 3,700,000
Payments to acquired business in cash	800,000
Goodwill	$ 1,000,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Per Share | $ / shares	$ 1.72
Business Combination, Consideration Transferred, Cash Paid for Each Share of Acquired Entity's Shares | $ / shares	$ 5
Consideration transferred, equity interest issued and issuable	$ 2,800,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares	285
Common Stock | FirstMerit Bank
Business Acquisition [Line Items]
Consideration transferred, equity interest issued and issuable	$ 2,800,000
Preferred Stock | FirstMerit Bank
Business Acquisition [Line Items]
Consideration transferred, equity interest issued and issuable	$ 100,000

ACQUISITION OF FIRSTMERIT COR60

ACQUISITION OF FIRSTMERIT CORPORATION - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Aug. 16, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets acquired:
Goodwill		$ 1,993	$ 1,993	$ 677
FirstMerit Bank
Assets acquired:
Goodwill	$ 1,000
Business Combination, Consideration Transferred [Abstract]
Consideration transferred, equity interest issued and issuable	2,800
Payments to acquired business in cash	800
FirstMerit Bank | Common Stock
Business Combination, Consideration Transferred [Abstract]
Consideration transferred, equity interest issued and issuable	2,800
FirstMerit Bank | Preferred Stock
Business Combination, Consideration Transferred [Abstract]
Consideration transferred, equity interest issued and issuable	100
FirstMerit Bank | Core deposit intangible
Assets acquired:
Intangible assets	310
FirstMerit Bank | Other
Assets acquired:
Intangible assets	$ 95

LOANS AND LEASES AND ALLOWANC61

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Gross, Commercial and Industrial	$ 28,107,000,000	$ 28,059,000,000
Loans net premium	334,000,000	120,000,000
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Future lease rental payments due	1,700,000,000
Future lease rental payments due, in 2016	600,000,000
Future lease rental payments due, in 2017	400,000,000
Future lease rental payments due, in 2018	300,000,000
Future lease rental payments due, in 2019	100,000,000
Future lease rental payments due, in 2020	100,000,000
Future lease rental payments due, after 2020	200,000,000
Allowance for loan and lease losses	691,000,000	638,000,000	$ 598,000,000	$ 605,000,000
Interest income under original terms for NAL loans	21,000,000	24,000,000	20,000,000
Interest income recorded for NAL loans	18,000,000	17,000,000	10,000,000
Interest income under original terms for TDR loans	49,000,000	49,000,000	46,000,000
Interest income recorded for TDR loans	$ 45,000,000	40,000,000	41,000,000
Threshold period of consecutive payments to remove from nonaccrual status	6 months
Amount of security for borrowing and advances	$ 31,700,000,000	19,700,000,000
Consumer loans	93,000,000	82,000,000
Loans Receivable, Gross, Commercial, Real Estate	7,225,000,000	7,301,000,000
Loans and Leases Receivable, Gross, Automobile	12,100,000,000	10,969,000,000
Loans and Leases Receivable, Gross, Consumer, Home Equity	10,099,000,000	10,106,000,000
Loans and Leases Receivable, Gross, Consumer, Mortgage	9,026,000,000	7,725,000,000
Loans Receivable, Gross, Recreation Finance	2,438,000,000	1,846,000,000
Loans and Leases Receivable, Gross, Consumer, Other	1,122,000,000	956,000,000
Loans and Leases Receivable, Gross	70,117,000,000	66,962,000,000
Loans and Leases Receivable, Net Amount	69,426,000,000	66,324,000,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Gross, Commercial and Industrial	28,107,000,000	28,059,000,000
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Allowance for loan and lease losses	482,000,000	451,000,000	399,000,000	390,000,000
Threshold outstanding balance for quarterly impairment evaluation	$ 1,000,000
Redefault status number of days	90 days
Threshold period past due for nonperforming status	90 days
Loans Receivable, Gross, Commercial, Real Estate	$ 7,225,000,000	7,301,000,000
Consumer
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Allowance for loan and lease losses	209,000,000	187,000,000	$ 199,000,000	$ 215,000,000
Loans and Leases Receivable, Gross, Automobile	12,099,000,000	10,967,000,000
Loans and Leases Receivable, Gross, Consumer, Home Equity	10,097,000,000	10,103,000,000
Loans and Leases Receivable, Gross, Consumer, Mortgage	8,937,000,000	7,650,000,000
Loans and Leases Receivable, Gross, Consumer, Other	1,122,000,000	956,000,000
Home Equity | Consumer
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Consumer loans	2,000,000	3,000,000
Loans and Leases Receivable, Gross	$ 10,099,000,000	10,106,000,000
Residential Mortgage | Consumer
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Threshold period past due for nonperforming status	150 days
Consumer loans	$ 89,000,000	75,000,000
Loans and Leases Receivable, Gross	$ 9,026,000,000	$ 7,725,000,000

LOANS AND LEASES AND ALLOWANC62

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Direct Financing Leases (Details) - Commercial Portfolio Segment [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease payments receivable	$ 1,645	$ 1,881
Estimated residual value of leased assets	755	798
Gross investment in commercial lease financing receivables	2,400	2,679
Deferred origination costs	18	13
Deferred fees	(225)	(254)
Total net investment in commercial lease financing receivables	$ 2,193	$ 2,438

LOANS AND LEASES AND ALLOWANC63

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Certain Loans Acquired Balances at Acquisition (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
FirstMerit Bank
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield	$ 33	$ 37	$ 0

LOANS AND LEASES AND ALLOWANC64

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Certain Loans Acquired Accretable Yield Roll Forward (Details) - FirstMerit Bank - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	$ 37	$ 0
Impact of acquisition on March 1, 2014	0	(18)
Accretion	(18)	(5)
Reclassification from nonaccretable difference	14	24
Balance, end of period	$ 33	$ 37

LOANS AND LEASES AND ALLOWANC65

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Certain Loans Acquired Ending and Unpaid Balances (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	$ 41	$ 102
FirstMerit Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	41	102
Acquired loans, unpaid balance	76	156
Commercial and Industrial | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	39	68
Commercial and Industrial | Commercial Portfolio Segment [Member] | FirstMerit Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	39	68
Acquired loans, unpaid balance	61	100
Commercial Real Estate Loan [Member] | Commercial Portfolio Segment [Member] | FirstMerit Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	2	34
Acquired loans, unpaid balance	15	56
Commercial Real Estate | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	2	34
Automobile | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	0	0
Home Equity | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	0	0
Residential Mortgage | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	0	0
RV and marine finance | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	0	0
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired loans, carrying amount	$ 0	$ 0

LOANS AND LEASES AND ALLOWANC66

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Nonaccrual Loans by Loan Class (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	$ 349	$ 423
Commercial Portfolio Segment [Member] | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	161	234
Commercial Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	29
Commercial Portfolio Segment [Member] | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans		20
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	6	6
Consumer | Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	68	72
Consumer | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	84	91
Consumer | RV and marine finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	1	0
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total nonaccrual loans	$ 0	$ 0

LOANS AND LEASES AND ALLOWANC67

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - NALs Past Due (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	$ 714	$ 719
Loans and leases, current	69,269	66,059
Loans and Leases Receivable, Gross	70,117	66,962
90 or more days past due and accruing	115	129
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	41	102
Consumer loans	93	82
30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	335	321
60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	108	109
90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	271	289
Commercial Portfolio Segment [Member] | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	114	136
Loans and leases, current	27,954	27,855
Loans and Leases Receivable, Gross	28,107	28,059
90 or more days past due and accruing	9	18
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	39	68
Consumer loans	0	0
Commercial Portfolio Segment [Member] | Commercial and Industrial | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	35	42
Commercial Portfolio Segment [Member] | Commercial and Industrial | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	14	20
Commercial Portfolio Segment [Member] | Commercial and Industrial | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	65	74
Commercial Portfolio Segment [Member] | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	22	54
Loans and leases, current	7,201	7,213
Loans and Leases Receivable, Gross	7,225	7,301
90 or more days past due and accruing	3	17
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	2	34
Consumer loans	0	0
Commercial Portfolio Segment [Member] | Commercial Real Estate | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	10	21
Commercial Portfolio Segment [Member] | Commercial Real Estate | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	1	3
Commercial Portfolio Segment [Member] | Commercial Real Estate | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	11	30
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	117	103
Loans and leases, current	11,982	10,864
Loans and Leases Receivable, Gross	12,100	10,969
90 or more days past due and accruing	7	10
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	0
Consumer loans	1	2
Consumer | Automobile | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	89	76
Consumer | Automobile | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	18	17
Consumer | Automobile | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	10	10
Consumer | Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	128	116
Loans and leases, current	9,969	9,987
Loans and Leases Receivable, Gross	10,099	10,106
90 or more days past due and accruing	18	12
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	0
Consumer loans	2	3
Consumer | Home Equity | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	49	39
Consumer | Home Equity | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	19	24
Consumer | Home Equity | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	60	53
Consumer | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	295	276
Loans and leases, current	8,642	7,374
Loans and Leases Receivable, Gross	9,026	7,725
90 or more days past due and accruing	72	67
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	0
Consumer loans	89	75
Consumer | Residential Mortgage | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	129	122
Consumer | Residential Mortgage | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	48	37
Consumer | Residential Mortgage | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	118	117
Consumer | RV and marine finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	16	14
Loans and leases, current	2,421	1,830
Loans and Leases Receivable, Gross	2,438	1,846
90 or more days past due and accruing	1	1
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	0
Consumer loans	1	2
Consumer | RV and marine finance | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	11	10
Consumer | RV and marine finance | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	3	2
Consumer | RV and marine finance | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	2	2
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	22	20
Loans and leases, current	1,100	936
Loans and Leases Receivable, Gross	1,122	956
90 or more days past due and accruing	5	4
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	0
Consumer loans	0	0
Consumer | Consumer | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	12	11
Consumer | Consumer | 60-89 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	5	6
Consumer | Consumer | 90 or more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, past due	$ 5	$ 3

LOANS AND LEASES AND ALLOWANC68

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
ALLL balance beginning of period	$ 638,000	$ 598,000	$ 605,000
Loan charge-offs	(252,000)	(227,000)	(218,000)
Recoveries of loans previously charged-off	93,000	118,000	130,000
Provision for loan and lease losses	(212,000)	(169,000)	(89,000)
Allowance for loans sold or transferred to loans held for sale	0	(20,000)	(8,000)
ALLL balance end of period	691,000	638,000	598,000
AULC balance beginning of period	98,000	72,000	61,000
Provision (reduction in allowance) for unfunded loan commitments and letters of credit	11,000	22,000	(11,000)
AULC balance end of period	87,000	98,000	72,000
ACL balance end of period	778,000	736,000	670,000
Additions to Unfunded Loan Commitments and Letters of Credit Allowance	0	4,000	0
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
ALLL balance beginning of period	451,000	399,000	390,000
Loan charge-offs	(72,000)	(92,000)	(98,000)
Recoveries of loans previously charged-off	41,000	73,000	86,000
Provision for loan and lease losses	(62,000)	(85,000)	(21,000)
Allowance for loans sold or transferred to loans held for sale	0	(14,000)	0
ALLL balance end of period	482,000	451,000	399,000
AULC balance beginning of period	87,000	64,000	55,000
Provision (reduction in allowance) for unfunded loan commitments and letters of credit	3,000	(19,000)	(9,000)
AULC balance end of period	84,000	87,000	64,000
ACL balance end of period	566,000	538,000	463,000
Additions to Unfunded Loan Commitments and Letters of Credit Allowance	0	4,000	0
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
ALLL balance beginning of period	187,000	199,000	215,000
Loan charge-offs	(180,000)	(135,000)	(120,000)
Recoveries of loans previously charged-off	52,000	45,000	44,000
Provision for loan and lease losses	(150,000)	(84,000)	(68,000)
Allowance for loans sold or transferred to loans held for sale	0	6,000	8,000
ALLL balance end of period	209,000	187,000	199,000
AULC balance beginning of period	11,000	8,000	6,000
Provision (reduction in allowance) for unfunded loan commitments and letters of credit	8,000	(3,000)	(2,000)
AULC balance end of period	3,000	11,000	8,000
ACL balance end of period	212,000	198,000	207,000
Additions to Unfunded Loan Commitments and Letters of Credit Allowance	$ 0	$ 0	$ 0

LOANS AND LEASES AND ALLOWANC69

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	$ 28,107	$ 28,059
Commercial real estate loans	7,225	7,301
Automobile loans	12,100	10,969
Home equity loans	10,099	10,106
Residential mortgage loans	9,026	7,725
Other consumer loans	1,122	956
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	28,107	28,059
Commercial real estate loans	7,225	7,301
Commercial Portfolio Segment [Member] | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	26,268	26,212
Commercial real estate loans	6,909	7,042
Commercial Portfolio Segment [Member] | OLEM
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	694	810
Commercial real estate loans	200	97
Commercial Portfolio Segment [Member] | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	1,116	1,029
Commercial real estate loans	115	159
Commercial Portfolio Segment [Member] | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial loans and leases	29	8
Commercial real estate loans	1	3
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Automobile loans	12,099	10,967
Home equity loans	10,097	10,103
Residential mortgage loans	8,937	7,650
Loans and Leases Receivable, Gross, Consumer, Recreation Finance	2,437	1,845
Other consumer loans	1,122	956
Consumer | FICO Score, Greater than 750
Accounts, Notes, Loans and Financing Receivable [Line Items]
Automobile loans	6,102	5,369
Home equity loans	6,352	6,280
Residential mortgage loans	5,697	4,663
Loans and Leases Receivable, Gross, Consumer, Recreation Finance	1,433	1,064
Other consumer loans	428	347
Consumer | 650-749
Accounts, Notes, Loans and Financing Receivable [Line Items]
Automobile loans	4,312	4,044
Home equity loans	3,024	2,891
Residential mortgage loans	2,581	2,285
Loans and Leases Receivable, Gross, Consumer, Recreation Finance	863	644
Other consumer loans	540	456
Consumer | 650
Accounts, Notes, Loans and Financing Receivable [Line Items]
Automobile loans	1,390	1,298
Home equity loans	617	638
Residential mortgage loans	605	615
Loans and Leases Receivable, Gross, Consumer, Recreation Finance	96	73
Other consumer loans	143	133
Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Automobile loans	295	256
Home equity loans	104	294
Residential mortgage loans	54	87
Loans and Leases Receivable, Gross, Consumer, Recreation Finance	45	64
Other consumer loans	$ 11	$ 20

LOANS AND LEASES AND ALLOWANC70

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - ALLL Attributable to Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Attributable to loans collectively evaluated for impairment	$ 650,000	$ 616,000
Attributable to loans individually evaluated for impairment	41,000	22,000
Total ALLL balance:	691,000	638,000	$ 598,000	$ 605,000
Collectively evaluated for impairment	68,760,000	65,904,000
Financing Receivable Evaluated For Impairment	70,024,000	66,880,000
Individually evaluated for impairment	1,223,000	874,000
Purchase credit-impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Attributable to loans collectively evaluated for impairment	0	0
Collectively evaluated for impairment	41,000	102,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ALLL balance:	482,000	451,000	399,000	390,000
Financing Receivable Evaluated For Impairment	35,332,000	35,360,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total ALLL balance:	209,000	187,000	$ 199,000	$ 215,000
Financing Receivable Evaluated For Impairment	$ 34,692,000	$ 31,520,000

