Comerica (CMA) 10-Q 31 Jul 18 2018 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 25, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Entity Registrant Name	Comerica INC /NEW/
Entity Central Index Key	28,412
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		171,399,203
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 1,424	$ 1,438
Interest-bearing deposits with banks	4,236	4,407
Other short-term investments	134	96
Investment securities available-for-sale	11,915	10,938	[1]
Investment securities held-to-maturity	0	1,266
Commercial loans	31,530	31,060
Real estate construction loans	3,257	2,961
Commercial mortgage loans	9,124	9,159
Lease financing	458	468
International loans	993	983
Residential mortgage loans	1,954	1,988
Consumer loans	2,476	2,554
Total loans	49,792	49,173
Less allowance for loan losses	(677)	(712)
Net loans	49,115	48,461
Premises and equipment	467	466
Accrued income and other assets	4,696	4,495
Total assets	71,987	71,567
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing deposits	30,316	32,071
Money market and interest-bearing checking deposits	22,544	21,500
Savings deposits	2,227	2,152
Customer certificates of deposit	2,089	2,165
Foreign office time deposits	34	15
Total interest-bearing deposits	26,894	25,832
Total deposits	57,210	57,903
Short-term borrowings	58	10
Accrued expenses and other liabilities	1,057	1,069
Medium- and long-term debt	5,583	4,622
Total liabilities	63,908	63,604
Common stock - $5 par value: Authorized - 325,000,000 shares; Issued - 228,164,824 shares	1,141	1,141
Capital surplus	2,144	2,122
Accumulated other comprehensive loss	(589)	(451)
Retained earnings	8,374	7,887
Less cost of common stock in treasury - 57,254,526 shares at 6/30/18 and 55,306,483 shares at 12/31/17	(2,991)	(2,736)
Total shareholders' equity	8,079	7,963
Total liabilities and shareholders' equity	$ 71,987	$ 71,567
[1]	Included auction-rate securities at amortized cost and fair value of $51 million and $49 million, respectively, as of December 31, 2017.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value	$ 5	$ 5
Common stock, authorized shares	325,000,000	325,000,000
Common stock, issued shares	228,164,824	228,164,824
Shares in treasury	57,254,526	55,306,483

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
INTEREST INCOME
Interest and fees on loans		$ 568		$ 453	$ 1,077		$ 874
Interest on investment securities		64		62	128		123
Interest on short-term investments		18		14	35		28
Total interest income		650		529	1,240		1,025
INTEREST EXPENSE
Interest on deposits		28		9	44		18
Interest on medium- and long-term debt	[1]	32		20	57		37
Total interest expense		60		29	101		55
Net interest income		590		500	1,139		970
Provision for credit losses		(29)		17	(17)		33
Net interest income after provision for credit losses		619		483	1,156		937
NONINTEREST INCOME
Card fees		60	[2]	80	119	[2]	157
Service charges on deposit accounts		53	[2]	57	107	[2]	115
Fiduciary income		52		51	104		100
Commercial lending fees		23		22	41		42
Letter of credit fees		11		11	21		23
Bank-owned life insurance		9		9	18		19
Foreign exchange income		12		11	24		22
Brokerage fees		6		6	13		11
Net securities gains		0		0	1		0
Other noninterest income		22		29	44		58
Total noninterest income		248		276	492		547
NONINTEREST EXPENSES
Salaries and benefits expense		250		231	505		476
Outside processing fee expense		64		88	125		175
Net occupancy expense		37		38	75		76
Equipment expense		11		11	22		22
Restructuring charges		11		14	27		25
Software expense		32		31	63		60
FDIC insurance expense		12		12	25		25
Advertising expense		8		7	14		11
Litigation-related expense		0		0	0		(2)
Other noninterest expenses		23		25	38		46
Total noninterest expenses		448		457	894		914
Income before income taxes		419		302	754		570
Provision for income taxes		93		99	147		165
Net Income		326		203	607		405
Less income allocated to participating securities		2		1	4		3
Net income attributable to common shares		$ 324		$ 202	$ 603		$ 402
Basic earnings per common share		$ 1.90		$ 1.15	$ 3.52		$ 2.30
Diluted earnings per common share		$ 1.87		$ 1.13	$ 3.46		$ 2.24
Comprehensive income		$ 290		$ 221	$ 468		$ 427
Cash dividends declared on common stock		$ 58		$ 46	$ 110		$ 88
Cash dividends declared per common share		$ 0.34		$ 0.26	$ 0.64		$ 0.49
[1]	Includes the effects of hedging.
[2]	Adoption of Topic 606 resulted in a change in presentation which records certain costs in the same category as the associated revenues. The effect of this change was to reduce card fees by $37 million and $71 million and service charges on deposit accounts by $1 million and 2 million for three- and six-month periods ended June 30, 2018, respectively. Refer to note 1 for further information.

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital Surplus	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock
BALANCE (Cumulative effect of change in accounting principle)	$ 1		$ 3		$ (2)
BALANCE at Dec. 31, 2016	7,796	$ 1,141	2,135	$ (383)	7,331	$ (2,428)
BALANCE (in shares) at Dec. 31, 2016		175.3
Net income	405				405
Other comprehensive income, net of tax	22			22
Cash dividends declared on common stock	(88)				(88)
Purchase of common stock	(257)					(257)
Purchase of common stock (in shares)		(3.7)
Net issuance of common stock under employee stock plans	82		(26)		(20)	128
Net issuance of common stock under employee stock plans (in shares)		2.8
Net issuance of common stock for warrants	0		(25)		(46)	71
Net issuance of common stock for warrants (in shares)		1.5
Share-based compensation	24		24
Other	0		(1)			1
Other (in shares)		0
BALANCE at Jun. 30, 2017	7,985	$ 1,141	2,110	(361)	7,580	(2,485)
BALANCE (in shares) at Jun. 30, 2017		175.9
BALANCE (Cumulative effect of change in accounting principle)	15			1	14
BALANCE at Dec. 31, 2017	7,963	$ 1,141	2,122	(451)	7,887	(2,736)
BALANCE (in shares) at Dec. 31, 2017		172.9
Net income	607				607
Other comprehensive income, net of tax	(139)			(139)
Cash dividends declared on common stock	(110)				(110)
Purchase of common stock	(328)					(328)
Purchase of common stock (in shares)		(3.4)
Net issuance of common stock under employee stock plans	37		(11)		(21)	69
Net issuance of common stock under employee stock plans (in shares)		1.3
Net issuance of common stock for warrants	0		(1)		(3)	4
Net issuance of common stock for warrants (in shares)		0.1
Share-based compensation	34		34
BALANCE at Jun. 30, 2018	$ 8,079	$ 1,141	$ 2,144	$ (589)	$ 8,374	$ (2,991)
BALANCE (in shares) at Jun. 30, 2018		170.9

Consolidated Statements Of Cha6

Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Stockholders' Equity [Abstract]
Cash dividends declared on common stock, per share	$ 0.34	$ 0.26	$ 0.64	$ 0.49

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net income	$ 607	$ 405
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(17)	33
Provision (benefit) for deferred income taxes	14	(19)
Depreciation and amortization	60	60
Net periodic defined benefit credit	(10)	(9)
Share-based compensation expense	34	24
Net amortization of securities	2	3
Accretion of loan purchase discount	0	2
Net securities gains	1	0
Net gains on sales of foreclosed property	1	1
Net change in accrued income receivable	(38)	(1)
Net change in accrued expenses payable	(51)	(17)
Other, net	15	174
Net cash provided by operating activities	614	650
INVESTING ACTIVITIES
Maturities and redemptions of investment securities available-for-sale	895	771
Sales of investment securities available-for-sale	5	1,259
Purchases of investment securities available-for-sale	(891)	(2,169)
Maturities and redemptions of investment securities held-to-maturity	0	153
Net change in loans	(651)	(370)
Proceeds from sales of foreclosed property	6	4
Net increase in premises and equipment	(41)	(27)
Purchases of Federal Home Loan Bank stock	(41)	(22)
Proceeds from settlement of BOLI policies	3	6
Other, net	(1)	2
Net cash used in investing activities	(716)	(393)
FINANCING ACTIVITIES
Net change in deposits	(737)	(2,084)
Net change in short-term borrowings	48	516
Federal Home Loan Bank advances of medium- and long-term debt	1,000	0
Terminations of medium- and long-term debt	0	16
Repurchases of common stock	(337)	(265)
Cash dividends paid on common stock	(104)	(81)
Issuances of common stock under employee stock plans	46	90
Other, net	1	(4)
Net cash used in financing activities	(83)	(1,844)
Net decrease in cash and cash equivalents	(185)	(1,587)
Cash and cash equivalents at beginning of period	5,845	7,218
Cash and cash equivalents at end of period	5,660	5,631
Interest paid	99	54
Income tax paid	94	130
Noncash investing and financing activities:
Loans transferred to other real estate	2	4
Securities transferred from held-to-maturity to available-for-sale	(1,266)	0
Securities transferred from available-for-sale to equity securities	$ 81	$ 0

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation and Accounting Policies	BASIS OF PRESENTATION AND ACCOUNTING POLICIES Organization The accompanying unaudited consolidated financial statements were prepared in accordance with United States (U.S.) generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, the statements do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation were included. The results of operations for the six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . Certain items in prior periods were reclassified to conform to the current presentation. For further information, refer to the consolidated financial statements and footnotes thereto included in the Annual Report of Comerica Incorporated and Subsidiaries (the Corporation) on Form 10-K for the year ended December 31, 2017 . Revenue Recognition Effective January 1, 2018, the Corporation adopted the provision of Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 606, "Revenue from Contracts with Customers" (Topic 606), using the modified retrospective method applied to all open contracts as of January 1, 2018. Under Topic 606, card fee revenue from certain products is generally presented net of network costs, including interchange costs, surcharge fees and assessment fees, as opposed to the previous presentation of associated network costs in outside processing fees in the Consolidated Statements of Comprehensive Income. Similar adjustments were made for other revenue streams that resulted in certain costs being recognized in the same category as the associated revenues in noninterest income. The adoption of Topic 606 resulted in decreases of $37 million in card fees and $1 million in service charges on deposits accounts, included in noninterest income, and a corresponding $38 million decrease in outside processing fees included in noninterest expenses, in the Consolidated Statements of Comprehensive Income for the three months ended June 30, 2018. For the six months ended June 30, 2018, the impact on the Consolidated Statements of Comprehensive Income was a $71 million decrease in card fees, a $2 million decrease in service charges on deposit accounts and a $73 million decrease in outside processing fee expense. The Corporation previously deferred recognition of certain treasury management fees included in service charges on deposit accounts in the Consolidated Statements of Comprehensive Income until the amount of compensation was considered fixed and determinable. Under the new guidance, the portion of these fees that are based on agreed upon rates less estimated credits expected to be earned by the customer is recognized as services are rendered. As a result, the Corporation recorded a transition adjustment of $14 million , after tax, to retained earnings, included in cumulative effect of change in accounting principles in the accompanying Consolidated Statements of Changes in Shareholders Equity. Similar adjustments were made for other revenue streams that resulted in an additional cumulative transition after-tax adjustment to retained earnings of $2 million . Revenues from contracts with customers may be recognized when services are complete or as they are rendered, although contracts are generally short-term by nature. Services provided over a period of time are typically transferred to customers evenly over the term of the contracts and revenue is recognized evenly over the period services are provided. Contract receivables are included in accrued income and other assets on the Consolidated Balance Sheets. Payment terms vary by services offered, and the timing between completion of performance obligations and payment is typically not significant. Card fees comprise interchange and other fee income earned on government card, commercial card, debit/Automated Teller Machine card and merchant payment processing programs. Card fees are presented net of network costs as performance obligations for card services are limited to transaction processing and settlement with the card network on behalf of the customers. Network costs were approximately $37 million and $26 million for the three months ended June 30, 2018 and 2017, respectively, and $71 million and $51 million for the six months ended June 30, 2018 and 2017, respectively. Fees for these services are primarily based on interchange rates set by the network and transaction volume. The Corporation also provides ongoing card program support services, for which fees are based on contractually agreed prices and customer demand for services. Service charges on deposit accounts comprise charges on retail and business accounts, including fees for treasury management services. These treasury management services include transaction-based services related to payment processing, overdrafts, non-sufficient funds and other deposit account activity, as well as account management services that are provided over time. Business customers can earn credits depending on deposit balances maintained with the Corporation, which may be used to offset fees. Fees and credits are based on predetermined, agreed upon rates. Fiduciary income includes fees and commissions from asset management, custody, recordkeeping, investment advisory and other services provided primarily to personal and institutional trust customers. Revenue is recognized as the services are performed and is based either on the market value of the assets managed or the services provided, as well as agreed upon rates. Commercial lending fees include both revenue from contracts with customers (primarily loan servicing fees) and other sources of revenue. Commercial loan servicing fees are based on contractually agreed prices and when the services are provided. Other sources of revenue in commercial lending fees primarily include fees assessed on the unused portion of commercial lines of credit (unused commitment fees) and syndication arrangements. Brokerage fees are commissions earned for facilitating securities transactions for customers, as well other brokerage services provided. Revenue is recognized when services are complete and are based on the type of services provided and agreed upon rates. The Corporation pays commissions based on brokerage fee revenue. These are typically recognized when incurred because the amortization period is one year or less and are included in salaries and benefits expense in the Consolidated Statements of Comprehensive Income. Other revenues, consisting primarily of other retail fees, investment banking fees and insurance commissions, are typically recognized when services or transactions are completed and are based on the type of services provided and agreed upon rates. Except as discussed above, commissions and other incentives paid to employees are generally based on several internal and external metrics and as a result are not solely dependent on revenue generating activities. Classification and Measurement of Financial Instruments Effective January 1, 2018, the Corporation adopted the provisions of Accounting Standards Update (ASU) No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities," (ASU 2016-01). ASU 2016-01 requires equity investments, other than equity method investments, to be measured at fair value with changes in fair value recognized in net income. At adoption, an immaterial amount of cumulative net unrealized losses on equity securities previously recognized in accumulated other comprehensive income (AOCI) was reclassified to the opening balance of retained earnings, included in cumulative effect of change in accounting principles in the accompanying Consolidated Statements of Changes in Shareholders Equity. Changes to the fair value of equity securities occurring after December 31, 2017, other than equity method investments, are included in net securities losses in the Consolidated Statements of Comprehensive Income. Also, as part of adopting ASU 2016-01, the Corporation refined the calculation used to determine the estimated fair value of loans disclosed in note 2 to the consolidated financial statements. Statement of Cash Flows The Corporation adopted FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” (ASU 2016-15) on January 1, 2018 and, as a result, reclassified $6 million of proceeds from settlement of bank-owned life insurance policies from operating activities to investing activities for the six-month period ended June 30, 2017. Defined Benefit Pension and Other Postretirement Costs The Corporation retrospectively adopted the provisions of ASU No. 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” (ASU 2017-07) on January 1, 2018, which requires employers to report service cost as part of compensation expense and the other components of net benefit credit separately from service cost. As a result, $12 million and $24 million of benefit from the other components of net benefit credit was reclassified from salaries and benefits expense to other noninterest expenses in the Consolidated Statements of Comprehensive Income for the three and six months ended June 30, 2017 , respectively. The Corporation based the adjustment to the prior periods on amounts disclosed in note 10. Derivatives Instruments and Hedging Activities The Corporation adopted ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” (ASU 2017-12), effective January 1, 2018. At transition, the Corporation elected to change the measurement methodology of all long-haul fair value hedges existing at December 31, 2017. The prior period effect of this election was a $1 million reduction to opening retained earnings, included in cumulative effect of change in accounting principles in the Consolidated Statements of Shareholders' Equity. In addition, the Corporation made a transition election to reclassify the portfolio of held-to-maturity securities to available-for-sale in January 2018 as the securities are eligible to be hedged. This resulted in the recognition of additional unrealized losses of $11 million at the date of transfer. Income Taxes The Tax Cuts and Jobs Act (the "Act"), enacted on December 22, 2017, reduced the U.S. federal corporate tax rate from 35 percent to 21 percent. Also, on December 22, 2017, the Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118), which provides guidance on accounting for tax effects of the Act. SAB 118 provides a measurement period of up to one year from the enactment date to complete the accounting. Based on the information available and current interpretation of the rules, the Corporation has made reasonable estimates of the impact of the reduction in the corporate tax rate and remeasurement of certain deferred tax assets and liabilities based on the rate at which they are expected to reverse in the future, generally 21 percent. The provisional amount recorded related to the remeasurement of the Corporation's deferred tax balance was $104 million , including $107 million recognized in the year ended December 31, 2017 and a $3 million downward revision to the estimated impact recorded in the six months ended June 30, 2018. The final impact of the Act may differ from these estimates as a result of changes in management’s interpretations and assumptions, as well as new guidance that may be issued by the Internal Revenue Service (IRS). Pending Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842),” (ASU 2016-02), to increase the transparency and comparability of lease recognition and disclosure. ASU 2016-02 requires lessees to recognize lease contracts with a term greater than one year on the balance sheet, while recognizing expenses on the income statement in a manner similar to current guidance. ASU 2016-02 is effective for the Corporation on January 1, 2019 and must be applied using the modified retrospective approach. In July 2018, the FASB issued ASU 2018-11 “Leases (Topic 842): Targeted Improvements,” which provides lessees the option to apply the new leasing standard to all open leases as of the adoption date. The Corporation expects to make use of this transition option and is currently finalizing review of key assumptions and evaluation of service contracts for embedded leases. Based on preliminary evaluation, the right-of-use asset and corresponding lease obligation liability are expected to range between $450 million and $550 million at adoption, resulting in an 8- to 10-basis point decrease in the common equity tier 1 capital (CET1) ratio. Preliminary estimates are based on the current interest rate environment which may differ from those at the time of adoption of the standard. The Corporation will continue to evaluate other impacts of adoption but does not anticipate these to be significant. In June 2016, the FASB issued ASU No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments," (ASU 2016-13), which addresses concerns regarding the perceived delay in recognition of credit losses under the existing incurred loss model. The amendment introduces a new, single model for recognizing credit losses on all financial instruments presented on cost basis. Under the new model, entities must estimate current expected credit losses by considering all available relevant information, including historical and current information, as well as reasonable and supportable forecasts of future events. The update also requires additional qualitative and quantitative information to allow users to better understand the credit risk within the portfolio and the methodologies for determining the allowance for credit losses. ASU 2016-13 is effective for the Corporation on January 1, 2020 and must be applied using the modified retrospective approach with limited exceptions. Early adoption is permitted. The Corporation will adopt the standard on January 1, 2020 and is currently evaluating the impact of adoption.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The Corporation utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. The determination of fair values of financial instruments often requires the use of estimates. In cases where quoted market values in an active market are not available, the Corporation uses present value techniques and other valuation methods to estimate the fair values of its financial instruments. These valuation methods require considerable judgment and the resulting estimates of fair value can be significantly affected by the assumptions made and methods used. Equity securities, investment securities available-for-sale, derivatives and deferred compensation plan assets and liabilities are recorded at fair value on a recurring basis. Additionally, from time to time, the Corporation may be required to record other assets and liabilities at fair value on a nonrecurring basis, such as impaired loans, other real estate (primarily foreclosed property), nonmarketable equity securities and certain other assets and liabilities. These nonrecurring fair value adjustments typically involve write-downs of individual assets or application of lower of cost or fair value accounting. Refer to note 1 to the consolidated financial statements in the Corporation's Annual Report on Form 10-K for the year ended December 31, 2017 for further information about the fair value hierarchy, descriptions of the valuation methodologies and key inputs used to measure financial assets and liabilities recorded at fair value, as well as a description of the methods and significant assumptions used to estimate fair value disclosures for financial instruments not recorded at fair value in their entirety on a recurring basis. ASSETS AND LIABILITIES RECORDED AT FAIR VALUE ON A RECURRING BASIS The following tables present the recorded amount of assets and liabilities measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 . (in millions) Total Level 1 Level 2 Level 3 June 30, 2018 Deferred compensation plan assets $ 91 $ 91 $ — $ — Equity securities 41 41 — — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,699 2,699 — — Residential mortgage-backed securities (a) 9,216 — 9,216 — Total investment securities available-for-sale 11,915 2,699 9,216 — Derivative assets: Interest rate contracts 35 — 29 6 Energy derivative contracts 177 — 177 — Foreign exchange contracts 39 — 39 — Warrants 2 — — 2 Total derivative assets 253 — 245 8 Total assets at fair value $ 12,300 $ 2,831 $ 9,461 $ 8 Derivative liabilities: Interest rate contracts $ 117 $ — $ 117 $ — Energy derivative contracts 177 — 177 — Foreign exchange contracts 32 — 32 — Total derivative liabilities 326 — 326 — Deferred compensation plan liabilities 91 91 — — Total liabilities at fair value $ 417 $ 91 $ 326 $ — December 31, 2017 Trading securities: Deferred compensation plan assets $ 92 $ 92 $ — $ — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,727 2,727 — — Residential mortgage-backed securities (a) 8,124 — 8,124 — State and municipal securities 5 — — 5 (b) Equity and other non-debt securities 82 38 — 44 (b) Total investment securities available-for-sale 10,938 2,765 8,124 49 Derivative assets: Interest rate contracts 57 — 43 14 Energy derivative contracts 93 — 93 — Foreign exchange contracts 42 — 42 — Warrants 2 — — 2 Total derivative assets 194 — 178 16 Total assets at fair value 11,224 $ 2,857 $ 8,302 $ 65 Derivative liabilities: Interest rate contracts 59 — 59 — Energy derivative contracts 91 — 91 — Foreign exchange contracts 40 — 40 — Total derivative liabilities 190 — 190 — Deferred compensation plan liabilities 92 92 — — Total liabilities at fair value $ 282 $ 92 $ 190 $ — (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Auction-rate securities. There were no transfers of assets or liabilities recorded at fair value on a recurring basis into or out of Level 1, Level 2 and Level 3 fair value measurements during each of the three- and six-month periods ended June 30, 2018 and 2017 . The following table summarizes the changes in Level 3 assets and liabilities measured at fair value on a recurring basis for the three- and six-month periods ended June 30, 2018 and 2017 . Net Realized/Unrealized Gains (Losses) (Pretax) Recorded in Earnings Balance at Beginning of Period Balance at End of Period Change in Classification (a) Sales and Redemptions (in millions) Realized Unrealized Three Months Ended June 30, 2018 Derivative assets: Interest rate contracts $ 7 $ — $ — $ (1 ) (b) $ — $ 6 Warrants 2 — 1 (b) — (1 ) 2 Three Months Ended June 30, 2017 Investment securities available-for-sale: State and municipal securities (c) $ 5 $ — $ — $ — $ — $ 5 Equity and other non-debt securities (c) 46 — — — — 46 Total investment securities available-for-sale 51 — — — — 51 Derivative assets: Interest rate contracts 11 — — 2 (b) — 13 Warrants 2 — 4 (b) — (4 ) 2 Six Months Ended June 30, 2018 Equity securities $ — $ 44 $ — $ — $ (44 ) $ — Investment securities available-for-sale: State and municipal securities (c) 5 — — — (5 ) — Equity and other non-debt securities (c) 44 (44 ) — — — — Total investment securities available-for-sale 49 (44 ) — — (5 ) — Derivative assets: Interest rate contracts 14 — — (8 ) (b) — 6 Warrants 2 — 1 (b) — (1 ) 2 Six Months Ended June 30, 2017 Investment securities available-for-sale: State and municipal securities (c) $ 7 $ — $ — $ — $ (2 ) $ 5 Equity and other non-debt securities (c) 47 — — — (1 ) 46 Total investment securities available-for-sale 54 — — — (3 ) 51 Derivative assets: Interest rate contracts 11 — — 2 (b) — 13 Warrants 3 — 5 (b) (1 ) (b) (5 ) 2 (a) Reflects the reclassification of equity securities resulting from the adoption of ASU 2016-01. (b) Realized and unrealized gains and losses due to changes in fair value recorded in Other Noninterest Income on the Consolidated Statements of Comprehensive Income. (c) Auction-rate securities. ASSESTS AND LIABILITIES AT FAIR VALUE ON A NONRECURRING BASIS The Corporation may be required to record certain assets and liabilities at fair value on a nonrecurring basis. These include assets that are recorded at the lower of cost or fair value, and were recognized at fair value since it was less than cost at the end of the period. The following table presents assets recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 . No liabilities were recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 . (in millions) Level 3 June 30, 2018 Loans: Commercial $ 76 Commercial mortgage 4 Total loans 80 Other real estate 1 Total assets at fair value $ 81 December 31, 2017 Loans: Commercial $ 111 Commercial mortgage 5 Total assets at fair value $ 116 Level 3 assets recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 included loans for which a specific allowance was established based on the fair value of collateral and other real estate for which fair value of the properties was less than the cost basis. For both asset classes, the unobservable inputs were the additional adjustments applied by management to the appraised values to reflect such factors as non-current appraisals and revisions to estimated time to sell. These adjustments are determined based on qualitative judgments made by management on a case-by-case basis and are not quantifiable inputs, although they are used in the determination of fair value. ESTIMATED FAIR VALUES OF FINANCIAL INSTRUMENTS NOT RECORDED AT FAIR VALUE ON A RECURRING BASIS The Corporation typically holds the majority of its financial instruments until maturity and thus does not expect to realize many of the estimated fair value amounts disclosed. The disclosures also do not include estimated fair value amounts for items that are not defined as financial instruments, but which have significant value. These include such items as core deposit intangibles, the future earnings potential of significant customer relationships and the value of trust operations and other fee generating businesses. The Corporation believes the imprecision of an estimate could be significant. The carrying amount and estimated fair value of financial instruments not recorded at fair value in their entirety on a recurring basis on the Corporation’s Consolidated Balance Sheets are as follows: Carrying Amount Estimated Fair Value (in millions) Total Level 1 Level 2 Level 3 June 30, 2018 Assets Cash and due from banks $ 1,424 $ 1,424 $ 1,424 $ — $ — Interest-bearing deposits with banks 4,236 4,236 4,236 — — Loans held-for-sale 2 2 — 2 — Total loans, net of allowance for loan losses (a) 49,115 48,929 — — 48,929 Customers’ liability on acceptances outstanding 3 3 3 — — Restricted equity investments 248 248 248 — — Nonmarketable equity securities (b) 6 11 Liabilities Demand deposits (noninterest-bearing) 30,316 30,316 — 30,316 — Interest-bearing deposits 24,805 24,805 — 24,805 — Customer certificates of deposit 2,089 2,061 — 2,061 — Total deposits 57,210 57,182 — 57,182 — Short-term borrowings 58 58 58 — — Acceptances outstanding 3 3 3 — — Medium- and long-term debt 5,583 5,588 — 5,588 — Credit-related financial instruments (60 ) (60 ) — — (60 ) December 31, 2017 Assets Cash and due from banks $ 1,438 $ 1,438 $ 1,438 $ — $ — Interest-bearing deposits with banks 4,407 4,407 4,407 — — Investment securities held-to-maturity 1,266 1,246 — 1,246 — Loans held-for-sale 4 4 — 4 — Total loans, net of allowance for loan losses (a) 48,461 48,153 — — 48,153 Customers’ liability on acceptances outstanding 2 2 2 — — Restricted equity investments 207 207 207 — — Nonmarketable equity securities (b) 6 9 Liabilities Demand deposits (noninterest-bearing) 32,071 32,071 — 32,071 — Interest-bearing deposits 23,667 23,667 — 23,667 — Customer certificates of deposit 2,165 2,142 — 2,142 — Total deposits 57,903 57,880 — 57,880 — Short-term borrowings 10 10 10 — — Acceptances outstanding 2 2 2 — — Medium- and long-term debt 4,622 4,636 — 4,636 — Credit-related financial instruments (67 ) (67 ) — — (67 ) (a) Included $80 million and $116 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 , respectively. (b) Certain investments that are measured at fair value using the net asset value have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES A summary of the Corporation’s investment securities follows: (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value June 30, 2018 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,744 $ — $ 45 $ 2,699 Residential mortgage-backed securities (a) 9,499 10 293 9,216 Total investment securities available-for-sale $ 12,243 $ 10 $ 338 $ 11,915 December 31, 2017 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,743 $ — $ 16 $ 2,727 Residential mortgage-backed securities (a) 8,230 22 128 8,124 State and municipal securities 5 — — 5 Equity and other non-debt securities 83 1 2 82 Total investment securities available-for-sale (b) $ 11,061 $ 23 $ 146 $ 10,938 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,266 $ — $ 20 $ 1,246 (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Included auction-rate securities at amortized cost and fair value of $51 million and $49 million , respectively, as of December 31, 2017 . (c) The amortized cost of investment securities held-to-maturity included net unrealized losses of $9 million at December 31, 2017 related to securities transferred from available-for-sale in 2014, which are included in accumulated other comprehensive loss. In connection with the adoption of ASU 2016-01 on January 1, 2018, cumulative unrealized gains and losses on available-for-sale equity and other non-debt securities were reclassified to retained earnings and the carrying value was reclassified to other short-term investments. Additionally, the Corporation transferred residential mortgage-backed securities with a book value of approximately $1.3 billion from held-to-maturity to available-for-sale upon the adoption of ASU 2017-12. For additional information about the adoption of ASU 2016-01, refer to note 1. A summary of the Corporation’s investment securities in an unrealized loss position as of June 30, 2018 and December 31, 2017 follows: Temporarily Impaired Less than 12 Months 12 Months or more Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses June 30, 2018 U.S. Treasury and other U.S. government agency securities $ 2,699 $ 45 $ — $ — $ 2,699 $ 45 Residential mortgage-backed securities (a) 4,544 106 3,934 187 8,478 293 Total temporarily impaired securities $ 7,243 $ 151 $ 3,934 $ 187 $ 11,177 $ 338 December 31, 2017 U.S. Treasury and other U.S. government agency securities $ 2,727 $ 16 $ — $ — $ 2,727 $ 16 Residential mortgage-backed securities (a) 3,845 32 4,003 125 7,848 157 State and municipal securities (b) — — 5 — (c) 5 — (c) Equity and other non-debt securities (b) — — 44 2 44 2 Total temporarily impaired securities $ 6,572 $ 48 $ 4,052 $ 127 $ 10,624 $ 175 (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Primarily auction-rate securities. (c) Unrealized losses less than $0.5 million. At June 30, 2018 , the Corporation had 399 securities in an unrealized loss position with no credit impairment, including 29 U.S. Treasury securities and 370 residential mortgage-backed securities. The unrealized losses for these securities resulted from changes in market interest rates, not changes in credit quality. The Corporation ultimately expects full collection of the carrying amount of these securities, does not intend to sell the securities in an unrealized loss position, and it is not more-likely-than-not that the Corporation will be required to sell the securities in an unrealized loss position prior to recovery of amortized cost. The Corporation does not consider these securities to be other-than-temporarily impaired at June 30, 2018 . The following table summarizes the amortized cost and fair values of debt securities by contractual maturity. Securities with multiple maturity dates are classified in the period of final maturity. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (in millions) June 30, 2018 Amortized Cost Fair Value Contractual maturity Within one year $ 100 $ 100 After one year through five years 3,008 2,963 After five years through ten years 1,752 1,722 After ten years 7,383 7,130 Total investment securities $ 12,243 $ 11,915 Included in the contractual maturity distribution in the table above were residential mortgage-backed securities with total amortized cost of $9.5 billion and fair value of $9.2 billion . The actual cash flows of mortgage-backed securities may differ from contractual maturity as the borrowers of the underlying loans may exercise prepayment options. At June 30, 2018 , investment securities with a carrying value of $393 million were pledged where permitted or required by law to secure $272 million of liabilities, primarily public and other deposits of state and local government agencies and derivative instruments.