LOANS AND LEASES AND ALLOWANC71

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Impaired Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, unpaid principle	$ 0	$ 0
Impaired loans and leases with no related allowance, average balance	0	0
Impaired loans and leases with no related allowance, interest income recognized	0	0
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, unpaid principle	0	0
Impaired loans and leases with no related allowance, average balance	0	0
Impaired loans and leases with no related allowance, interest income recognized	0	0
Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, unpaid principle	0	0
Impaired loans and leases with no related allowance, average balance	0	0
Impaired loans and leases with no related allowance, interest income recognized	0	0
RV and marine finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, unpaid principle	0	0
Impaired loans and leases with no related allowance, average balance	0	0
Impaired loans and leases with no related allowance, interest income recognized	0	0
Commercial Portfolio Segment [Member] | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	284	300
Impaired loans and leases with no related allowance, unpaid principle	311	359
Impaired loans and leases with no related allowance, average balance	206	293
Impaired loans and leases with no related allowance, interest income recognized	12	9
Impaired loans and leases with an allowance recorded, ending balance	257	406
Impaired loans and leases with an allowance recorded, unpaid principle	280	448
Impaired loans and leases with an allowance recorded, related allowance	29	22
Impaired Financing Receivable, Average Recorded Investment	498	595
Impaired loans and leases with an allowance recorded, average balance	292	302
Impaired loans and leases with an allowance recorded, interest income recognized	16	8
Considered impaired due to TDR status	382	317
Impaired Financing Receivable, Recorded Investment	541	706
Impaired Financing Receivable, Unpaid Principal Balance	591	807
Impaired Financing Receivable, Interest Income, Accrual Method	28	17
Commercial Portfolio Segment [Member] | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	56	89
Impaired loans and leases with no related allowance, unpaid principle	81	126
Impaired loans and leases with no related allowance, average balance	64	73
Impaired loans and leases with no related allowance, interest income recognized	8	4
Impaired loans and leases with an allowance recorded, ending balance	51	97
Impaired loans and leases with an allowance recorded, unpaid principle	51	108
Impaired loans and leases with an allowance recorded, related allowance	3	3
Impaired Financing Receivable, Average Recorded Investment	116	142
Impaired loans and leases with an allowance recorded, average balance	52	69
Impaired loans and leases with an allowance recorded, interest income recognized	2	3
Considered impaired due to TDR status	93	82
Impaired Financing Receivable, Recorded Investment	107	186
Impaired Financing Receivable, Unpaid Principal Balance	132	234
Impaired Financing Receivable, Interest Income, Accrual Method	10	7
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	0	0
Impaired loans and leases with an allowance recorded, ending balance	36	31
Impaired loans and leases with an allowance recorded, unpaid principle	40	31
Impaired loans and leases with an allowance recorded, related allowance	2	2
Impaired Financing Receivable, Average Recorded Investment	33	32
Impaired loans and leases with an allowance recorded, average balance	33	32
Impaired loans and leases with an allowance recorded, interest income recognized	2	2
Impaired Financing Receivable, Recorded Investment	36	31
Impaired Financing Receivable, Unpaid Principal Balance	40	31
Impaired Financing Receivable, Interest Income, Accrual Method	2	2
Consumer | Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	0	0
Impaired loans and leases with an allowance recorded, ending balance	334	319
Impaired loans and leases with an allowance recorded, unpaid principle	385	353
Impaired loans and leases with an allowance recorded, related allowance	14	15
Impaired Financing Receivable, Average Recorded Investment	329	278
Impaired loans and leases with an allowance recorded, average balance	329	278
Impaired loans and leases with an allowance recorded, interest income recognized	15	13
Impaired Financing Receivable, Recorded Investment	334	319
Impaired Financing Receivable, Unpaid Principal Balance	385	353
Impaired Financing Receivable, Interest Income, Accrual Method	15	13
Consumer | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	0	0
Impaired loans and leases with an allowance recorded, ending balance	308	328
Impaired loans and leases with an allowance recorded, unpaid principle	338	363
Impaired loans and leases with an allowance recorded, related allowance	4	13
Impaired Financing Receivable, Average Recorded Investment	325	348
Impaired loans and leases with an allowance recorded, average balance	325	348
Impaired loans and leases with an allowance recorded, interest income recognized	12	12
Impaired Financing Receivable, Recorded Investment	308	328
Impaired Financing Receivable, Unpaid Principal Balance	338	363
Impaired Financing Receivable, Interest Income, Accrual Method	12	12
Consumer | RV and marine finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	0	0
Impaired loans and leases with an allowance recorded, ending balance	2	0
Impaired loans and leases with an allowance recorded, unpaid principle	3	0
Impaired loans and leases with an allowance recorded, related allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	1	0
Impaired loans and leases with an allowance recorded, average balance	1	0
Impaired loans and leases with an allowance recorded, interest income recognized	0	0
Impaired Financing Receivable, Recorded Investment	2	0
Impaired Financing Receivable, Unpaid Principal Balance	3	0
Impaired Financing Receivable, Interest Income, Accrual Method	0	0
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans and leases with no related allowance, ending balance	0	0
Impaired loans and leases with no related allowance, unpaid principle	0	0
Impaired loans and leases with no related allowance, average balance	0	0
Impaired loans and leases with no related allowance, interest income recognized	0	0
Impaired loans and leases with an allowance recorded, ending balance	8	4
Impaired loans and leases with an allowance recorded, unpaid principle	8	4
Impaired loans and leases with an allowance recorded, related allowance	2	0
Impaired Financing Receivable, Average Recorded Investment	5	4
Impaired loans and leases with an allowance recorded, average balance	5	4
Impaired loans and leases with an allowance recorded, interest income recognized	0	0
Impaired Financing Receivable, Recorded Investment	8	4
Impaired Financing Receivable, Unpaid Principal Balance	8	4
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0

LOANS AND LEASES AND ALLOWANC72

LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - TDRs (Details)	12 Months Ended
	Dec. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	6,745,000,000	5,053,000,000
Post-modification Outstanding Balance (2)	$ 853,000,000	$ 678,000,000
Financial effects of modification	$ (13,000,000)	$ 12,000,000
Commercial Portfolio Segment [Member] | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts	9,000,000	4,000,000
Post-modification Outstanding Balance (2)	$ 1,000,000	$ 0
Financial effects of modification	0	$ 0
Commercial Portfolio Segment [Member] | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract		872,000,000
Post-modification Outstanding Balance (2)	600,000,000	$ 490,000,000
Financial effects of modification	$ (9,000,000)	$ 9,000,000
Commercial Portfolio Segment [Member] | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	4,000,000	20,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 3,000,000
Financial effects of modification	$ 0	$ 0
Commercial Portfolio Segment [Member] | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,047,000,000	896,000,000
Post-modification Outstanding Balance (2)	$ 601,000,000	$ 493,000,000
Financial effects of modification	$ (9,000,000)	$ 9,000,000
Commercial Portfolio Segment [Member] | Commercial and Industrial | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,034,000,000
Commercial Portfolio Segment [Member] | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	111,000,000	117,000,000
Post-modification Outstanding Balance (2)	$ 122,000,000	$ 69,000,000
Financial effects of modification	$ (1,000,000)	$ 2,000,000
Commercial Portfolio Segment [Member] | Commercial Real Estate | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	3,000,000	2,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Commercial Portfolio Segment [Member] | Commercial Real Estate | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	106,000,000	111,000,000
Post-modification Outstanding Balance (2)	$ 122,000,000	$ 69,000,000
Financial effects of modification	$ (1,000,000)	$ 2,000,000
Commercial Portfolio Segment [Member] | Commercial Real Estate | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	2,000,000	4,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	2,741,000,000	2,669,000,000
Post-modification Outstanding Balance (2)	$ 23,000,000	$ 23,000,000
Financial effects of modification	$ (1,000,000)	$ (1,000,000)
Consumer | Automobile | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	31,000,000	17,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Automobile | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,727,000,000	1,593,000,000
Post-modification Outstanding Balance (2)	$ 15,000,000	$ 15,000,000
Financial effects of modification	$ (1,000,000)	$ (1,000,000)
Consumer | Automobile | Chapter 7 bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	983,000,000	1,059,000,000
Post-modification Outstanding Balance (2)	$ 8,000,000	$ 8,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Automobile | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	922,000,000	915,000,000
Post-modification Outstanding Balance (2)	$ 50,000,000	$ 45,000,000
Financial effects of modification	$ (2,000,000)	$ 0
Consumer | Home Equity | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	36,000,000	55,000,000
Post-modification Outstanding Balance (2)	$ 2,000,000	$ 3,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Home Equity | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	517,000,000	578,000,000
Post-modification Outstanding Balance (2)	$ 33,000,000	$ 32,000,000
Financial effects of modification	$ (4,000,000)	$ (4,000,000)
Consumer | Home Equity | Chapter 7 bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	299,000,000	282,000,000
Post-modification Outstanding Balance (2)	$ 11,000,000	$ 10,000,000
Financial effects of modification	$ (2,000,000)	$ (4,000,000)
Consumer | Home Equity | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	70,000,000	0
Post-modification Outstanding Balance (2)	$ 4,000,000	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	453,000,000	442,000,000
Post-modification Outstanding Balance (2)	$ 49,000,000	$ 47,000,000
Financial effects of modification	$ (2,000,000)	$ (2,000,000)
Consumer | Residential Mortgage | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	3,000,000	13,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 1,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Residential Mortgage | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	349,000,000	363,000,000
Post-modification Outstanding Balance (2)	$ 40,000,000	$ 39,000,000
Financial effects of modification	$ (2,000,000)	$ (2,000,000)
Consumer | Residential Mortgage | Chapter 7 bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	79,000,000	62,000,000
Post-modification Outstanding Balance (2)	$ 7,000,000	$ 6,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Residential Mortgage | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	22,000,000	4,000,000
Post-modification Outstanding Balance (2)	$ 2,000,000	$ 1,000,000
Financial effects of modification	$ 0	$ 0
Consumer | RV and marine finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	131,000,000	0
Post-modification Outstanding Balance (2)	$ 2,000,000	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | RV and marine finance | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,000,000	0
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | RV and marine finance | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	42,000,000	0
Post-modification Outstanding Balance (2)	$ 1,000,000	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | RV and marine finance | Chapter 7 bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	88,000,000	0
Post-modification Outstanding Balance (2)	$ 1,000,000	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | RV and marine finance | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,340,000,000	14,000,000
Post-modification Outstanding Balance (2)	$ 6,000,000	$ 1,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Consumer | Interest rate reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	19,000,000	0
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Consumer | Amortization or maturity date change
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	1,312,000,000	6,000,000
Post-modification Outstanding Balance (2)	$ 6,000,000	$ 1,000,000
Financial effects of modification	$ 0	$ 0
Consumer | Consumer | Chapter 7 bankruptcy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	9,000,000	8,000,000
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0
Consumer | Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Post-modification Outstanding Balance (2)	$ 0	$ 0
Financial effects of modification	$ 0	$ 0

AVAILABLE-FOR-SALE AND OTHER 73

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Pledged investment securities to secure public and trust deposits, trading account liabilities, US Treasury demand notes and security repurchase agreements	$ 6,000
Nonmarketable equity securities
Schedule of Available-for-sale Securities [Line Items]
Stock issued by Federal Reserve Banks included in other securities	293	$ 299
Nonmarketable equity securities | Federal Home Loan Bank of Cincinnati
Schedule of Available-for-sale Securities [Line Items]
Federal home loan bank stock	$ 287	$ 249

AVAILABLE-FOR-SALE AND OTHER 74

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Contractual Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amortized Cost:
Amortized cost, under 1 year	$ 111	$ 224
Amortized cost, 1-5 years	1,333	1,147
Amortized cost, 6-10 years	2,088	1,957
Amortized cost, over 10 years	11,595	11,885
Amortized cost	15,727	15,777
Fair Value:
Fair value, under 1 year	111	222
Amortized cost, 1-5 years	1,327	1,150
Fair value, 6-10 years	2,083	1,962
Amortized cost, over 10 years	11,348	11,665
Fair Value	15,469	15,563
Nonmarketable equity securities
Amortized Cost:
Amortized cost	581	548
Fair Value:
Fair Value	581	548
Mutual Fund [Member]
Amortized Cost:
Amortized cost	18	15
Fair Value:
Fair Value	18	15
Equity Securities [Member]
Amortized Cost:
Amortized cost	1	1
Fair Value:
Fair Value	$ 1	$ 1

AVAILABLE-FOR-SALE AND OTHER 75

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Schedule of Amortized Cost, Fair Value, and Gross Unrealized Gains/(Losses) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 15,727	$ 15,777
Gross Gains	28	48
Gross Losses	(286)	(262)
Fair Value	15,469	15,563
U.S. Treasury securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5	6
Gross Gains	0	0
Gross Losses	0	0
Fair Value	5	6
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,661	6,955
Gross Gains	1	6
Gross Losses	(178)	(151)
Fair Value	6,484	6,810
Commercial MBS
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,539	3,700
Gross Gains	0	2
Gross Losses	(52)	(39)
Fair Value	2,487	3,663
Residential MBS
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,371	196
Gross Gains	1	5
Gross Losses	(5)	(1)
Fair Value	1,367	200
Other agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	69	73
Gross Gains	1	0
Gross Losses	0	0
Fair Value	70	73
Total Federal agencies and other agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,645	10,930
Gross Gains	3	13
Gross Losses	(235)	(191)
Fair Value	10,413	10,752
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,892	3,260
Gross Gains	21	29
Gross Losses	(35)	(39)
Fair Value	3,878	3,250
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	482	824
Gross Gains	1	2
Gross Losses	(16)	(32)
Fair Value	467	794
Corporate debt
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	106	195
Gross Gains	3	4
Gross Losses	0	0
Fair Value	109	199
Other securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	602	568
Gross Gains	0	0
Gross Losses	0	0
Fair Value	$ 602	$ 568

AVAILABLE-FOR-SALE AND OTHER 76

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Continuous Unrealized Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	$ 5,545	$ 10,687
Over 12 Months, Fair Value	6,728	495
Total, Fair Value	12,273	11,182
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(61)	(222)
Over 12 Months, Unrealized Losses	(225)	(40)
Total, Unrealized Losses	(286)	(262)
Collateralized Mortgage Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	1,660	5,858
Over 12 Months, Fair Value	4,520	21
Total, Fair Value	6,180	5,879
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(19)	(150)
Over 12 Months, Unrealized Losses	(159)	(1)
Total, Unrealized Losses	(178)	(151)
Commercial MBS
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	960	3,019
Over 12 Months, Fair Value	1,527	21
Total, Fair Value	2,487	3,040
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(15)	(39)
Over 12 Months, Unrealized Losses	(37)	0
Total, Unrealized Losses	(52)	(39)
Residential MBS
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	1,078	31
Over 12 Months, Fair Value	11	0
Total, Fair Value	1,089	31
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(5)	(1)
Over 12 Months, Unrealized Losses	0	0
Total, Unrealized Losses	(5)	(1)
Other agencies
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	39	1
Over 12 Months, Fair Value	0	0
Total, Fair Value	39	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	0	0
Over 12 Months, Unrealized Losses	0	0
Total, Unrealized Losses	0	0
Total Federal agencies and other agencies
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	3,737	8,909
Over 12 Months, Fair Value	6,058	42
Total, Fair Value	9,795	8,951
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(39)	(190)
Over 12 Months, Unrealized Losses	(196)	(1)
Total, Unrealized Losses	(235)	(191)
Municipal securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	1,681	1,412
Over 12 Months, Fair Value	497	272
Total, Fair Value	2,178	1,684
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(21)	(29)
Over 12 Months, Unrealized Losses	(14)	(10)
Total, Unrealized Losses	(35)	(39)
Asset-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	127	361
Over 12 Months, Fair Value	173	179
Total, Fair Value	300	540
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	(1)	(3)
Over 12 Months, Unrealized Losses	(15)	(29)
Total, Unrealized Losses	(16)	(32)
Corporate debt
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	0	4
Over 12 Months, Fair Value	0	0
Total, Fair Value	0	4
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	0	0
Over 12 Months, Unrealized Losses	0	0
Total, Unrealized Losses	0	0
Other securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, Fair Value	0	1
Over 12 Months, Fair Value	0	2
Total, Fair Value	0	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Unrealized Losses	0	0
Over 12 Months, Unrealized Losses	0	0
Total, Unrealized Losses	$ 0	$ 0

AVAILABLE-FOR-SALE AND OTHER 77

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Realized Securities Gains (Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Gross gains on sales of securities	$ 10	$ 23	$ 7
Gross (losses) on sales of securities	(10)	(21)	(4)
Gain (Loss) on Sale of Securities, Net	0	2	3
Net gain (loss) on sales of securities	(4)	0	1
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	$ (4)	$ (2)	$ (2)

AVAILABLE-FOR-SALE AND OTHER 78

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Collateralized Debt Obligation Securities (Details) $ in Millions	Dec. 31, 2017USD ($)issuer	Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Unrealized Loss | $	$ (286)	$ (262)
Collateralized Debt Obligations
Schedule of Available-for-sale Securities [Line Items]
Par Value | $	35	137
Amortized Cost | $	35	101
Fair Value | $	24	76
Unrealized Loss | $	$ (11)	$ (25)
Collateralized Debt Obligations | Alesco II
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	30
Number of Issuers Currently Remaining	32
Collateralized Debt Obligations | ICONS
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	19
Number of Issuers Currently Remaining	21
Collateralized Debt Obligations | MM Comm III
Schedule of Available-for-sale Securities [Line Items]
Par Value | $	$ 4
Amortized Cost | $	4
Fair Value | $	4
Unrealized Loss | $	$ 0
Number of Issuers Currently Performing	5
Number of Issuers Currently Remaining	8
Collateralized Debt Obligations | Pre TSL IX
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	27
Number of Issuers Currently Remaining	38
Collateralized Debt Obligations | Pre TSL XI
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	42
Number of Issuers Currently Remaining	55
Collateralized Debt Obligations | Pre TSL XIII
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	47
Number of Issuers Currently Remaining	56
Collateralized Debt Obligations | Reg Diversified
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	23
Number of Issuers Currently Remaining	39
Collateralized Debt Obligations | Soloso
Schedule of Available-for-sale Securities [Line Items]
Number of Issuers Currently Performing	30
Number of Issuers Currently Remaining	40
Collateralized Debt Obligations | Tropic III [Member]
Schedule of Available-for-sale Securities [Line Items]
Par Value | $	$ 31
Amortized Cost | $	31
Fair Value | $	20
Unrealized Loss | $	$ (11)

AVAILABLE-FOR-SALE AND OTHER 79

AVAILABLE-FOR-SALE AND OTHER SECURITIES - Security Impairment (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Impairment losses recognized in earnings on available-for-sale securities	$ (4)	$ (4)	$ (2)	$ (2)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of year	$ 12	12	18	31
Reductions from sales		(15)	(8)	(15)
Credit losses not previously recognized		4	2	0
Additional credit losses		0	0	2
Balance, end of year		1	12	18
Collateralized Debt Obligations
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Impairment losses recognized in earnings on available-for-sale securities		(4)	0	(2)
Municipal Securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Impairment losses recognized in earnings on available-for-sale securities		$ 0	$ (2)	$ 0

HELD-TO-MATURITY SECURITIES - N

HELD-TO-MATURITY SECURITIES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity Securities [Abstract]
Available-for-sale securities transferred to held-to-maturity securities	$ 1,000,000,000	$ 2,870,000,000
Unrealized Net Losses Recognized In OCI At Time Of Transfer Of Available For Sale Securities Transferred To Held To Maturity Securities	14,000,000
Unrealized Net Gains Recognized In OCI At Time Of Transfer Of Available For Sale Securities Transferred To Held To Maturity Securities	58,000,000
Other than temporary impairment losses, held-to-maturity	$ 0	$ 0

HELD-TO-MATURITY SECURITIES - C

HELD-TO-MATURITY SECURITIES - Contractual Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost	$ 9,091	$ 7,807
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity Securities, Fair Value	8,971	7,787
Collateralized Mortgage Obligations [Member]
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Held-to-maturity Securities, Under 1 year	0	0
Held-to-maturity Securities, 1-5 years	0	0
Held-to-maturity Securities, 6-10 years	0	0
Held-to-maturity Securities, Over 10 years	3,714	4,189
Amortized Cost	3,714	4,189
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value, Under 1 year	0	0
Fair Value, 1-5 years	0	0
Fair Value, 6-10 years	0	0
Fair Value, Over 10 Years	3,657	4,163
Held-to-maturity Securities, Fair Value	3,657	4,163
Residential MBS
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Held-to-maturity Securities, Under 1 year	0	0
Held-to-maturity Securities, 1-5 years	0	0
Held-to-maturity Securities, 6-10 years	28	15
Held-to-maturity Securities, Over 10 years	1,021	83
Amortized Cost	1,049	98
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value, Under 1 year	0	0
Fair Value, 1-5 years	0	0
Fair Value, 6-10 years	28	15
Fair Value, Over 10 Years	1,016	86
Held-to-maturity Securities, Fair Value	1,044	101
Commercial MBS
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Held-to-maturity Securities, Under 1 year	0	0
Held-to-maturity Securities, 1-5 years	38	0
Held-to-maturity Securities, 6-10 years	1	26
Held-to-maturity Securities, Over 10 years	3,752	2,885
Amortized Cost	3,791	2,911
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value, Under 1 year	0	0
Fair Value, 1-5 years	37	0
Fair Value, 6-10 years	1	25
Fair Value, Over 10 Years	3,698	2,891
Held-to-maturity Securities, Fair Value	3,736	2,916
Other agencies
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Held-to-maturity Securities, Under 1 year	0	0
Held-to-maturity Securities, 1-5 years	7	0
Held-to-maturity Securities, 6-10 years	362	399
Held-to-maturity Securities, Over 10 years	163	204
Amortized Cost	532	603
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value, Under 1 year	0	0
Fair Value, 1-5 years	8	0
Fair Value, 6-10 years	360	399
Fair Value, Over 10 Years	161	202
Held-to-maturity Securities, Fair Value	529	601
Total Federal agencies and other agencies
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Amortized Cost	9,086	7,801
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Held-to-maturity Securities, Fair Value	8,966	7,781
Municipal securities
Held-to-maturity Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Held-to-maturity Securities, Under 1 year	0	0
Held-to-maturity Securities, 1-5 years	0	0
Held-to-maturity Securities, 6-10 years	0	0
Held-to-maturity Securities, Over 10 years	5	6
Amortized Cost	5	6
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Fair Value, Under 1 year	0	0
Fair Value, 1-5 years	0	0
Fair Value, 6-10 years	0	0
Fair Value, Over 10 Years	5	6
Held-to-maturity Securities, Fair Value	$ 5	$ 6

HELD-TO-MATURITY SECURITIES - S

HELD-TO-MATURITY SECURITIES - Schedule of Amortized Cost, Gross Unrealized Gains and Losses, & Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity Securities [Abstract]
Amortized Cost	$ 9,091	$ 7,807
Unrealized Gross Gains	4	22
Unrealized Gross Losses	(124)	(42)
Fair Value	8,971	7,787
Collateralized Mortgage Obligations [Member]
Held-to-maturity Securities [Abstract]
Amortized Cost	3,714	4,189
Unrealized Gross Gains	1	7
Unrealized Gross Losses	(58)	(33)
Fair Value	3,657	4,163
Residential MBS
Held-to-maturity Securities [Abstract]
Amortized Cost	1,049	98
Unrealized Gross Gains	2	3
Unrealized Gross Losses	(7)	0
Fair Value	1,044	101
Commercial MBS
Held-to-maturity Securities [Abstract]
Amortized Cost	3,791	2,911
Unrealized Gross Gains	0	10
Unrealized Gross Losses	(55)	(5)
Fair Value	3,736	2,916
Other agencies
Held-to-maturity Securities [Abstract]
Amortized Cost	532	603
Unrealized Gross Gains	1	2
Unrealized Gross Losses	(4)	(4)
Fair Value	529	601
Total Federal agencies and other agencies
Held-to-maturity Securities [Abstract]
Amortized Cost	9,086	7,801
Unrealized Gross Gains	4	22
Unrealized Gross Losses	(124)	(42)
Fair Value	8,966	7,781
Municipal securities
Held-to-maturity Securities [Abstract]
Amortized Cost	5	6
Unrealized Gross Gains	0	0
Unrealized Gross Losses	0	0
Fair Value	$ 5	$ 6

HELD-TO-MATURITY SECURITIES -83

HELD-TO-MATURITY SECURITIES - Schedule of Continuous Unrealized Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	$ 7,048	$ 3,275
Over Twelve Months, Fair Value	1,416	186
Fair Value	8,464	3,461
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(84)	(35)
Over 12 Months, Unrealized Losses	(40)	(7)
Unrealized Losses	(124)	(42)
Commercial MBS
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	3,456	352
Over Twelve Months, Fair Value	253	0
Fair Value	3,709	352
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(49)	(5)
Over 12 Months, Unrealized Losses	(6)	0
Unrealized Losses	(55)	(5)
Residential MBS
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	974	20
Over Twelve Months, Fair Value	0	0
Fair Value	974	20
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(7)	0
Over 12 Months, Unrealized Losses	0	0
Unrealized Losses	(7)	0
Collateralized Mortgage Obligations [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	2,369	2,483
Over Twelve Months, Fair Value	1,019	186
Fair Value	3,388	2,669
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(26)	(26)
Over 12 Months, Unrealized Losses	(32)	(7)
Unrealized Losses	(58)	(33)
Other agencies
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	249	414
Over Twelve Months, Fair Value	139	0
Fair Value	388	414
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(2)	(4)
Over 12 Months, Unrealized Losses	(2)	0
Unrealized Losses	(4)	(4)
Total Federal agencies and other agencies
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	7,048	3,269
Over Twelve Months, Fair Value	1,411	186
Fair Value	8,459	3,455
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	(84)	(35)
Over 12 Months, Unrealized Losses	(40)	(7)
Unrealized Losses	(124)	(42)
Municipal securities
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value:
Less Than Twelve Months, Fair Value	0	6
Over Twelve Months, Fair Value	5	0
Fair Value	5	6
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss:
Less than 12 Months, Unrealized Losses	0	0
Over 12 Months, Unrealized Losses	0	0
Unrealized Losses	$ 0	$ 0

LOAN SALES AND SECURITIZATION84

LOAN SALES AND SECURITIZATIONS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
2015-1 Automobile Trust
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction	$ 750
Residential Mortgage
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Servicing Asset at Fair Value, Other Changes in Fair Value		$ 11	$ 14
Servicing Asset at Fair Value, Period Increase (Decrease)		3	4
Servicing, late and other ancillary fees included in mortgage banking income		56	50	$ 47
Unpaid principal balance of third party serviced loans	16,200	19,800	18,900	16,200
Pretax gains resulting from above loan sales		99	97	83
Automobile
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Servicing, late and other ancillary fees included in mortgage banking income		18	9	5
Unpaid principal balance of third party serviced loans	900	1,000	1,700	900
Total of automobile loans transferred In securitization transaction				750
Proceeds from new transfers				780
Automobile | 2015-1 Automobile Trust
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction			1,500
Proceeds from new transfers			1,552
Commercial
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Servicing, late and other ancillary fees included in mortgage banking income		11	9	8
Unpaid principal balance of third party serviced loans	$ 1,000	$ 1,400	$ 1,100	$ 1,000

LOAN SALES AND SECURITIZATION85

LOAN SALES AND SECURITIZATIONS - Residential Mortgage Portfolio (Details) - Residential Mortgage - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Residential mortgage loans sold with servicing retained	$ 3,985	$ 3,632	$ 3,323
Pretax gains resulting from above loan sales	$ 99	$ 97	$ 83

LOAN SALES AND SECURITIZATION86

LOAN SALES AND SECURITIZATIONS - Residential Mortgage Portfolio, MSRs Amortization Method (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Fair value, end of year	$ 238	$ 226
Residential Mortgage
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Carrying value, beginning of year	172	143
New servicing assets created	44	38
Servicing assets acquired	0	15
Impairment recovery (charge)	(1)	2
Amortization and other	(26)	(26)
Carrying value, end of year	191	172
Fair value, end of year	$ 191	$ 173
Residential Mortgage | Sensitivity Analysis Amortization Carrying Method
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Weighted-average life (years)	7 years 1 month	7 years 2 months

LOAN SALES AND SECURITIZATION87

LOAN SALES AND SECURITIZATIONS - Residential Mortgage Portfolio, MSRs Fair Value Method Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Residential Mortgage | Sensitivity Analysis Fair Value Carrying Method
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Spread over forward interest rate swap rates	0.00%	5.00%

LOAN SALES AND SECURITIZATION88

LOAN SALES AND SECURITIZATIONS - Residential Mortgage Portfolio, MSRs Amortization Method Assumptions (Details) - Sensitivity Analysis Amortization Carrying Method - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Automobile
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Spread over forward interest rate swap rates	0.00%	5.00%
Residential Mortgage
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Constant prepayment rate (annualized)	8.30%	7.80%
Constant prepayment rate (annualized), Decline in fair value due to 10% adverse change	$ 0	$ 0
Constant prepayment rate (annualized), Decline in fair value due to 20% adverse change	$ 0	$ 0
Spread over forward interest rate swap rates	0.00%	9.00%
Spread over forward interest rate swap rates, Decline in fair value due to 10% adverse change	$ 0	$ 0
Spread over forward interest rate swap rates, Decline in fair value due to 20% adverse change	$ 0	$ 0

LOAN SALES AND SECURITIZATION89

LOAN SALES AND SECURITIZATIONS - Automobile Loans (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Automobile
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction					$ 750
Proceeds from new transfers					780
Gain (Loss) on Sale of Mortgage Loans			$ 0	$ 6	5
New servicing assets created					$ 11
Trust 2016 Unconsolidated
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction	$ 1,500
Trust 2016 Unconsolidated | Automobile
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction			0
Proceeds from new transfers			0
New servicing assets created			$ 0
2015-1 Automobile Trust
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction		$ 750
2015-1 Automobile Trust | Automobile
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total of automobile loans transferred In securitization transaction				1,500
Proceeds from new transfers				1,552
New servicing assets created				$ 15

LOAN SALES AND SECURITIZATION90

LOAN SALES AND SECURITIZATIONS - Automobile Loans, MSRs Amortization Method (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Fair value, end of year	$ 238	$ 226
Automobile
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Carrying value, beginning of year	18	9
New servicing assets created			$ 11
Amortization and other	(10)	(6)
Carrying value, end of year	8	18	$ 9
Fair value, end of year	$ 9	$ 18
Automobile | Sensitivity Analysis Amortization Carrying Method
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Weighted-average life (years)	3 years 6 months	4 years 2 months

LOAN SALES AND SECURITIZATION91

LOAN SALES AND SECURITIZATIONS - Automobile Loans, MSRs Amortization Method Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Automobile | Sensitivity Analysis Amortization Carrying Method
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Spread over forward interest rate swap rates	0.00%	5.00%

LOAN SALES AND SECURITIZATION92

LOAN SALES AND SECURITIZATIONS - Small Business Association Portfolio (Details) - Commercial - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Residential mortgage loans sold with servicing retained	$ 413	$ 270	$ 233
Pretax gains resulting from above loan sales	$ 32	$ 21	$ 19

LOAN SALES AND SECURITIZATION93

LOAN SALES AND SECURITIZATIONS - Small Business Association, MSRs Amortization Method (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Fair value, end of year	$ 238	$ 226
Commercial
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Carrying value, beginning of year	21	20
New servicing assets created	14	9
Amortization and other	(8)	(8)
Carrying value, end of year	27	21
Fair value, end of year	$ 30	$ 24
Commercial | Sensitivity Analysis Amortization Carrying Method
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Weighted-average life (years)	3 years 4 months	3 years 3 months 18 days

GOODWILL AND OTHER INTANGIBLE94

GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Goodwill by business segment
Beginning Balance		$ 1,993,000	$ 677,000
Goodwill acquired during the period			1,321,000
Adjustments		0	5,000
Impairment		0
Ending Balance	$ 1,993,000	1,993,000	1,993,000
Operating Segments | Consumer & Business Banking
Goodwill by business segment
Beginning Balance		1,398,000	368,000
Goodwill acquired during the period			1,030,000
Adjustments		0	0
Ending Balance	1,398,000	1,398,000	1,398,000
Operating Segments | Commercial Banking
Goodwill by business segment
Beginning Balance		453,000	215,000
Goodwill acquired during the period			238,000
Adjustments		(28,000)	0
Ending Balance	453,000	425,000	453,000
Operating Segments | Vehicle Finance
Goodwill by business segment
Beginning Balance		0	0
Goodwill acquired during the period			0
Adjustments		0	0
Ending Balance	0	0	0
Operating Segments | RBHPCG
Goodwill by business segment
Beginning Balance		142,000	89,000
Goodwill acquired during the period			53,000
Adjustments		28,000	0
Ending Balance	142,000	170,000	142,000
Treasury / Other
Goodwill by business segment
Beginning Balance		0	5,000
Goodwill acquired during the period			0
Adjustments	0		(5,000)
Ending Balance	$ 0	$ 0	$ 0

GOODWILL AND OTHER INTANGIBLE95

GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 1,993	$ 1,993	$ 677
Contribution of intangible asset	$ 14
Total other intangible assets, gross carrying amount		515	520
Total other intangible assets, accumulated amortization		(169)	(118)
Total other intangible assets, net of carrying value		346	402
Goodwill, Other Increase (Decrease)		0	(5)
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets, gross carrying amount		325	325
Total other intangible assets, accumulated amortization		(61)	(27)
Total other intangible assets, net of carrying value		264	298
Customer relationship
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets, gross carrying amount		190	195
Total other intangible assets, accumulated amortization		(108)	(91)
Total other intangible assets, net of carrying value		$ 82	$ 104

GOODWILL AND OTHER INTANGIBLE96

GOODWILL AND OTHER INTANGIBLE ASSETS - Future Amortization of Intangible Assets (Details) $ in Millions	Dec. 31, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 0
2,017	0
2,018	0
2,019	0
2,020	$ 0

GOODWILL AND OTHER INTANGIBLE97

GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)segments	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Number of Reportable Segments | segments	4
Goodwill	$ 1,993,000	$ 1,993,000	$ 677,000
Other intangible assets	346,000	402,000
Goodwill acquired during the period		$ 1,321,000
Impairment of goodwill	$ 0

PREMISES AND EQUIPMENT (Details

PREMISES AND EQUIPMENT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment, Net, by Type [Abstract]
Premises and equipment, gross	$ 1,742	$ 1,709
Less accumulated depreciation and amortization	(878)	(893)
Net premises and equipment	864	816
Property Plant and Equipment Income Statement Disclosures [Abstract]
Total depreciation and amortization of premises and equipment	123	126	$ 86
Rental income credited to occupancy expense	14	13	$ 13
Land and land improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Premises and equipment, gross	193	199
Buildings
Property, Plant and Equipment, Net, by Type [Abstract]
Premises and equipment, gross	563	523
Leasehold improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Premises and equipment, gross	240	265
Equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Premises and equipment, gross	$ 746	$ 722

SHORT-TERM BORROWINGS (Details)

SHORT-TERM BORROWINGS (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Short-term Debt [Line Items]
Total short-term borrowings	$ 5,056	$ 3,693
Federal funds purchased and securities sold under agreements to repurchase
Short-term Debt [Line Items]
Total short-term borrowings	1,318	1,248
Federal Home Loan Bank advances
Short-term Debt [Line Items]
Total short-term borrowings	3,725	2,425
Other borrowings
Short-term Debt [Line Items]
Total short-term borrowings	$ 13	$ 20