Credit Quality And Allowance Fo

Credit Quality And Allowance For Credit Losses	6 Months Ended
	Jun. 30, 2018
Credit Quality And Allowance For Credit Losses [Abstract]
Credit Quality And Allowance For Credit Losses	CREDIT QUALITY AND ALLOWANCE FOR CREDIT LOSSES The following table presents an aging analysis of the recorded balance of loans. Loans Past Due and Still Accruing (in millions) 30-59 Days 60-89 Days 90 Days or More Total Nonaccrual Loans Current Loans Total Loans June 30, 2018 Business loans: Commercial $ 66 $ 8 $ 13 $ 87 $ 171 $ 31,272 $ 31,530 Real estate construction: Commercial Real Estate business line (a) 6 — — 6 — 2,882 2,888 Other business lines (b) 6 — — 6 — 363 369 Total real estate construction 12 — — 12 — 3,245 3,257 Commercial mortgage: Commercial Real Estate business line (a) 4 10 — 14 9 1,724 1,747 Other business lines (b) 21 5 7 33 20 7,324 7,377 Total commercial mortgage 25 15 7 47 29 9,048 9,124 Lease financing — — — — 2 456 458 International 2 — — 2 4 987 993 Total business loans 105 23 20 148 206 45,008 45,362 Retail loans: Residential mortgage 16 1 — 17 29 1,908 1,954 Consumer: Home equity 4 1 — 5 19 1,707 1,731 Other consumer 2 — — 2 — 743 745 Total consumer 6 1 — 7 19 2,450 2,476 Total retail loans 22 2 — 24 48 4,358 4,430 Total loans $ 127 $ 25 $ 20 $ 172 $ 254 $ 49,366 $ 49,792 December 31, 2017 Business loans: Commercial $ 79 $ 134 $ 12 $ 225 $ 309 $ 30,526 $ 31,060 Real estate construction: Commercial Real Estate business line (a) 3 — — 3 — 2,627 2,630 Other business lines (b) 4 — — 4 — 327 331 Total real estate construction 7 — — 7 — 2,954 2,961 Commercial mortgage: Commercial Real Estate business line (a) 14 — — 14 9 1,808 1,831 Other business lines (b) 27 6 22 55 22 7,251 7,328 Total commercial mortgage 41 6 22 69 31 9,059 9,159 Lease financing — — — — 4 464 468 International 13 — — 13 6 964 983 Total business loans 140 140 34 314 350 43,967 44,631 Retail loans: Residential mortgage 10 2 — 12 31 1,945 1,988 Consumer: Home equity 5 1 — 6 21 1,789 1,816 Other consumer 4 — 1 5 — 733 738 Total consumer 9 1 1 11 21 2,522 2,554 Total retail loans 19 3 1 23 52 4,467 4,542 Total loans $ 159 $ 143 $ 35 $ 337 $ 402 $ 48,434 $ 49,173 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. The following table presents loans by credit quality indicator, based on internal risk ratings assigned to each business loan at the time of approval and subjected to subsequent reviews, generally at least annually, and to pools of retail loans with similar risk characteristics. Internally Assigned Rating (in millions) Pass (a) Special Mention (b) Substandard (c) Nonaccrual (d) Total June 30, 2018 Business loans: Commercial $ 30,185 $ 580 $ 594 $ 171 $ 31,530 Real estate construction: Commercial Real Estate business line (e) 2,868 20 — — 2,888 Other business lines (f) 362 7 — — 369 Total real estate construction 3,230 27 — — 3,257 Commercial mortgage: Commercial Real Estate business line (e) 1,678 15 45 9 1,747 Other business lines (f) 7,144 133 80 20 7,377 Total commercial mortgage 8,822 148 125 29 9,124 Lease financing 449 4 3 2 458 International 969 2 18 4 993 Total business loans 43,655 761 740 206 45,362 Retail loans: Residential mortgage 1,925 — — 29 1,954 Consumer: Home equity 1,704 — 8 19 1,731 Other consumer 743 1 1 — 745 Total consumer 2,447 1 9 19 2,476 Total retail loans 4,372 1 9 48 4,430 Total loans $ 48,027 $ 762 $ 749 $ 254 $ 49,792 December 31, 2017 Business loans: Commercial $ 29,263 $ 591 $ 897 $ 309 $ 31,060 Real estate construction: Commercial Real Estate business line (e) 2,630 — — — 2,630 Other business lines (f) 327 4 — — 331 Total real estate construction 2,957 4 — — 2,961 Commercial mortgage: Commercial Real Estate business line (e) 1,759 20 43 9 1,831 Other business lines (f) 7,099 115 92 22 7,328 Total commercial mortgage 8,858 135 135 31 9,159 Lease financing 440 23 1 4 468 International 946 11 20 6 983 Total business loans 42,464 764 1,053 350 44,631 Retail loans: Residential mortgage 1,955 2 — 31 1,988 Consumer: Home equity 1,786 1 8 21 1,816 Other consumer 737 1 — — 738 Total consumer 2,523 2 8 21 2,554 Total retail loans 4,478 4 8 52 4,542 Total loans $ 46,942 $ 768 $ 1,061 $ 402 $ 49,173 (a) Includes all loans not included in the categories of special mention, substandard or nonaccrual. (b) Special mention loans are accruing loans that have potential credit weaknesses that deserve management’s close attention, such as loans to borrowers who may be experiencing financial difficulties that may result in deterioration of repayment prospects from the borrower at some future date. This category is generally consistent with the "special mention" category as defined by regulatory authorities. (c) Substandard loans are accruing loans that have a well-defined weakness, or weaknesses, such as loans to borrowers who may be experiencing losses from operations or inadequate liquidity of a degree and duration that jeopardizes the orderly repayment of the loan. Substandard loans also are distinguished by the distinct possibility of loss in the future if these weaknesses are not corrected. This category is generally consistent with the "substandard" category as defined by regulatory authorities. (d) Nonaccrual loans are loans for which the accrual of interest has been discontinued. For further information regarding nonaccrual loans, refer to the Nonperforming Assets subheading in Note 1 - Basis of Presentation and Accounting Policies - on pages F-51 and F-52 in the Corporation's 2017 Annual Report. A significant majority of nonaccrual loans are generally consistent with the "substandard" category and the remainder are generally consistent with the "doubtful" category as defined by regulatory authorities. (e) Primarily loans to real estate developers. (f) Primarily loans secured by owner-occupied real estate. The following table summarizes nonperforming assets. (in millions) June 30, 2018 December 31, 2017 Nonaccrual loans $ 254 $ 402 Reduced-rate loans (a) 8 8 Total nonperforming loans 262 410 Foreclosed property (b) 2 5 Total nonperforming assets $ 264 $ 415 (a) There were no reduced-rate business loans at both June 30, 2018 and December 31, 2017 . Reduced-rate retail loans were $8 million at both June 30, 2018 and December 31, 2017 . (b) Included $1 million and $4 million of foreclosed residential real estate properties at June 30, 2018 and December 31, 2017 , respectively. There were no retail loans secured by residential real estate properties in process of foreclosure included in nonaccrual loans at both June 30, 2018 and December 31, 2017 . Allowance for Credit Losses The following table details the changes in the allowance for loan losses and related loan amounts. 2018 2017 (in millions) Business Loans Retail Loans Total Business Loans Retail Loans Total Three Months Ended June 30 Allowance for loan losses: Balance at beginning of period $ 653 $ 45 $ 698 $ 661 $ 47 $ 708 Loan charge-offs (18 ) (2 ) (20 ) (37 ) (2 ) (39 ) Recoveries on loans previously charged-off 22 1 23 20 1 21 Net loan recoveries (charge-offs) 4 (1 ) 3 (17 ) (1 ) (18 ) Provision for loan losses (21 ) (2 ) (23 ) 17 (2 ) 15 Foreign currency translation adjustment (1 ) — (1 ) — — — Balance at end of period $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 Six Months Ended June 30 Allowance for loan losses: Balance at beginning of period $ 661 $ 51 $ 712 $ 682 $ 48 $ 730 Loan charge-offs (54 ) (3 ) (57 ) (79 ) (4 ) (83 ) Recoveries on loans previously charged-off 30 2 32 29 3 32 Net loan charge-offs (24 ) (1 ) (25 ) (50 ) (1 ) (51 ) Provision for loan losses (1 ) (8 ) (9 ) 29 (3 ) 26 Foreign currency translation adjustment (1 ) — (1 ) — — — Balance at end of period $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 As a percentage of total loans 1.40 % 0.96 % 1.36 % 1.47 % 0.98 % 1.43 % June 30 Allowance for loan losses: Individually evaluated for impairment $ 39 $ — $ 39 $ 93 $ 1 $ 94 Collectively evaluated for impairment 596 42 638 568 43 611 Total allowance for loan losses $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 Loans: Individually evaluated for impairment $ 310 $ 30 $ 340 $ 509 $ 41 $ 550 Collectively evaluated for impairment 45,052 4,400 49,452 44,388 4,470 48,858 Total loans evaluated for impairment $ 45,362 $ 4,430 $ 49,792 $ 44,897 $ 4,511 $ 49,408 Changes in the allowance for credit losses on lending-related commitments, included in accrued expenses and other liabilities on the Consolidated Balance Sheets, are summarized in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Balance at beginning of period $ 40 $ 46 $ 42 $ 41 Provision for credit losses on lending-related commitments (6 ) 2 (8 ) 7 Balance at end of period $ 34 $ 48 $ 34 $ 48 Individually Evaluated Impaired Loans The following table presents additional information regarding individually evaluated impaired loans. Recorded Investment In: (in millions) Impaired Loans with No Related Allowance Impaired Loans with Related Allowance Total Impaired Loans Unpaid Principal Balance Related Allowance for Loan Losses June 30, 2018 Business loans: Commercial $ 85 $ 154 $ 239 $ 313 $ 35 Commercial mortgage: Commercial Real Estate business line (a) 37 3 40 49 — Other business lines (b) — 26 26 29 3 Total commercial mortgage 37 29 66 78 3 International 3 2 5 9 1 Total business loans 125 185 310 400 39 Retail loans: Residential mortgage 11 8 19 20 — Consumer: Home equity 10 — 10 13 — Other consumer 1 — 1 1 — Total consumer 11 — 11 14 — Total retail loans (c) 22 8 30 34 — Total individually evaluated impaired loans $ 147 $ 193 $ 340 $ 434 $ 39 December 31, 2017 Business loans: Commercial $ 105 $ 267 $ 372 $ 460 $ 63 Commercial mortgage: Commercial Real Estate business line (a) 39 1 40 49 — Other business lines (b) 3 22 25 29 3 Total commercial mortgage 42 23 65 78 3 International — 6 6 17 1 Total business loans 147 296 443 555 67 Retail loans: Residential mortgage 14 8 22 22 — Consumer: Home equity 11 — 11 14 — Other consumer 1 — 1 2 — Total consumer 12 — 12 16 — Total retail loans (c) 26 8 34 38 — Total individually evaluated impaired loans $ 173 $ 304 $ 477 $ 593 $ 67 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. (c) Individually evaluated retail loans generally have no related allowance for loan losses, primarily due to policy which results in direct write-downs of most restructured retail loans. The following table presents information regarding average individually evaluated impaired loans and the related interest recognized as of June 30, 2018 and 2017. Interest income recognized for the period primarily related to performing restructured loans. Individually Evaluated Impaired Loans 2018 2017 (in millions) Average Balance for the Period Interest Income Recognized for the Period Average Balance for the Period Interest Income Recognized for the Period Three Months Ended June 30 Business loans: Commercial $ 277 $ 1 $ 473 $ 2 Commercial mortgage: Commercial Real Estate business line (a) 40 1 7 — Other business lines (b) 25 — 35 — Total commercial mortgage 65 1 42 — International 4 — 7 — Total business loans 346 2 522 2 Retail loans: Residential mortgage 19 — 27 — Consumer loans: Home equity 11 — 12 — Other consumer 1 — 2 — Total consumer 12 — 14 — Total retail loans 31 — 41 — Total individually evaluated impaired loans $ 377 $ 2 $ 563 $ 2 Six Months Ended June 30 Business loans: Commercial $ 309 $ 2 $ 487 $ 4 Commercial mortgage: Commercial Real Estate business line (a) 40 2 7 — Other business lines (b) 25 — 34 — Total commercial mortgage 65 2 41 — International 5 — 9 — Total business loans 379 4 537 4 Retail loans: Residential mortgage 20 — 27 — Consumer: Home equity 11 — 13 — Other consumer 1 — 3 — Total consumer 12 — 16 — Total retail loans 32 — 43 — Total individually evaluated impaired loans $ 411 $ 4 $ 580 $ 4 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. Troubled Debt Restructurings The following table details the recorded balance at June 30, 2018 and 2017 of loans considered to be troubled debt restructurings (TDRs) that were restructured during the three- and six-month periods ended June 30, 2018 and 2017 , by type of modification. In cases of loans with more than one type of modification, the loans were categorized based on the most significant modification. 2018 2017 Type of Modification Type of Modification (in millions) Principal Deferrals (a) Interest Rate Reductions Total Modifications Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Three Months Ended June 30 Business loans: Commercial $ 25 $ — $ 25 $ 47 $ — $ 36 $ 83 Commercial mortgage: Other business lines (c) — — — 1 — — 1 Total business loans 25 — 25 48 — 36 84 Retail loans: Consumer: Home equity (d) — 1 1 — 1 — 1 Total loans $ 25 $ 1 $ 26 $ 48 $ 1 $ 36 $ 85 Six Months Ended June 30 Business loans: Commercial $ 45 $ — $ 45 $ 96 $ — $ 36 $ 132 Commercial mortgage: Other business lines (c) 1 — 1 4 — — 4 Total business loans 46 — 46 100 — 36 136 Retail loans: Consumer: Home equity (d) 1 1 2 1 2 — 3 Total loans $ 47 $ 1 $ 48 $ 101 $ 2 $ 36 $ 139 (a) Primarily represents loan balances where terms were extended 90 days or more at or above contractual interest rates. (b) Loan restructurings whereby the original loan is restructured into two notes: an "A" note, which generally reflects the portion of the modified loan which is expected to be collected; and a "B" note, which is generally fully charged off. (c) Primarily loans to secured by owner-occupied real estate. (d) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt. At June 30, 2018 and December 31, 2017 , commitments to lend additional funds to borrowers whose terms have been modified in TDRs totaled $44 million and $31 million , respectively. The majority of the modifications considered to be TDRs that occurred during the six months ended June 30, 2018 and 2017 were principal deferrals. The Corporation charges interest on principal balances outstanding during deferral periods. Additionally, none of the modifications involved forgiveness of principal. As a result, the current and future financial effects of the recorded balance of loans considered to be TDRs that were restructured during the six months ended June 30, 2018 and 2017 were insignificant. On an ongoing basis, the Corporation monitors the performance of modified loans to their restructured terms. The allowance for loan losses continues to be reassessed on the basis of an individual evaluation of the loan. The following table presents information regarding the recorded balance at June 30, 2018 and 2017 of loans modified by principal deferral and interest rate reduction during the twelve-month periods ended June 30, 2018 and 2017 . Principal Deferrals Interest Rate Reductions (in millions) 2018 2017 2018 2017 Balance at June 30, Business loans: Commercial $ 97 $ 141 $ — $ — Commercial mortgage: Commercial Real Estate business line (a) 37 1 — — Other business lines (b) 2 7 — — Total commercial mortgage 39 8 — — Total business loans 136 149 — — Retail loans: Consumer: Home equity (c) 1 2 2 3 Total principal deferrals $ 137 $ 151 $ 2 $ 3 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. (c) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt. There were no loans restructured into two notes (AB note restructures) during the twelve-month periods ended June 30, 2018 , compared to loans with a carrying value of $68 million during the twelve-month period ended June 30, 2017 . For principal deferrals, incremental deterioration in the credit quality of the loan, represented by a downgrade in the risk rating of the loan, for example, due to missed interest payments or a reduction of collateral value, is considered a subsequent default. For interest rate reductions and AB note restructures, a subsequent payment default is defined in terms of delinquency, when a principal or interest payment is 90 days past due. There were no subsequent defaults of principal deferrals, interest rate reductions or AB note restructures during the three- and six-month periods ended June 30, 2018 and 2017 .

Derivative And Credit-Related F

Derivative And Credit-Related Financial Instruments	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative And Credit-Related Financial Instruments	DERIVATIVE AND CREDIT-RELATED FINANCIAL INSTRUMENTS In the normal course of business, the Corporation enters into various transactions involving derivative and credit-related financial instruments to manage exposure to fluctuations in interest rate, foreign currency and other market risks and to meet the financing needs of customers (customer-initiated derivatives). These financial instruments involve, to varying degrees, elements of market and credit risk. Market and credit risk are included in the determination of fair value. Market risk is the potential loss that may result from movements in interest rates, foreign currency exchange rates or energy commodity prices that cause an unfavorable change in the value of a financial instrument. The Corporation manages this risk by establishing monetary exposure limits and monitoring compliance with those limits. Market risk inherent in interest rate and energy contracts entered into on behalf of customers is mitigated by taking offsetting positions, except in those circumstances when the amount, tenor and/or contract rate level results in negligible economic risk, whereby the cost of purchasing an offsetting contract is not economically justifiable. The Corporation mitigates most of the inherent market risk in foreign exchange contracts entered into on behalf of customers by taking offsetting positions and manages the remainder through individual foreign currency position limits and aggregate value-at-risk limits. These limits are established annually and positions are monitored quarterly. Market risk inherent in derivative instruments held or issued for risk management purposes is typically offset by changes in the fair value of the assets or liabilities being hedged. Credit risk is the possible loss that may occur in the event of nonperformance by the counterparty to a financial instrument. The Corporation attempts to minimize credit risk arising from customer-initiated derivatives by evaluating the creditworthiness of each customer, adhering to the same credit approval process used for traditional lending activities and obtaining collateral as deemed necessary. Derivatives with dealer counterparties are either cleared through a clearinghouse or settled directly with a single counterparty. For derivatives settled directly with dealer counterparties, the Corporation utilizes counterparty risk limits and monitoring procedures as well as master netting arrangements and bilateral collateral agreements to facilitate the management of credit risk. Master netting arrangements effectively reduce credit risk by permitting settlement of positive and negative positions and offset cash collateral held with the same counterparty on a net basis. Bilateral collateral agreements require daily exchange of cash or highly rated securities issued by the U.S. Treasury or other U.S. government entities to collateralize amounts due to either party. At June 30, 2018 , counterparties with bilateral collateral agreements had pledged $3 million of marketable investment securities and deposited $10 million of cash with the Corporation to secure the fair value of contracts in an unrealized gain position, and the Corporation had pledged $10 million of marketable investment securities and posted $131 million of cash as collateral for contracts in an unrealized loss position. For those counterparties not covered under bilateral collateral agreements, collateral is obtained, if deemed necessary, based on the results of management’s credit evaluation of the counterparty. Collateral varies, but may include cash, investment securities, accounts receivable, equipment or real estate. Included in the fair value of derivative instruments are credit valuation adjustments reflecting counterparty credit risk. These adjustments are determined by applying a credit spread for the counterparty or the Corporation, as appropriate, to the total expected exposure of the derivative. There were no derivative instruments with credit-risk-related contingent features that were in a liability position at June 30, 2018 . Derivative Instruments Derivative instruments utilized by the Corporation are negotiated over-the-counter and primarily include swaps, caps and floors, forward contracts and options, each of which may relate to interest rates, energy commodity prices or foreign currency exchange rates. Swaps are agreements in which two parties periodically exchange cash payments based on specified indices applied to a specified notional amount until a stated maturity. Caps and floors are agreements which entitle the buyer to receive cash payments based on the difference between a specified reference rate or price and an agreed strike rate or price, applied to a specified notional amount until a stated maturity. Forward contracts are over-the-counter agreements to buy or sell an asset at a specified future date and price. Options are similar to forward contracts except the purchaser has the right, but not the obligation, to buy or sell the asset during a specified period or at a specified future date. Over-the-counter contracts are tailored to meet the needs of the counterparties involved and, therefore, contain a greater degree of credit risk and liquidity risk than exchange-traded contracts, which have standardized terms and readily available price information. The Corporation reduces exposure to market and liquidity risks from over-the-counter derivative instruments entered into for risk management purposes, and transactions entered into to mitigate the market risk associated with customer-initiated transactions, by conducting hedging transactions with investment grade domestic and foreign financial institutions and subjecting counterparties to credit approvals, limits and collateral monitoring procedures similar to those used in making other extensions of credit. In addition, certain derivative contracts executed bilaterally with a dealer counterparty in the over-the-counter market are cleared through a clearinghouse, whereby the clearinghouse becomes the counterparty to the transaction. The following table presents the composition of the Corporation’s derivative instruments held or issued for risk management purposes or in connection with customer-initiated and other activities at June 30, 2018 and December 31, 2017 . The table excludes commitments and warrants accounted for as derivatives. June 30, 2018 December 31, 2017 Fair Value Fair Value (in millions) Notional/ Contract Amount (a) Gross Derivative Assets Gross Derivative Liabilities Notional/ Contract Amount (a) Gross Derivative Assets Gross Derivative Liabilities Risk management purposes Derivatives designated as hedging instruments Interest rate contracts: Swaps - fair value - receive fixed/pay floating $ 1,775 $ — $ 3 $ 1,775 $ — $ 2 Derivatives used as economic hedges Foreign exchange contracts: Spot, forwards and swaps 793 2 1 650 — 2 Total risk management purposes 2,568 2 4 2,425 — 4 Customer-initiated and other activities Interest rate contracts: Caps and floors written 715 — 2 635 — — Caps and floors purchased 715 2 — 635 — — Swaps 12,590 33 112 13,119 57 57 Total interest rate contracts 14,020 35 114 14,389 57 57 Energy contracts: Caps and floors written 172 — 16 164 — 11 Caps and floors purchased 172 16 — 164 11 — Swaps 2,046 161 161 1,519 82 80 Total energy contracts 2,390 177 177 1,847 93 91 Foreign exchange contracts: Spot, forwards, options and swaps 1,919 37 31 1,884 42 38 Total customer-initiated and other activities 18,329 249 322 18,120 192 186 Total gross derivatives $ 20,897 $ 251 $ 326 $ 20,545 $ 192 $ 190 Amounts offset in the Consolidated Balance Sheets: Netting adjustment - Offsetting derivative assets/liabilities (48 ) (48 ) (49 ) (49 ) Netting adjustment - Cash collateral received/posted (6 ) (130 ) (1 ) (39 ) Net derivatives included in the Consolidated Balance Sheets (b) 197 148 142 102 Amounts not offset in the Consolidated Balance Sheets: Marketable securities pledged under bilateral collateral agreements (3 ) (10 ) (3 ) (24 ) Net derivatives after deducting amounts not offset in the Consolidated Balance Sheets $ 194 $ 138 $ 139 $ 78 (a) Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Balance Sheets. (b) Net derivative assets are included in accrued income and other assets and net derivative liabilities are included in accrued expenses and other liabilities on the Consolidated Balance Sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of net derivative assets included credit valuation adjustments for counterparty credit risk of $4 million at both June 30, 2018 and December 31, 2017 , respectively. Risk Management The Corporation's derivative instruments used for managing interest rate risk currently comprise swaps converting fixed-rate long-term debt to variable rates. The following table details the effects of fair value hedging on the Consolidated Statements of Comprehensive Income. Interest on Medium- and Long-Term Debt Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Total interest on medium-and long-term debt (a) $ 32 $ 20 $ 57 $ 37 Fair value hedging relationships: Interest rate contracts: Hedged items 15 23 30 45 Derivatives designated as hedging instruments (2 ) (10 ) (5 ) (20 ) (a) Includes the effects of hedging. The following table summarizes the expected weighted average remaining maturity of the notional amount of risk management interest rate swaps, the carrying amount of the related hedged items and the weighted average interest rates associated with amounts expected to be received or paid on interest rate swap agreements as of June 30, 2018 and December 31, 2017 . Weighted Average (dollar amounts in millions) Derivative Notional Amount Carrying Value of Hedged Items (a) Remaining Maturity (in years) Receive Rate Pay Rate (b) June 30, 2018 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt $ 1,775 $ 1,783 4.1 3.26 % 3.06 % December 31, 2017 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt 1,775 1,822 4.6 3.26 2.35 (a) Included $ 16 million and $ 56 million of cumulative hedging adjustments at June 30, 2018 and December 31, 2017 , respectively, which included $ 8 million and $ 9 million , respectively, of hedging adjustment on a discontinued hedging relationship. (b) Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at June 30, 2018 and December 31, 2017 . Foreign exchange rate risk arises from changes in the value of certain assets and liabilities denominated in foreign currencies. The Corporation employs spot and forward contracts in addition to swap contracts to manage exposure to these and other risks. These instruments are used as economic hedges and net gains or losses are included in other noninterest income in the Consolidated Statements of Comprehensive Income. Customer-Initiated and Other The Corporation enters into derivative transactions at the request of customers and generally takes offsetting positions with dealer counterparties to mitigate the inherent market risk. Income primarily results from the spread between the customer derivative and the offsetting dealer position. For customer-initiated foreign exchange contracts where offsetting positions have not been taken, the Corporation manages the remaining inherent market risk through individual foreign currency position limits and aggregate value-at-risk limits. These limits are established annually and reviewed quarterly. For those customer-initiated derivative contracts which were not offset or where the Corporation holds a position within the limits described above, the Corporation recognized no net gains or losses in other noninterest income in the Consolidated Statements of Comprehensive Income for both the three- and six-month periods ended June 30, 2018 and 2017 . Fair values of customer-initiated and other derivative instruments represent the net unrealized gains or losses on such contracts and are recorded in the Consolidated Balance Sheets. Changes in fair value are recognized in the Consolidated Statements of Comprehensive Income. The net gains recognized in income on customer-initiated derivative instruments, net of the impact of offsetting positions, were as follows . Three Months Ended June 30, Six Months Ended June 30, (in millions) Location of Gain 2018 2017 2018 2017 Interest rate contracts Other noninterest income $ 7 $ 7 $ 11 $ 13 Energy contracts Other noninterest income — 1 — 1 Foreign exchange contracts Foreign exchange income 12 11 24 22 Total $ 19 $ 19 $ 35 $ 36 Credit-Related Financial Instruments The Corporation issues off-balance sheet financial instruments in connection with commercial and consumer lending activities. The Corporation’s credit risk associated with these instruments is represented by the contractual amounts indicated in the following table. (in millions) June 30, 2018 December 31, 2017 Unused commitments to extend credit: Commercial and other $ 23,424 $ 22,636 Bankcard, revolving check credit and home equity loan commitments 2,937 2,833 Total unused commitments to extend credit $ 26,361 $ 25,469 Standby letters of credit $ 3,236 $ 3,228 Commercial letters of credit 48 39 The Corporation maintains an allowance to cover probable credit losses inherent in lending-related commitments, including unused commitments to extend credit, letters of credit and financial guarantees. The allowance for credit losses on lending-related commitments, included in accrued expenses and other liabilities was $34 million and $42 million at June 30, 2018 and December 31, 2017 , respectively. Unused Commitments to Extend Credit Commitments to extend credit are legally binding agreements to lend to a customer, provided there is no violation of any condition established in the contract. These commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many commitments expire without being drawn upon, the total contractual amount of commitments does not necessarily represent future cash requirements of the Corporation. Commercial and other unused commitments are primarily variable rate commitments. The allowance for credit losses on lending-related commitments included $24 million and $27 million at June 30, 2018 and December 31, 2017 , respectively, for probable credit losses inherent in the Corporation’s unused commitments to extend credit. Standby and Commercial Letters of Credit Standby letters of credit represent conditional obligations of the Corporation which guarantee the performance of a customer to a third party. Standby letters of credit are primarily issued to support public and private borrowing arrangements, including commercial paper, bond financing and similar transactions. Commercial letters of credit are issued to finance foreign or domestic trade transactions. These contracts expire in decreasing amounts through the year 2028 . The Corporation may enter into participation arrangements with third parties that effectively reduce the maximum amount of future payments which may be required under standby and commercial letters of credit. These risk participations covered $127 million of the $3.3 billion standby and commercial letters of credit outstanding at both June 30, 2018 and December 31, 2017 . The carrying value of the Corporation’s standby and commercial letters of credit, included in accrued expenses and other liabilities, totaled $36 million at June 30, 2018 , including $26 million in deferred fees and $10 million in the allowance for credit losses on lending-related commitments. At December 31, 2017 , the comparable amounts were $40 million , $25 million and $15 million , respectively. The following table presents a summary of criticized standby and commercial letters of credit at June 30, 2018 and December 31, 2017 . The Corporation's criticized list is generally consistent with the Special Mention, Substandard and Doubtful categories defined by regulatory authorities. The Corporation manages credit risk through underwriting, periodically reviewing and approving its credit exposures using Board committee approved credit policies and guidelines. (dollar amounts in millions) June 30, 2018 December 31, 2017 Total criticized standby and commercial letters of credit $ 83 $ 88 As a percentage of total outstanding standby and commercial letters of credit 2.5 % 2.7 % Other Credit-Related Financial Instruments The Corporation enters into credit risk participation agreements, under which the Corporation assumes credit exposure associated with a borrower’s performance related to certain interest rate derivative contracts. The Corporation is not a party to the interest rate derivative contracts and only enters into these credit risk participation agreements in instances in which the Corporation is also a party to the related loan participation agreement for such borrowers. The Corporation manages its credit risk on the credit risk participation agreements by monitoring the creditworthiness of the borrowers, which is based on the normal credit review process had it entered into the derivative instruments directly with the borrower. The notional amount of such credit risk participation agreement reflects the pro-rata share of the derivative instrument, consistent with its share of the related participated loan. As of June 30, 2018 and December 31, 2017 , the total notional amount of the credit risk participation agreements was approximately $586 million and $549 million , respectively, and the fair value was insignificant for both periods. The maximum estimated exposure to these agreements, as measured by projecting a maximum value of the guaranteed derivative instruments, assuming 100 percent default by all obligors on the maximum values, was insignificant at June 30, 2018 and December 31, 2017 . In the event of default, the lead bank has the ability to liquidate the assets of the borrower, in which case the lead bank would be required to return a percentage of the recouped assets to the participating banks. As of June 30, 2018 , the weighted average remaining maturity of outstanding credit risk participation agreements was 2.7 years.

Variable Interest Entities (VIE

Variable Interest Entities (VIEs)	6 Months Ended
	Jun. 30, 2018
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Variable Interest Entities (VIEs)	VARIABLE INTEREST ENTITIES (VIEs) The Corporation evaluates its interest in certain entities to determine if these entities meet the definition of a VIE and whether the Corporation is the primary beneficiary and should consolidate the entity based on the variable interests it held both at inception and when there is a change in circumstances that requires a reconsideration. The Corporation holds ownership interests in funds in the form of limited partnerships or limited liability companies (LLCs) investing in affordable housing projects that qualify for the low-income housing tax credit (LIHTC). The Corporation also directly invests in limited partnerships and LLCs which invest in community development projects which generate similar tax credits to investors (other tax credit entities). As an investor, the Corporation obtains income tax credits and deductions from the operating losses of these tax credit entities. These tax credit entities meet the definition of a VIE; however, the Corporation is not the primary beneficiary of the entities, as the general partner or the managing member has both the power to direct the activities that most significantly impact the economic performance of the entities and the obligation to absorb losses or the right to receive benefits that could be significant to the entities. The Corporation accounts for its interests in LIHTC entities using the proportional amortization method. Exposure to loss as a result of the Corporation’s involvement with LIHTC entities at June 30, 2018 was limited to $409 million . Ownership interests in other tax credit entities are accounted for under either the cost or equity method. Exposure to loss as a result of the Corporation's involvement in other tax credit entities at June 30, 2018 was limited to $7 million . Investment balances, including all legally binding commitments to fund future investments, are included in accrued income and other assets on the Consolidated Balance Sheets. A liability is recognized in accrued expenses and other liabilities on the Consolidated Balance Sheets for all legally binding unfunded commitments to fund tax credit entities ( $150 million at June 30, 2018 ). Amortization and other write-downs of LIHTC investments are presented on a net basis as a component of the provision for income taxes on the Consolidated Statements of Comprehensive Income, while amortization and write-downs of other tax credit investments are recorded in other noninterest income. The income tax credits and deductions are recorded as a reduction of income tax expense and a reduction of federal income taxes payable. The Corporation provided no financial or other support that was not contractually required to any of the above VIEs during the six months ended June 30, 2018 and 2017 . The following table summarizes the impact of these tax credit entities on line items on the Corporation’s Consolidated Statements of Comprehensive Income. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Other noninterest income: Amortization of other tax credit investments $ 1 $ — $ 2 $ 1 Provision for income taxes: Amortization of LIHTC investments 16 16 31 32 Low income housing tax credits (15 ) (16 ) (30 ) (31 ) Other tax benefits related to tax credit entities (4 ) (6 ) (7 ) (12 ) Total provision for income taxes $ (3 ) $ (6 ) $ (6 ) $ (11 ) For further information on the Corporation’s consolidation policy, see note 1 to the consolidated financial statements in the Corporation's 2017 Annual Report.

Medium- And Long-Term Debt

Medium- And Long-Term Debt	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Medium- And Long-Term Debt	MEDIUM- AND LONG-TERM DEBT Medium- and long-term debt is summarized as follows: (in millions) June 30, 2018 December 31, 2017 Parent company Subordinated notes: 3.80% subordinated notes due 2026 (a) $ 245 $ 255 Medium-term notes: 2.125% notes due 2019 (a) 346 347 Total parent company 591 602 Subsidiaries Subordinated notes: 4.00% subordinated notes due 2025 (a) 335 347 7.875% subordinated notes due 2026 (a) 198 208 Total subordinated notes 533 555 Medium-term notes: 2.50% notes due 2020 (a) 659 665 Federal Home Loan Bank (FHLB) advances: Floating-rate based on FHLB auction rate due 2026 2,800 2,800 Floating-rate based on FHLB auction rate due 2028 1,000 — Total FHLB advances 3,800 2,800 Total subsidiaries 4,992 4,020 Total medium- and long-term debt $ 5,583 $ 4,622 (a) The fixed interest rates on these notes have been swapped to a variable rate and designated in a hedging relationship. Accordingly, carrying value has been adjusted to reflect the change in the fair value of the debt as a result of changes in the benchmark rate. Subordinated notes with remaining maturities greater than one year qualify as Tier 2 capital. Comerica Bank (the Bank), a wholly-owned subsidiary of the Corporation, is a member of the FHLB, which provides short- and long-term funding to its members through advances collateralized by real estate-related assets. On February 7, 2018 , the Bank borrowed an additional $1.0 billion of 10-year, floating-rate FHLB advances due January 26, 2028 . The interest rate on the FHLB advances resets between four and eight weeks, based on the FHLB auction rate. At June 30, 2018 , the weighted-average rate on the FHLB advances was 2.06% . Each note may be prepaid in full, without penalty, at each scheduled reset date. Borrowing capacity is contingent on the amount of collateral available to be pledged to the FHLB. At June 30, 2018 , $16.0 billion of real estate-related loans were pledged to the FHLB as blanket collateral for current and potential future borrowings of approximately $5.5 billion . Unamortized debt issuance costs deducted from the carrying amount of medium- and long-term debt totaled $4 million at June 30, 2018 and $5 million at December 31, 2017 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table presents a reconciliation of the changes in the components of accumulated other comprehensive loss and details the components of other comprehensive income (loss) for the six months ended June 30, 2018 and 2017 , including the amount of income tax expense (benefit) allocated to each component of other comprehensive income (loss). Six Months Ended June 30, (in millions) 2018 2017 Accumulated net unrealized losses on investment securities: Balance at beginning of period, net of tax $ (101 ) $ (33 ) Cumulative effect of change in accounting principle 1 — Net unrealized holding (losses) gains arising during the period (197 ) 21 Less: (Benefit) provision for income taxes (46 ) 8 Net unrealized holding (losses) gains arising during the period, net of tax (151 ) 13 Less: Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax — (1 ) Change in net unrealized losses on investment securities, net of tax (151 ) 14 Balance at end of period, net of tax $ (251 ) $ (19 ) Accumulated defined benefit pension and other postretirement plans adjustment: Balance at beginning of period, net of tax $ (350 ) $ (350 ) Amortization of actuarial net loss 30 25 Amortization of prior service credit (14 ) (13 ) Amounts recognized in other noninterest expense 16 12 Less: Provision for income taxes 4 4 Change in defined benefit pension and other postretirement plans adjustment, net of tax 12 8 Balance at end of period, net of tax $ (338 ) $ (342 ) Total accumulated other comprehensive loss at end of period, net of tax $ (589 ) $ (361 )

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Income Per Common Share	NET INCOME PER COMMON SHARE Basic and diluted net income per common share are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per share data) 2018 2017 2018 2017 Basic and diluted Net income $ 326 $ 203 $ 607 $ 405 Less: Income allocated to participating securities 2 1 4 3 Net income attributable to common shares $ 324 $ 202 $ 603 $ 402 Basic average common shares 171 175 171 175 Basic net income per common share $ 1.90 $ 1.15 $ 3.52 $ 2.30 Basic average common shares 171 175 171 175 Dilutive common stock equivalents: Net effect of the assumed exercise of stock options 2 3 2 3 Net effect of the assumed exercise of warrants 1 1 1 2 Diluted average common shares 174 179 174 180 Diluted net income per common share $ 1.87 $ 1.13 $ 3.46 $ 2.24 There were no anti-dilutive options for any of the three- and six-month periods ended June 30, 2018 and 2017 .

Employee Benefit Plans

Employee Benefit Plans	6 Months Ended
	Jun. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Net periodic defined benefit cost (credit) comprise services cost and other components of net benefit cost (credit). Service costs are included in salaries and benefits expense and other components of net benefit cost (credit) are included in other noninterest expenses on the Consolidated Statements of Comprehensive Income. For further information on the Corporation's employee benefit plans, refer to note 17 to the consolidated financial statements in the Corporation's 2017 Annual Report. The components of net periodic benefit cost (credit) for the Corporation's qualified pension plan, non-qualified pension plan and postretirement benefit plan are as follows. Qualified Defined Benefit Pension Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Service cost $ 8 $ 7 $ 15 $ 14 Other components of net benefit credit: Interest cost 18 19 37 39 Expected return on plan assets (41 ) (39 ) (82 ) (79 ) Amortization of prior service credit (4 ) (4 ) (9 ) (9 ) Amortization of net loss 12 10 25 21 Total other components of net benefit credit (15 ) (14 ) (29 ) (28 ) Net periodic defined benefit credit $ (7 ) $ (7 ) $ (14 ) $ (14 ) Non-Qualified Defined Benefit Pension Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Service cost $ 1 $ — $ 1 $ 1 Other components of net benefit cost: Interest cost 2 2 4 4 Amortization of prior service credit (3 ) (2 ) (5 ) (4 ) Amortization of net loss 3 2 5 4 Total other components of net benefit cost 2 2 4 4 Net periodic defined benefit cost $ 3 $ 2 $ 5 $ 5 Postretirement Benefit Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Other components of net benefit credit: Interest cost $ — $ — $ 1 $ 1 Expected return on plan assets (1 ) — (2 ) (1 ) Net periodic defined benefit credit $ (1 ) $ — $ (1 ) $ —

Income Taxes And Tax-Related It

Income Taxes And Tax-Related Items	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes and Tax-Related Items	INCOME TAXES AND TAX-RELATED ITEMS Net unrecognized tax benefits were $10 million at both June 30, 2018 and December 31, 2017 . The Corporation anticipates it is reasonably possible that final settlements with tax authorities will result in a decrease in net unrecognized tax benefits of $1 million within the next twelve months. The liability for tax-related interest and penalties included in accrued expenses and other liabilities was $10 million at both June 30, 2018 and December 31, 2017 . Net deferred tax assets were $169 million at June 30, 2018 , compared to $141 million at December 31, 2017 . The $28 million increase in net deferred tax assets resulted primarily from an increase in deferred tax assets related to unrealized losses on investment securities available-for-sale, partially offset by the decrease in the allowance for loan losses and an increase in deferred tax liabilities related to defined benefit pension plans. Included in deferred tax assets at both June 30, 2018 and December 31, 2017 were $4 million of state net operating loss carryforwards, which expire between 2018 and 2027 . The Corporation believes it is more likely than not the benefit from certain of these state net operating loss carryforwards will not be realized and, accordingly, maintained a valuation allowance of $3 million at both June 30, 2018 and December 31, 2017 . In the ordinary course of business, the Corporation enters into certain transactions that have tax consequences. From time to time, the Internal Revenue Service (IRS) or other tax jurisdictions may review and/or challenge specific interpretive tax positions taken by the Corporation with respect to those transactions. The Corporation believes its tax returns were filed based upon applicable statutes, regulations and case law in effect at the time of the transactions. The IRS or other tax jurisdictions, an administrative authority or a court, if presented with the transactions, could disagree with the Corporation’s interpretation of the tax law. Based on current knowledge and probability assessment of various potential outcomes, the Corporation believes the current tax reserves are adequate, and the amount of any potential incremental liability arising is not expected to have a material adverse effect on the Corporation’s consolidated financial condition or results of operations. Probabilities and outcomes are reviewed as events unfold, and adjustments to the reserves are made when necessary.