LONG-TERM DEBT - Schedule of Lo

LONG-TERM DEBT - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term borrowings	$ 9,206,000	$ 9,206,000	$ 8,309,000
Subordinated Notes
Debt Instrument [Line Items]
Long-term borrowings	5,733,000	5,733,000	4,821,000
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026
Debt Instrument [Line Items]
Long-term borrowings	$ 238,000	$ 238,000	239,000
Stated rate	3.86%	3.86%
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026
Debt Instrument [Line Items]
Long-term borrowings	$ 129,000	$ 129,000	132,000
Stated rate	6.67%	6.67%
Subordinated Notes | 5.45% Huntington National Bank subordinated notes due 2019
Debt Instrument [Line Items]
Long-term borrowings	$ 77,000	$ 77,000	81,000
Stated rate	5.45%	5.45%
Senior Notes | 2.24% Huntington National Bank senior notes due 2018
Debt Instrument [Line Items]
Long-term borrowings	$ 844,000	$ 844,000	844,000
Stated rate	2.24%	2.24%
Senior Notes | 2.10% Huntington National Bank senior notes due 2018
Debt Instrument [Line Items]
Long-term borrowings	$ 748,000	$ 748,000	747,000
Stated rate	2.10%	2.10%
Senior Notes | 2.47% Huntington National Bank senior notes due 2020
Debt Instrument [Line Items]
Long-term borrowings	$ 694,000	$ 694,000	0
Stated rate	2.47%	2.47%
Senior Notes | 2.55% Huntington National Bank senior notes due 2022
Debt Instrument [Line Items]
Long-term borrowings	$ 685,000	$ 685,000	0
Stated rate	2.50%	2.50%
Senior Notes | 2.43% Huntington National Bank senior notes due 2020
Debt Instrument [Line Items]
Long-term borrowings	$ 498,000	$ 498,000	498,000
Stated rate	2.43%	2.43%
Senior Notes | 2.23% Huntington National Bank senior note due 2019
Debt Instrument [Line Items]
Long-term borrowings	$ 497,000	$ 497,000	500,000
Stated rate	2.23%	2.23%
Senior Notes | 1.75% Huntington National Bank senior notes due 2018
Debt Instrument [Line Items]
Long-term borrowings	$ 496,000	$ 496,000	500,000
Stated rate	1.75%	1.75%
Senior Notes | 2.97% Huntington National Bank senior notes due 2020
Debt Instrument [Line Items]
Long-term borrowings	$ 492,000	$ 492,000	495,000
Stated rate	2.97%	2.97%
Senior Notes | 2.20% Huntington National Bank senior notes due 2020 (5)
Debt Instrument [Line Items]
Long-term borrowings	$ 300,000	$ 300,000	0
Stated rate	1.71%	1.71%
Senior Notes | 5.04% Huntington National Bank medium-term notes due 2018
Debt Instrument [Line Items]
Long-term borrowings	$ 35,000	$ 35,000	36,000
Stated rate	5.04%	5.04%
Senior Notes | 2.23% Huntington National Bank senior note due 2017
Debt Instrument [Line Items]
Long-term borrowings	$ 0	$ 0	499,000
Stated rate	2.23%	2.23%
Senior Notes | 1.42% Huntington National Bank senior notes due 2017
Debt Instrument [Line Items]
Long-term borrowings	$ 0	$ 0	250,000
Stated rate	1.42%	1.42%
Effective rate	0.74%	0.74%
Senior Notes | 2.23% Huntington National Bank senior note due 2017
Debt Instrument [Line Items]
Basis spread on variable rate	5100.00%
Senior Notes | London Interbank Offered Rate (LIBOR) [Member] | 1.42% Huntington National Bank senior notes due 2017
Debt Instrument [Line Items]
Basis spread on variable rate		0.425%
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Long-term borrowings	$ 7,000	$ 7,000	8,000
Other borrowings
Debt Instrument [Line Items]
Long-term borrowings	$ 338,000	$ 338,000	335,000
Other borrowings | Federal Home Loan Bank advances
Debt Instrument [Line Items]
Effective rate	3.51%	3.51%
Other borrowings | Huntington Technology Finance nonrecourse debt, 3.63% effective interest rate, varying maturities
Debt Instrument [Line Items]
Long-term borrowings	$ 263,000	$ 263,000	278,000
Effective rate	3.63%	3.63%
Other borrowings | 3.57% Huntington Preferred Capital II - Class F securities
Debt Instrument [Line Items]
Long-term borrowings	$ 75,000	$ 75,000	0
Stated rate	3.57%	3.57%
Other borrowings | Huntington Technology Finance ABS Trust 2014 1.70% due 2020
Debt Instrument [Line Items]
Long-term borrowings	$ 0	$ 0	57,000
Stated rate	1.70%	1.70%
Other borrowings | London Interbank Offered Rate (LIBOR) [Member] | 3.57% Huntington Preferred Capital II - Class F securities
Debt Instrument [Line Items]
Basis spread on variable rate		1.88%
Parent Company
Debt Instrument [Line Items]
Long-term borrowings	$ 3,128,000	$ 3,128,000	3,145,000
Parent Company | Subordinated Notes | 7.00% Huntington Bancshares Incorporated subordinated notes due 2020
Debt Instrument [Line Items]
Long-term borrowings	$ 312,000	$ 312,000	320,000
Stated rate	7.00%	7.00%
Parent Company | Subordinated Notes | 3.55% Huntington Bancshares Incorporated subordinated notes due 2023
Debt Instrument [Line Items]
Long-term borrowings	$ 245,000	$ 245,000	248,000
Stated rate	3.55%	3.55%
Parent Company | Subordinated Notes | Huntington Capital I Trust Preferred 2.39% junior subordinated debentures due 2027
Debt Instrument [Line Items]
Long-term borrowings	$ 69,000	$ 69,000	69,000
Effective rate	2.39%	2.39%
Parent Company | Subordinated Notes | Sky Financial Capital Trust IV 1.73% Junior Subordinated Debentures Due 2036
Debt Instrument [Line Items]
Long-term borrowings	$ 74,000	$ 74,000	74,000
Effective rate	3.09%	3.09%
Parent Company | Subordinated Notes | Sky Financial Capital Trust III 2.40% Junior Subordinated Debentures Due 2036 [Member]
Debt Instrument [Line Items]
Long-term borrowings	$ 72,000	$ 72,000	72,000
Effective rate	3.09%	3.09%
Parent Company | Subordinated Notes | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028
Debt Instrument [Line Items]
Long-term borrowings	$ 31,000	$ 31,000	32,000
Effective rate	1.76%	1.76%
Parent Company | Subordinated Notes | Camco Statutory Trust I 2.95% due 2037
Debt Instrument [Line Items]
Long-term borrowings	$ 4,000	$ 4,000	4,000
Effective rate	3.02%	3.02%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Huntington Capital I Trust Preferred 2.39% junior subordinated debentures due 2027
Debt Instrument [Line Items]
Basis spread on variable rate		0.70%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Sky Financial Capital Trust IV 1.73% Junior Subordinated Debentures Due 2036
Debt Instrument [Line Items]
Basis spread on variable rate		1.40%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Sky Financial Capital Trust III 2.40% Junior Subordinated Debentures Due 2036 [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.40%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028
Debt Instrument [Line Items]
Basis spread on variable rate		0.625%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Camco Statutory Trust I 2.95% due 2037
Debt Instrument [Line Items]
Basis spread on variable rate		1.33%
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | 2.20% Huntington National Bank senior notes due 2020 (5)
Debt Instrument [Line Items]
Basis spread on variable rate		0.51%
Parent Company | Senior Notes | 3.19% Huntington Bancshares Incorporated medium-term notes due 2021
Debt Instrument [Line Items]
Long-term borrowings	$ 969,000	$ 969,000	973,000
Parent Company | Senior Notes | 2.33% Huntington Bancshares Incorporated senior note due 2022
Debt Instrument [Line Items]
Long-term borrowings	953,000	953,000	954,000
Parent Company | Senior Notes | 2.64% Huntington Bancshares Incorporated senior note due 2018
Debt Instrument [Line Items]
Long-term borrowings	$ 399,000	$ 399,000	$ 399,000
Stated rate	3.19%	3.19%

LONG-TERM DEBT - Maturities (De

LONG-TERM DEBT - Maturities (Details) $ in Millions	Dec. 31, 2017USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	$ 2,688
2,019	619
2,020	2,397
2,021	1,048
2,022	1,750
Thereafter	833
Long-term Debt, Gross	9,335
Parent Company | Senior Notes
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	400
2,019	0
2,020	0
2,021	1,000
2,022	1,000
Thereafter	0
Long-term Debt, Gross	2,400
Parent Company | Subordinated Notes
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	0
2,019	0
2,020	300
2,021	0
2,022	0
Thereafter	504
Long-term Debt, Gross	804
Bank | Senior Notes
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	2,135
2,019	500
2,020	2,000
2,021	0
2,022	700
Thereafter	0
Long-term Debt, Gross	5,335
Bank | Subordinated Notes
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	125
2,019	76
2,020	0
2,021	0
2,022	0
Thereafter	325
Long-term Debt, Gross	526
Bank | Federal Home Loan Bank advances
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	1
2,019	0
2,020	2
2,021	0
2,022	0
Thereafter	4
Long-term Debt, Gross	7
Bank | Other borrowings
Long-term Debt, Fiscal Year Maturity [Abstract]
2,018	27
2,019	43
2,020	95
2,021	48
2,022	50
Thereafter	0
Long-term Debt, Gross	$ 263

LONG-TERM DEBT - Narrative (Det

LONG-TERM DEBT - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 28, 2015	Apr. 30, 2014	Dec. 31, 2017	Dec. 31, 2017	Aug. 07, 2017	Mar. 07, 2017	Dec. 31, 2016	Aug. 16, 2016	Aug. 09, 2016	Mar. 14, 2016
Debt Instrument [Line Items]
Long-term debt			$ 9,206,000,000	$ 9,206,000,000			$ 8,309,000,000
Senior Notes | Senior notes due 2020
Debt Instrument [Line Items]
Debt face amount						$ 700,000,000
Debt percent of value issued						99.994%
Stated rate						2.375%
Redemption price percentage			100.00%
Senior Notes | 2.23% Huntington National Bank senior note due 2017
Debt Instrument [Line Items]
Debt face amount						$ 300,000,000
Debt percent of value issued						100.00%
Debt Instrument, Description of Variable Rate Basis			three month LIBOR
Basis spread on variable rate			5100.00%
Senior Notes | Huntington National Bank Senior Note Due August 2022, 2.5 Percent [Member]
Debt Instrument [Line Items]
Debt face amount					$ 700,000,000
Debt percent of value issued					99.762%
Stated rate					2.50%
Senior Notes | Senior Notes Due January 2022
Debt Instrument [Line Items]
Debt face amount									$ 1,000,000,000
Debt percent of value issued									99.849%
Stated rate									2.30%
Debt Issuance Costs, Net									$ 5,000,000
Senior Notes | Three point One Five Percent Senior notes Due March 2021
Debt Instrument [Line Items]
Debt face amount										$ 1,000,000,000
Debt percent of value issued										99.803%
Stated rate										3.15%
Debt Issuance Costs, Net										$ 5,000,000
Subordinated Notes
Debt Instrument [Line Items]
Long-term debt			$ 5,733,000,000	5,733,000,000			4,821,000,000
Other borrowings
Debt Instrument [Line Items]
Long-term debt			338,000,000	338,000,000			335,000,000
Parent Company
Debt Instrument [Line Items]
Long-term debt			$ 3,128,000,000	$ 3,128,000,000			3,145,000,000
Parent Company | Subordinated Notes | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028
Debt Instrument [Line Items]
Effective rate			1.76%	1.76%
Long-term debt			$ 31,000,000	$ 31,000,000			$ 32,000,000
Parent Company | Subordinated Notes | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028 | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate				0.625%
Bank | Senior Notes | Senior Notes Due February 2018 | One month prior to maturity date
Debt Instrument [Line Items]
Redemption price percentage	100.00%
Bank | Senior Notes | Senior Notes Due April 24, 2017, Variable Rate | One month prior to maturity date
Debt Instrument [Line Items]
Redemption price percentage		100.00%
FirstMerit Bank | Subordinated Notes
Debt Instrument [Line Items]
Long-term Debt								$ 520,000,000

OTHER COMPREHENSIVE INCOME - Ac

OTHER COMPREHENSIVE INCOME - Activity/Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pretax
Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold	$ 4,000	$ 1,000	$ 20,000
Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period	3,000	2,000	13,000
Less: Reclassification adjustment for net (gains) losses included in net income	1,000	0	(1,000)
Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships	4,000	2,000	12,000
Defined benefit pension items			(8,000)
Net change in pension and post-retirement obligations	0	(38,000)	8,000
Total other comprehensive income (loss), pretax	(52,000)	(269,000)	(6,000)
Tax (Expense) Benefit
Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold	(2,000)	0	(7,000)
Unrealized gains (losses) on derivatives used in cash flow hedging relationships arising during the period	(1,000)	(1,000)	(4,000)
Less: Reclassification adjustment for net (gains) losses included in net income	0	0	0
Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships	(1,000)	(1,000)	(4,000)
Defined benefit pension items			(3,000)
Net change in pension and other post-retirement obligations	0	(13,000)	3,000
Total other comprehensive income (loss)	18,000	94,000	2,000
After-tax
Noncredit-related impairment recoveries (losses) on debt securities not expected to be sold	2,000	1,000	13,000
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	(39,000)	(202,000)	(20,000)
Unrealized gains and losses on derivatives used in cash flow hedging relationships arising during the period	2,000	1,000	9,000
Less: Reclassification adjustment for net losses (gains) losses included in net income	1,000	0	(1,000)
Net change in unrealized gains (losses) on derivatives used in cash flow hedging relationships	3,000	1,000	8,000
Defined benefit pension items			(5,000)
Net change in pension and post-retirement obligations	0	25,000	(5,000)
Other comprehensive loss, net of tax	(34,000)	(175,000)	(4,000)
Equity Securities [Member]
Pretax
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	1,000	0	0
Tax (Expense) Benefit
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	(1,000)	0	0
After-tax
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	0	0	0
Debt securities
Pretax
Unrealized holding gains (losses) on available-for-sale debt securities arising during the period	(87,000)	(203,000)	(26,000)
Less: Reclassification adjustment for net losses (gains) included in net income	26,000	(107,000)	(4,000)
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	(57,000)	(309,000)	(10,000)
Tax (Expense) Benefit
Unrealized holding gains (losses) on available-for-sale debt securities arising during the period	31,000	70,000	9,000
Less: Reclassification adjustment for net losses (gains) included in net income	(9,000)	38,000	1,000
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	20,000	108,000	3,000
After-tax
Unrealized holding gains (losses) on available-for-sale debt securities arising during the period	(56,000)	(133,000)	(17,000)
Less: Reclassification adjustment for net gains (losses) included in net income	17,000	(69,000)	(3,000)
Net change in unrealized holding gains (losses) on available-for-sale debt/equity securities	$ (37,000)	$ (201,000)	$ (7,000)

OTHER COMPREHENSIVE INCOME - AO

OTHER COMPREHENSIVE INCOME - AOCI Roll Forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 10,308	$ 6,595	$ 6,328
Other comprehensive income before reclassifications	(62)	(131)
Amounts reclassified from accumulated OCI to earnings	28	(44)
Period change	(34)	(175)
Ending balance	10,814	10,308	6,595
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings	0
AOCI attributable to parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(401)	(226)	(222)
Ending balance	(528)	(401)	(226)
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings	(93)
Unrealized gains and (losses) on securities | Debt securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(193)	8
Other comprehensive income before reclassifications	(54)	(132)
Amounts reclassified from accumulated OCI to earnings	17	(69)
Period change	(37)	(201)
Ending balance	(278)	(193)	8
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings	(48)
Unrealized gains and (losses) on securities | Equity Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0	0
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated OCI to earnings	0	0
Period change	0	0
Ending balance	0	0	0
Unrealized gains (losses) on cash flow hedging derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3)	(4)
Other comprehensive income before reclassifications	2	1
Amounts reclassified from accumulated OCI to earnings	1	0
Period change	3	1
Ending balance	0	(3)	(4)
Unrealized gains (losses) for pension and other post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(205)	(230)
Other comprehensive income before reclassifications	(10)	0
Amounts reclassified from accumulated OCI to earnings	10	25
Period change	0	25
Ending balance	(250)	(205)	$ (230)
Tax Cuts and Job Acts of 2017, Reclassification from AOCI to Retained Earnings	(45)
Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Transferred from AFS to HTM	(95)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains and (losses) on securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated OCI to earnings	17	(69)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on cash flow hedging derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated OCI to earnings	1	0
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) for pension and other post-retirement obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated OCI to earnings	$ 10	$ 25

OTHER COMPREHENSIVE INCOME - Re

OTHER COMPREHENSIVE INCOME - Reclassifications (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income—held-to-maturity securities—taxable		$ 193	$ 138	$ 87
Gain (Loss) on Sale of Securities, Net		0	2	3
Noninterest income—net gains (losses) on sale of securities, OTTI	$ (4)	(4)	(2)	(2)
Interest income - loans and leases		2,838	2,178	1,760
Noninterest income - other income		185	157	167
Noninterest expense—personnel costs		1,524	1,349	$ 1,122
Net of tax		(28)	44
Unrealized gains (losses) on cash flow hedging derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		(1)	0
Unrealized gains (losses) for pension and other post-retirement obligations
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		(10)	(25)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains and (losses) on securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income—held-to-maturity securities—taxable		(8)	91
Gain (Loss) on Sale of Securities, Net		(14)	18
Noninterest income—net gains (losses) on sale of securities, OTTI		(4)	(2)
Total before tax		(26)	107
Tax (expense) benefit		9	(38)
Net of tax		(17)	69
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on cash flow hedging derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(1)	0
Tax (expense) benefit		0	0
Net of tax		(1)	0
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on cash flow hedging derivatives | Interest Rate Contract
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income - loans and leases		(1)	0
Noninterest income - other income		0	0
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) for pension and other post-retirement obligations
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(16)	(38)
Tax (expense) benefit		6	13
Net of tax		(10)	(25)
Reclassification out of Accumulated Other Comprehensive Income | Actuarial gains (losses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Noninterest expense—personnel costs		(18)	(40)
Reclassification out of Accumulated Other Comprehensive Income | Net periodic benefit costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Noninterest expense—personnel costs		$ 2	$ 2

SHAREHOLDERS' EQUITY - Preferre

SHAREHOLDERS' EQUITY - Preferred Stock Issued and Outstanding (Details) $ / shares in Units, $ in Millions	Aug. 16, 2016$ / shares	Mar. 14, 2016$ / shares	Mar. 31, 2012	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2008$ / sharesshares	Jan. 16, 2012$ / shares
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				1,098,006	1,098,006
Preferred Stock, Value, Outstanding | $				$ 1,071
Preferred Stock, Value, Issued | $				$ 1,071	$ 1,071
Preferred Stock
Class of Stock [Line Items]
Preferred stock, liquidation preference per share (in dollars per share)				$ 1,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				362,506
Preferred Stock, Value, Outstanding | $				$ 363
Preferred stock, dividend percentage				.0850
Number of shares issued for each share of convertible preferred stock | shares						83.668
Conversion price (in dollars per share)						$ 11.95
Convertible preferred stock, threshold percentage of stock price trigger						130.00%
Convertible preferred stock, threshold consecutive trading days						30 days
Series B Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				35,500
Preferred Stock, Value, Outstanding | $				$ 23
Preferred stock, dividend percentage				three-month LIBOR plus a spread of 2.70%
Preferred Stock, Redemption Date				Jan. 15, 2017
Preferred stock, liquidation preference per share (in dollars per share)							$ 1,000
Depositary Shares, Liquidation Preference Per Share							$ 25
Depository share, percent interest in preferred stock			0.025
Series D Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				400,000
Preferred Stock, Value, Outstanding | $				$ 386
Preferred stock, dividend percentage				.0625
Preferred Stock, Redemption Date				Jul. 15, 2021
Preferred stock, liquidation preference per share (in dollars per share)		$ 1,000
Depositary Shares, Liquidation Preference Per Share		$ 25
Preferred Stock, Redemption Period		90 days
Preferred Stock, Dividend Rate, Percentage					6.25%
Series D Preferred Stock2
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				200,000
Preferred Stock, Value, Outstanding | $				$ 199
Series C Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding | shares				100,000
Preferred Stock, Value, Outstanding | $				$ 100
Preferred stock, dividend percentage				.05875
Preferred Stock, Redemption Date				Jan. 15, 2022
Preferred stock, liquidation preference per share (in dollars per share)	$ 1,000
Depositary Shares, Liquidation Preference Per Share	$ 25
Preferred Stock, Redemption Period	90 days
Preferred Stock, Dividend Rate, Percentage					5.875%