Contingent Liabilities

Contingent Liabilities	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities	CONTINGENT LIABILITIES Legal Proceedings As previously reported in the Corporation's Form 10-K for the year ended December 31, 2017 and Form 10-Q for the period ended March 31, 2018, Comerica Bank, a wholly owned subsidiary of the Corporation, was named in November 2011 as a third-party defendant in Butte Local Development v. Masters Group v. Comerica Bank (“the case”), for lender liability. The case was tried in January 2014, in the Montana Second District Judicial Court for Silver Bow County in Butte, Montana. On January 17, 2014 , a jury awarded Masters $52 million against the Bank. On July 1, 2015, after an appeal filed by the Corporation, the Montana Supreme Court reversed the judgment against the Corporation and remanded the case for a new trial with instructions that Michigan contract law should apply and dismissing all other claims. The case was retried in the same district court, without a jury, in January 2017, and the Corporation awaits a ruling. Management believes current reserves related to this case are adequate in the event of a negative outcome. The Corporation and certain of its subsidiaries are subject to various other pending or threatened legal proceedings arising out of the normal course of business or operations. The Corporation believes it has meritorious defenses to the claims asserted against it in its other currently outstanding legal proceedings and, with respect to such legal proceedings, intends to continue to defend itself vigorously, litigating or settling cases according to management’s judgment as to what is in the best interests of the Corporation and its shareholders. Settlement may result from the Corporation's determination that it may be more prudent financially to settle, rather than litigate, and should not be regarded as an admission of liability. On at least a quarterly basis, the Corporation assesses its potential liabilities and contingencies in connection with outstanding legal proceedings utilizing the latest information available. On a case-by-case basis, reserves are established for those legal claims for which it is probable that a loss will be incurred either as a result of a settlement or judgment, and the amount of such loss can be reasonably estimated. The actual costs of resolving these claims may be substantially higher or lower than the amounts reserved. Based on current knowledge, and after consultation with legal counsel, management believes current reserves are adequate, and the amount of any incremental liability arising from these matters is not expected to have a material adverse effect on the Corporation’s consolidated financial condition, results of operations or cash flows. Legal fees of $4 million and $5 million were included in other noninterest expenses for the three-month periods ended June 30, 2018 and 2017 , respectively, and $7 million and $10 million for the six-month periods ended June 30, 2018 and 2017 , respectively. For matters where a loss is not probable, the Corporation has not established legal reserves. The Corporation believes the estimate of the aggregate range of reasonably possible losses, in excess of reserves established, for all legal proceedings in which it is involved is from zero to approximately $33 million at June 30, 2018 . This estimated aggregate range of reasonably possible losses is based upon currently available information for those proceedings in which the Corporation is involved, taking into account the Corporation’s best estimate of such losses for those cases for which such estimate can be made. For certain cases, the Corporation does not believe an estimate can currently be made. The Corporation’s estimate involves significant judgment, given the varying stages of the proceedings (including the fact many are currently in preliminary stages), the existence in certain proceedings of multiple defendants (including the Corporation) whose share of liability has yet to be determined, the numerous yet-unresolved issues in many of the proceedings (including issues regarding class certification and the scope of many of the claims) and the attendant uncertainty of the various potential outcomes of such proceedings. Accordingly, the Corporation’s estimate will change from time to time, and actual losses may be more or less than the current estimate. In the event of unexpected future developments, it is possible the ultimate resolution of these matters, if unfavorable, may be material to the Corporation's consolidated financial condition, results of operations or cash flows. For information regarding income tax contingencies, refer to note 11 .

Restructuring Charges

Restructuring Charges	6 Months Ended
	Jun. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring Charges	RESTRUCTURING CHARGES The Corporation launched an initiative in 2016 designed to reduce overhead and increase revenue (the "GEAR Up" initiative). The actions in the initiative include, but are not limited to, a reduction in workforce, a new retirement program, streamlining operational processes, real estate optimization including consolidating banking centers as well as reducing office and operations space, selective outsourcing of technology functions, reduction of technology system applications, enhanced sales tools and training, expanded product offerings and improved customer analytics to drive opportunities. Certain actions associated with the GEAR Up initiative result in restructuring charges. Generally, costs associated with or incurred to generate revenue as part of the initiative are recorded according to the nature of the cost and are not included in restructuring charges. The Corporation considers the following costs associated with the initiative to be restructuring charges: • Employee costs: Primarily severance costs in accordance with the Corporation’s severance plan. • Facilities costs: Costs pertaining to consolidating banking centers and other facilities, such as lease termination costs and decommissioning costs. Also includes accelerated depreciation and impairment of owned property to be sold. • Technology costs: Impairment and other costs associated with optimizing technology infrastructure and reducing the number of applications. • Other costs: Includes primarily professional fees, as well as other contract termination fees and legal fees incurred in the execution of the initiative. Restructuring charges are recorded as a component of noninterest expenses on the Consolidated Statements of Comprehensive Income. The following table presents changes in restructuring reserves, cumulative charges incurred to date and total expected restructuring charges: (in millions) Employee Costs Facilities Costs Technology Costs Other Costs Total Three Months Ended June 30, 2018 Balance at beginning of period $ 10 $ — $ 9 $ — $ 19 Restructuring charges — 1 10 — 11 Payments (6 ) (1 ) (8 ) — (15 ) Balance at end of period $ 4 $ — $ 11 $ — $ 15 Three Months Ended June 30, 2017 Balance at beginning of period $ 7 $ — $ 3 $ 3 $ 13 Restructuring charges 3 4 6 1 14 Payments (4 ) (4 ) (4 ) (2 ) (14 ) Adjustments for non-cash charges (a) — — (2 ) — (2 ) Balance at end of period $ 6 $ — $ 3 $ 2 $ 11 Six Months Ended June 30, 2018 Balance at beginning of period $ 8 $ — $ 6 $ 1 $ 15 Restructuring charges 5 2 20 — 27 Payments (9 ) (2 ) (15 ) (1 ) (27 ) Balance at end of period $ 4 $ — $ 11 $ — $ 15 Six Months Ended June 30, 2017 Balance at beginning of period $ 10 $ 4 $ — $ 4 $ 18 Restructuring charges 4 5 12 4 25 Payments (8 ) (9 ) (4 ) (6 ) (27 ) Adjustments for non-cash charges (a) — — (5 ) — (5 ) Balance at end of period $ 6 $ — $ 3 $ 2 $ 11 Total restructuring charges incurred to date $ 67 $ 19 $ 46 $ 33 $ 165 Total expected restructuring charges (b) 70 20 60 - 65 35 185 - 190 (a) Adjustments for non-cash charges primarily relate to impairments of previously capitalized software costs in Technology Costs. (b) Restructuring activities are expected to be substantially completed by 12/31/2018 . Restructuring charges directly attributable to a business segment are assigned to that business segment. Restructuring charges incurred by areas whose services support the overall Corporation are allocated based on the methodology described in note 22 to the consolidated financial statements in the Corporation's 2017 Annual Report. Total restructuring charges assigned to the Business Bank, Retail Bank and Wealth Management were $6 million , $4 million and $1 million , respectively, for the three months ended June 30, 2018 and $15 million , $9 million , and $3 million , respectively, for six months ended June 30, 2018 . Total restructuring charges assigned to the Business Bank, Retail Bank and Wealth Management were $7 million , $4 million , and $3 million , respectively, for the three months ended June 30, 2017 and $13 million , $8 million , and $4 million , respectively, for the six months ended June 30, 2017 . Remaining expected restructuring charges will be assigned to the business segments using the same methodology. Facilities costs pertaining to the consolidation of banking centers primarily impacted the Retail Bank.

Business Segment Information

Business Segment Information	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Business Segment Information	BUSINESS SEGMENT INFORMATION The Corporation has strategically aligned its operations into three major business segments: the Business Bank, the Retail Bank and Wealth Management. These business segments are differentiated based on the type of customer and the related products and services provided. In addition to the three major business segments, the Finance Division is also reported as a segment. Business segment results are produced by the Corporation’s internal management accounting system. This system measures financial results based on the internal business unit structure of the Corporation. The performance of the business segments is not comparable with the Corporation's consolidated results and is not necessarily comparable with similar information for any other financial institution. 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. The management accounting system assigns balance sheet and income statement items to each business segment using certain methodologies, which are regularly reviewed and refined. From time to time, the Corporation may make reclassifications among the segments to more appropriately reflect management's current view of the segments, and methodologies may be modified as the management accounting system is enhanced and changes occur in the organizational structure and/or product lines. For comparability purposes, amounts in all periods are based on business unit structure and methodologies in effect at June 30, 2018 . The following discussion provides information about the activities of each business segment. A discussion of the financial results and the factors impacting performance can be found in the section entitled "Business Segments" in the financial review. The Business Bank meets the needs of middle market businesses, multinational corporations and governmental entities by offering various products and services, including commercial loans and lines of credit, deposits, cash management, capital market products, international trade finance, letters of credit, foreign exchange management services and loan syndication services. The Retail Bank includes small business banking and personal financial services, consisting of consumer lending, consumer deposit gathering and mortgage loan origination. In addition to a full range of financial services provided to small business customers, this business segment offers a variety of consumer products, including deposit accounts, installment loans, credit cards, student loans, home equity lines of credit and residential mortgage loans. Wealth Management offers products and services consisting of fiduciary services, private banking, retirement services, investment management and advisory services, investment banking and brokerage services. This business segment also offers the sale of annuity products, as well as life, disability and long-term care insurance products. The Finance segment includes the Corporation’s securities portfolio and asset and liability management activities. This segment is responsible for managing the Corporation’s funding, liquidity and capital needs, performing interest sensitivity analysis and executing various strategies to manage the Corporation’s exposure to liquidity, interest rate risk and foreign exchange risk. The Other category includes the income and expense impact of equity and cash, tax benefits not assigned to specific business segments, charges of an unusual or infrequent nature that are not reflective of the normal operations of the business segments and miscellaneous other expenses of a corporate nature. For further information on the methodologies which form the basis for these results refer to note 23 to the consolidated financial statements in the Corporation's 2017 Annual Report. Business segment financial results are as follows: (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended June 30, 2018 Earnings summary: Net interest income $ 341 $ 169 $ 40 $ 26 $ 14 $ 590 Provision for credit losses (17 ) (9 ) 1 — (4 ) (29 ) Noninterest income 126 42 67 12 1 248 Noninterest expenses 182 178 75 (1 ) 14 448 Provision for income taxes 68 10 7 6 2 (a) 93 Net income $ 234 $ 32 $ 24 $ 33 $ 3 $ 326 Net credit-related charge-offs (recoveries) $ — $ (4 ) $ 1 $ — $ — $ (3 ) Selected average balances: Assets $ 39,961 $ 6,412 $ 5,260 $ 13,735 $ 5,152 $ 70,520 Loans 38,332 5,766 5,127 — — 49,225 Deposits 26,582 24,161 3,852 1,093 142 55,830 Statistical data: Return on average assets (b) 2.34 % 0.52 % 1.90 % N/M N/M 1.85 % Efficiency ratio (c) 39.00 84.05 69.03 N/M N/M 53.24 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 336 $ 162 $ 42 $ (49 ) $ 9 $ 500 Provision for credit losses 12 5 (2 ) — 2 17 Noninterest income 152 48 64 10 2 276 Noninterest expenses 196 180 71 (1 ) 11 457 Provision (benefit) for income taxes 100 9 14 (17 ) (7 ) (a) 99 Net income (loss) $ 180 $ 16 $ 23 $ (21 ) $ 5 $ 203 Net credit-related charge-offs (recoveries) $ 10 $ 9 $ (1 ) $ — $ — $ 18 Selected average balances: Assets $ 38,881 $ 6,487 $ 5,432 $ 13,936 $ 6,610 $ 71,346 Loans 37,580 5,865 5,278 — — 48,723 Deposits 28,748 23,935 4,106 156 183 57,128 Statistical data: Return on average assets (b) 1.85 % 0.27 % 1.76 % N/M N/M 1.14 % Efficiency ratio (c) 40.25 84.80 66.44 N/M N/M 58.70 (a) Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Six Months Ended June 30, 2018 Earnings summary: Net interest income $ 671 $ 334 $ 81 $ 27 $ 26 $ 1,139 Provision for credit losses (7 ) (5 ) (3 ) — (2 ) (17 ) Noninterest income 247 84 135 23 3 492 Noninterest expenses 366 355 147 (2 ) 28 894 Provision (benefit) for income taxes 127 16 17 7 (20 ) (a) 147 Net income $ 432 $ 52 $ 55 $ 45 $ 23 $ 607 Net credit-related charge-offs (recoveries) $ 18 $ 8 $ (1 ) $ — $ — $ 25 Selected average balances: Assets $ 39,438 $ 6,420 $ 5,316 $ 13,757 $ 5,492 $ 70,423 Loans 37,853 5,786 5,186 — — 48,825 Deposits 26,946 24,112 3,824 959 118 55,959 Statistical data: Return on average assets (b) 2.21 % 0.42 % 2.10 % N/M N/M 1.74 % Efficiency ratio (c) 39.85 84.54 68.06 N/M N/M 54.74 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Six Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 668 $ 322 $ 83 $ (120 ) $ 17 $ 970 Provision for credit losses 22 17 (3 ) — (3 ) 33 Noninterest income 296 96 128 21 6 547 Noninterest expenses 393 359 141 (2 ) 23 914 Provision (benefit) for income taxes 192 15 27 (41 ) (28 ) (a) 165 Net income $ 357 $ 27 $ 46 $ (56 ) $ 31 $ 405 Net credit-related charge-offs (recoveries) $ 40 $ 14 $ (3 ) $ — $ — $ 51 Selected average balances: Assets $ 38,488 $ 6,506 $ 5,419 $ 13,940 $ 7,228 $ 71,581 Loans 37,169 5,880 5,264 — — 48,313 Deposits 29,196 23,866 4,042 149 199 57,452 Statistical data: Return on average assets (b) 1.87 % 0.22 % 1.73 % N/M N/M 1.14 % Efficiency ratio (c) 40.82 85.40 66.81 N/M N/M 60.17 (a) Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful The Corporation operates in three primary markets - Texas, California, and Michigan, as well as in Arizona and Florida, with select businesses operating in several other states, and in Canada and Mexico. The Corporation produces market segment results for the Corporation’s three primary geographic markets as well as Other Markets. Other Markets includes Florida, Arizona, the International Finance division and businesses with a national perspective. The Finance & Other category includes the Finance segment and the Other category as previously described. Market segment results are provided as supplemental information to the business segment results and may not meet all operating segment criteria as set forth in GAAP. For comparability purposes, amounts in all periods are based on market segments and methodologies in effect at June 30, 2018 . A discussion of the financial results and the factors impacting performance can be found in the section entitled "Market Segments" in the financial review. Market segment financial results are as follows: (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended June 30, 2018 Earnings summary: Net interest income $ 167 $ 183 $ 117 $ 83 $ 40 $ 590 Provision for credit losses 1 (9 ) (15 ) (2 ) (4 ) (29 ) Noninterest income 73 42 30 90 13 248 Noninterest expenses 144 105 92 94 13 448 Provision for income taxes 22 32 16 15 8 (a) 93 Net income $ 73 $ 97 $ 54 $ 66 $ 36 $ 326 Net credit-related charge-offs (recoveries) $ — $ — $ 3 $ (6 ) $ — $ (3 ) Selected average balances: Assets $ 13,427 $ 18,697 $ 10,439 $ 9,070 $ 18,887 $ 70,520 Loans 12,641 18,435 9,862 8,287 — 49,225 Deposits 20,904 16,642 8,967 8,082 1,235 55,830 Statistical data: Return on average assets (b) 1.37 % 2.06 % 2.08 % 2.93 % N/M 1.85 % Efficiency ratio (c) 59.77 46.94 62.17 53.72 N/M 53.24 (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 167 $ 178 $ 113 $ 82 $ (40 ) $ 500 Provision for credit losses (2 ) 24 (15 ) 8 2 17 Noninterest income 81 45 33 105 12 276 Noninterest expenses 145 98 94 110 10 457 Provision (benefit) for income taxes 38 40 25 20 (24 ) (a) 99 Net income (loss) $ 67 $ 61 $ 42 $ 49 $ (16 ) $ 203 Net credit-related charge-offs (recoveries) $ (1 ) $ 8 $ 5 $ 6 $ — $ 18 Selected average balances: Assets $ 13,371 $ 18,474 $ 10,481 $ 8,474 $ 20,546 $ 71,346 Loans 12,712 18,194 10,015 7,802 — 48,723 Deposits 21,698 17,344 9,632 8,115 339 57,128 Statistical data: Return on average assets (b) 1.20 % 1.33 % 1.52 % 2.24 % N/M 1.14 % Efficiency ratio (c) 58.18 43.85 64.39 58.59 N/M 58.70 (a) Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful (dollar amounts in millions) Michigan California Texas Other Finance Total Six Months Ended June 30, 2018 Earnings summary: Net interest income $ 336 $ 363 $ 226 $ 161 $ 53 $ 1,139 Provision for credit losses 34 (11 ) (28 ) (10 ) (2 ) (17 ) Noninterest income 146 81 61 178 26 492 Noninterest expenses 288 211 184 185 26 894 Provision (benefit) for income taxes 38 62 30 30 (13 ) (a) 147 Net income $ 122 $ 182 $ 101 $ 134 $ 68 $ 607 Net credit-related charge-offs (recoveries) $ (1 ) $ 13 $ 8 $ 5 $ — $ 25 Selected average balances: Assets $ 13,411 $ 18,639 $ 10,406 $ 8,718 $ 19,249 $ 70,423 Loans 12,623 18,391 9,846 7,965 — 48,825 Deposits 21,064 16,865 9,077 7,876 1,077 55,959 Statistical data: Return on average assets (b) 1.13 % 1.96 % 1.96 % 3.11 % N/M 1.74 % Efficiency ratio (c) 59.64 47.66 63.85 54.41 N/M 54.74 (dollar amounts in millions) Michigan California Texas Other Finance Total Six Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 337 $ 349 $ 226 $ 161 $ (103 ) $ 970 Provision for credit losses (4 ) 45 (24 ) 19 (3 ) 33 Noninterest income 164 86 65 205 27 547 Noninterest expenses 295 194 188 216 21 914 Provision (benefit) for income taxes 75 76 47 36 (69 ) (a) 165 Net income (loss) $ 135 $ 120 $ 80 $ 95 $ (25 ) $ 405 Net credit-related charge-offs (recoveries) $ (4 ) $ 18 $ 27 $ 10 $ — $ 51 Selected average balances: Assets $ 13,313 $ 18,217 $ 10,518 $ 8,365 $ 21,168 $ 71,581 Loans 12,650 17,938 10,062 7,663 — 48,313 Deposits 21,923 17,294 9,871 8,016 348 57,452 Statistical data: Return on average assets (b) 1.20 % 1.33 % 1.44 % 2.17 % N/M 1.14 % Efficiency ratio (c) 58.79 44.53 64.59 59.01 N/M 60.17 (a) Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS Revenue from contracts with customers comprises the noninterest income earned by the Corporation in exchange for services provided to customers. The following table presents the composition of revenue from contracts with customers, segregated from other sources of noninterest income, by business segment. Business Bank Retail Bank Wealth Management Finance & Other Total (in millions) Three Months Ended June 30, 2018 Revenue from contracts with customers: Card fees (a) $ 47 $ 12 $ 1 $ — $ 60 Service charges on deposit accounts (a) 28 23 2 — 53 Fiduciary income — — 52 — 52 Commercial loan servicing fees (b) 5 — — — 5 Brokerage fees — — 6 — 6 Other noninterest income (c) 3 3 5 — 11 Total revenue from contracts with customers 83 38 66 — 187 Other sources of noninterest income 43 4 1 13 61 Total noninterest income $ 126 $ 42 $ 67 $ 13 $ 248 Three Months Ended June 30, 2017 Revenue from contracts with customers: Card fees $ 65 $ 14 $ 1 $ — $ 80 Service charges on deposit accounts 30 25 2 — 57 Fiduciary income — — 51 — 51 Commercial loan servicing fees (b) 6 — — — 6 Brokerage fees — — 6 — 6 Other noninterest income (c) 2 7 3 — 12 Total revenue from contracts with customers 103 46 63 — 212 Other sources of noninterest income 49 2 1 12 64 Total noninterest income $ 152 $ 48 $ 64 $ 12 $ 276 Six Months Ended June 30, 2018 Revenue from contracts with customers: Card fees (a) $ 94 $ 23 $ 2 $ — $ 119 Service charges on deposit accounts (a) 58 46 3 — 107 Fiduciary income — — 104 — 104 Commercial loan servicing fees (b) 9 — — — 9 Brokerage fees — — 13 — 13 Other noninterest income (c) 6 8 9 — 23 Total revenue from contracts with customers 167 77 131 — 375 Other sources of noninterest income 80 7 4 26 117 Total noninterest income $ 247 $ 84 $ 135 $ 26 $ 492 Six Months Ended June 30, 2017 Revenue from contracts with customers: Card fees $ 129 $ 26 $ 2 $ — $ 157 Service charges on deposit accounts 62 50 3 — 115 Fiduciary income — — 100 — 100 Commercial loan servicing fees (b) 9 — — — 9 Brokerage fees — — 11 — 11 Other noninterest income (c) 6 15 8 — 29 Total revenue from contracts with customers 206 91 124 — 421 Other sources of noninterest income 90 5 4 27 126 Total noninterest income $ 296 $ 96 $ 128 $ 27 $ 547 (a) Adoption of Topic 606 resulted in a change in presentation which records certain costs in the same category as the associated revenues. The effect of this change was to reduce card fees by $ 37 million and $71 million and service charges on deposit accounts by $ 1 million and 2 million for three- and six-month periods ended June 30, 2018 , respectively. Refer to note 1 for further information. (b) Included in commercial lending fees on the Consolidated Statements of Comprehensive Income. (c) Excludes derivative, warrant and other miscellaneous income. Adjustments to revenue during the three- and six-month periods ended June 30, 2018 for refunds or credits relating to prior periods were not significant. Revenue from contracts with customers did not generate significant contract assets and liabilities.