SHAREHOLDERS' EQUITY - Share Re

SHAREHOLDERS' EQUITY - Share Repurchase Program (Details) - 2017 Share Repurchase Program shares in Millions	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock shares (in shares) | shares	19.4
Common Stock Repurchased And Retired Average Cost Per Share | $ / shares	$ 13.38

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	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
Basic earnings per common share:
Net income	$ 432,000	$ 275,000	$ 272,000	$ 207,000	$ 239,000	$ 127,000	$ 175,000	$ 171,000	$ 1,186,000	$ 712,000	$ 693,000
Preferred stock dividends	(19,000)	(19,000)	(19,000)	(19,000)	(19,000)	(18,000)	(20,000)	(8,000)	(76,000)	(65,000)	(32,000)
Net income available to common shareholders	$ 413,000	$ 256,000	$ 253,000	$ 188,000	$ 220,000	$ 109,000	$ 155,000	$ 163,000	$ 1,110,000	$ 647,000	$ 661,000
Average common shares issued and outstanding (in shares)									1,084,686	904,438	803,412
Basic earnings per common share (in USD per share)	$ 0.38	$ 0.24	$ 0.23	$ 0.17	$ 0.20	$ 0.12	$ 0.19	$ 0.21	$ 1.02	$ 0.72	$ 0.82
Diluted earnings per common share:
Net income available to common shareholders	$ 413,000	$ 256,000	$ 253,000	$ 188,000	$ 220,000	$ 109,000	$ 155,000	$ 163,000	$ 1,110,000	$ 647,000	$ 661,000
Effect of assumed preferred stock conversion									31,000	0	0
Net income applicable to diluted earnings per share									$ 1,141,000	$ 647,000	$ 661,000
Dilutive potential common shares
Stock options and restricted stock units and awards (in shares)									17,883	11,728	11,633
Shares held in deferred compensation plans (in shares)									3,160	2,486	1,912
Other (in shares)									30,457	138	172
Dilutive potential common shares: (in shares)									51,500	14,352	13,717
Total diluted average common shares issued and outstanding (in shares)									1,136,186	918,790	817,129
Diluted earnings per common share (in USD per share)	$ 0.37	$ 0.23	$ 0.23	$ 0.17	$ 0.20	$ 0.11	$ 0.19	$ 0.20	$ 1	$ 0.70	$ 0.81
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options outstanding to purchase common stock shares having antidilutive effect (in shares)									1,000	3,100	2,000

SHARE-BASED COMPENSATION - Narr

SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	30
Shares available for grant	7.9
Cash received for exercises of stock options	$ 11	$ 17	$ 19
Tax benefit realized from exercise of options	$ 5	$ 3	$ 7
Granted (in USD per share)	$ 11.13	$ 9.59	$ 10.86
Total fair value of awards vested	$ 53	$ 31	$ 30
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Cash received for exercises of stock options	$ 11	$ 14	$ 26
Total unrecognized compensation cost related to nonvested awards	$ 93
Cost not yet recognized period for recognition	2 years 4 months
Stock Option | Prior to May 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards expiration period	10 years
Stock Option | After May 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards expiration period	7 years
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in USD per share)	$ 0
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Granted (in USD per share)	$ 12.18

SHARE-BASED COMPENSATION - Sche

SHARE-BASED COMPENSATION - Schedule of Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assumptions
Risk-free interest rate	2.04%	1.63%	2.13%
Expected dividend yield	3.31%	3.18%	2.57%
Expected volatility of Huntington’s common stock	29.50%	30.00%	29.00%
Expected option term (years)	6 years 6 months	6 years 6 months	6 years 6 months
Weighted-average grant date fair value per share	$ 2.81	$ 2.17	$ 2.57

SHARE-BASED COMPENSATION - Shar

SHARE-BASED COMPENSATION - Share-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense	$ 92	$ 66	$ 51
Tax benefit	$ 32	$ 22	$ 18

SHARE-BASED COMPENSATION - S112

SHARE-BASED COMPENSATION - Schedule of Stock Option Activity (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Options (in shares):
Outstanding at beginning of period (in shares)	15
Granted (in shares)	1
Exercised (in shares)	(2)
Forfeited'expired (in shares)	0
Outstanding at end of period (in shares)	14
Expected to vest at end of period (in shares)	4
Exercisable at end of period (in shares)	10
Weighted- Average Exercise Price (USD per share):
Outstanding at beginning of period (USD per share) | $ / shares	$ 7.50
Granted (USD per share) | $ / shares	13.09
Exercised (USD per share) | $ / shares	6.72
Forfeited or expired (USD per share) | $ / shares	11.17
Outstanding at end of period (USD per share) | $ / shares	8.21
Vested and expected to vest (USD per share) | $ / shares	11.33
Exercisable (USD per share) | $ / shares	$ 7.11
Weighted-Average Remaining Contractual Life (Years)/Aggregate Intrinsic Value
Outstanding, weighted-average remaining contractual life (years)	3 years 6 months
Expected to vest, weighted-average remaining contractual period (years)	8 years
Exercisable, weighted-average remaining contractual term (years)	1 year 11 months
Outstanding aggregate intrinsic value | $	$ 88
Expected to vest, aggregate intrinsic value | $	11
Exercisable, aggregate intrinsic value | $	$ 77
Expected to be forfeited (in shares)	0

SHARE-BASED COMPENSATION - Rest

SHARE-BASED COMPENSATION - Restricted Stock, RSUs, Performance Shares (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted-Average Grant Date Fair Value Per Share (USD per share):
Granted (in USD per share)	$ 11.13	$ 9.59	$ 10.86
Restricted Stock Awards
Shares:
Nonvested at beginning of period (in shares)	656
Granted (in shares)	0
Assumed (in shares)	0
Vested (in shares)	(174)
Forfeited (in shares)	(34)
Nonvested at end of period (in shares)	448	656
Weighted-Average Grant Date Fair Value Per Share (USD per share):
Nonvested at beginning of period (in USD per share)	$ 9.68
Granted (in USD per share)	0
Assumed (in USD per share)	0
Vested (in USD per share)	9.68
Forfeited (in USD per share)	9.68
Nonvested at end of period (in USD per share)	$ 9.68	$ 9.68
Restricted Stock Units
Shares:
Nonvested at beginning of period (in shares)	14,733
Granted (in shares)	6,232
Assumed (in shares)	0
Vested (in shares)	(4,267)
Forfeited (in shares)	(539)
Nonvested at end of period (in shares)	16,159	14,733
Weighted-Average Grant Date Fair Value Per Share (USD per share):
Nonvested at beginning of period (in USD per share)	$ 9.61
Granted (in USD per share)	13.45
Assumed (in USD per share)	0
Vested (in USD per share)	8.72
Forfeited (in USD per share)	10.91
Nonvested at end of period (in USD per share)	$ 11.26	$ 9.61
Performance Share Awards
Shares:
Nonvested at beginning of period (in shares)	3,307
Granted (in shares)	1,278
Assumed (in shares)	0
Vested (in shares)	(1,550)
Forfeited (in shares)	(17)
Nonvested at end of period (in shares)	3,018	3,307
Weighted-Average Grant Date Fair Value Per Share (USD per share):
Nonvested at beginning of period (in USD per share)	$ 9.63
Granted (in USD per share)	12.18
Assumed (in USD per share)	0
Vested (in USD per share)	9
Forfeited (in USD per share)	11.07
Nonvested at end of period (in USD per share)	$ 10.67	$ 9.63

BENEFIT PLANS - Narrative (Deta

BENEFIT PLANS - Narrative (Details)	Jan. 01, 2015USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)age	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Aug. 16, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		$ 903,000,000	$ 903,000,000	$ 841,000,000
Employer Contributions			0
Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year:
Future amortization of transition obligation (asset)		0	0
Future amortization of prior service cost (credit)		2,000,000	2,000,000
Future amortization gain (loss)		8,000,000	$ 8,000,000
Defined Contribution Plan:
Employer matching contribution, percent of match			4.00%
Discretionary profit-share contribution, percent of annual base pay			1.00%	1.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		903,000,000	$ 903,000,000	$ 841,000,000	$ 874,000,000
Employer Contributions			0	150,000,000
Accumulated benefit obligation		900,000,000	900,000,000	851,000,000
Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets:
Accumulated benefit obligations in excess of plan assets, aggregate projected benefit obligation		$ 3,000,000	3,000,000
Defined benefit plan expenses			2,000,000	2,000,000	4,000,000
Estimated net periodic pension cost in next fiscal year			$ 9,000,000
Defined Benefit Plan, Information about Plan Assets:
Average duration of plan assets investment in bonds, years			13 years 8 months
Estimated life of benefit obligations			13 years 6 months
Pension Benefits | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets:
Actual plan asset allocations		38.00%	38.00%
Defined Benefit Plan, Target Allocation Percentage			.50
Pension Benefits | Bonds
Defined Benefit Plan, Information about Plan Assets:
Actual plan asset allocations		59.00%	59.00%
Pension Benefits | Cash and cash equivalents
Defined Benefit Plan, Information about Plan Assets:
Actual plan asset allocations		3.00%	3.00%
Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Healthcare and life insurance benefits, employee retirement age | age			55
Healthcare and life insurance benefits, requisite service period			10 years
Life insurance coverage, maximum			$ 50,000
Reduction in liability due to plan amendment	$ 5,000,000
Life insurance buyout		$ 4,000,000
Defined Benefit Plan, Information about Plan Assets:
Estimated future employer contributions in next fiscal year		$ 0	$ 0
Defined Benefit Plan, Assumed Health Care Cost Trend Rates:
Health care cost trend rate assumed for next fiscal year		6.60%	6.60%
Ultimate health care cost trend rate		4.50%	4.50%
Year that rate reaches ultimate trend rate			2,028
Supplemental Executive Retirement Plan
Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets:
Defined benefit plan expenses			$ 1,000,000	1,000,000	$ 1,000,000
Defined Benefit Plan, Assumed Health Care Cost Trend Rates:
Accrued pension liability		$ 35,000,000	$ 35,000,000	$ 33,000,000
FirstMerit Bank
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets						$ 280,000,000
Minimum | Pension Benefits | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets:
Defined Benefit Plan, Target Allocation Percentage			.20
Minimum | Pension Benefits | Bonds
Defined Benefit Plan, Information about Plan Assets:
Defined Benefit Plan, Target Allocation Percentage			.5
Maximum | Pension Benefits | Bonds
Defined Benefit Plan, Information about Plan Assets:
Defined Benefit Plan, Target Allocation Percentage			.80

BENEFIT PLANS - Weighted Averag

BENEFIT PLANS - Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits
Weighted-average assumptions used to determine benefit obligations
Discount rate	3.73%	4.38%
Weighted-average assumptions used to determine net periodic benefit cost
Discount Rate	4.38%	4.54%
Long-term Return on Assets	6.50%	6.75%
Post-Retirement Benefits
Weighted-average assumptions used to determine benefit obligations
Discount rate	3.34%	3.64%
Weighted-average assumptions used to determine net periodic benefit cost
Discount Rate	3.64%	3.81%

BENEFIT PLANS - Projected Benef

BENEFIT PLANS - Projected Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits
Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of measurement year	$ 851,000	$ 1,084,000
Service cost	3,000	5,000	$ 2,000
Interest cost	30,000	30,000	32,000
Benefits Paid	27,000	20,000
Settlements	(31,000)	(203,000)
Plan Amendment	0	0
Actuarial assumptions and gains and losses	74,000	(45,000)
Total changes	49,000	(233,000)
Projected benefit obligation at end of measurement year	900,000	851,000	1,084,000
Post-Retirement Benefits
Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of measurement year	14,000	15,000
Service cost	0	0	0
Interest cost	0	0	0
Benefits Paid	2,000	1,000
Settlements	(4,000)	0
Plan Amendment	(2,000)	0
Actuarial assumptions and gains and losses	1,000	0
Total changes	(7,000)	(1,000)
Projected benefit obligation at end of measurement year	$ 7,000	$ 14,000	$ 15,000

BENEFIT PLANS - Fair Value of P

BENEFIT PLANS - Fair Value of Plan Assets (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Change in Fair Value of Plan Assets [Abstract]
Fair value of plan assets at beginning of measurement year	$ 841
Employer Contributions	0
Fair value of plan assets at end of measurement year	903	$ 841
Pension Benefits
Change in Fair Value of Plan Assets [Abstract]
Fair value of plan assets at beginning of measurement year	841	874
Actual return on plan assets	118	37
Employer Contributions	0	(150)
Settlements	(29)	(199)
Defined Benefit Plan, Plan Assets, Benefits Paid	27	21
Total changes	62	(33)
Fair value of plan assets at end of measurement year	$ 903	$ 841

BENEFIT PLANS - Net Periodic Be

BENEFIT PLANS - Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits
Components of net periodic benefit expense [Abstract]
Service cost	$ 3,000	$ 5,000	$ 2,000
Interest cost	30,000	30,000	32,000
Expected return on plan assets	(55,000)	(45,000)	(44,000)
Amortization of prior service credit	0	0	0
Amortization of (gain) / loss	7,000	7,000	8,000
Settlements	11,000	(8,000)	12,000
Benefit costs	(4,000)	(11,000)	10,000
Post-Retirement Benefits
Components of net periodic benefit expense [Abstract]
Service cost	0	0	0
Interest cost	0	0	0
Expected return on plan assets	0	0	0
Amortization of prior service credit	(2,000)	(2,000)	(2,000)
Amortization of (gain) / loss	0	0	0
Settlements	0	0	(3,000)
Benefit costs	$ (2,000)	$ (2,000)	$ (5,000)

BENEFIT PLANS - Fair Value o119

BENEFIT PLANS - Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Aug. 16, 2016
Summary of plan assets investments
Fair value of plan assets	$ 903	$ 841
Fair value of plan assets, Percentage	100.00%	100.00%
Mutual Funds-money market
Summary of plan assets investments
Fair value of plan assets	$ 14	$ 21
Fair value of plan assets, Percentage	2.00%	3.00%
U.S. Treasury securities
Summary of plan assets investments
Fair value of plan assets	$ 5	$ 0
Fair value of plan assets, Percentage	1.00%	0.00%
Corporate obligations
Summary of plan assets investments
Fair value of plan assets	$ 293	$ 218
Fair value of plan assets, Percentage	32.00%	26.00%
U.S. Government obligations
Summary of plan assets investments
Fair value of plan assets	$ 216	$ 165
Fair value of plan assets, Percentage	24.00%	19.00%
Mutual funds-fixed income
Summary of plan assets investments
Fair value of plan assets	$ 0	$ 51
Fair value of plan assets, Percentage	0.00%	6.00%
U.S. Government Agencies
Summary of plan assets investments
Fair value of plan assets	$ 23	$ 10
Fair value of plan assets, Percentage	3.00%	1.00%
Mutual funds-equities
Summary of plan assets investments
Fair value of plan assets	$ 118	$ 150
Fair value of plan assets, Percentage	13.00%	18.00%
Common stock
Summary of plan assets investments
Fair value of plan assets	$ 158	$ 182
Fair value of plan assets, Percentage	17.00%	22.00%
Preferred stock
Summary of plan assets investments
Fair value of plan assets	$ 5	$ 5
Fair value of plan assets, Percentage	1.00%	1.00%
Exchange Traded Funds
Summary of plan assets investments
Fair value of plan assets	$ 58	$ 28
Fair value of plan assets, Percentage	6.00%	3.00%
Limited Partnerships
Summary of plan assets investments
Fair value of plan assets	$ 13	$ 11
Fair value of plan assets, Percentage	1.00%	1.00%
FirstMerit Bank
Summary of plan assets investments
Fair value of plan assets			$ 280

BENEFIT PLANS - Expected Future

BENEFIT PLANS - Expected Future Benefit Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Benefits
Estimated Future Benefit Payments [Abstract]
2,017	$ 50
2,018	49
2,019	48
2,020	47
2,021	47
2022 through 2026	233
Post-Retirement Benefits
Estimated Future Benefit Payments [Abstract]
2,017	1
2,018	1
2,019	1
2,020	1
2,021	1
2022 through 2026	$ 2

BENEFIT PLANS - Amounts Recogni

BENEFIT PLANS - Amounts Recognized in the Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Current pension liability		$ 2
Amounts Recognized in Balance Sheet [Abstract]
Noncurrent liabilities	$ 78	$ 189

BENEFIT PLANS - Amounts Reco122

BENEFIT PLANS - Amounts Recognized in AOCI (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Retirement Benefits [Abstract]
Net actuarial loss	$ (264)	$ (217)	$ (244)
Prior service cost	14	12	14
Defined benefit pension plans	$ (250)	$ (205)	$ (230)	$ (226)

BENEFIT PLANS - Amounts Reco123

BENEFIT PLANS - Amounts Recognized in OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pretax Roll Forward:
Balance, beginning of year	$ (316)	$ (354)	$ (347)
Net actuarial (loss) gain:
Amounts arising during the year	(16)	38	(25)
Amortization included in net periodic benefit costs	18	2	20
Prior service cost:
Amounts arising during the year	0	0	0
Amortization included in net periodic benefit costs	(2)	(2)	(2)
Balance, end of year	(316)	(316)	(354)
Tax Roll Forward:
Balance, beginning of year	111	124	121
Net actuarial (loss) gain:
Amounts arising during the year	6	(13)	9
Amortization included in net periodic benefit costs	(7)	(1)	(7)
Prior service cost:
Amounts arising during the year	0	0	0
Amortization included in net periodic benefit costs	1	1	1
Balance, end of year	111	111	124
After-tax Roll Forward:
Balance, beginning of year	(205)	(230)	(226)
Net actuarial (loss) gain:
Amounts arising during the year	(10)	25	(16)
Amortization included in net periodic benefit costs	11	1	13
Prior service cost:
Amounts arising during the year	0	0	0
Amortization included in net periodic benefit costs	(1)	(1)	(1)
Balance, end of year	(250)	$ (205)	$ (230)
OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossTaxCutsAndJobsActOf2017NetOfTax	(47)
OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTaxCutsAndJobsActsof2017NetOfTax	$ 2