Basis of Presentation and Acc23

Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Revenue Recognition	Revenue Recognition Effective January 1, 2018, the Corporation adopted the provision of Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 606, "Revenue from Contracts with Customers" (Topic 606), using the modified retrospective method applied to all open contracts as of January 1, 2018. Under Topic 606, card fee revenue from certain products is generally presented net of network costs, including interchange costs, surcharge fees and assessment fees, as opposed to the previous presentation of associated network costs in outside processing fees in the Consolidated Statements of Comprehensive Income. Similar adjustments were made for other revenue streams that resulted in certain costs being recognized in the same category as the associated revenues in noninterest income. The adoption of Topic 606 resulted in decreases of $37 million in card fees and $1 million in service charges on deposits accounts, included in noninterest income, and a corresponding $38 million decrease in outside processing fees included in noninterest expenses, in the Consolidated Statements of Comprehensive Income for the three months ended June 30, 2018. For the six months ended June 30, 2018, the impact on the Consolidated Statements of Comprehensive Income was a $71 million decrease in card fees, a $2 million decrease in service charges on deposit accounts and a $73 million decrease in outside processing fee expense. The Corporation previously deferred recognition of certain treasury management fees included in service charges on deposit accounts in the Consolidated Statements of Comprehensive Income until the amount of compensation was considered fixed and determinable. Under the new guidance, the portion of these fees that are based on agreed upon rates less estimated credits expected to be earned by the customer is recognized as services are rendered. As a result, the Corporation recorded a transition adjustment of $14 million , after tax, to retained earnings, included in cumulative effect of change in accounting principles in the accompanying Consolidated Statements of Changes in Shareholders Equity. Similar adjustments were made for other revenue streams that resulted in an additional cumulative transition after-tax adjustment to retained earnings of $2 million . Revenues from contracts with customers may be recognized when services are complete or as they are rendered, although contracts are generally short-term by nature. Services provided over a period of time are typically transferred to customers evenly over the term of the contracts and revenue is recognized evenly over the period services are provided. Contract receivables are included in accrued income and other assets on the Consolidated Balance Sheets. Payment terms vary by services offered, and the timing between completion of performance obligations and payment is typically not significant. Card fees comprise interchange and other fee income earned on government card, commercial card, debit/Automated Teller Machine card and merchant payment processing programs. Card fees are presented net of network costs as performance obligations for card services are limited to transaction processing and settlement with the card network on behalf of the customers. Network costs were approximately $37 million and $26 million for the three months ended June 30, 2018 and 2017, respectively, and $71 million and $51 million for the six months ended June 30, 2018 and 2017, respectively. Fees for these services are primarily based on interchange rates set by the network and transaction volume. The Corporation also provides ongoing card program support services, for which fees are based on contractually agreed prices and customer demand for services. Service charges on deposit accounts comprise charges on retail and business accounts, including fees for treasury management services. These treasury management services include transaction-based services related to payment processing, overdrafts, non-sufficient funds and other deposit account activity, as well as account management services that are provided over time. Business customers can earn credits depending on deposit balances maintained with the Corporation, which may be used to offset fees. Fees and credits are based on predetermined, agreed upon rates. Fiduciary income includes fees and commissions from asset management, custody, recordkeeping, investment advisory and other services provided primarily to personal and institutional trust customers. Revenue is recognized as the services are performed and is based either on the market value of the assets managed or the services provided, as well as agreed upon rates. Commercial lending fees include both revenue from contracts with customers (primarily loan servicing fees) and other sources of revenue. Commercial loan servicing fees are based on contractually agreed prices and when the services are provided. Other sources of revenue in commercial lending fees primarily include fees assessed on the unused portion of commercial lines of credit (unused commitment fees) and syndication arrangements. Brokerage fees are commissions earned for facilitating securities transactions for customers, as well other brokerage services provided. Revenue is recognized when services are complete and are based on the type of services provided and agreed upon rates. The Corporation pays commissions based on brokerage fee revenue. These are typically recognized when incurred because the amortization period is one year or less and are included in salaries and benefits expense in the Consolidated Statements of Comprehensive Income. Other revenues, consisting primarily of other retail fees, investment banking fees and insurance commissions, are typically recognized when services or transactions are completed and are based on the type of services provided and agreed upon rates. Except as discussed above, commissions and other incentives paid to employees are generally based on several internal and external metrics and as a result are not solely dependent on revenue generating activities.
Classification and Measurement of Financial Instruments	Classification and Measurement of Financial Instruments Effective January 1, 2018, the Corporation adopted the provisions of Accounting Standards Update (ASU) No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities," (ASU 2016-01). ASU 2016-01 requires equity investments, other than equity method investments, to be measured at fair value with changes in fair value recognized in net income. At adoption, an immaterial amount of cumulative net unrealized losses on equity securities previously recognized in accumulated other comprehensive income (AOCI) was reclassified to the opening balance of retained earnings, included in cumulative effect of change in accounting principles in the accompanying Consolidated Statements of Changes in Shareholders Equity. Changes to the fair value of equity securities occurring after December 31, 2017, other than equity method investments, are included in net securities losses in the Consolidated Statements of Comprehensive Income. Also, as part of adopting ASU 2016-01, the Corporation refined the calculation used to determine the estimated fair value of loans disclosed in note 2 to the consolidated financial statements.
Statement of Cash Flows	Statement of Cash Flows The Corporation adopted FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” (ASU 2016-15) on January 1, 2018 and, as a result, reclassified $6 million of proceeds from settlement of bank-owned life insurance policies from operating activities to investing activities for the six-month period ended June 30, 2017.
Defined Benefit Pension and Other Postretirement Costs	Defined Benefit Pension and Other Postretirement Costs The Corporation retrospectively adopted the provisions of ASU No. 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” (ASU 2017-07) on January 1, 2018, which requires employers to report service cost as part of compensation expense and the other components of net benefit credit separately from service cost. As a result, $12 million and $24 million of benefit from the other components of net benefit credit was reclassified from salaries and benefits expense to other noninterest expenses in the Consolidated Statements of Comprehensive Income for the three and six months ended June 30, 2017 , respectively. The Corporation based the adjustment to the prior periods on amounts disclosed in note 10.
Derivatives Instruments and Hedging Activities	Derivatives Instruments and Hedging Activities The Corporation adopted ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” (ASU 2017-12), effective January 1, 2018. At transition, the Corporation elected to change the measurement methodology of all long-haul fair value hedges existing at December 31, 2017. The prior period effect of this election was a $1 million reduction to opening retained earnings, included in cumulative effect of change in accounting principles in the Consolidated Statements of Shareholders' Equity. In addition, the Corporation made a transition election to reclassify the portfolio of held-to-maturity securities to available-for-sale in January 2018 as the securities are eligible to be hedged. This resulted in the recognition of additional unrealized losses of $11 million at the date of transfer.
Income Taxes	Income Taxes The Tax Cuts and Jobs Act (the "Act"), enacted on December 22, 2017, reduced the U.S. federal corporate tax rate from 35 percent to 21 percent. Also, on December 22, 2017, the Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118), which provides guidance on accounting for tax effects of the Act. SAB 118 provides a measurement period of up to one year from the enactment date to complete the accounting. Based on the information available and current interpretation of the rules, the Corporation has made reasonable estimates of the impact of the reduction in the corporate tax rate and remeasurement of certain deferred tax assets and liabilities based on the rate at which they are expected to reverse in the future, generally 21 percent. The provisional amount recorded related to the remeasurement of the Corporation's deferred tax balance was $104 million , including $107 million recognized in the year ended December 31, 2017 and a $3 million downward revision to the estimated impact recorded in the six months ended June 30, 2018. The final impact of the Act may differ from these estimates as a result of changes in management’s interpretations and assumptions, as well as new guidance that may be issued by the Internal Revenue Service (IRS).
Pending Accounting Pronouncements	Pending Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842),” (ASU 2016-02), to increase the transparency and comparability of lease recognition and disclosure. ASU 2016-02 requires lessees to recognize lease contracts with a term greater than one year on the balance sheet, while recognizing expenses on the income statement in a manner similar to current guidance. ASU 2016-02 is effective for the Corporation on January 1, 2019 and must be applied using the modified retrospective approach. In July 2018, the FASB issued ASU 2018-11 “Leases (Topic 842): Targeted Improvements,” which provides lessees the option to apply the new leasing standard to all open leases as of the adoption date. The Corporation expects to make use of this transition option and is currently finalizing review of key assumptions and evaluation of service contracts for embedded leases. Based on preliminary evaluation, the right-of-use asset and corresponding lease obligation liability are expected to range between $450 million and $550 million at adoption, resulting in an 8- to 10-basis point decrease in the common equity tier 1 capital (CET1) ratio. Preliminary estimates are based on the current interest rate environment which may differ from those at the time of adoption of the standard. The Corporation will continue to evaluate other impacts of adoption but does not anticipate these to be significant. In June 2016, the FASB issued ASU No. 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments," (ASU 2016-13), which addresses concerns regarding the perceived delay in recognition of credit losses under the existing incurred loss model. The amendment introduces a new, single model for recognizing credit losses on all financial instruments presented on cost basis. Under the new model, entities must estimate current expected credit losses by considering all available relevant information, including historical and current information, as well as reasonable and supportable forecasts of future events. The update also requires additional qualitative and quantitative information to allow users to better understand the credit risk within the portfolio and the methodologies for determining the allowance for credit losses. ASU 2016-13 is effective for the Corporation on January 1, 2020 and must be applied using the modified retrospective approach with limited exceptions. Early adoption is permitted. The Corporation will adopt the standard on January 1, 2020 and is currently evaluating the impact of adoption.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Assets And Liabilities Recorded At Fair Value On A Recurring Basis	The following tables present the recorded amount of assets and liabilities measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 . (in millions) Total Level 1 Level 2 Level 3 June 30, 2018 Deferred compensation plan assets $ 91 $ 91 $ — $ — Equity securities 41 41 — — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,699 2,699 — — Residential mortgage-backed securities (a) 9,216 — 9,216 — Total investment securities available-for-sale 11,915 2,699 9,216 — Derivative assets: Interest rate contracts 35 — 29 6 Energy derivative contracts 177 — 177 — Foreign exchange contracts 39 — 39 — Warrants 2 — — 2 Total derivative assets 253 — 245 8 Total assets at fair value $ 12,300 $ 2,831 $ 9,461 $ 8 Derivative liabilities: Interest rate contracts $ 117 $ — $ 117 $ — Energy derivative contracts 177 — 177 — Foreign exchange contracts 32 — 32 — Total derivative liabilities 326 — 326 — Deferred compensation plan liabilities 91 91 — — Total liabilities at fair value $ 417 $ 91 $ 326 $ — December 31, 2017 Trading securities: Deferred compensation plan assets $ 92 $ 92 $ — $ — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,727 2,727 — — Residential mortgage-backed securities (a) 8,124 — 8,124 — State and municipal securities 5 — — 5 (b) Equity and other non-debt securities 82 38 — 44 (b) Total investment securities available-for-sale 10,938 2,765 8,124 49 Derivative assets: Interest rate contracts 57 — 43 14 Energy derivative contracts 93 — 93 — Foreign exchange contracts 42 — 42 — Warrants 2 — — 2 Total derivative assets 194 — 178 16 Total assets at fair value 11,224 $ 2,857 $ 8,302 $ 65 Derivative liabilities: Interest rate contracts 59 — 59 — Energy derivative contracts 91 — 91 — Foreign exchange contracts 40 — 40 — Total derivative liabilities 190 — 190 — Deferred compensation plan liabilities 92 92 — — Total liabilities at fair value $ 282 $ 92 $ 190 $ — (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Auction-rate securities.
Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis	The following table summarizes the changes in Level 3 assets and liabilities measured at fair value on a recurring basis for the three- and six-month periods ended June 30, 2018 and 2017 . Net Realized/Unrealized Gains (Losses) (Pretax) Recorded in Earnings Balance at Beginning of Period Balance at End of Period Change in Classification (a) Sales and Redemptions (in millions) Realized Unrealized Three Months Ended June 30, 2018 Derivative assets: Interest rate contracts $ 7 $ — $ — $ (1 ) (b) $ — $ 6 Warrants 2 — 1 (b) — (1 ) 2 Three Months Ended June 30, 2017 Investment securities available-for-sale: State and municipal securities (c) $ 5 $ — $ — $ — $ — $ 5 Equity and other non-debt securities (c) 46 — — — — 46 Total investment securities available-for-sale 51 — — — — 51 Derivative assets: Interest rate contracts 11 — — 2 (b) — 13 Warrants 2 — 4 (b) — (4 ) 2 Six Months Ended June 30, 2018 Equity securities $ — $ 44 $ — $ — $ (44 ) $ — Investment securities available-for-sale: State and municipal securities (c) 5 — — — (5 ) — Equity and other non-debt securities (c) 44 (44 ) — — — — Total investment securities available-for-sale 49 (44 ) — — (5 ) — Derivative assets: Interest rate contracts 14 — — (8 ) (b) — 6 Warrants 2 — 1 (b) — (1 ) 2 Six Months Ended June 30, 2017 Investment securities available-for-sale: State and municipal securities (c) $ 7 $ — $ — $ — $ (2 ) $ 5 Equity and other non-debt securities (c) 47 — — — (1 ) 46 Total investment securities available-for-sale 54 — — — (3 ) 51 Derivative assets: Interest rate contracts 11 — — 2 (b) — 13 Warrants 3 — 5 (b) (1 ) (b) (5 ) 2 (a) Reflects the reclassification of equity securities resulting from the adoption of ASU 2016-01. (b) Realized and unrealized gains and losses due to changes in fair value recorded in Other Noninterest Income on the Consolidated Statements of Comprehensive Income. (c) Auction-rate securities.
Assets And Liabilities Recorded At Fair Value On A Nonrecurring Basis	The following table presents assets recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 . No liabilities were recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 . (in millions) Level 3 June 30, 2018 Loans: Commercial $ 76 Commercial mortgage 4 Total loans 80 Other real estate 1 Total assets at fair value $ 81 December 31, 2017 Loans: Commercial $ 111 Commercial mortgage 5 Total assets at fair value $ 116
Estimated Fair Values Of Financial Instruments Not Recorded At Fair Value In Their Entirety On A Recurring Basis	The carrying amount and estimated fair value of financial instruments not recorded at fair value in their entirety on a recurring basis on the Corporation’s Consolidated Balance Sheets are as follows: Carrying Amount Estimated Fair Value (in millions) Total Level 1 Level 2 Level 3 June 30, 2018 Assets Cash and due from banks $ 1,424 $ 1,424 $ 1,424 $ — $ — Interest-bearing deposits with banks 4,236 4,236 4,236 — — Loans held-for-sale 2 2 — 2 — Total loans, net of allowance for loan losses (a) 49,115 48,929 — — 48,929 Customers’ liability on acceptances outstanding 3 3 3 — — Restricted equity investments 248 248 248 — — Nonmarketable equity securities (b) 6 11 Liabilities Demand deposits (noninterest-bearing) 30,316 30,316 — 30,316 — Interest-bearing deposits 24,805 24,805 — 24,805 — Customer certificates of deposit 2,089 2,061 — 2,061 — Total deposits 57,210 57,182 — 57,182 — Short-term borrowings 58 58 58 — — Acceptances outstanding 3 3 3 — — Medium- and long-term debt 5,583 5,588 — 5,588 — Credit-related financial instruments (60 ) (60 ) — — (60 ) December 31, 2017 Assets Cash and due from banks $ 1,438 $ 1,438 $ 1,438 $ — $ — Interest-bearing deposits with banks 4,407 4,407 4,407 — — Investment securities held-to-maturity 1,266 1,246 — 1,246 — Loans held-for-sale 4 4 — 4 — Total loans, net of allowance for loan losses (a) 48,461 48,153 — — 48,153 Customers’ liability on acceptances outstanding 2 2 2 — — Restricted equity investments 207 207 207 — — Nonmarketable equity securities (b) 6 9 Liabilities Demand deposits (noninterest-bearing) 32,071 32,071 — 32,071 — Interest-bearing deposits 23,667 23,667 — 23,667 — Customer certificates of deposit 2,165 2,142 — 2,142 — Total deposits 57,903 57,880 — 57,880 — Short-term borrowings 10 10 10 — — Acceptances outstanding 2 2 2 — — Medium- and long-term debt 4,622 4,636 — 4,636 — Credit-related financial instruments (67 ) (67 ) — — (67 ) (a) Included $80 million and $116 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017 , respectively. (b) Certain investments that are measured at fair value using the net asset value have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary Of Investment Securities	A summary of the Corporation’s investment securities follows: (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value June 30, 2018 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,744 $ — $ 45 $ 2,699 Residential mortgage-backed securities (a) 9,499 10 293 9,216 Total investment securities available-for-sale $ 12,243 $ 10 $ 338 $ 11,915 December 31, 2017 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,743 $ — $ 16 $ 2,727 Residential mortgage-backed securities (a) 8,230 22 128 8,124 State and municipal securities 5 — — 5 Equity and other non-debt securities 83 1 2 82 Total investment securities available-for-sale (b) $ 11,061 $ 23 $ 146 $ 10,938 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,266 $ — $ 20 $ 1,246 (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Included auction-rate securities at amortized cost and fair value of $51 million and $49 million , respectively, as of December 31, 2017 . (c) The amortized cost of investment securities held-to-maturity included net unrealized losses of $9 million at December 31, 2017 related to securities transferred from available-for-sale in 2014, which are included in accumulated other comprehensive loss.
Summary Of Investment Securities In Unrealized Loss Positions	A summary of the Corporation’s investment securities in an unrealized loss position as of June 30, 2018 and December 31, 2017 follows: Temporarily Impaired Less than 12 Months 12 Months or more Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses June 30, 2018 U.S. Treasury and other U.S. government agency securities $ 2,699 $ 45 $ — $ — $ 2,699 $ 45 Residential mortgage-backed securities (a) 4,544 106 3,934 187 8,478 293 Total temporarily impaired securities $ 7,243 $ 151 $ 3,934 $ 187 $ 11,177 $ 338 December 31, 2017 U.S. Treasury and other U.S. government agency securities $ 2,727 $ 16 $ — $ — $ 2,727 $ 16 Residential mortgage-backed securities (a) 3,845 32 4,003 125 7,848 157 State and municipal securities (b) — — 5 — (c) 5 — (c) Equity and other non-debt securities (b) — — 44 2 44 2 Total temporarily impaired securities $ 6,572 $ 48 $ 4,052 $ 127 $ 10,624 $ 175 (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Primarily auction-rate securities. (c) Unrealized losses less than $0.5 million.
Contractual Maturity Distribution Of Debt Securities	The following table summarizes the amortized cost and fair values of debt securities by contractual maturity. Securities with multiple maturity dates are classified in the period of final maturity. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (in millions) June 30, 2018 Amortized Cost Fair Value Contractual maturity Within one year $ 100 $ 100 After one year through five years 3,008 2,963 After five years through ten years 1,752 1,722 After ten years 7,383 7,130 Total investment securities $ 12,243 $ 11,915

Credit Quality And Allowance 26

Credit Quality And Allowance For Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2018
Credit Quality And Allowance For Credit Losses [Abstract]
Aging Analysis Of Loans	The following table presents an aging analysis of the recorded balance of loans. Loans Past Due and Still Accruing (in millions) 30-59 Days 60-89 Days 90 Days or More Total Nonaccrual Loans Current Loans Total Loans June 30, 2018 Business loans: Commercial $ 66 $ 8 $ 13 $ 87 $ 171 $ 31,272 $ 31,530 Real estate construction: Commercial Real Estate business line (a) 6 — — 6 — 2,882 2,888 Other business lines (b) 6 — — 6 — 363 369 Total real estate construction 12 — — 12 — 3,245 3,257 Commercial mortgage: Commercial Real Estate business line (a) 4 10 — 14 9 1,724 1,747 Other business lines (b) 21 5 7 33 20 7,324 7,377 Total commercial mortgage 25 15 7 47 29 9,048 9,124 Lease financing — — — — 2 456 458 International 2 — — 2 4 987 993 Total business loans 105 23 20 148 206 45,008 45,362 Retail loans: Residential mortgage 16 1 — 17 29 1,908 1,954 Consumer: Home equity 4 1 — 5 19 1,707 1,731 Other consumer 2 — — 2 — 743 745 Total consumer 6 1 — 7 19 2,450 2,476 Total retail loans 22 2 — 24 48 4,358 4,430 Total loans $ 127 $ 25 $ 20 $ 172 $ 254 $ 49,366 $ 49,792 December 31, 2017 Business loans: Commercial $ 79 $ 134 $ 12 $ 225 $ 309 $ 30,526 $ 31,060 Real estate construction: Commercial Real Estate business line (a) 3 — — 3 — 2,627 2,630 Other business lines (b) 4 — — 4 — 327 331 Total real estate construction 7 — — 7 — 2,954 2,961 Commercial mortgage: Commercial Real Estate business line (a) 14 — — 14 9 1,808 1,831 Other business lines (b) 27 6 22 55 22 7,251 7,328 Total commercial mortgage 41 6 22 69 31 9,059 9,159 Lease financing — — — — 4 464 468 International 13 — — 13 6 964 983 Total business loans 140 140 34 314 350 43,967 44,631 Retail loans: Residential mortgage 10 2 — 12 31 1,945 1,988 Consumer: Home equity 5 1 — 6 21 1,789 1,816 Other consumer 4 — 1 5 — 733 738 Total consumer 9 1 1 11 21 2,522 2,554 Total retail loans 19 3 1 23 52 4,467 4,542 Total loans $ 159 $ 143 $ 35 $ 337 $ 402 $ 48,434 $ 49,173 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate.
Loans By Credit Quality Indicator	The following table presents loans by credit quality indicator, based on internal risk ratings assigned to each business loan at the time of approval and subjected to subsequent reviews, generally at least annually, and to pools of retail loans with similar risk characteristics. Internally Assigned Rating (in millions) Pass (a) Special Mention (b) Substandard (c) Nonaccrual (d) Total June 30, 2018 Business loans: Commercial $ 30,185 $ 580 $ 594 $ 171 $ 31,530 Real estate construction: Commercial Real Estate business line (e) 2,868 20 — — 2,888 Other business lines (f) 362 7 — — 369 Total real estate construction 3,230 27 — — 3,257 Commercial mortgage: Commercial Real Estate business line (e) 1,678 15 45 9 1,747 Other business lines (f) 7,144 133 80 20 7,377 Total commercial mortgage 8,822 148 125 29 9,124 Lease financing 449 4 3 2 458 International 969 2 18 4 993 Total business loans 43,655 761 740 206 45,362 Retail loans: Residential mortgage 1,925 — — 29 1,954 Consumer: Home equity 1,704 — 8 19 1,731 Other consumer 743 1 1 — 745 Total consumer 2,447 1 9 19 2,476 Total retail loans 4,372 1 9 48 4,430 Total loans $ 48,027 $ 762 $ 749 $ 254 $ 49,792 December 31, 2017 Business loans: Commercial $ 29,263 $ 591 $ 897 $ 309 $ 31,060 Real estate construction: Commercial Real Estate business line (e) 2,630 — — — 2,630 Other business lines (f) 327 4 — — 331 Total real estate construction 2,957 4 — — 2,961 Commercial mortgage: Commercial Real Estate business line (e) 1,759 20 43 9 1,831 Other business lines (f) 7,099 115 92 22 7,328 Total commercial mortgage 8,858 135 135 31 9,159 Lease financing 440 23 1 4 468 International 946 11 20 6 983 Total business loans 42,464 764 1,053 350 44,631 Retail loans: Residential mortgage 1,955 2 — 31 1,988 Consumer: Home equity 1,786 1 8 21 1,816 Other consumer 737 1 — — 738 Total consumer 2,523 2 8 21 2,554 Total retail loans 4,478 4 8 52 4,542 Total loans $ 46,942 $ 768 $ 1,061 $ 402 $ 49,173 (a) Includes all loans not included in the categories of special mention, substandard or nonaccrual. (b) Special mention loans are accruing loans that have potential credit weaknesses that deserve management’s close attention, such as loans to borrowers who may be experiencing financial difficulties that may result in deterioration of repayment prospects from the borrower at some future date. This category is generally consistent with the "special mention" category as defined by regulatory authorities. (c) Substandard loans are accruing loans that have a well-defined weakness, or weaknesses, such as loans to borrowers who may be experiencing losses from operations or inadequate liquidity of a degree and duration that jeopardizes the orderly repayment of the loan. Substandard loans also are distinguished by the distinct possibility of loss in the future if these weaknesses are not corrected. This category is generally consistent with the "substandard" category as defined by regulatory authorities. (d) Nonaccrual loans are loans for which the accrual of interest has been discontinued. For further information regarding nonaccrual loans, refer to the Nonperforming Assets subheading in Note 1 - Basis of Presentation and Accounting Policies - on pages F-51 and F-52 in the Corporation's 2017 Annual Report. A significant majority of nonaccrual loans are generally consistent with the "substandard" category and the remainder are generally consistent with the "doubtful" category as defined by regulatory authorities. (e) Primarily loans to real estate developers. (f) Primarily loans secured by owner-occupied real estate.
Schedule Of Nonaccrual, Reduced-Rate Loans And Foreclosed Property	The following table summarizes nonperforming assets. (in millions) June 30, 2018 December 31, 2017 Nonaccrual loans $ 254 $ 402 Reduced-rate loans (a) 8 8 Total nonperforming loans 262 410 Foreclosed property (b) 2 5 Total nonperforming assets $ 264 $ 415 (a) There were no reduced-rate business loans at both June 30, 2018 and December 31, 2017 . Reduced-rate retail loans were $8 million at both June 30, 2018 and December 31, 2017 . (b) Included $1 million and $4 million of foreclosed residential real estate properties at June 30, 2018 and December 31, 2017 , respectively.
Changes In The Allowance For Loan Losses And Related Loan Amounts	The following table details the changes in the allowance for loan losses and related loan amounts. 2018 2017 (in millions) Business Loans Retail Loans Total Business Loans Retail Loans Total Three Months Ended June 30 Allowance for loan losses: Balance at beginning of period $ 653 $ 45 $ 698 $ 661 $ 47 $ 708 Loan charge-offs (18 ) (2 ) (20 ) (37 ) (2 ) (39 ) Recoveries on loans previously charged-off 22 1 23 20 1 21 Net loan recoveries (charge-offs) 4 (1 ) 3 (17 ) (1 ) (18 ) Provision for loan losses (21 ) (2 ) (23 ) 17 (2 ) 15 Foreign currency translation adjustment (1 ) — (1 ) — — — Balance at end of period $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 Six Months Ended June 30 Allowance for loan losses: Balance at beginning of period $ 661 $ 51 $ 712 $ 682 $ 48 $ 730 Loan charge-offs (54 ) (3 ) (57 ) (79 ) (4 ) (83 ) Recoveries on loans previously charged-off 30 2 32 29 3 32 Net loan charge-offs (24 ) (1 ) (25 ) (50 ) (1 ) (51 ) Provision for loan losses (1 ) (8 ) (9 ) 29 (3 ) 26 Foreign currency translation adjustment (1 ) — (1 ) — — — Balance at end of period $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 As a percentage of total loans 1.40 % 0.96 % 1.36 % 1.47 % 0.98 % 1.43 % June 30 Allowance for loan losses: Individually evaluated for impairment $ 39 $ — $ 39 $ 93 $ 1 $ 94 Collectively evaluated for impairment 596 42 638 568 43 611 Total allowance for loan losses $ 635 $ 42 $ 677 $ 661 $ 44 $ 705 Loans: Individually evaluated for impairment $ 310 $ 30 $ 340 $ 509 $ 41 $ 550 Collectively evaluated for impairment 45,052 4,400 49,452 44,388 4,470 48,858 Total loans evaluated for impairment $ 45,362 $ 4,430 $ 49,792 $ 44,897 $ 4,511 $ 49,408
Changes In the Allowance For Credit Losses On Lending-Related Commitments	Changes in the allowance for credit losses on lending-related commitments, included in accrued expenses and other liabilities on the Consolidated Balance Sheets, are summarized in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Balance at beginning of period $ 40 $ 46 $ 42 $ 41 Provision for credit losses on lending-related commitments (6 ) 2 (8 ) 7 Balance at end of period $ 34 $ 48 $ 34 $ 48
Individually Evaluated Impaired Loans	The following table presents additional information regarding individually evaluated impaired loans. Recorded Investment In: (in millions) Impaired Loans with No Related Allowance Impaired Loans with Related Allowance Total Impaired Loans Unpaid Principal Balance Related Allowance for Loan Losses June 30, 2018 Business loans: Commercial $ 85 $ 154 $ 239 $ 313 $ 35 Commercial mortgage: Commercial Real Estate business line (a) 37 3 40 49 — Other business lines (b) — 26 26 29 3 Total commercial mortgage 37 29 66 78 3 International 3 2 5 9 1 Total business loans 125 185 310 400 39 Retail loans: Residential mortgage 11 8 19 20 — Consumer: Home equity 10 — 10 13 — Other consumer 1 — 1 1 — Total consumer 11 — 11 14 — Total retail loans (c) 22 8 30 34 — Total individually evaluated impaired loans $ 147 $ 193 $ 340 $ 434 $ 39 December 31, 2017 Business loans: Commercial $ 105 $ 267 $ 372 $ 460 $ 63 Commercial mortgage: Commercial Real Estate business line (a) 39 1 40 49 — Other business lines (b) 3 22 25 29 3 Total commercial mortgage 42 23 65 78 3 International — 6 6 17 1 Total business loans 147 296 443 555 67 Retail loans: Residential mortgage 14 8 22 22 — Consumer: Home equity 11 — 11 14 — Other consumer 1 — 1 2 — Total consumer 12 — 12 16 — Total retail loans (c) 26 8 34 38 — Total individually evaluated impaired loans $ 173 $ 304 $ 477 $ 593 $ 67 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. (c) Individually evaluated retail loans generally have no related allowance for loan losses, primarily due to policy which results in direct write-downs of most restructured retail loans.
Average Individually Evaluated Impaired Loans And Related Interest Recognized	The following table presents information regarding average individually evaluated impaired loans and the related interest recognized as of June 30, 2018 and 2017. Interest income recognized for the period primarily related to performing restructured loans. Individually Evaluated Impaired Loans 2018 2017 (in millions) Average Balance for the Period Interest Income Recognized for the Period Average Balance for the Period Interest Income Recognized for the Period Three Months Ended June 30 Business loans: Commercial $ 277 $ 1 $ 473 $ 2 Commercial mortgage: Commercial Real Estate business line (a) 40 1 7 — Other business lines (b) 25 — 35 — Total commercial mortgage 65 1 42 — International 4 — 7 — Total business loans 346 2 522 2 Retail loans: Residential mortgage 19 — 27 — Consumer loans: Home equity 11 — 12 — Other consumer 1 — 2 — Total consumer 12 — 14 — Total retail loans 31 — 41 — Total individually evaluated impaired loans $ 377 $ 2 $ 563 $ 2 Six Months Ended June 30 Business loans: Commercial $ 309 $ 2 $ 487 $ 4 Commercial mortgage: Commercial Real Estate business line (a) 40 2 7 — Other business lines (b) 25 — 34 — Total commercial mortgage 65 2 41 — International 5 — 9 — Total business loans 379 4 537 4 Retail loans: Residential mortgage 20 — 27 — Consumer: Home equity 11 — 13 — Other consumer 1 — 3 — Total consumer 12 — 16 — Total retail loans 32 — 43 — Total individually evaluated impaired loans $ 411 $ 4 $ 580 $ 4 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate.
Troubled Debt Restructurings By Type Of Modification	The following table details the recorded balance at June 30, 2018 and 2017 of loans considered to be troubled debt restructurings (TDRs) that were restructured during the three- and six-month periods ended June 30, 2018 and 2017 , by type of modification. In cases of loans with more than one type of modification, the loans were categorized based on the most significant modification. 2018 2017 Type of Modification Type of Modification (in millions) Principal Deferrals (a) Interest Rate Reductions Total Modifications Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Three Months Ended June 30 Business loans: Commercial $ 25 $ — $ 25 $ 47 $ — $ 36 $ 83 Commercial mortgage: Other business lines (c) — — — 1 — — 1 Total business loans 25 — 25 48 — 36 84 Retail loans: Consumer: Home equity (d) — 1 1 — 1 — 1 Total loans $ 25 $ 1 $ 26 $ 48 $ 1 $ 36 $ 85 Six Months Ended June 30 Business loans: Commercial $ 45 $ — $ 45 $ 96 $ — $ 36 $ 132 Commercial mortgage: Other business lines (c) 1 — 1 4 — — 4 Total business loans 46 — 46 100 — 36 136 Retail loans: Consumer: Home equity (d) 1 1 2 1 2 — 3 Total loans $ 47 $ 1 $ 48 $ 101 $ 2 $ 36 $ 139 (a) Primarily represents loan balances where terms were extended 90 days or more at or above contractual interest rates. (b) Loan restructurings whereby the original loan is restructured into two notes: an "A" note, which generally reflects the portion of the modified loan which is expected to be collected; and a "B" note, which is generally fully charged off. (c) Primarily loans to secured by owner-occupied real estate. (d) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.
Troubled Debt Restructuring Subsequent Default	The following table presents information regarding the recorded balance at June 30, 2018 and 2017 of loans modified by principal deferral and interest rate reduction during the twelve-month periods ended June 30, 2018 and 2017 . Principal Deferrals Interest Rate Reductions (in millions) 2018 2017 2018 2017 Balance at June 30, Business loans: Commercial $ 97 $ 141 $ — $ — Commercial mortgage: Commercial Real Estate business line (a) 37 1 — — Other business lines (b) 2 7 — — Total commercial mortgage 39 8 — — Total business loans 136 149 — — Retail loans: Consumer: Home equity (c) 1 2 2 3 Total principal deferrals $ 137 $ 151 $ 2 $ 3 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. (c) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.

Derivative And Credit-Related27

Derivative And Credit-Related Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule Of Derivative Instruments	The following table presents the composition of the Corporation’s derivative instruments held or issued for risk management purposes or in connection with customer-initiated and other activities at June 30, 2018 and December 31, 2017 . The table excludes commitments and warrants accounted for as derivatives. June 30, 2018 December 31, 2017 Fair Value Fair Value (in millions) Notional/ Contract Amount (a) Gross Derivative Assets Gross Derivative Liabilities Notional/ Contract Amount (a) Gross Derivative Assets Gross Derivative Liabilities Risk management purposes Derivatives designated as hedging instruments Interest rate contracts: Swaps - fair value - receive fixed/pay floating $ 1,775 $ — $ 3 $ 1,775 $ — $ 2 Derivatives used as economic hedges Foreign exchange contracts: Spot, forwards and swaps 793 2 1 650 — 2 Total risk management purposes 2,568 2 4 2,425 — 4 Customer-initiated and other activities Interest rate contracts: Caps and floors written 715 — 2 635 — — Caps and floors purchased 715 2 — 635 — — Swaps 12,590 33 112 13,119 57 57 Total interest rate contracts 14,020 35 114 14,389 57 57 Energy contracts: Caps and floors written 172 — 16 164 — 11 Caps and floors purchased 172 16 — 164 11 — Swaps 2,046 161 161 1,519 82 80 Total energy contracts 2,390 177 177 1,847 93 91 Foreign exchange contracts: Spot, forwards, options and swaps 1,919 37 31 1,884 42 38 Total customer-initiated and other activities 18,329 249 322 18,120 192 186 Total gross derivatives $ 20,897 $ 251 $ 326 $ 20,545 $ 192 $ 190 Amounts offset in the Consolidated Balance Sheets: Netting adjustment - Offsetting derivative assets/liabilities (48 ) (48 ) (49 ) (49 ) Netting adjustment - Cash collateral received/posted (6 ) (130 ) (1 ) (39 ) Net derivatives included in the Consolidated Balance Sheets (b) 197 148 142 102 Amounts not offset in the Consolidated Balance Sheets: Marketable securities pledged under bilateral collateral agreements (3 ) (10 ) (3 ) (24 ) Net derivatives after deducting amounts not offset in the Consolidated Balance Sheets $ 194 $ 138 $ 139 $ 78 (a) Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Balance Sheets. (b) Net derivative assets are included in accrued income and other assets and net derivative liabilities are included in accrued expenses and other liabilities on the Consolidated Balance Sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of net derivative assets included credit valuation adjustments for counterparty credit risk of $4 million at both June 30, 2018 and December 31, 2017 , respectively.
Schedule of the Effects of Fair Value Hedging on the Consolidated Statements of Comprehensive Income	The following table details the effects of fair value hedging on the Consolidated Statements of Comprehensive Income. Interest on Medium- and Long-Term Debt Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Total interest on medium-and long-term debt (a) $ 32 $ 20 $ 57 $ 37 Fair value hedging relationships: Interest rate contracts: Hedged items 15 23 30 45 Derivatives designated as hedging instruments (2 ) (10 ) (5 ) (20 ) (a) Includes the effects of hedging.
Schedule Of Weighted Average Maturity And Interest Rates On Risk Management Interest Rate Swaps	The following table summarizes the expected weighted average remaining maturity of the notional amount of risk management interest rate swaps, the carrying amount of the related hedged items and the weighted average interest rates associated with amounts expected to be received or paid on interest rate swap agreements as of June 30, 2018 and December 31, 2017 . Weighted Average (dollar amounts in millions) Derivative Notional Amount Carrying Value of Hedged Items (a) Remaining Maturity (in years) Receive Rate Pay Rate (b) June 30, 2018 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt $ 1,775 $ 1,783 4.1 3.26 % 3.06 % December 31, 2017 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt 1,775 1,822 4.6 3.26 2.35 (a) Included $ 16 million and $ 56 million of cumulative hedging adjustments at June 30, 2018 and December 31, 2017 , respectively, which included $ 8 million and $ 9 million , respectively, of hedging adjustment on a discontinued hedging relationship. (b) Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at June 30, 2018 and December 31, 2017
Schedule Of Net Gains Recognized In Income On Customer-Initiated Derivatives	The net gains recognized in income on customer-initiated derivative instruments, net of the impact of offsetting positions, were as follows . Three Months Ended June 30, Six Months Ended June 30, (in millions) Location of Gain 2018 2017 2018 2017 Interest rate contracts Other noninterest income $ 7 $ 7 $ 11 $ 13 Energy contracts Other noninterest income — 1 — 1 Foreign exchange contracts Foreign exchange income 12 11 24 22 Total $ 19 $ 19 $ 35 $ 36
Schedule Of Financial Instruments With Off-Balance Sheet Credit Risk	The Corporation’s credit risk associated with these instruments is represented by the contractual amounts indicated in the following table. (in millions) June 30, 2018 December 31, 2017 Unused commitments to extend credit: Commercial and other $ 23,424 $ 22,636 Bankcard, revolving check credit and home equity loan commitments 2,937 2,833 Total unused commitments to extend credit $ 26,361 $ 25,469 Standby letters of credit $ 3,236 $ 3,228 Commercial letters of credit 48 39
Summary Of Criticized Letters Of Credit	The following table presents a summary of criticized standby and commercial letters of credit at June 30, 2018 and December 31, 2017 . The Corporation's criticized list is generally consistent with the Special Mention, Substandard and Doubtful categories defined by regulatory authorities. The Corporation manages credit risk through underwriting, periodically reviewing and approving its credit exposures using Board committee approved credit policies and guidelines. (dollar amounts in millions) June 30, 2018 December 31, 2017 Total criticized standby and commercial letters of credit $ 83 $ 88 As a percentage of total outstanding standby and commercial letters of credit 2.5 % 2.7 %

Variable Interest Entities (V28

Variable Interest Entities (VIEs) (Tables)	6 Months Ended
	Jun. 30, 2018
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]
Impact Of VIEs On The Consolidated Statements Of Comprehensive Income	The following table summarizes the impact of these tax credit entities on line items on the Corporation’s Consolidated Statements of Comprehensive Income. Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Other noninterest income: Amortization of other tax credit investments $ 1 $ — $ 2 $ 1 Provision for income taxes: Amortization of LIHTC investments 16 16 31 32 Low income housing tax credits (15 ) (16 ) (30 ) (31 ) Other tax benefits related to tax credit entities (4 ) (6 ) (7 ) (12 ) Total provision for income taxes $ (3 ) $ (6 ) $ (6 ) $ (11 )

Medium- And Long-Term Debt (Tab

Medium- And Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule Of Medium- And Long-Term Debt	Medium- and long-term debt is summarized as follows: (in millions) June 30, 2018 December 31, 2017 Parent company Subordinated notes: 3.80% subordinated notes due 2026 (a) $ 245 $ 255 Medium-term notes: 2.125% notes due 2019 (a) 346 347 Total parent company 591 602 Subsidiaries Subordinated notes: 4.00% subordinated notes due 2025 (a) 335 347 7.875% subordinated notes due 2026 (a) 198 208 Total subordinated notes 533 555 Medium-term notes: 2.50% notes due 2020 (a) 659 665 Federal Home Loan Bank (FHLB) advances: Floating-rate based on FHLB auction rate due 2026 2,800 2,800 Floating-rate based on FHLB auction rate due 2028 1,000 — Total FHLB advances 3,800 2,800 Total subsidiaries 4,992 4,020 Total medium- and long-term debt $ 5,583 $ 4,622 (a) The fixed interest rates on these notes have been swapped to a variable rate and designated in a hedging relationship. Accordingly, carrying value has been adjusted to reflect the change in the fair value of the debt as a result of changes in the benchmark rate.

Accumulated Other Comprehensi30

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule Of Accumulated Other Comprehensive Loss	The following table presents a reconciliation of the changes in the components of accumulated other comprehensive loss and details the components of other comprehensive income (loss) for the six months ended June 30, 2018 and 2017 , including the amount of income tax expense (benefit) allocated to each component of other comprehensive income (loss). Six Months Ended June 30, (in millions) 2018 2017 Accumulated net unrealized losses on investment securities: Balance at beginning of period, net of tax $ (101 ) $ (33 ) Cumulative effect of change in accounting principle 1 — Net unrealized holding (losses) gains arising during the period (197 ) 21 Less: (Benefit) provision for income taxes (46 ) 8 Net unrealized holding (losses) gains arising during the period, net of tax (151 ) 13 Less: Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax — (1 ) Change in net unrealized losses on investment securities, net of tax (151 ) 14 Balance at end of period, net of tax $ (251 ) $ (19 ) Accumulated defined benefit pension and other postretirement plans adjustment: Balance at beginning of period, net of tax $ (350 ) $ (350 ) Amortization of actuarial net loss 30 25 Amortization of prior service credit (14 ) (13 ) Amounts recognized in other noninterest expense 16 12 Less: Provision for income taxes 4 4 Change in defined benefit pension and other postretirement plans adjustment, net of tax 12 8 Balance at end of period, net of tax $ (338 ) $ (342 ) Total accumulated other comprehensive loss at end of period, net of tax $ (589 ) $ (361 )

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Basic And Diluted Net Income Per Common Share	Basic and diluted net income per common share are presented in the following table. Three Months Ended June 30, Six Months Ended June 30, (in millions, except per share data) 2018 2017 2018 2017 Basic and diluted Net income $ 326 $ 203 $ 607 $ 405 Less: Income allocated to participating securities 2 1 4 3 Net income attributable to common shares $ 324 $ 202 $ 603 $ 402 Basic average common shares 171 175 171 175 Basic net income per common share $ 1.90 $ 1.15 $ 3.52 $ 2.30 Basic average common shares 171 175 171 175 Dilutive common stock equivalents: Net effect of the assumed exercise of stock options 2 3 2 3 Net effect of the assumed exercise of warrants 1 1 1 2 Diluted average common shares 174 179 174 180 Diluted net income per common share $ 1.87 $ 1.13 $ 3.46 $ 2.24

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Components of Net Periodic Benefit Cost	The components of net periodic benefit cost (credit) for the Corporation's qualified pension plan, non-qualified pension plan and postretirement benefit plan are as follows. Qualified Defined Benefit Pension Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Service cost $ 8 $ 7 $ 15 $ 14 Other components of net benefit credit: Interest cost 18 19 37 39 Expected return on plan assets (41 ) (39 ) (82 ) (79 ) Amortization of prior service credit (4 ) (4 ) (9 ) (9 ) Amortization of net loss 12 10 25 21 Total other components of net benefit credit (15 ) (14 ) (29 ) (28 ) Net periodic defined benefit credit $ (7 ) $ (7 ) $ (14 ) $ (14 ) Non-Qualified Defined Benefit Pension Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Service cost $ 1 $ — $ 1 $ 1 Other components of net benefit cost: Interest cost 2 2 4 4 Amortization of prior service credit (3 ) (2 ) (5 ) (4 ) Amortization of net loss 3 2 5 4 Total other components of net benefit cost 2 2 4 4 Net periodic defined benefit cost $ 3 $ 2 $ 5 $ 5 Postretirement Benefit Plan Three Months Ended June 30, Six Months Ended June 30, (in millions) 2018 2017 2018 2017 Other components of net benefit credit: Interest cost $ — $ — $ 1 $ 1 Expected return on plan assets (1 ) — (2 ) (1 ) Net periodic defined benefit credit $ (1 ) $ — $ (1 ) $ —

Restructuring Charges (Tables)

Restructuring Charges (Tables)	6 Months Ended
	Jun. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The following table presents changes in restructuring reserves, cumulative charges incurred to date and total expected restructuring charges: (in millions) Employee Costs Facilities Costs Technology Costs Other Costs Total Three Months Ended June 30, 2018 Balance at beginning of period $ 10 $ — $ 9 $ — $ 19 Restructuring charges — 1 10 — 11 Payments (6 ) (1 ) (8 ) — (15 ) Balance at end of period $ 4 $ — $ 11 $ — $ 15 Three Months Ended June 30, 2017 Balance at beginning of period $ 7 $ — $ 3 $ 3 $ 13 Restructuring charges 3 4 6 1 14 Payments (4 ) (4 ) (4 ) (2 ) (14 ) Adjustments for non-cash charges (a) — — (2 ) — (2 ) Balance at end of period $ 6 $ — $ 3 $ 2 $ 11 Six Months Ended June 30, 2018 Balance at beginning of period $ 8 $ — $ 6 $ 1 $ 15 Restructuring charges 5 2 20 — 27 Payments (9 ) (2 ) (15 ) (1 ) (27 ) Balance at end of period $ 4 $ — $ 11 $ — $ 15 Six Months Ended June 30, 2017 Balance at beginning of period $ 10 $ 4 $ — $ 4 $ 18 Restructuring charges 4 5 12 4 25 Payments (8 ) (9 ) (4 ) (6 ) (27 ) Adjustments for non-cash charges (a) — — (5 ) — (5 ) Balance at end of period $ 6 $ — $ 3 $ 2 $ 11 Total restructuring charges incurred to date $ 67 $ 19 $ 46 $ 33 $ 165 Total expected restructuring charges (b) 70 20 60 - 65 35 185 - 190 (a) Adjustments for non-cash charges primarily relate to impairments of previously capitalized software costs in Technology Costs. (b) Restructuring activities are expected to be substantially completed by 12/31/2018 .

Business Segment Information (T

Business Segment Information (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Business Segment Financial Results	Business segment financial results are as follows: (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended June 30, 2018 Earnings summary: Net interest income $ 341 $ 169 $ 40 $ 26 $ 14 $ 590 Provision for credit losses (17 ) (9 ) 1 — (4 ) (29 ) Noninterest income 126 42 67 12 1 248 Noninterest expenses 182 178 75 (1 ) 14 448 Provision for income taxes 68 10 7 6 2 (a) 93 Net income $ 234 $ 32 $ 24 $ 33 $ 3 $ 326 Net credit-related charge-offs (recoveries) $ — $ (4 ) $ 1 $ — $ — $ (3 ) Selected average balances: Assets $ 39,961 $ 6,412 $ 5,260 $ 13,735 $ 5,152 $ 70,520 Loans 38,332 5,766 5,127 — — 49,225 Deposits 26,582 24,161 3,852 1,093 142 55,830 Statistical data: Return on average assets (b) 2.34 % 0.52 % 1.90 % N/M N/M 1.85 % Efficiency ratio (c) 39.00 84.05 69.03 N/M N/M 53.24 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 336 $ 162 $ 42 $ (49 ) $ 9 $ 500 Provision for credit losses 12 5 (2 ) — 2 17 Noninterest income 152 48 64 10 2 276 Noninterest expenses 196 180 71 (1 ) 11 457 Provision (benefit) for income taxes 100 9 14 (17 ) (7 ) (a) 99 Net income (loss) $ 180 $ 16 $ 23 $ (21 ) $ 5 $ 203 Net credit-related charge-offs (recoveries) $ 10 $ 9 $ (1 ) $ — $ — $ 18 Selected average balances: Assets $ 38,881 $ 6,487 $ 5,432 $ 13,936 $ 6,610 $ 71,346 Loans 37,580 5,865 5,278 — — 48,723 Deposits 28,748 23,935 4,106 156 183 57,128 Statistical data: Return on average assets (b) 1.85 % 0.27 % 1.76 % N/M N/M 1.14 % Efficiency ratio (c) 40.25 84.80 66.44 N/M N/M 58.70 (a) Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Six Months Ended June 30, 2018 Earnings summary: Net interest income $ 671 $ 334 $ 81 $ 27 $ 26 $ 1,139 Provision for credit losses (7 ) (5 ) (3 ) — (2 ) (17 ) Noninterest income 247 84 135 23 3 492 Noninterest expenses 366 355 147 (2 ) 28 894 Provision (benefit) for income taxes 127 16 17 7 (20 ) (a) 147 Net income $ 432 $ 52 $ 55 $ 45 $ 23 $ 607 Net credit-related charge-offs (recoveries) $ 18 $ 8 $ (1 ) $ — $ — $ 25 Selected average balances: Assets $ 39,438 $ 6,420 $ 5,316 $ 13,757 $ 5,492 $ 70,423 Loans 37,853 5,786 5,186 — — 48,825 Deposits 26,946 24,112 3,824 959 118 55,959 Statistical data: Return on average assets (b) 2.21 % 0.42 % 2.10 % N/M N/M 1.74 % Efficiency ratio (c) 39.85 84.54 68.06 N/M N/M 54.74 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Six Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 668 $ 322 $ 83 $ (120 ) $ 17 $ 970 Provision for credit losses 22 17 (3 ) — (3 ) 33 Noninterest income 296 96 128 21 6 547 Noninterest expenses 393 359 141 (2 ) 23 914 Provision (benefit) for income taxes 192 15 27 (41 ) (28 ) (a) 165 Net income $ 357 $ 27 $ 46 $ (56 ) $ 31 $ 405 Net credit-related charge-offs (recoveries) $ 40 $ 14 $ (3 ) $ — $ — $ 51 Selected average balances: Assets $ 38,488 $ 6,506 $ 5,419 $ 13,940 $ 7,228 $ 71,581 Loans 37,169 5,880 5,264 — — 48,313 Deposits 29,196 23,866 4,042 149 199 57,452 Statistical data: Return on average assets (b) 1.87 % 0.22 % 1.73 % N/M N/M 1.14 % Efficiency ratio (c) 40.82 85.40 66.81 N/M N/M 60.17 (a) Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful
Market Segment Financial Results	Market segment financial results are as follows: (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended June 30, 2018 Earnings summary: Net interest income $ 167 $ 183 $ 117 $ 83 $ 40 $ 590 Provision for credit losses 1 (9 ) (15 ) (2 ) (4 ) (29 ) Noninterest income 73 42 30 90 13 248 Noninterest expenses 144 105 92 94 13 448 Provision for income taxes 22 32 16 15 8 (a) 93 Net income $ 73 $ 97 $ 54 $ 66 $ 36 $ 326 Net credit-related charge-offs (recoveries) $ — $ — $ 3 $ (6 ) $ — $ (3 ) Selected average balances: Assets $ 13,427 $ 18,697 $ 10,439 $ 9,070 $ 18,887 $ 70,520 Loans 12,641 18,435 9,862 8,287 — 49,225 Deposits 20,904 16,642 8,967 8,082 1,235 55,830 Statistical data: Return on average assets (b) 1.37 % 2.06 % 2.08 % 2.93 % N/M 1.85 % Efficiency ratio (c) 59.77 46.94 62.17 53.72 N/M 53.24 (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 167 $ 178 $ 113 $ 82 $ (40 ) $ 500 Provision for credit losses (2 ) 24 (15 ) 8 2 17 Noninterest income 81 45 33 105 12 276 Noninterest expenses 145 98 94 110 10 457 Provision (benefit) for income taxes 38 40 25 20 (24 ) (a) 99 Net income (loss) $ 67 $ 61 $ 42 $ 49 $ (16 ) $ 203 Net credit-related charge-offs (recoveries) $ (1 ) $ 8 $ 5 $ 6 $ — $ 18 Selected average balances: Assets $ 13,371 $ 18,474 $ 10,481 $ 8,474 $ 20,546 $ 71,346 Loans 12,712 18,194 10,015 7,802 — 48,723 Deposits 21,698 17,344 9,632 8,115 339 57,128 Statistical data: Return on average assets (b) 1.20 % 1.33 % 1.52 % 2.24 % N/M 1.14 % Efficiency ratio (c) 58.18 43.85 64.39 58.59 N/M 58.70 (a) Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful (dollar amounts in millions) Michigan California Texas Other Finance Total Six Months Ended June 30, 2018 Earnings summary: Net interest income $ 336 $ 363 $ 226 $ 161 $ 53 $ 1,139 Provision for credit losses 34 (11 ) (28 ) (10 ) (2 ) (17 ) Noninterest income 146 81 61 178 26 492 Noninterest expenses 288 211 184 185 26 894 Provision (benefit) for income taxes 38 62 30 30 (13 ) (a) 147 Net income $ 122 $ 182 $ 101 $ 134 $ 68 $ 607 Net credit-related charge-offs (recoveries) $ (1 ) $ 13 $ 8 $ 5 $ — $ 25 Selected average balances: Assets $ 13,411 $ 18,639 $ 10,406 $ 8,718 $ 19,249 $ 70,423 Loans 12,623 18,391 9,846 7,965 — 48,825 Deposits 21,064 16,865 9,077 7,876 1,077 55,959 Statistical data: Return on average assets (b) 1.13 % 1.96 % 1.96 % 3.11 % N/M 1.74 % Efficiency ratio (c) 59.64 47.66 63.85 54.41 N/M 54.74 (dollar amounts in millions) Michigan California Texas Other Finance Total Six Months Ended June 30, 2017 Earnings summary: Net interest income (expense) $ 337 $ 349 $ 226 $ 161 $ (103 ) $ 970 Provision for credit losses (4 ) 45 (24 ) 19 (3 ) 33 Noninterest income 164 86 65 205 27 547 Noninterest expenses 295 194 188 216 21 914 Provision (benefit) for income taxes 75 76 47 36 (69 ) (a) 165 Net income (loss) $ 135 $ 120 $ 80 $ 95 $ (25 ) $ 405 Net credit-related charge-offs (recoveries) $ (4 ) $ 18 $ 27 $ 10 $ — $ 51 Selected average balances: Assets $ 13,313 $ 18,217 $ 10,518 $ 8,365 $ 21,168 $ 71,581 Loans 12,650 17,938 10,062 7,663 — 48,313 Deposits 21,923 17,294 9,871 8,016 348 57,452 Statistical data: Return on average assets (b) 1.20 % 1.33 % 1.44 % 2.17 % N/M 1.14 % Efficiency ratio (c) 58.79 44.53 64.59 59.01 N/M 60.17 (a) Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively. (b) Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity. (c) Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares. N/M – not meaningful