BENEFIT PLANS - Defined Contrib

BENEFIT PLANS - Defined Contribution Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Defined contribution plan	$ 35	$ 36	$ 32
Shares in Huntington common stock (in shares)	13,566	11,748
Market value of Huntington common stock	$ 198	$ 162
Dividends received on shares of Huntington stock	$ 4	$ 4

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%
Tax benefit as a result of TCJA relating primarily to revaluation of net deferred tax liabilities		$ 123
Unrecognized tax benefits		50	$ 24	$ 23
Net deferred tax asset, operating loss carryforwards		261
Net deferred tax asset, operating loss carryforwards, domestic		65
Deferred Tax Assets, Charitable Contribution Carryforwards		1
Net deferred tax asset, operating loss carryforwards, state and local		42
Net deferred tax asset, alternative minimum tax carryforward		121
Net deferred tax asset, general business credit carryforward		32
Federal capital loss carryforward valuation allowance		6	5
Bad debt reserves with no federal income tax liability		12
Unrecognized deferred tax liability from cumulative bad debt reduction		$ 3
Forecast
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Operating Loss Carryforward Federal
Operating Loss Carryforwards [Line Items]
Net deferred tax asset carryforward expiration date		Dec. 31, 2023
Operating Loss Carryforward State
Operating Loss Carryforwards [Line Items]
Net deferred tax asset carryforward expiration date		Dec. 31, 2018
Federal capital loss carryforward valuation allowance		$ 6	$ 5
General Business Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Net deferred tax asset carryforward expiration date		Dec. 31, 2037

INCOME TAXES - Gross Unrecogniz

INCOME TAXES - Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of period	$ 24	$ 23
Gross increases for tax positions taken during current period	0	1
Gross increases for tax positions taken during prior years	26	0
Unrecognized tax benefits at end of period	$ 50	$ 24

INCOME TAXES - Provision (Benef

INCOME TAXES - Provision (Benefit) for Income Taxes (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
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Impact om TCJA, Amount									$ (123)	$ 0	$ 0
Current tax provision (benefit)
Federal									41	40	146
State									(1)	3	6
Total current tax provision (benefit)									40	43	152
Deferred tax provision (benefit)
Federal									151	161	67
State									17	4	2
Total deferred tax provision (benefit)									168	165	69
Provision (benefit) for income taxes	$ (20)	$ 90	$ 79	$ 59	$ 74	$ 25	$ 54	$ 55	$ 208	$ 208	$ 221

INCOME TAXES - Effective Income

INCOME TAXES - Effective Income Tax Rate Reconciliation (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
Income Tax Disclosure [Abstract]
Provision for income taxes computed at the statutory rate									$ 488	$ 322	$ 320
Increases (decreases):
Tax-exempt income									(31)	(27)	(21)
Tax-exempt bank owned life insurance income									(23)	(20)	(18)
General business credits									(71)	(64)	(48)
Impact from TCJA									(67)	(46)	(46)
Effective Income Tax Rate Reconciliation, Impact om TCJA, Amount									(123)	0	0
Affordable housing investment amortization, net of tax benefits									46	37	32
State deferred tax asset valuation allowance adjustment, net									11	5	5
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount									(13)	(4)	0
Other									(9)	5	(3)
Provision (benefit) for income taxes	$ (20)	$ 90	$ 79	$ 59	$ 74	$ 25	$ 54	$ 55	$ 208	$ 208	$ 221

INCOME TAXES - Deferred Tax Ass

INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets, Gross [Abstract]
Allowances for credit losses	$ 162	$ 255
Tax credit carryforward	142	217
Fair value adjustments	108	141
Net operating and other loss carryforward	17	64
Market discount	7	23
Pension and other employee benefits	10	8
Partnership investments	0	35
Purchase accounting adjustments	153	76
Other assets	6	11
Total deferred tax assets	605	830
Deferred tax liabilities:
Lease financing	249	325
Deferred dividend income	116	138
Deferred dividend income	77	0
Purchase accounting adjustments	39	51
Operating assets	53	54
Mortgage servicing rights	6	56
Securities adjustments	68	74
Pension and other employee benefits	5	0
Other liabilities	18	9
Total deferred tax liabilities	631	707
Net deferred tax asset (liability) before valuation allowance	(26)	123
Valuation allowance	(6)	(5)
Total deferred tax liabilities	$ (32)
Net deferred tax (liability) asset		$ 118

FAIR VALUES OF ASSETS AND LI130

FAIR VALUES OF ASSETS AND LIABILITIES - Narrative (Details) - Level 1	12 Months Ended
	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of available-for-sale and trading securities in Level 1 (less than)	1.00%
Percentage of available-for-sale and trading securities in Level 2	78.00%
Percentage of available-for-sale and trading securities in Level 3	21.00%

FAIR VALUES OF ASSETS AND LI131

FAIR VALUES OF ASSETS AND LIABILITIES - Recurring basis (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets measured at fair value on a recurring basis
Trading account securities	$ 86	$ 133
Available-for-sale and other securities	15,469	15,563
Consumer loans	93	82
Derivative assets gross	322	420
Derivative assets netting	(190)	(182)
Derivative assets	132	238
Liabilities measured at fair value on a recurring basis
Gross amounts of recognized liabilities	331	371
Derivative liabilities netting	(245)	(272)
Derivative liabilities	86	99
U.S. Treasury securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	5	6
Residential MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	1,367	200
Commercial MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	2,487	3,663
Other agencies
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	70	73
Municipal securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	3,878	3,250
Asset-backed securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	467	794
Corporate debt
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	109	199
Recurring
Assets measured at fair value on a recurring basis
Loans held for sale	413	438
Trading account securities	86	133
Available-for-sale and other securities	14,888	15,015
MSRs	11	14
Derivative assets netting	(190)	(182)
Derivative assets	132	238
Liabilities measured at fair value on a recurring basis
Derivative liabilities netting	(245)	(272)
Derivative liabilities	86	99
Short-term borrowings	0	0
Recurring | U.S. Treasury securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	5	6
Recurring | Residential CMOs
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	6,484	6,810
Recurring | Residential MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	1,367	200
Recurring | Commercial MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	2,487	3,663
Recurring | Other agencies
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	70	73
Recurring | Municipal securities
Assets measured at fair value on a recurring basis
Trading account securities		1
Available-for-sale and other securities	3,878	3,250
Recurring | Asset-backed securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	467	794
Recurring | Corporate debt
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	109	199
Recurring | Other securities
Assets measured at fair value on a recurring basis
Trading account securities	86	132
Available-for-sale and other securities	21	20
Recurring | Level 1
Assets measured at fair value on a recurring basis
Loans held for sale	0	0
Trading account securities	83	132
Available-for-sale and other securities	25	22
Consumer loans	0	0
MSRs	0	0
Derivative assets gross	0	0
Liabilities measured at fair value on a recurring basis
Gross amounts of recognized liabilities	0	0
Short-term borrowings	0	0
Recurring | Level 1 | U.S. Treasury securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	5	6
Recurring | Level 1 | Residential CMOs
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 1 | Other agencies
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 1 | Municipal securities
Assets measured at fair value on a recurring basis
Trading account securities		0
Available-for-sale and other securities	0	0
Recurring | Level 1 | Asset-backed securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 1 | Corporate debt
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 1 | Other securities
Assets measured at fair value on a recurring basis
Trading account securities	83	132
Available-for-sale and other securities	20	16
Recurring | Level 2
Assets measured at fair value on a recurring basis
Loans held for sale	413	438
Trading account securities	3	1
Available-for-sale and other securities	11,672	12,119
Consumer loans	55	34
MSRs	0	0
Derivative assets gross	316	414
Liabilities measured at fair value on a recurring basis
Gross amounts of recognized liabilities	326	363
Short-term borrowings	0	0
Recurring | Level 2 | U.S. Treasury securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 2 | Residential CMOs
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	6,484	6,810
Recurring | Level 2 | Residential MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	1,367	200
Recurring | Level 2 | Commercial MBS
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	2,487	3,663
Recurring | Level 2 | Other agencies
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	70	73
Recurring | Level 2 | Municipal securities
Assets measured at fair value on a recurring basis
Trading account securities		1
Available-for-sale and other securities	711	452
Recurring | Level 2 | Asset-backed securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	443	718
Recurring | Level 2 | Corporate debt
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	109	199
Recurring | Level 2 | Other securities
Assets measured at fair value on a recurring basis
Trading account securities	3	0
Available-for-sale and other securities	1	4
Recurring | Level 3
Assets measured at fair value on a recurring basis
Loans held for sale	0	0
Trading account securities	0	0
Available-for-sale and other securities	3,191	2,874
Consumer loans	38	48
MSRs	11	14
Derivative assets gross	6	6
Liabilities measured at fair value on a recurring basis
Gross amounts of recognized liabilities	5	8
Short-term borrowings	0	0
Recurring | Level 3 | U.S. Treasury securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 3 | Residential CMOs
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 3 | Other agencies
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 3 | Municipal securities
Assets measured at fair value on a recurring basis
Trading account securities		0
Available-for-sale and other securities	3,167	2,798
Recurring | Level 3 | Asset-backed securities
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	24	76
Recurring | Level 3 | Corporate debt
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	0	0
Recurring | Level 3 | Other securities
Assets measured at fair value on a recurring basis
Trading account securities	0	0
Available-for-sale and other securities	$ 0	$ 0

FAIR VALUES OF ASSETS AND LI132

FAIR VALUES OF ASSETS AND LIABILITIES - Level 3 Roll Forward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative instruments
Opening balance	$ (2)	$ 6	$ 3
Transfers into Level 3	0	0	0
Transfers out of Level 3	(15)	(7)	(2)
Total gains/losses for the period:
Included in earnings	16	(1)	5
Included in OCI	0	0	0
Purchases/originations	0	0	0
Sales	0	0	0
Repayments	0	0	0
Settlements	0	0	0
Opening balance	(1)	(2)	6
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date	0	(1)	5
MSRs
Level 3 Assets Roll Forward:
Opening balance	14	18	23
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Total gains/losses for the period:
Included in earnings	(3)	(4)	(5)
Included in OCI	0	0	0
Purchases/originations	0	0	0
Sales	0	0	0
Repayments	0	0	0
Settlements	0	0	0
Closing balance	11	14	18
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date	(3)	(4)	(5)
Municipal securities
Level 3 Assets Roll Forward:
Opening balance	2,798	2,095	1,418
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Total gains/losses for the period:
Included in earnings	(2)	7	0
Included in OCI	(8)	(28)	(4)
Purchases/originations	787	1,399	1,002
Sales	0	(37)	(10)
Repayments	0	0	0
Settlements	(408)	(638)	(311)
Closing balance	3,167	2,798	2,095
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date	0	(33)	0
Private-label CMO
Level 3 Assets Roll Forward:
Opening balance		0	30
Transfers into Level 3			0
Transfers out of Level 3			0
Total gains/losses for the period:
Included in earnings			0
Included in OCI			2
Purchases/originations			0
Sales			(30)
Repayments			0
Settlements			(2)
Closing balance			0
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date			0
Asset-backed securities
Level 3 Assets Roll Forward:
Opening balance	76	100	83
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Total gains/losses for the period:
Included in earnings	(5)	(2)	(3)
Included in OCI	14	6	25
Purchases/originations	0	0	0
Sales	(60)	(25)	0
Repayments	0	0	0
Settlements	(1)	(3)	(5)
Closing balance	24	76	100
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date	(4)	4	(3)
Automobile
Level 3 Assets Roll Forward:
Opening balance	48	2	10
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Total gains/losses for the period:
Included in earnings	1	(2)	0
Included in OCI	0	0	0
Purchases/originations	0	56	0
Sales	0	0	0
Repayments	(11)	(8)	(8)
Settlements	0	0	0
Closing balance	38	48	2
Change in unrealized gains or losses for the period included in earnings for assets held at end of the reporting date	$ 0	$ 0	$ 0

FAIR VALUES OF ASSETS AND LI133

FAIR VALUES OF ASSETS AND LIABILITIES - Level 3 Classification of Gains/Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivatives gain (loss) included in earnings	$ 16	$ (1)	$ 5
MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(3)	(4)	(5)
Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(2)	7	0
Private-label CMO
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings			0
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(5)	(2)	(3)
Automobile
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	1	(2)	0
Mortgage banking income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivatives gain (loss) included in earnings	16	(1)	5
Mortgage banking income | MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(3)	(4)	(5)
Mortgage banking income | Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Mortgage banking income | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Mortgage banking income | Automobile
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Securities gains (losses)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivatives gain (loss) included in earnings	0	0	0
Securities gains (losses) | MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Securities gains (losses) | Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	1	0
Securities gains (losses) | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(5)	(2)	(3)
Securities gains (losses) | Automobile
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Interest and fee income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivatives gain (loss) included in earnings	0	0	0
Interest and fee income | MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Interest and fee income | Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	(2)	0	0
Interest and fee income | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Interest and fee income | Automobile
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Noninterest income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net derivatives gain (loss) included in earnings	0	0	0
Noninterest income | MSRs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Noninterest income | Municipal securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	6	0
Noninterest income | Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	0	0	0
Noninterest income | Automobile
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets gain (loss) included in earnings	$ 1	$ (2)	$ 0

FAIR VALUES OF ASSETS AND LI134

FAIR VALUES OF ASSETS AND LIABILITIES - Fair Value Option (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Option, Quantitative Disclosures [Line Items]
Automobile loans, fair value	$ 93,000	$ 82,000
Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans held for sale	413,000	438,000
Fair Value, Measurements, Recurring [Member] | Mortgages Held For Sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans held for sale, aggregate unpaid principle	400,000	434,000
Aggregate difference	(13,000)	(4,000)
Loans held for sale	413,000	438,000
Fair Value, Measurements, Recurring [Member] | Mortgages Held To Maturity [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans held for investment, aggregate unpaid principle	102,000	92,000
Automobile loans, fair value	93,000	82,000
Aggregate difference	(9,000)	(10,000)
Fair Value, Measurements, Recurring [Member] | 90 or more days | Mortgages Held For Sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans held for sale, aggregate unpaid principle	1,000	0
Aggregate difference	0	0
Loans held for sale	1,000	0
Fair Value, Measurements, Recurring [Member] | 90 or more days | Mortgages Held To Maturity [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans held for investment, aggregate unpaid principle	11,000	11,000
Automobile loans, fair value	10,000	8,000
Aggregate difference	$ (1,000)	$ (3,000)

FAIR VALUES OF ASSETS AND LI135

FAIR VALUES OF ASSETS AND LIABILITIES - Fair Value Option-Changes in Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Measurements, Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains (losses) from fair value changes	$ 8	$ 7	$ (2)
Loans held for investment
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains (losses) from fair value changes	$ 0	$ 0	$ (1)

FAIR VALUES OF ASSETS AND LI136

FAIR VALUES OF ASSETS AND LIABILITIES - Non-recurring/Fair Values of Financial Instruments (Details) - Nonrecurring $ in Millions	Dec. 31, 2017USD ($)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs	$ 190
Impaired loans	36
Other real estate owned	33
Total Gains/(Losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs	1
Impaired loans	(5)
Other real estate owned	(2)
Level 1 | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs	0
Impaired loans	0
Other real estate owned	0
Level 2 | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs	0
Impaired loans	0
Other real estate owned	0
Level 3 | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
MSRs	190
Impaired loans	36
Other real estate owned	$ 33

FAIR VALUES OF ASSETS AND LI137

FAIR VALUES OF ASSETS AND LIABILITIES - Significant Unobservable Level 3 Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative assets gross	$ 322	$ 420
Gross amounts of recognized liabilities	331	371
Available-for-sale and other securities	15,469	15,563
Consumer loans	$ 93	82
Derivative Liabilities | Maximum | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Timing of the resolution of the litigation	Jun. 30, 2020
Derivative Liabilities | Minimum | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Estimated conversion factor	165.00%
Fair Value Inputs, Estimated growth rate of Visa Class A shares	7.00%
Discount rate	3.00%
Fair Value Inputs, Timing of the resolution of the litigation	Dec. 31, 2017
Derivative Liabilities | Weighted Average | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Timing of the resolution of the litigation	Jun. 30, 2020
MSRs | Maximum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	33.00%
Spread over forward interest rate swap rates	0.100
MSRs | Minimum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	8.00%
Spread over forward interest rate swap rates	0.080
MSRs | Weighted Average | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	12.00%
Spread over forward interest rate swap rates	0.080
Derivative Assets | Maximum | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Net market price	20.00%
Estimated Pull through %	100.00%
Derivative Assets | Minimum | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Net market price	(5.00%)
Estimated Pull through %	3.00%
Derivative Assets | Weighted Average | Consensus Pricing | Level 3
Quantitative information about level 3 fair value measurements
Net market price	2.00%
Estimated Pull through %	75.00%
Municipal securities | Maximum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Discount rate	10.00%
Cumulative default	64.00%
Loss given default	90.00%
Municipal securities | Minimum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Discount rate	0.00%
Cumulative default	0.00%
Loss given default	5.00%
Municipal securities | Weighted Average | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Discount rate	4.00%
Cumulative default	3.00%
Loss given default	24.00%
Asset-backed securities | Maximum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	72.00%
Discount rate	7.00%
Cumulative default	53.00%
Loss given default	100.00%
Cure given deferral	50.00%
Asset-backed securities | Minimum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	0.00%
Discount rate	7.00%
Cumulative default	3.00%
Loss given default	90.00%
Cure given deferral	50.00%
Asset-backed securities | Weighted Average | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	7.00%
Discount rate	7.00%
Cumulative default	7.00%
Loss given default	100.00%
Cure given deferral	50.00%
Automobile | Maximum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	18.00%
Discount rate	22.00%
Life of pool cumulative losses	2.10%
Automobile | Minimum | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	700.00%
Discount rate	0.20%
Life of pool cumulative losses	2.10%
Automobile | Weighted Average | Discounted cash flow | Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	8.00%
Discount rate	9.00%
Life of pool cumulative losses	2.10%
Recurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	$ 11	14
Available-for-sale and other securities	14,888	15,015
Recurring | Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	11	14
Derivative assets gross	6	6
Gross amounts of recognized liabilities	5	8
Available-for-sale and other securities	3,191	2,874
Consumer loans	38	48
Fair Value
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Available-for-sale and other securities	15,469	$ 15,563
Fair Value | Nonrecurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	190
Impaired loans	36
Other real estate owned	33
Fair Value | Nonrecurring | Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	190
Impaired loans	36
Other real estate owned	$ 33