Revenue from Contracts with C35

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Composition of Revenue from Contracts with Customers	The following table presents the composition of revenue from contracts with customers, segregated from other sources of noninterest income, by business segment. Business Bank Retail Bank Wealth Management Finance & Other Total (in millions) Three Months Ended June 30, 2018 Revenue from contracts with customers: Card fees (a) $ 47 $ 12 $ 1 $ — $ 60 Service charges on deposit accounts (a) 28 23 2 — 53 Fiduciary income — — 52 — 52 Commercial loan servicing fees (b) 5 — — — 5 Brokerage fees — — 6 — 6 Other noninterest income (c) 3 3 5 — 11 Total revenue from contracts with customers 83 38 66 — 187 Other sources of noninterest income 43 4 1 13 61 Total noninterest income $ 126 $ 42 $ 67 $ 13 $ 248 Three Months Ended June 30, 2017 Revenue from contracts with customers: Card fees $ 65 $ 14 $ 1 $ — $ 80 Service charges on deposit accounts 30 25 2 — 57 Fiduciary income — — 51 — 51 Commercial loan servicing fees (b) 6 — — — 6 Brokerage fees — — 6 — 6 Other noninterest income (c) 2 7 3 — 12 Total revenue from contracts with customers 103 46 63 — 212 Other sources of noninterest income 49 2 1 12 64 Total noninterest income $ 152 $ 48 $ 64 $ 12 $ 276 Six Months Ended June 30, 2018 Revenue from contracts with customers: Card fees (a) $ 94 $ 23 $ 2 $ — $ 119 Service charges on deposit accounts (a) 58 46 3 — 107 Fiduciary income — — 104 — 104 Commercial loan servicing fees (b) 9 — — — 9 Brokerage fees — — 13 — 13 Other noninterest income (c) 6 8 9 — 23 Total revenue from contracts with customers 167 77 131 — 375 Other sources of noninterest income 80 7 4 26 117 Total noninterest income $ 247 $ 84 $ 135 $ 26 $ 492 Six Months Ended June 30, 2017 Revenue from contracts with customers: Card fees $ 129 $ 26 $ 2 $ — $ 157 Service charges on deposit accounts 62 50 3 — 115 Fiduciary income — — 100 — 100 Commercial loan servicing fees (b) 9 — — — 9 Brokerage fees — — 11 — 11 Other noninterest income (c) 6 15 8 — 29 Total revenue from contracts with customers 206 91 124 — 421 Other sources of noninterest income 90 5 4 27 126 Total noninterest income $ 296 $ 96 $ 128 $ 27 $ 547 (a) Adoption of Topic 606 resulted in a change in presentation which records certain costs in the same category as the associated revenues. The effect of this change was to reduce card fees by $ 37 million and $71 million and service charges on deposit accounts by $ 1 million and 2 million for three- and six-month periods ended June 30, 2018 , respectively. Refer to note 1 for further information. (b) Included in commercial lending fees on the Consolidated Statements of Comprehensive Income. (c) Excludes derivative, warrant and other miscellaneous income.

Basis of Presentation and Acc36

Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended			12 Months Ended
	Jun. 30, 2018		Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017	Dec. 31, 2017	Jan. 01, 2018	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of changes to retained earnings as a result of adoption of ASU	$ 8,079		$ 7,985	$ 8,079		$ 7,985	$ 7,963		$ 7,796
Network costs to be presented net of card fee revenue	60	[1]	80	119	[1]	157
Proceeds from settlement of BOLI policies				3		6
Remeasurement of the Corporation's deferred tax balance				104			$ 107
Deferred tax balance downward revision to the estimated impact				3
Accounting Standards Codification (ASC) Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in card fees due to change in presentation	37			71
Decrease in service charges on deposit accounts due to change in presentation	1			2
Decrease in processing fee expense due to change in presentation	38			73
Treasury management fee transition adjustment to retained earnings								$ 14
Cumulative effect of changes to retained earnings as a result of adoption of ASU								$ 2
Network costs to be presented net of card fee revenue	37		26	71		51
Accounting Standards Update 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from settlement of BOLI policies						6
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net benefit cost to be reclassified			$ 12			$ 24
Accounting Standards Update 2017-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change to retained earnings as a result of adoption of ASU				1
Recognition of additional unrealized losses from the transfer of Held-to-maturity to Available-for-sale securities				11
Minimum | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Preliminary right-of-use asset value from the implementation of ASU 2016-02	450			450
Preliminary lease oligation liability from the implementation of ASU 2016-02	450			450
Maximum | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Preliminary right-of-use asset value from the implementation of ASU 2016-02	550			550
Preliminary lease oligation liability from the implementation of ASU 2016-02	$ 550			$ 550
[1]	Adoption of Topic 606 resulted in a change in presentation which records certain costs in the same category as the associated revenues. The effect of this change was to reduce card fees by $37 million and $71 million and service charges on deposit accounts by $1 million and 2 million for three- and six-month periods ended June 30, 2018, respectively. Refer to note 1 for further information.

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Recurring
Transfers into or out of Level 1 or Level 2 or Level 3	$ 0	$ 0	$ 0	$ 0
Total liabilities at fair value	417		417		$ 282
Nonrecurring
Total liabilities at fair value	$ 0		$ 0		$ 0

Fair Value Measurements (Assets

Fair Value Measurements (Assets And Liabilities Recorded At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions		Jun. 30, 2018		Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		$ 11,915		$ 10,938	[1]
Derivative assets		251		192
Derivative liabilities	[2]	148		102
Equity and other non-debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale				82
U.S. Treasury and other U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		2,699		2,727
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[3]	9,216		8,124
State and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale				5
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		11,915		10,938
Derivative assets		253		194
Total assets at fair value		12,300		11,224
Derivative liabilities		326		190
Deferred compensation plan liabilities		91		92
Total liabilities at fair value		417		282
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		2,699		2,765
Derivative assets		0		0
Total assets at fair value		2,831		2,857
Derivative liabilities		0		0
Deferred compensation plan liabilities		91		92
Total liabilities at fair value		91		92
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		9,216		8,124
Derivative assets		245		178
Total assets at fair value		9,461		8,302
Derivative liabilities		326		190
Deferred compensation plan liabilities		0		0
Total liabilities at fair value		326		190
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0		49
Derivative assets		8		16
Total assets at fair value		8		65
Derivative liabilities		0		0
Deferred compensation plan liabilities		0		0
Total liabilities at fair value		0		0
Recurring | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		35		57
Derivative liabilities		117		59
Recurring | Interest rate contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring | Interest rate contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		29		43
Derivative liabilities		117		59
Recurring | Interest rate contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		6		14
Derivative liabilities		0		0
Recurring | Energy derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		177		93
Derivative liabilities		177		91
Recurring | Energy derivative contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring | Energy derivative contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		177		93
Derivative liabilities		177		91
Recurring | Energy derivative contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		39		42
Derivative liabilities		32		40
Recurring | Foreign exchange contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring | Foreign exchange contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		39		42
Derivative liabilities		32		40
Recurring | Foreign exchange contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Derivative liabilities		0		0
Recurring | Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		2		2
Recurring | Warrants | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Recurring | Warrants | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0		0
Recurring | Warrants | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		2		2
Recurring | Deferred compensation plan assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		91		92
Recurring | Deferred compensation plan assets | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		91		92
Recurring | Deferred compensation plan assets | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Recurring | Deferred compensation plan assets | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		0		0
Recurring | Equity and other non-debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other equity securities		41
Investment securities available-for-sale				82
Recurring | Equity and other non-debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other equity securities		41
Investment securities available-for-sale				38
Recurring | Equity and other non-debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other equity securities		0
Investment securities available-for-sale				0
Recurring | Equity and other non-debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other equity securities		0
Recurring | U.S. Treasury and other U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		2,699		2,727
Recurring | U.S. Treasury and other U.S. government agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		2,699		2,727
Recurring | U.S. Treasury and other U.S. government agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0		0
Recurring | U.S. Treasury and other U.S. government agency securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		0		0
Recurring | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		9,216	[4]	8,124
Recurring | Residential mortgage-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[4]	0		0
Recurring | Residential mortgage-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[4]	9,216		8,124
Recurring | Residential mortgage-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[4]	$ 0		0
Recurring | State and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale				5
Recurring | State and municipal securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale				0
Recurring | State and municipal securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale				0
Equity and other non-debt securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[5]			44
State and municipal securities | Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[5]			$ 5
[1]	Included auction-rate securities at amortized cost and fair value of $51 million and $49 million, respectively, as of December 31, 2017.
[2]	Net derivative assets are included in accrued income and other assets and net derivative liabilities are included in accrued expenses and other liabilities on the Consolidated Balance Sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of net derivative assets included credit valuation adjustments for counterparty credit risk of $4 million at both June 30, 2018 and December 31, 2017, respectively.
[3]	Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.
[4]	Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.
[5]	Auction-rate securities.

Fair Value Measurements (Change

Fair Value Measurements (Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017		Mar. 31, 2018
Change in classification		$ (81)	$ 0		$ (81)	$ 0
Interest rate contracts
Balance at beginning of period		7	11		14	11
Change in classification	[1]	0	0		0	0		$ 0
Realized gains (losses) recorded in earnings		0	0		0	0
Unrealized gains (losses) recorded in earnings	[2]	(1)	2		(8)	2
Sales and redemptions		0	0		0	0
Balance at end of period		6	13		6	13
Warrants
Balance at beginning of period		2	2		2	3
Change in classification	[1]	0	0		0	0		0
Realized gains (losses) recorded in earnings	[2]	1	4		1	5
Unrealized gains (losses) recorded in earnings		0	0		0	(1)	[2]
Sales and redemptions		(1)	(4)		(1)	(5)
Balance at end of period		2	2		2	2
Investment Securities Available-For-Sale
Balance at beginning of period			51		49	54
Change in classification	[1]		0			0		(44)
Realized gains (losses) recorded in earnings			0		0	0
Unrealized gains (losses) recorded in earnings			0		0	0
Sales and redemptions			0		(5)	(3)
Balance at end of period		0	51		0	51
Equity and other non-debt securities | Equity and other non-debt securities
Balance at beginning of period					0
Change in classification	[1]							(44)
Realized gains (losses) recorded in earnings					0
Unrealized gains (losses) recorded in earnings					0
Sales and redemptions					(44)
Balance at end of period		0			0
Equity and other non-debt securities | Investment Securities Available-For-Sale
Balance at beginning of period	[3]		46		44	47
Change in classification	[1],[3]		0			0		(44)
Realized gains (losses) recorded in earnings	[3]		0		0	0
Unrealized gains (losses) recorded in earnings	[3]		0		0	0
Sales and redemptions	[3]		0		0	(1)
Balance at end of period	[3]	0	46		0	46
State and municipal securities | Investment Securities Available-For-Sale
Balance at beginning of period	[3]		5		5	7
Change in classification	[1],[3]		0			0		$ 0
Realized gains (losses) recorded in earnings	[3]		0		0	0
Unrealized gains (losses) recorded in earnings	[3]		0		0	0
Sales and redemptions	[3]		0		(5)	(2)
Balance at end of period	[3]	$ 0	$ 5	[2]	$ 0	$ 5	[2]
[1]	Reflects the reclassification of equity securities resulting from the adoption of ASU 2016-01.
[2]	Realized and unrealized gains and losses due to changes in fair value recorded in Other Noninterest Income on the Consolidated Statements of Comprehensive Income.
[3]	Auction-rate securities.

Fair Value Measurements (Asse40

Fair Value Measurements (Assets And Liabilities Recorded At Fair Value On A Nonrecurring Basis) (Details) - Nonrecurring - Level 3 - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 80
Other real estate	1
Total assets at fair value	81	$ 116
Commercial borrower | Domestic loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	76	111
Commercial borrower | Commercial Mortgage Loans | Domestic loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 4	$ 5

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values Of Financial Instruments Not Recorded At Fair Value In Their Entirety On A Recurring Basis) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Cash and due from banks		$ 1,424	$ 1,438
Interest-bearing deposits with banks		4,236	4,407
Investment securities held-to-maturity		0	1,266
Total loans, net of allowance for loan losses		49,115	48,461
Demand deposits (noninterest-bearing)		30,316	32,071
Customer certificates of deposit		2,089	2,165
Total deposits		57,210	57,903
Short-term borrowings		58	10
Medium- and long-term debt		5,583	4,622
Carrying Amount
Cash and due from banks		1,424	1,438
Interest-bearing deposits with banks		4,236	4,407
Investment securities held-to-maturity			1,266
Loans held-for-sale		2	4
Total loans, net of allowance for loan losses	[1]	49,115	48,461
Customers' liability on acceptances outstanding		3	2
Restricted equity investments		248	207
Nonmarketable equity securities	[2]	6	6
Demand deposits (noninterest-bearing)		30,316	32,071
Interest-bearing deposits		24,805	23,667
Customer certificates of deposit		2,089	2,165
Total deposits		57,210	57,903
Short-term borrowings		58	10
Acceptances outstanding		3	2
Medium- and long-term debt		5,583	4,622
Credit-related financial instruments		(60)	(67)
Estimated Fair Value
Cash and due from banks		1,424	1,438
Interest-bearing deposits with banks		4,236	4,407
Investment securities held-to-maturity			1,246
Loans held-for-sale		2	4
Total loans, net of allowance for loan losses	[1]	48,929	48,153
Customers' liability on acceptances outstanding		3	2
Restricted equity investments		248	207
Nonmarketable equity securities	[2]	11	9
Demand deposits (noninterest-bearing)		30,316	32,071
Interest-bearing deposits		24,805	23,667
Customer certificates of deposit		2,061	2,142
Total deposits		57,182	57,880
Short-term borrowings		58	10
Acceptances outstanding		3	2
Medium- and long-term debt		5,588	4,636
Credit-related financial instruments		(60)	(67)
Level 1 | Estimated Fair Value
Cash and due from banks		1,424	1,438
Interest-bearing deposits with banks		4,236	4,407
Investment securities held-to-maturity			0
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	0	0
Customers' liability on acceptances outstanding		3	2
Restricted equity investments		248	207
Demand deposits (noninterest-bearing)		0	0
Interest-bearing deposits		0	0
Customer certificates of deposit		0	0
Total deposits		0	0
Short-term borrowings		58	10
Acceptances outstanding		3	2
Medium- and long-term debt		0	0
Credit-related financial instruments		0	0
Level 2 | Estimated Fair Value
Cash and due from banks		0	0
Interest-bearing deposits with banks		0	0
Investment securities held-to-maturity			1,246
Loans held-for-sale		2	4
Total loans, net of allowance for loan losses	[1]	0	0
Customers' liability on acceptances outstanding		0	0
Restricted equity investments		0	0
Demand deposits (noninterest-bearing)		30,316	32,071
Interest-bearing deposits		24,805	23,667
Customer certificates of deposit		2,061	2,142
Total deposits		57,182	57,880
Short-term borrowings		0	0
Acceptances outstanding		0	0
Medium- and long-term debt		5,588	4,636
Credit-related financial instruments		0	0
Level 3 | Estimated Fair Value
Cash and due from banks		0	0
Interest-bearing deposits with banks		0	0
Investment securities held-to-maturity			0
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	48,929	48,153
Customers' liability on acceptances outstanding		0	0
Restricted equity investments		0	0
Demand deposits (noninterest-bearing)		0	0
Interest-bearing deposits		0	0
Customer certificates of deposit		0	0
Total deposits		0	0
Short-term borrowings		0	0
Acceptances outstanding		0	0
Medium- and long-term debt		0	0
Credit-related financial instruments		(60)	(67)
Nonrecurring
Total loans, net of allowance for loan losses		$ 80	$ 116
[1]	Included $80 million and $116 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2018 and December 31, 2017, respectively.
[2]	Certain investments that are measured at fair value using the net asset value have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.

Investment Securities (Narrativ

Investment Securities (Narrative) (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018USD ($)Security	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Security	Jun. 30, 2017USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2017USD ($)
Residential mortgage-backed securities transferred from held-to-maturity to available-for-sale		$ 1,266	$ 0	$ 1,266	$ 0
Securities with no credit impairment in unrealized loss position | Security		399		399
Investment securities available-for-sale, Amortized Cost		$ 12,243		$ 12,243			$ 11,061	[1]
Investment securities available-for-sale, Fair Value		11,915		11,915			10,938	[1]
Carrying value of securities pledged		393		393
Liabilities secured by pledged collateral		$ 272		$ 272
U.S. Treasury and other U.S. government agency securities
Securities with no credit impairment in unrealized loss position		29		29
Investment securities available-for-sale, Amortized Cost		$ 2,744		$ 2,744			2,743
Investment securities available-for-sale, Fair Value		$ 2,699		$ 2,699			2,727
Residential mortgage-backed securities
Securities with no credit impairment in unrealized loss position | Security		370		370
Investment securities available-for-sale, Amortized Cost	[2]	$ 9,499		$ 9,499			8,230
Investment securities available-for-sale, Fair Value	[2]	9,216		9,216			8,124
Equity and other non-debt securities
Securities gains		0	0	0	0
Securities losses		0	0	0	0
Investment securities available-for-sale, Amortized Cost							83
Investment securities available-for-sale, Fair Value							$ 82
Debt securities
Securities gains		0	0	0	0
Securities losses		0	$ 0	0	$ 0
Investment securities available-for-sale, Amortized Cost		12,243		12,243
Investment securities available-for-sale, Fair Value		11,915		11,915
Prepayment options | Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	[2]	9,499		9,499
Investment securities available-for-sale, Fair Value	[2]	$ 9,216		$ 9,216
Accounting Standards Update 2016-01 | Residential mortgage-backed securities
Residential mortgage-backed securities transferred from held-to-maturity to available-for-sale						$ 1,266
[1]	Included auction-rate securities at amortized cost and fair value of $51 million and $49 million, respectively, as of December 31, 2017.
[2]	Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Investment securities available-for-sale, Amortized Cost		$ 12,243	$ 11,061	[1]
Investment securities available-for-sale securities, Gross Unrealized Gains		10	23	[1]
Investment securities available-for-sale securities, Gross Unrealized Losses		338	146	[1]
Investment securities available-for-sale, Fair Value		11,915	10,938	[1]
Investment securities held-to-maturity, Amortized Cost		0	1,266
Net unrealized losses on available-for-sale securities transferred to held-to-maturity			9
U.S. Treasury and other U.S. government agency securities
Investment securities available-for-sale, Amortized Cost		2,744	2,743
Investment securities available-for-sale securities, Gross Unrealized Gains		0	0
Investment securities available-for-sale securities, Gross Unrealized Losses		45	16
Investment securities available-for-sale, Fair Value		2,699	2,727
Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	[2]	9,499	8,230
Investment securities available-for-sale securities, Gross Unrealized Gains	[2]	10	22
Investment securities available-for-sale securities, Gross Unrealized Losses	[2]	293	128
Investment securities available-for-sale, Fair Value	[2]	$ 9,216	8,124
Investment securities held-to-maturity, Amortized Cost	[2],[3]		1,266
Investment securities held-to-maturity, Gross Unrealized Gains	[2],[3]		0
Investment securities held-to-maturity, Gross Unrealized Losses	[2],[3]		20
Investment securities held-to-maturity, Fair Value	[2],[3]		1,246
State and municipal securities
Investment securities available-for-sale, Amortized Cost			5
Investment securities available-for-sale securities, Gross Unrealized Gains			0
Investment securities available-for-sale securities, Gross Unrealized Losses			0
Investment securities available-for-sale, Fair Value			5
Equity and other non-debt securities
Investment securities available-for-sale, Amortized Cost			83
Investment securities available-for-sale securities, Gross Unrealized Gains			1
Investment securities available-for-sale securities, Gross Unrealized Losses			2
Investment securities available-for-sale, Fair Value			82
Auction-rate securities
Investment securities available-for-sale, Amortized Cost			51
Investment securities available-for-sale, Fair Value			$ 49
[1]	Included auction-rate securities at amortized cost and fair value of $51 million and $49 million, respectively, as of December 31, 2017.
[2]	Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.
[3]	The amortized cost of investment securities held-to-maturity included net unrealized losses of $9 million at December 31, 2017 related to securities transferred from available-for-sale in 2014, which are included in accumulated other comprehensive loss.

Investment Securities (Summar44

Investment Securities (Summary Of Investment Securities Available-For-Sale In Unrealized Loss Positions) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Temporarily Impaired Less than 12 months, Fair Value		$ 7,243	$ 6,572
Temporarily Impaired Less than 12 Months, Unrealized Losses		151	48
Temporarily Impaired 12 months or more, Fair Value		3,934	4,052
Temporarily Impaired 12 Months or more, Unrealized Losses		187	127
Temporarily Impaired Total, Fair Value		11,177	10,624
Temporarily Impaired Total, Unrealized Losses		338	175
U.S. Treasury and other U.S. government agency securities
Temporarily Impaired Less than 12 months, Fair Value		2,699	2,727
Temporarily Impaired Less than 12 Months, Unrealized Losses		45	16
Temporarily Impaired 12 months or more, Fair Value		0	0
Temporarily Impaired 12 Months or more, Unrealized Losses		0	0
Temporarily Impaired Total, Fair Value		2,699	2,727
Temporarily Impaired Total, Unrealized Losses		45	16
Residential mortgage-backed securities
Temporarily Impaired Less than 12 months, Fair Value	[1]	4,544	3,845
Temporarily Impaired Less than 12 Months, Unrealized Losses	[1]	106	32
Temporarily Impaired 12 months or more, Fair Value	[1]	3,934	4,003
Temporarily Impaired 12 Months or more, Unrealized Losses	[1]	187	125
Temporarily Impaired Total, Fair Value	[1]	8,478	7,848
Temporarily Impaired Total, Unrealized Losses	[1]	$ 293	157
State and municipal securities
Temporarily Impaired Less than 12 months, Fair Value	[2]		0
Temporarily Impaired Less than 12 Months, Unrealized Losses	[2]		0
Temporarily Impaired 12 months or more, Fair Value	[2]		5
Temporarily Impaired 12 Months or more, Unrealized Losses	[2],[3]		0
Temporarily Impaired Total, Fair Value	[2]		5
Temporarily Impaired Total, Unrealized Losses	[2],[3]		0
Equity and other non-debt securities
Temporarily Impaired Less than 12 months, Fair Value	[2]		0
Temporarily Impaired Less than 12 Months, Unrealized Losses	[2]		0
Temporarily Impaired 12 months or more, Fair Value	[2]		44
Temporarily Impaired 12 Months or more, Unrealized Losses	[2]		2
Temporarily Impaired Total, Fair Value	[2]		44
Temporarily Impaired Total, Unrealized Losses	[2]		$ 2
[1]	Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises
[2]	Primarily auction-rate securities.
[3]	Unrealized losses less than $0.5 million.

Investment Securities (Contract

Investment Securities (Contractual Maturity Distribution Of Debt Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	[1]
Investment securities available-for-sale, Amortized Cost	$ 12,243	$ 11,061
Investment securities available-for-sale, Fair Value	11,915	$ 10,938
Debt securities
Available-for-sale, Within one year, Amortized Cost	100
Available-for-sale, After one year through five years, Amortized Cost	3,008
Available-for-sale, After five years through ten years, Amortized Cost	1,752
Available-for-sale, After ten years, Amortized Cost	7,383
Investment securities available-for-sale, Amortized Cost	12,243
Available-for-sale, Within one year, Fair Value	100
Available-for-sale, After one year through five years, Fair Value	2,963
Available-for-sale, After five years through ten years, Fair Value	1,722
Available-for-sale, After ten years, Fair Value	7,130
Investment securities available-for-sale, Fair Value	$ 11,915
[1]	Included auction-rate securities at amortized cost and fair value of $51 million and $49 million, respectively, as of December 31, 2017.