FAIR VALUES OF ASSETS AND LI138

FAIR VALUES OF ASSETS AND LIABILITIES - Balance Sheet Location (Details) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Financial Assets:
Trading account securities	$ 86	$ 133
Loans held for sale	488	513
Available-for-sale and other securities	15,469	15,563
Held-to-maturity securities	9,091	7,807
Loans and Leases Receivable, Net Amount	69,426	66,324
Derivatives	132	238
Financial Liabilities:
Deposits	77,041	75,608
Short-term borrowings	5,056	3,693
Long-term borrowings	9,206	8,309
Derivatives	86	99
Carrying Amount
Financial Assets:
Cash and short term assets	1,567	1,443
Trading account securities	86	133
Loans held for sale	488	513
Available-for-sale and other securities	15,469	15,563
Held-to-maturity securities	9,091	7,807
Loans and Leases Receivable, Net Amount	69,426	66,324
Derivatives	132	238
Financial Liabilities:
Deposits	77,041	75,608
Short-term borrowings	5,056	3,693
Long-term borrowings	9,206	8,309
Derivatives	86	98
Fair Value
Financial Assets:
Cash and short term assets	1,567	1,443
Trading account securities	86	133
Loans held for sale	491	516
Available-for-sale and other securities	15,469	15,563
Held-to-maturity securities	8,971	7,787
Loans and Leases Receivable, Net Amount	69,146	66,295
Derivatives	132	238
Financial Liabilities:
Deposits	77,010	76,161
Short-term borrowings	5,056	3,693
Long-term borrowings	9,402	8,387
Derivatives	86	98
Level 1 | Fair Value
Financial Assets:
Held-to-maturity securities	0	0
Loans and Leases Receivable, Net Amount	0	0
Financial Liabilities:
Deposits	0	0
Short-term borrowings	0	1
Long-term borrowings	0	0
Level 2 | Fair Value
Financial Assets:
Held-to-maturity securities	8,971	7,787
Loans and Leases Receivable, Net Amount	0	0
Financial Liabilities:
Deposits	73,975	72,319
Short-term borrowings	0	0
Long-term borrowings	8,944	7,980
Level 3 | Fair Value
Financial Assets:
Held-to-maturity securities	0	0
Loans and Leases Receivable, Net Amount	69,146	66,295
Financial Liabilities:
Deposits	3,035	3,842
Short-term borrowings	5,056	$ 3,692
Long-term borrowings	$ 458

DERIVATIVE FINANCIAL INSTRUM139

DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Management (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Total notional value	$ 8,375	$ 10,800
Gross amounts of recognized assets	322	420
Gross amounts of recognized liabilities	331	371
Fair Value Hedges
Derivative [Line Items]
Total notional value	8,375	7,475
Cash Flow Hedges
Derivative [Line Items]
Total notional value	0	3,325
Loans
Derivative [Line Items]
Total notional value	0	3,325
Loans | Fair Value Hedges
Derivative [Line Items]
Total notional value	0	0
Loans | Cash Flow Hedges
Derivative [Line Items]
Total notional value	0	3,325
Subordinated notes
Derivative [Line Items]
Total notional value	950	950
Subordinated notes | Fair Value Hedges
Derivative [Line Items]
Total notional value	950	950
Subordinated notes | Cash Flow Hedges
Derivative [Line Items]
Total notional value	0	0
Other long-term debt
Derivative [Line Items]
Total notional value	7,425	6,525
Other long-term debt | Fair Value Hedges
Derivative [Line Items]
Total notional value	7,425	6,525
Other long-term debt | Cash Flow Hedges
Derivative [Line Items]
Total notional value	0	0
Accrued income and other assets
Derivative [Line Items]
Interest Rate Fair Value Hedge Asset at Fair Value	22	46
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	187	233
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	18	23
Price Risk Derivative Instruments Not Designated as Hedging Instruments Asset, at Fair Value	92	108
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	3	10
Gross amounts of recognized assets	322	420
Accrued expenses and other liabilities
Derivative [Line Items]
Interest Rate Fair Value Hedge Liability at Fair Value	121	100
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	100	141
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	18	20
Price Risk Derivative Instruments Not Designated as Hedging Instruments Liability, at Fair Value	87	104
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	5	6
Gross amounts of recognized liabilities	331	371
Interest rate lock agreements
Derivative [Line Items]
Gross amounts of recognized assets	6	6
Gross amounts of recognized liabilities	0	(2)
Forward trades and options
Derivative [Line Items]
Gross amounts of recognized assets	1	13
Gross amounts of recognized liabilities	0	(1)
Derivative used in Mortgage Banking Activities
Derivative [Line Items]
Total notional value	188	308
Gross amounts of recognized assets	7	19
Gross amounts of recognized liabilities	$ 0	$ (3)

DERIVATIVE FINANCIAL INSTRUM140

DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Management Add Info (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Value	$ 8,375	$ 10,800
Average Maturity (years)	2 years 6 months	2 years 4 months
Fair Value	$ (99)	$ (54)
Weighted-Average Rate Receive	1.56%	1.35%
Weighted-Average Rate Pay	1.44%	0.89%
Asset conversion swaps - Receive Fixed - Generic
Derivative [Line Items]
Notional Value	$ 0	$ 3,325
Average Maturity (years)	0 years	7 months 6 days
Fair Value	$ 0	$ (2)
Weighted-Average Rate Receive	0.00%	1.04%
Weighted-Average Rate Pay	0.00%	0.91%
Liability conversion swaps Receive Fixed Generic
Derivative [Line Items]
Notional Value	$ 8,375	$ 7,475
Average Maturity (years)	2 years 6 months	3 years 1 month 6 days
Fair Value	$ (99)	$ (52)
Weighted-Average Rate Receive	1.56%	1.49%
Weighted-Average Rate Pay	1.44%	0.88%

DERIVATIVE FINANCIAL INSTRUM141

DERIVATIVE FINANCIAL INSTRUMENTS - Hedging instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Asset derivatives included in accrued income and other assets
Total derivative assets	$ 322	$ 420
Liability derivatives included in accrued expenses and other liabilities
Total derivative liabilities	331	371
Accrued income and other assets
Asset derivatives included in accrued income and other assets
Interest rate contracts designated as hedging instruments	22	46
Interest rate contracts not designated as hedging instruments	187	233
Foreign exchange contracts not designated as hedging instruments	18	23
Commodities contracts not designated as hedging instruments	92	108
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	3	10
Total derivative assets	322	420
Accrued expenses and other liabilities
Liability derivatives included in accrued expenses and other liabilities
Interest rate contracts designated as hedging instruments	121	100
Interest rate contracts not designated as hedging instruments	100	141
Foreign exchange contracts not designated as hedging instruments	18	20
Commodities contracts not designated as hedging instruments	87	104
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	5	6
Total derivative liabilities	$ 331	$ 371

DERIVATIVE FINANCIAL INSTRUM142

DERIVATIVE FINANCIAL INSTRUMENTS - Cash Flow Hedges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in OCI on derivatives (effective portion)	$ 2	$ 1	$ 9
Amount of (gain) or loss reclassified from accumulated OCI into earnings (effective portion) (pre-tax)	1	0	(1)
Deposits | Interest expense deposits
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	0	0	(1)
Hedged deposits | Interest expense deposits
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	0	0	1
Subordinated notes | Interest expense subordinated notes and other long term debt
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	(14)	(48)	(8)
Hedged subordinated notes | Interest expense subordinated notes and other long term debt
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	17	45	8
Other long-term debt | Interest expense subordinated notes and other long term debt
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	(39)	(74)	4
Hedged Other long term debt | Interest expense subordinated notes and other long term debt
Derivative Instruments, Gain (Loss) [Line Items]
Increase or (decrease) to interest expense for derivatives designated as fair value hedges	37	67	(4)
Loans | Interest and fee income—loans and leases | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in OCI on derivatives (effective portion)	2	1	9
Amount of (gain) or loss reclassified from accumulated OCI into earnings (effective portion) (pre-tax)	$ 1	$ 0	$ (1)

DERIVATIVE FINANCIAL INSTRUM143

DERIVATIVE FINANCIAL INSTRUMENTS - Mortgage Banking Activities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative assets:
Derivative assets gross	$ 322	$ 420
Derivative liabilities:
Total derivative liabilities	(331)	(371)
Interest rate lock agreements
Derivative assets:
Derivative assets gross	6	6
Derivative liabilities:
Total derivative liabilities	0	2
Forward trades and options
Derivative assets:
Derivative assets gross	1	13
Derivative liabilities:
Total derivative liabilities	0	1
Derivative used in Mortgage Banking Activities
Derivative assets:
Derivative assets gross	7	19
Derivative liabilities:
Total derivative liabilities	$ 0	$ 3

DERIVATIVE FINANCIAL INSTRUM144

DERIVATIVE FINANCIAL INSTRUMENTS - Offsetting Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative Asset [Abstract]
Gross amounts of recognized assets	$ 322	$ 420
Gross amounts offset in the consolidated balance sheets	(190)	(182)
Net amounts of assets presented in the consolidated balance sheets	132	238
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross amounts not offset in the statement of financial position - financial instruments	(11)	(34)
Gross amounts not offset in the statement of financial position - cash collateral received	(18)	(5)
Net amount	$ 103	$ 199

DERIVATIVE FINANCIAL INSTRUM145

DERIVATIVE FINANCIAL INSTRUMENTS - Offsetting Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivative Liability [Abstract]
Gross amounts of recognized liabilities	$ 331	$ 371
Gross amounts offset in the consolidated balance sheets	(245)	(272)
Net amounts of assets presented in the consolidated balance sheets	86	99
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross amounts not offset in the consolidated balance sheets, financial instruments	0	(8)
Gross amounts not offset in the consolidated balance sheets, cash collateral received	(21)	(24)
Net amount	$ 65	$ 67

DERIVATIVE FINANCIAL INSTRUM146

DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Increase (decrease) to net interest income due to derivative adjustment	$ 23	$ 72	$ 108
Gross amounts of recognized liabilities (less than)	331	371
Purchase of interest rate caps and derivative financial instruments, notional value	8,375	10,800
Notional amount corresponds to trading liabilities, fair value	3
Total notional amount corresponds to trading assets, fair value (less than)	1
Credit risks from interest rate swaps used for trading purposes	119	196
Aggregate credit risk, net of collateral	30	26
Investment securities and cash collateral pledged by Huntington	122
Investment securities and cash collateral pledged to Huntington	$ 75
Derivative liabilities	The following table presents additional information about the interest rate swaps used in Huntington’s asset and liability management activities at December 31, 2017 and December 31, 2016 : December 31, 2017 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ — 0 $ — — % — % Liability conversion swaps Receive fixed—generic 8,375 2.5 (99 ) 1.56 1.44 Total swap portfolio at December 31, 2017 $ 8,375 2.5 $ (99 ) 1.56 % 1.44 % December 31, 2016 Weighted-Average (dollar amounts in millions) Notional Value Average Maturity (years) Fair Value Receive Pay Asset conversion swaps Receive fixed—generic $ 3,325 0.6 $ (2 ) 1.04 % 0.91 % Liability conversion swaps Receive fixed—generic 7,475 3.1 (52 ) 1.49 0.88 Total swap portfolio at December 31, 2016 $ 10,800 2.3 $ (54 ) 1.35 % 0.89 %
Swap
Derivative [Line Items]
Gross amounts of recognized liabilities (less than)	$ 1
Derivative liabilities	5
Derivative used in trading activity
Derivative [Line Items]
Net derivative asset (liability)	$ 88	80
Derivative financial instruments used by Huntington on behalf of customers including offsetting derivatives, notional value	22,000	21,000
Derivative used in Mortgage Banking Activities
Derivative [Line Items]
Gross amounts of recognized liabilities (less than)	0	(3)
Purchase of interest rate caps and derivative financial instruments, notional value	188	308
Gains (losses) related to derivative instruments Included in total MSR	$ 1	$ (1)	$ (2)

VIEs - Narrative (Details)

VIEs - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Variable Interest Entity [Line Items]
Maximum year to defer payment of interest on Debenture			5 years
Trust 2016 Unconsolidated
Variable Interest Entity [Line Items]
Total of automobile loans transferred In securitization transaction	$ 1,500
2015-1 Automobile Trust
Variable Interest Entity [Line Items]
Total of automobile loans transferred In securitization transaction		$ 750

VIEs - Consolidated VIEs (Detai

VIEs - Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Cash	$ 1,520	$ 1,385
Loans and Leases Receivable, Net Amount	69,426	66,324
Accrued income and other assets	2,151	2,062
Total assets	104,185	99,714
Liabilities
Long-term debt	9,206	8,309
Accrued interest and other liabilities	2,068	1,796
Total liabilities	93,371	89,406
Equity:
Total liabilities and shareholders’ equity	104,185	99,714
Total ALLL balance:	$ 691	638	$ 598	$ 605
Macquarie Equipment Funding Trust Series 2014A
Assets:
Cash		2
Loans and Leases Receivable, Net Amount		70
Accrued income and other assets		0
Total assets		72
Liabilities
Long-term debt		57
Accrued interest and other liabilities		0
Total liabilities		57
Equity:
Beneficial Interest owned by third party		14
Total liabilities and shareholders’ equity		71
Franklin 2009 Trust
Assets:
Cash		0
Loans and Leases Receivable, Net Amount		0
Accrued income and other assets		0
Total assets		0
Liabilities
Long-term debt		0
Accrued interest and other liabilities		0
Total liabilities		0
Equity:
Beneficial Interest owned by third party		0
Total liabilities and shareholders’ equity		0
Trusts
Assets:
Cash		2
Loans and Leases Receivable, Net Amount		70
Accrued income and other assets		0
Total assets		72
Liabilities
Long-term debt		57
Accrued interest and other liabilities		0
Total liabilities		57
Equity:
Beneficial Interest owned by third party		14
Total liabilities and shareholders’ equity		$ 71

VIEs - Unconsolidated VIEs (Det

VIEs - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Total Assets	$ 775	$ 687
Total Liabilities	640	588
Maximum Exposure to Loss	761	673
Trust 2016 Unconsolidated
Variable Interest Entity [Line Items]
Total Assets	7	15
Total Liabilities	0	0
Maximum Exposure to Loss	7	15
2015-1 Automobile Trust
Variable Interest Entity [Line Items]
Total Assets	1	2
Total Liabilities	0	0
Maximum Exposure to Loss	1	2
Trust Preferred Securities
Variable Interest Entity [Line Items]
Total Assets	14	14
Total Liabilities	252	253
Maximum Exposure to Loss	0	0
Affordable Housing Tax Credit Partnerships
Variable Interest Entity [Line Items]
Total Assets	636	577
Total Liabilities	335	293
Maximum Exposure to Loss	636	577
Other Investments
Variable Interest Entity [Line Items]
Total Assets	117	79
Total Liabilities	53	42
Maximum Exposure to Loss	$ 117	$ 79

VIEs - Trust Preferred Securiti

VIEs - Trust Preferred Securities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Variable Interest Entity [Line Items]
Principal amount of subordinated note/ debenture issued to trust	$ 9,335
Huntington Capital I
Variable Interest Entity [Line Items]
Rate	2.39%
Principal amount of subordinated note/ debenture issued to trust	$ 70
Investment in unconsolidated subsidiary	$ 6
Huntington Capital I | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Basis spread on variable rate	0.70%
Huntington Capital II
Variable Interest Entity [Line Items]
Rate	2.32%
Principal amount of subordinated note/ debenture issued to trust	$ 32
Investment in unconsolidated subsidiary	$ 3
Huntington Capital II | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Basis spread on variable rate	0.625%
Sky Financial Capital Trust III
Variable Interest Entity [Line Items]
Rate	3.09%
Principal amount of subordinated note/ debenture issued to trust	$ 72
Investment in unconsolidated subsidiary	$ 2
Sky Financial Capital Trust III | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Basis spread on variable rate	1.40%
Sky Financial Capital Trust IV
Variable Interest Entity [Line Items]
Rate	3.09%
Principal amount of subordinated note/ debenture issued to trust	$ 74
Investment in unconsolidated subsidiary	$ 2
Sky Financial Capital Trust IV | London Interbank Offered Rate (LIBOR) [Member]
Variable Interest Entity [Line Items]
Basis spread on variable rate	1.33%
Camco Financial Trust
Variable Interest Entity [Line Items]
Rate	3.02%
Principal amount of subordinated note/ debenture issued to trust	$ 4
Investment in unconsolidated subsidiary	1
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Principal amount of subordinated note/ debenture issued to trust	252
Investment in unconsolidated subsidiary	$ 14

VIEs - Low Income Housing Tax C

VIEs - Low Income Housing Tax Credit Partnerships (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Affordable Housing Tax Credit Partnerships
Variable Interest Entity [Line Items]
Affordable housing tax credit investments	$ 996	$ 877
Less: amortization	(360)	(300)
Net affordable housing tax credit investments	636	577
Unfunded commitments	335	293
Tax credits and other tax benefits recognized	91	80	$ 60
Proportional Amortization Method
Variable Interest Entity [Line Items]
Tax credit amortization expense included in provision for income taxes (1)	70	53	43
Proportional amortization method
Tax credit amortization expense included in provision for income taxes (1)	70	53	43
Equity Method
Equity method
Tax credit investment losses included in noninterest income	$ 0	$ 1	$ 0

COMMITMENTS AND CONTINGENT L152

COMMITMENTS AND CONTINGENT LIABILITIES - Commitments to Extend Credit (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Commercial
Guarantor Obligations [Line Items]
Contract amount represents credit risk	$ 16,219	$ 15,190
Consumer
Guarantor Obligations [Line Items]
Contract amount represents credit risk	13,384	12,236
Commercial real estate
Guarantor Obligations [Line Items]
Contract amount represents credit risk	1,366	1,698
Standby letters of credit
Guarantor Obligations [Line Items]
Contract amount represents credit risk	510	637
Commercial and Industrial Sector [Member] | Commercial letters-of-credit
Guarantor Obligations [Line Items]
Contract amount represents credit risk	$ 21	$ 5

COMMITMENTS AND CONTINGENT L153

COMMITMENTS AND CONTINGENT LIABILITIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 28, 2015
Future minimum sublease rental payments:
Operating leases, future minimum payments due, future minimum sublease rentals, total	$ 6
2,016	2
2,017	2
2,018	1
2,019	0
2,020	0
Thereafter	0
Operating lease, future minimum payments due:
2,016	59
2,017	55
2,018	53
2,019	38
2,020	34
Thereafter	135
Total rental expense for all operating leases	76	$ 65	$ 58
Maximum
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	55
Minimum
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	0
Commitments to Sell Loans
Loss Contingencies [Line Items]
Commitments to sell residential real estate loans	$ 700	819
Maturity period of forward contracts relating mortgage banking business (less than)	1 year
Standby letters of credit
Loss Contingencies [Line Items]
Contract amount represents credit risk	$ 510	637
Maturity period of guarantee	2 years
Outstanding standby letters of credit	$ 10	$ 8
Cyberco Litigation
Loss Contingencies [Line Items]
Bankruptcy Court recommended judgment amount in Cyberco case, principle				$ 72
Commercial Portfolio Segment [Member] | Commercial letters-of-credit
Loss Contingencies [Line Items]
Maturity period of guarantee	90 days

OTHER REGULATORY MATTERS (Detai

OTHER REGULATORY MATTERS (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one risk based capital required for capital adequacy to risk weighted assets	4.50%
Common Equity Tier One Risk Based Capital Conservation Buffer Plus Capital Required for Capital Adequacy to Risk Weighted Assets	5.75%
Common Equity Tier One Capital Ratio	10.01%	9.56%
Common Equity Tier One Capital	$ 8,041	$ 7,486
Tier 1 risk based capital required to be well capitalized to risk weighted assets	6.00%
Tier 1 risk based capital required for capital adequacy to risk weighted assets	6.00%
Tier One Risk Based Capital Conservation Buffer Plus Capital Required for Capital Adequacy to Risk Weighted Assets	7.25%
Tier 1 capital ratio	11.34%	10.92%
Tier 1 capital amount	$ 9,110	$ 8,547
Capital required to be well capitalized to risk weighted assets	10.00%
Capital required for capital adequacy to risk weighted assets	8.00%
Capital Conservation Buffer Plus Capital required for Capital Adequacy to Risk Weighted Assets	9.25%
Risk based capital ratio	13.39%	13.05%
Risk based capital amount	$ 10,757	$ 10,215
Tier 1 leverage capital required for capital adequacy to average assets	4.00%
Tier 1 leverage ratio	9.09%	8.70%
Tier 1 leverage amount	$ 9,110	$ 8,547
Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one risked based capital required to be well capitalized to risk weighted assets	6.50%
Common equity tier one risk based capital required for capital adequacy to risk weighted assets	4.50%
Common Equity Tier One Risk Based Capital Conservation Buffer Plus Capital Required for Capital Adequacy to Risk Weighted Assets	5.75%
Common Equity Tier One Capital Ratio	11.02%	10.42%
Common Equity Tier One Capital	$ 8,856	$ 8,153
Tier 1 risk based capital required to be well capitalized to risk weighted assets	8.00%
Tier 1 risk based capital required for capital adequacy to risk weighted assets	6.00%
Tier One Risk Based Capital Conservation Buffer Plus Capital Required for Capital Adequacy to Risk Weighted Assets	7.25%
Tier 1 capital ratio	12.10%	11.61%
Tier 1 capital amount	$ 9,727	$ 9,086
Capital required to be well capitalized to risk weighted assets	10.00%
Capital required for capital adequacy to risk weighted assets	8.00%
Capital Conservation Buffer Plus Capital required for Capital Adequacy to Risk Weighted Assets	9.25%
Risk based capital ratio	14.33%	13.83%
Risk based capital amount	$ 11,517	$ 10,818
Tier 1 leverage capital required to be well capitalized to average assets	5.00%
Tier 1 leverage capital required for capital adequacy to average assets	4.00%
Tier 1 leverage ratio	9.70%	9.29%
Tier 1 leverage amount	$ 9,727	$ 9,086

OTHER REGULATORY MATTERS - Narr

OTHER REGULATORY MATTERS - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Average required reserve balance on deposits	$ 0	$ 0
Amount bank could lend to single affiliate	1,000
Cash dividends paid to the holding company	$ 724

PARENT COMPANY FINANCIAL STA156

PARENT COMPANY FINANCIAL STATEMENTS - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 1,520	$ 1,385	$ 847	$ 1,221
Accrued interest receivable and other assets	2,151	2,062
Total assets	104,185	99,714
Liabilities and shareholders’ equity
Long-term borrowings	9,206	8,309
Accrued expenses and other liabilities	2,068	1,796
Total liabilities	93,371	89,406
Shareholders’ equity	10,814	10,308	6,595	6,328
Total liabilities and shareholders’ equity	104,185	99,714
Parent Company
Assets
Cash and due from banks	1,618	1,753	$ 917	$ 663
Due from The Huntington National Bank	798	730
Due from non-bank subsidiaries	58	45
Investment in The Huntington National Bank	11,696	10,668
Investment in non-bank subsidiaries	111	500
Accrued interest receivable and other assets	252	321
Total assets	14,533	14,017
Liabilities and shareholders’ equity
Long-term borrowings	3,128	3,145
Accrued expenses and other liabilities	591	564
Total liabilities	3,719	3,709
Shareholders’ equity	10,814	10,308
Total liabilities and shareholders’ equity	$ 14,533	$ 14,017

PARENT COMPANY FINANCIAL STA157

PARENT COMPANY FINANCIAL STATEMENTS - Income Statement (Details) - USD ($) $ in Thousands	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
Interest from
Other Income									$ 185,000	$ 157,000	$ 167,000
Expense
Personnel costs									1,524,000	1,349,000	1,122,000
Other									231,000	184,000	201,000
Total noninterest expense	$ 633,000	$ 680,000	$ 694,000	$ 707,000	$ 681,000	$ 713,000	$ 523,000	$ 491,000	2,714,000	2,408,000	1,976,000
Income before income taxes	412,000	365,000	351,000	266,000	313,000	152,000	229,000	226,000	1,394,000	920,000	914,000
Provision (benefit) for income taxes	(20,000)	90,000	79,000	59,000	74,000	25,000	54,000	55,000	208,000	208,000	221,000
Increase (decrease) in undistributed net income (loss) of:
Net income	$ 432,000	$ 275,000	$ 272,000	$ 207,000	$ 239,000	$ 127,000	$ 175,000	$ 171,000	1,186,000	712,000	693,000
Other comprehensive income (loss)									(34,000)	(175,000)
Parent Company
Dividends from
The Huntington National Bank									298,000	188,000	822,000
Non-bank subsidiaries									14,000	11,000	39,000
Interest from
The Huntington National Bank									20,000	14,000	6,000
Non-bank subsidiaries									2,000	3,000	2,000
Other Income									4,000	0	5,000
Total income									338,000	216,000	874,000
Expense
Personnel costs									19,000	12,000	5,000
Interest on borrowings									91,000	59,000	17,000
Other									115,000	123,000	93,000
Total noninterest expense									225,000	194,000	115,000
Income before income taxes									113,000	22,000	759,000
Provision (benefit) for income taxes									(56,000)	(56,000)	(110,000)
Income (loss) before equity in undistributed net income of subsidiaries									169,000	78,000	869,000
Increase (decrease) in undistributed net income (loss) of:
The Huntington National Bank									1,015,000	629,000	(161,000)
Non-bank subsidiaries									2,000	5,000	(15,000)
Net income									1,186,000	712,000	693,000
Other comprehensive income (loss)									(34,000)	(175,000)	(4,000)
Comprehensive income									$ 1,152,000	$ 537,000	$ 689,000

PARENT COMPANY FINANCIAL STA158

PARENT COMPANY FINANCIAL STATEMENTS - Cash Flow Statement (Details) - USD ($) $ in Thousands	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
Operating activities
Net income	$ 432,000	$ 275,000	$ 272,000	$ 207,000	$ 239,000	$ 127,000	$ 175,000	$ 171,000	$ 1,186,000	$ 712,000	$ 693,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization									413,000	380,000	341,000
Net cash provided by (used in) operating activities									1,954,000	1,215,000	1,033,000
Investing activities
Sales of available-for-sale securities									2,490,000	6,154,000	163,000
Cash paid for acquisitions, net of cash received									0	(133,000)	(458,000)
Net cash provided by (used in) investing activities									(4,866,000)	(3,445,000)	(4,929,000)
Financing activities
Proceeds from issuance of long-term borrowings									1,816,000	2,128,000	3,232,000
Payment of borrowings									1,371,000	1,900,000	(1,819,000)
Net proceeds from issuance of preferred stock									0	585,000	0
Repurchases of common stock									(260,000)	0	(252,000)
Other, net									0	4,000	8,000
Net cash provided by (used) financing activities									3,047,000	2,768,000	3,522,000
Increase (decrease) in cash and cash equivalents									135,000	538,000	(374,000)
Cash and cash equivalents at beginning of period				1,385,000				847,000	1,385,000	847,000	1,221,000
Cash and cash equivalents at end of period	1,520,000				1,385,000				1,520,000	1,385,000	847,000
Supplemental disclosures:
Interest paid									409,000	241,000	150,000
Parent Company
Operating activities
Net income									1,186,000	712,000	693,000
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of subsidiaries									(997,000)	(634,000)	176,000
Depreciation and amortization									4,000	(1,000)	1,000
Loss on sales of securities available-for-sale									0	0	0
Other, net									(37,000)	(24,000)	(45,000)
Net cash provided by (used in) operating activities									156,000	53,000	825,000
Investing activities
Repayments from subsidiaries									442,000	464,000	495,000
Advances to subsidiaries									(29,000)	(1,758,000)	(612,000)
Sales of available-for-sale securities									1,000	(2,000)	0
Cash paid for acquisitions, net of cash received									0	(133,000)	0
Proceeds from business divestitures									0	0	9,000
Net cash provided by (used in) investing activities									414,000	(1,429,000)	(108,000)
Financing activities
Proceeds from issuance of long-term borrowings									0	1,990,000	0
Payment of borrowings									0	(65,000)	0
Dividends paid on stock									(425,000)	(299,000)	(225,000)
Net proceeds from issuance of preferred stock									0	585,000	0
Repurchases of common stock									(260,000)	0	(252,000)
Other, net									(20,000)	1,000	14,000
Net cash provided by (used) financing activities									(705,000)	2,212,000	(463,000)
Increase (decrease) in cash and cash equivalents									(135,000)	836,000	254,000
Cash and cash equivalents at beginning of period				$ 1,753,000				$ 917,000	1,753,000	917,000	663,000
Cash and cash equivalents at end of period	$ 1,618,000				$ 1,753,000				1,618,000	1,753,000	917,000
Supplemental disclosures:
Interest paid									$ 90,000	$ 36,000	$ 17,000

SEGMENT REPORTING (Details)

SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)segments	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Net interest income	$ 770,000	$ 758,000	$ 745,000	$ 729,000	$ 735,000	$ 625,000	$ 506,000	$ 503,000	$ 3,002,000	$ 2,369,000	$ 1,951,000
Provision for credit losses	65,000	43,000	25,000	68,000	75,000	63,000	25,000	28,000	201,000	191,000	100,000
Noninterest income	340,000	330,000	325,000	312,000	334,000	303,000	271,000	242,000	1,307,000	1,150,000	1,039,000
Noninterest expense	633,000	680,000	694,000	707,000	681,000	713,000	523,000	491,000	2,714,000	2,408,000	1,976,000
Provision (benefit) for income taxes	(20,000)	90,000	79,000	59,000	74,000	25,000	54,000	55,000	208,000	208,000	221,000
Net income	432,000	$ 275,000	$ 272,000	$ 207,000	239,000	$ 127,000	$ 175,000	$ 171,000	1,186,000	712,000	693,000
Total assets	104,185,000				99,714,000				104,185,000	99,714,000
Deposits	77,041,000				75,608,000				$ 77,041,000	75,608,000
Number of Reportable Segments | segments									4
Operating Segments | Consumer & Business Banking
Segment Reporting Information [Line Items]
Net interest income									$ 1,555,000	1,224,000	995,000
Provision for credit losses									110,000	68,000	45,000
Noninterest income									735,000	650,000	566,000
Noninterest expense									1,647,000	1,338,000	1,192,000
Provision (benefit) for income taxes									187,000	164,000	113,000
Net income									346,000	304,000	211,000
Total assets	26,220,000				25,333,000				26,220,000	25,333,000
Deposits	45,643,000				45,356,000				45,643,000	45,356,000
Operating Segments | Commercial Banking
Segment Reporting Information [Line Items]
Net interest income									899,000	725,000	560,000
Provision for credit losses									28,000	79,000	16,000
Noninterest income									278,000	244,000	214,000
Noninterest expense									474,000	398,000	343,000
Provision (benefit) for income taxes									236,000	172,000	145,000
Net income									439,000	320,000	270,000
Total assets	32,118,000				31,566,000				32,118,000	31,566,000
Deposits	21,235,000				19,597,000				21,235,000	19,597,000
Operating Segments | Vehicle Finance
Segment Reporting Information [Line Items]
Net interest income									424,000	345,000	262,000
Provision for credit losses									63,000	47,000	39,000
Noninterest income									14,000	14,000	13,000
Noninterest expense									150,000	118,000	93,000
Provision (benefit) for income taxes									79,000	68,000	50,000
Net income									146,000	126,000	93,000
Total assets	17,865,000				16,132,000				17,865,000	16,132,000
Deposits	358,000				349,000				358,000	349,000
Operating Segments | RBHPCG
Segment Reporting Information [Line Items]
Net interest income									184,000	152,000	125,000
Provision for credit losses									0	(3,000)	0
Noninterest income									188,000	177,000	174,000
Noninterest expense									243,000	229,000	241,000
Provision (benefit) for income taxes									45,000	36,000	21,000
Net income									84,000	67,000	37,000
Total assets	5,821,000				5,328,000				5,821,000	5,328,000
Deposits	6,057,000				6,214,000				6,057,000	6,214,000
Treasury / Other
Segment Reporting Information [Line Items]
Net interest income									(60,000)	(77,000)	9,000
Provision for credit losses									0	0	0
Noninterest income									92,000	65,000	72,000
Noninterest expense									200,000	325,000	107,000
Provision (benefit) for income taxes									(339,000)	(232,000)	(108,000)
Net income									171,000	(105,000)	$ 82,000
Total assets	22,161,000				21,355,000				22,161,000	21,355,000
Deposits	$ 3,748,000				$ 4,092,000				$ 3,748,000	$ 4,092,000

QUARTERLY RESULTS OF OPERATI160

QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	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]
Interest income	$ 894,000	$ 873,000	$ 846,000	$ 820,000	$ 815,000	$ 694,000	$ 566,000	$ 557,000	$ 3,433,000	$ 2,632,000	$ 2,115,000
Interest expense	124,000	115,000	101,000	91,000	80,000	69,000	60,000	54,000	431,000	263,000	164,000
Net interest income	770,000	758,000	745,000	729,000	735,000	625,000	506,000	503,000	3,002,000	2,369,000	1,951,000
Provision for credit losses	65,000	43,000	25,000	68,000	75,000	63,000	25,000	28,000	201,000	191,000	100,000
Noninterest income	340,000	330,000	325,000	312,000	334,000	303,000	271,000	242,000	1,307,000	1,150,000	1,039,000
Noninterest expense	633,000	680,000	694,000	707,000	681,000	713,000	523,000	491,000	2,714,000	2,408,000	1,976,000
Income before income taxes	412,000	365,000	351,000	266,000	313,000	152,000	229,000	226,000	1,394,000	920,000	914,000
Provision for income taxes	(20,000)	90,000	79,000	59,000	74,000	25,000	54,000	55,000	208,000	208,000	221,000
Net income	432,000	275,000	272,000	207,000	239,000	127,000	175,000	171,000	1,186,000	712,000	693,000
Dividends on preferred shares	19,000	19,000	19,000	19,000	19,000	18,000	20,000	8,000	76,000	65,000	32,000
Net income available to common shareholders	$ 413,000	$ 256,000	$ 253,000	$ 188,000	$ 220,000	$ 109,000	$ 155,000	$ 163,000	$ 1,110,000	$ 647,000	$ 661,000
Basic earnings per common share (in USD per share)	$ 0.38	$ 0.24	$ 0.23	$ 0.17	$ 0.20	$ 0.12	$ 0.19	$ 0.21	$ 1.02	$ 0.72	$ 0.82
Diluted earnings per common share (in USD per share)	$ 0.37	$ 0.23	$ 0.23	$ 0.17	$ 0.20	$ 0.11	$ 0.19	$ 0.20	$ 1	$ 0.70	$ 0.81