Credit Quality And Allowance 46

Credit Quality And Allowance For Credit Losses (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Retail loans secured by residential real estate in process of foreclosure	$ 0		$ 0		$ 0
Commitments to lend additional funds to TDR borrowers	44		$ 44		$ 31
Principal Deferrals
Days past due defined as subsequent default			90 days	90 days
Balance	137	$ 151	$ 137	$ 151
Subsequent default during period	0	0	$ 0
Interest Rate Reductions
Days past due defined as subsequent default			90 days	90 days
Balance	2	3	$ 2	$ 3
Subsequent default during period	0	0	$ 0	$ 0
AB Note Restructures
Days past due defined as subsequent default			90 days	90 days
Balance	0	68	$ 0	$ 68
Subsequent default during period	$ 0	$ 0	$ 0	$ 0

Credit Quality And Allowance 47

Credit Quality And Allowance For Credit Losses (Aging Analysis Of Loans) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		$ 172	$ 337
Nonaccrual loans		254	402
Current loans		49,366	48,434
Total loans		49,792	49,173
30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		127	159
60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		25	143
90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		20	35
Business loans | Commercial borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		148	314
Nonaccrual loans		206	350
Current loans		45,008	43,967
Total loans		45,362	44,631
Business loans | Commercial borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		105	140
Business loans | Commercial borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		23	140
Business loans | Commercial borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		20	34
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		87	225
Nonaccrual loans		171	309
Current loans		31,272	30,526
Total loans		31,530	31,060
Business loans | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		66	79
Business loans | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		8	134
Business loans | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		13	12
Business loans | Commercial borrower | International loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	13
Nonaccrual loans		4	6
Current loans		987	964
Total loans		993	983
Business loans | Commercial borrower | International loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	13
Business loans | Commercial borrower | International loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Commercial borrower | International loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		12	7
Nonaccrual loans		0	0
Current loans		3,245	2,954
Total loans		3,257	2,961
Business loans | Real estate construction | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		12	7
Business loans | Real estate construction | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	6	3
Nonaccrual loans	[1]	0	0
Current loans	[1]	2,882	2,627
Total loans	[1],[2]	2,888	2,630
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	6	3
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	6	4
Nonaccrual loans	[3]	0	0
Current loans	[3]	363	327
Total loans	[3],[4]	369	331
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	6	4
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		47	69
Nonaccrual loans		29	31
Current loans		9,048	9,059
Total loans		9,124	9,159
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		25	41
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		15	6
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		7	22
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	14	14
Nonaccrual loans	[1]	9	9
Current loans	[1]	1,724	1,808
Total loans	[1],[2]	1,747	1,831
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	4	14
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	10	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[1]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	33	55
Nonaccrual loans	[3]	20	22
Current loans	[3]	7,324	7,251
Total loans	[3],[4]	7,377	7,328
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	21	27
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	5	6
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing	[3]	7	22
Business loans | Lease financing | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Nonaccrual loans		2	4
Current loans		456	464
Total loans		458	468
Business loans | Lease financing | Commercial borrower | Domestic loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Lease financing | Commercial borrower | Domestic loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Business loans | Lease financing | Commercial borrower | Domestic loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		24	23
Nonaccrual loans		48	52
Current loans		4,358	4,467
Total loans		4,430	4,542
Retail loans | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		22	19
Retail loans | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	3
Retail loans | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	1
Retail loans | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		7	11
Nonaccrual loans		19	21
Current loans		2,450	2,522
Total loans		2,476	2,554
Retail loans | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		6	9
Retail loans | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	1
Retail loans | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	1
Retail loans | Real estate mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		17	12
Nonaccrual loans		29	31
Current loans		1,908	1,945
Total loans		1,954	1,988
Retail loans | Real estate mortgage | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		16	10
Retail loans | Real estate mortgage | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	2
Retail loans | Real estate mortgage | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Home equity | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		5	6
Nonaccrual loans		19	21
Current loans		1,707	1,789
Total loans		1,731	1,816
Retail loans | Home equity | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		4	5
Retail loans | Home equity | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		1	1
Retail loans | Home equity | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	5
Nonaccrual loans		0	0
Current loans		743	733
Total loans		745	738
Retail loans | Other consumer | Consumer borrower | 30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		2	4
Retail loans | Other consumer | Consumer borrower | 60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		0	0
Retail loans | Other consumer | Consumer borrower | 90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		$ 0	$ 1
[1]	Primarily loans to real estate developers.
[2]	Primarily loans to real estate developers.
[3]	Primarily loans secured by owner-occupied real estate.
[4]	Primarily loans secured by owner-occupied real estate.

Credit Quality And Allowance 48

Credit Quality And Allowance For Credit Losses (Loans By Credit Quality Indicator) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans		$ 49,792	$ 49,173
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	48,027	46,942
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	762	768
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	749	1,061
Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	254	402
Business loans | Commercial borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		45,362	44,631
Business loans | Commercial borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	43,655	42,464
Business loans | Commercial borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	761	764
Business loans | Commercial borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	740	1,053
Business loans | Commercial borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	206	350
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		31,530	31,060
Business loans | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	30,185	29,263
Business loans | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	580	591
Business loans | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	594	897
Business loans | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	171	309
Business loans | Commercial borrower | International loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		993	983
Business loans | Commercial borrower | International loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	969	946
Business loans | Commercial borrower | International loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	2	11
Business loans | Commercial borrower | International loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	18	20
Business loans | Commercial borrower | International loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	4	6
Business loans | Real estate construction | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		3,257	2,961
Business loans | Real estate construction | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	3,230	2,957
Business loans | Real estate construction | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	27	4
Business loans | Real estate construction | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment [Line Items]
Total loans	[5],[6]	2,888	2,630
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[5]	2,868	2,630
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[5]	20	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[5]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[5]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	[7],[8]	369	331
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[7]	362	327
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[7]	7	4
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[7]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[7]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		9,124	9,159
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	8,822	8,858
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	148	135
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	125	135
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	29	31
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment [Line Items]
Total loans	[5],[6]	1,747	1,831
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[5]	1,678	1,759
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[5]	15	20
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[5]	45	43
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[5]	9	9
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	[7],[8]	7,377	7,328
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[7]	7,144	7,099
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[7]	133	115
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[7]	80	92
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[7]	20	22
Business loans | Lease financing | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		458	468
Business loans | Lease financing | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	449	440
Business loans | Lease financing | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	4	23
Business loans | Lease financing | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	3	1
Business loans | Lease financing | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	2	4
Retail loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		4,430	4,542
Retail loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	4,372	4,478
Retail loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	1	4
Retail loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	9	8
Retail loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	48	52
Retail loans | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		2,476	2,554
Retail loans | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	2,447	2,523
Retail loans | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	1	2
Retail loans | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	9	8
Retail loans | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	19	21
Retail loans | Real estate mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans		1,954	1,988
Retail loans | Real estate mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	1,925	1,955
Retail loans | Real estate mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	0	2
Retail loans | Real estate mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	0	0
Retail loans | Real estate mortgage | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	29	31
Retail loans | Home equity | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		1,731	1,816
Retail loans | Home equity | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	1,704	1,786
Retail loans | Home equity | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	0	1
Retail loans | Home equity | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	8	8
Retail loans | Home equity | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	19	21
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		745	738
Retail loans | Other consumer | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	743	737
Retail loans | Other consumer | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	1	1
Retail loans | Other consumer | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	1	0
Retail loans | Other consumer | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	$ 0	$ 0
[1]	Includes all loans not included in the categories of special mention, substandard or nonaccrual.
[2]	Special mention loans are accruing loans that have potential credit weaknesses that deserve management’s close attention, such as loans to borrowers who may be experiencing financial difficulties that may result in deterioration of repayment prospects from the borrower at some future date. This category is generally consistent with the "special mention" category as defined by regulatory authorities.
[3]	Substandard loans are accruing loans that have a well-defined weakness, or weaknesses, such as loans to borrowers who may be experiencing losses from operations or inadequate liquidity of a degree and duration that jeopardizes the orderly repayment of the loan. Substandard loans also are distinguished by the distinct possibility of loss in the future if these weaknesses are not corrected. This category is generally consistent with the "substandard" category as defined by regulatory authorities.
[4]	Nonaccrual loans are loans for which the accrual of interest has been discontinued. For further information regarding nonaccrual loans, refer to the Nonperforming Assets subheading in Note 1 - Basis of Presentation and Accounting Policies - on pages F-51 and F-52 in the Corporation's 2017 Annual Report. A significant majority of nonaccrual loans are generally consistent with the "substandard" category and the remainder are generally consistent with the "doubtful" category as defined by regulatory authorities.
[5]	Primarily loans to real estate developers.
[6]	Primarily loans to real estate developers.
[7]	Primarily loans secured by owner-occupied real estate.
[8]	Primarily loans secured by owner-occupied real estate.

Credit Quality And Allowance 49

Credit Quality And Allowance For Credit Losses (Schedule Of Nonaccrual, Reduced-Rate Loans And Foreclosed Property) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Nonaccrual loans		$ 254	$ 402
Reduced-rate loans	[1]	8	8
Total nonperforming loans		262	410
Foreclosed property	[2]	2	5
Total nonperforming assets		264	415
Residential Real Estate
Foreclosed property		1	4
Business loans
Reduced-rate loans		0	0
Retail loans
Nonaccrual loans		48	52
Reduced-rate loans		$ 8	$ 8
[1]	There were no reduced-rate business loans at both June 30, 2018 and December 31, 2017. Reduced-rate retail loans were $8 million at both June 30, 2018 and December 31, 2017.
[2]	Included $1 million and $4 million of foreclosed residential real estate properties at June 30, 2018 and December 31, 2017, respectively.

Credit Quality And Allowance 50

Credit Quality And Allowance For Credit Losses (Changes In The Allowance For Loan Losses And Related Loan Amounts) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan losses	$ (29)	$ 17	$ (17)	$ 33
Total loans					$ 49,792	$ 49,173
Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	698	708	712	730
Loan charge-offs	(20)	(39)	(57)	(83)
Recoveries on loans previously charged-off	23	21	32	32
Net loan recoveries (charge-offs)	3	(18)	(25)	(51)
Provision for loan losses	(23)	15	(9)	26
Foreign currency translation adjustment	1	0	1	0
Balance at end of period	677	705	677	705
As a percentage of total loans					1.36%		1.43%
Allowance for loan losses individually evaluated for impairment					$ 39		$ 94
Allowance for loan losses collectively evaluated for impairment					638		611
Total allowance for loan losses	698	708	712	730	677	712	705
Loans individually evaluated for impairment					340		550
Loans collectively evaluated for impairment					49,452		48,858
Total loans					$ 49,792		$ 49,408
Business loans | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	653	661	661	682
Loan charge-offs	(18)	(37)	(54)	(79)
Recoveries on loans previously charged-off	22	20	30	29
Net loan recoveries (charge-offs)	4	(17)	(24)	(50)
Provision for loan losses	(21)	17	(1)	29
Foreign currency translation adjustment	1	0	1	0
Balance at end of period	635	661	635	661
As a percentage of total loans					1.40%		1.47%
Allowance for loan losses individually evaluated for impairment					$ 39		$ 93
Allowance for loan losses collectively evaluated for impairment					596		568
Total allowance for loan losses	653	661	661	682	635	661	661
Loans individually evaluated for impairment					310		509
Loans collectively evaluated for impairment					45,052		44,388
Total loans					45,362		$ 44,897
Retail loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans					$ 4,430	4,542
Retail loans | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	45	47	51	48
Loan charge-offs	(2)	(2)	(3)	(4)
Recoveries on loans previously charged-off	1	1	2	3
Net loan recoveries (charge-offs)	(1)	(1)	(1)	(1)
Provision for loan losses	(2)	(2)	(8)	(3)
Foreign currency translation adjustment	0	0	0	0
Balance at end of period	42	44	42	44
As a percentage of total loans					0.96%		0.98%
Allowance for loan losses individually evaluated for impairment					$ 0		$ 1
Allowance for loan losses collectively evaluated for impairment					42		43
Total allowance for loan losses	$ 45	$ 47	$ 51	$ 48	42	$ 51	44
Loans individually evaluated for impairment					30		41
Loans collectively evaluated for impairment					4,400		4,470
Total loans					$ 4,430		$ 4,511

Credit Quality And Allowance 51

Credit Quality And Allowance For Credit Losses (Changes In The Allowance For Credit Losses On Lending-Related Commitments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses	$ (29)	$ 17	$ (17)	$ 33
Lending-related commitments
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	40	46	42	41
Provision for credit losses	(6)	2	(8)	7
Balance at end of period	$ 34	$ 48	$ 34	$ 48

Credit Quality And Allowance 52

Credit Quality And Allowance For Credit Losses (Individually Evaluated Impaired Loans) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		$ 147	$ 173
Recorded investment in impaired loans with related allowance		193	304
Recorded investment total impaired loans		340	477
Unpaid principal balance		434	593
Related allowance for loan losses		39	67
Business loans | Commercial borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		125	147
Recorded investment in impaired loans with related allowance		185	296
Recorded investment total impaired loans		310	443
Unpaid principal balance		400	555
Related allowance for loan losses		39	67
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		85	105
Recorded investment in impaired loans with related allowance		154	267
Recorded investment total impaired loans		239	372
Unpaid principal balance		313	460
Related allowance for loan losses		35	63
Business loans | Commercial borrower | International loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		3	0
Recorded investment in impaired loans with related allowance		2	6
Recorded investment total impaired loans		5	6
Unpaid principal balance		9	17
Related allowance for loan losses		1	1
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		37	42
Recorded investment in impaired loans with related allowance		29	23
Recorded investment total impaired loans		66	65
Unpaid principal balance		78	78
Related allowance for loan losses		3	3
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance	[1]	37	39
Recorded investment in impaired loans with related allowance	[1]	3	1
Recorded investment total impaired loans	[1]	40	40
Unpaid principal balance	[1]	49	49
Related allowance for loan losses	[1]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance	[2]	0	3
Recorded investment in impaired loans with related allowance	[2]	26	22
Recorded investment total impaired loans	[2]	26	25
Unpaid principal balance	[2]	29	29
Related allowance for loan losses	[2]	3	3
Retail loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance	[3]	22	26
Recorded investment in impaired loans with related allowance	[3]	8	8
Recorded investment total impaired loans	[3]	30	34
Unpaid principal balance	[3]	34	38
Related allowance for loan losses	[3]	0	0
Retail loans | Consumer borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		11	12
Recorded investment in impaired loans with related allowance		0	0
Recorded investment total impaired loans		11	12
Unpaid principal balance		14	16
Related allowance for loan losses		0	0
Retail loans | Real estate mortgage
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		11	14
Recorded investment in impaired loans with related allowance		8	8
Recorded investment total impaired loans		19	22
Unpaid principal balance		20	22
Related allowance for loan losses		0	0
Retail loans | Home equity | Consumer borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		10	11
Recorded investment in impaired loans with related allowance		0	0
Recorded investment total impaired loans		10	11
Unpaid principal balance		13	14
Related allowance for loan losses		0	0
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		1	1
Recorded investment in impaired loans with related allowance		0	0
Recorded investment total impaired loans		1	1
Unpaid principal balance		1	2
Related allowance for loan losses		$ 0	$ 0
[1]	Primarily loans to real estate developers.
[2]	Primarily loans secured by owner-occupied real estate.
[3]	Individually evaluated retail loans generally have no related allowance for loan losses, primarily due to policy which results in direct write-downs of most restructured retail loans.

Credit Quality And Allowance 53

Credit Quality And Allowance For Credit Losses (Average Individually Evaluated Impaired Loans And Related Interest Recognized) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		$ 377	$ 563	$ 411	$ 580
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		2	2	4	4
Business loans | Commercial borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		346	522	379	537
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		2	2	4	4
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		277	473	309	487
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		1	2	2	4
Business loans | Commercial borrower | International loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		4	7	5	9
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		65	42	65	41
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		1	0	2	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period	[1]	40	7	40	7
Individually Evaluated Impaired Loans Interest Income Recognized for the Period	[1]	1	0	2	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period	[2]	25	35	25	34
Individually Evaluated Impaired Loans Interest Income Recognized for the Period	[2]	0	0	0	0
Retail loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		31	41	32	43
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0	0
Retail loans | Consumer borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		12	14	12	16
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0	0
Retail loans | Real estate mortgage
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		19	27	20	27
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0	0
Retail loans | Home equity | Consumer borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		11	12	11	13
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		0	0	0	0
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		1	2	1	3
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		$ 0	$ 0	$ 0	$ 0
[1]	Primarily loans to real estate developers.
[2]	Primarily loans secured by owner-occupied real estate.

Credit Quality And Allowance 54

Credit Quality And Allowance For Credit Losses (Troubled Debt Restructurings By Type Of Modification) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		$ 26	$ 85	$ 48	$ 139
Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		25	84	46	136
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		25	83	45	132
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1]	0	1	1	4
Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[2]	1	1	2	3
Principal Deferrals
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3]	25	48	47	101
Principal Deferrals | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3]	25	48	46	100
Principal Deferrals | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3]	25	47	45	96
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1],[3]	0	1	1	4
Principal Deferrals | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[2],[3]	0	0	1	1
Interest Rate Reductions
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		1	1	1	2
Interest Rate Reductions | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		0	0	0	0
Interest Rate Reductions | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		0	0	0	0
Interest Rate Reductions | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1]	0	0	0	0
Interest Rate Reductions | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[2]	$ 1	1	$ 1	2
AB Note Restructures
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]		36		36
AB Note Restructures | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]		36		36
AB Note Restructures | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]		36		36
AB Note Restructures | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1],[4]		0		0
AB Note Restructures | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[2],[4]		$ 0		$ 0
[1]	Primarily loans to secured by owner-occupied real estate.
[2]	Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.
[3]	Primarily represents loan balances where terms were extended 90 days or more at or above contractual interest rates.
[4]	Loan restructurings whereby the original loan is restructured into two notes: an "A" note, which generally reflects the portion of the modified loan which is expected to be collected; and a "B" note, which is generally fully charged off.

Credit Quality And Allowance 55

Credit Quality And Allowance For Credit Losses Credit Quality And Allowance For Credit Losses (Troubled Debt Restructuring Subsequent Default) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Jun. 30, 2017
Principal Deferrals
Financing Receivable, Modifications [Line Items]
Balance		$ 137	$ 151
Principal Deferrals | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Balance		136	149
Principal Deferrals | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		97	141
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		39	8
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Balance	[1]	37	1
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Balance	[2]	2	7
Principal Deferrals | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Balance	[3]	1	2
Interest Rate Reductions
Financing Receivable, Modifications [Line Items]
Balance		2	3
Interest Rate Reductions | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Balance		0	0
Interest Rate Reductions | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		0	0
Interest Rate Reductions | Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		0	0
Interest Rate Reductions | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Balance	[1]	0	0
Interest Rate Reductions | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Balance	[2]	0	0
Interest Rate Reductions | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Balance	[3]	$ 2	$ 3
[1]	Primarily loans to real estate developers.
[2]	Primarily loans secured by owner-occupied real estate.
[3]	Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.

Derivative And Credit-Related56

Derivative And Credit-Related Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Effects of fair value hedging on the Consolidated Statements o Comprehensive Income [Line Items]
Fair value of securities pledged as collateral for derivative liabilities	$ 3		$ 3
Cash received as collateral for derivative assets	10		10
Fair value of securities received as collateral for derivative assets	10		10
Cash posted as collateral for derivative liabilities	131		131
Aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	0		0
Net gain on open foreign currency positions	0	$ 0	0	$ 0
Allowance for credit losses on lending-related commitments	34		34		$ 42
Allowance for credit losses on lending-related commitments, amount related to unused commitments to extend credit	24		$ 24		27
Final year of expiration for outstanding letters of credit			2,028
Risk participation agreements covering standby and commercial letters of credit	127		$ 127		127
Standby and commercial letters of credit	3,000		3,000		3,300
Carrying value of standby and commercial letters of credit included in accrued expenses and other liabilities	36		36		40
Deferred fees on standby and commercial letters of credit included in accrued expenses and other liabilities	26		26		25
Allowance for credit losses on lending-related commitments, amount related to standby and commercial letters of credit	10		10		15
Notional amount of derivative credit risk participation agreements	586		586		549
Maximum estimated exposure to credit risk participation agreements assuming 100% default	$ 0		$ 0		$ 0
Weighted average remaining maturity of credit risk participation agreements, in years			2 years 8 months 12 days

Derivative And Credit-Related57

Derivative And Credit-Related Financial Instruments (Schedule Of Derivative Instruments) (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	$ 20,897	$ 20,545
Fair Value of Gross Derivative Assets		251	192
Fair Value of Gross Derivative Liabilities		326	190
Derivative assets, Netting adjustment - Offsetting derivative liabilities		(48)	(49)
Derivative liabilities, Netting adjustment - Offsetting derivative assets		(48)	(49)
Derivative assets, Netting adjustment - Cash collateral received		(6)	(1)
Derivative liabilities, Netting adjustment, Cash collateral posted		(130)	(39)
Net derivative assets included in the consolidated balance sheets	[2]	197	142
Net derivative liabilities included in the consolidated balance sheets	[2]	148	102
Derivative asset, securities pledged as collateral		(3)	(3)
Derivative liability, securities pledged as collateral		(10)	(24)
Net derivative assets after deducting amounts not offset in the consolidated balance sheets		194	139
Net derivative liabilities after deducting amounts not offset in the consolidated balance sheets		138	78
Credit valuation adjustments for counterparty credit risk		4	4
Risk management purposes
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,568	2,425
Fair Value of Gross Derivative Assets		2	0
Fair Value of Gross Derivative Liabilities		4	4
Risk management purposes | Derivatives designated as hedging instruments | Fair Value Hedging | Interest rate swap
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	1,775	1,775
Fair Value of Gross Derivative Assets		0	0
Fair Value of Gross Derivative Liabilities		3	2
Risk management purposes | Derivatives used as economic hedges | Foreign exchange spot, forwards and swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	793	650
Fair Value of Gross Derivative Assets		2	0
Fair Value of Gross Derivative Liabilities		1	2
Customer-initiated and other activities
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	18,329	18,120
Fair Value of Gross Derivative Assets		249	192
Fair Value of Gross Derivative Liabilities		322	186
Customer-initiated and other activities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	14,020	14,389
Fair Value of Gross Derivative Assets		35	57
Fair Value of Gross Derivative Liabilities		114	57
Customer-initiated and other activities | Interest rate caps and floors written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	715	635
Fair Value of Gross Derivative Assets		0	0
Fair Value of Gross Derivative Liabilities		2	0
Customer-initiated and other activities | Interest rate caps and floors purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	715	635
Fair Value of Gross Derivative Assets		2	0
Fair Value of Gross Derivative Liabilities		0	0
Customer-initiated and other activities | Interest rate swap
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	12,590	13,119
Fair Value of Gross Derivative Assets		33	57
Fair Value of Gross Derivative Liabilities		112	57
Customer-initiated and other activities | Energy contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,390	1,847
Fair Value of Gross Derivative Assets		177	93
Fair Value of Gross Derivative Liabilities		177	91
Customer-initiated and other activities | Energy caps and floors written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	172	164
Fair Value of Gross Derivative Assets		0	0
Fair Value of Gross Derivative Liabilities		16	11
Customer-initiated and other activities | Energy caps and floors purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	172	164
Fair Value of Gross Derivative Assets		16	11
Fair Value of Gross Derivative Liabilities		0	0
Customer-initiated and other activities | Energy swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,046	1,519
Fair Value of Gross Derivative Assets		161	82
Fair Value of Gross Derivative Liabilities		161	80
Customer-initiated and other activities | Foreign exchange spot, options and swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	1,919	1,884
Fair Value of Gross Derivative Assets		37	42
Fair Value of Gross Derivative Liabilities		$ 31	$ 38
[1]	Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Balance Sheets.
[2]	Net derivative assets are included in accrued income and other assets and net derivative liabilities are included in accrued expenses and other liabilities on the Consolidated Balance Sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of net derivative assets included credit valuation adjustments for counterparty credit risk of $4 million at both June 30, 2018 and December 31, 2017, respectively.

Derivative And Credit-Related58

Derivative And Credit-Related Financial Instruments Derivative and Credit-Related Financial Instruments (Schedule of the Effects of Fair Value Hedging on the Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total interest on medium- and long-term debt	[1]	$ 32	$ 20	$ 57	$ 37
Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Interest rate contract: Hedge items interest expense		15	23	30	45
Interest rate contracts: Derivatives designated as hedging instruments net interest income		$ (2)	$ (10)	$ (5)	$ (20)
[1]	Includes the effects of hedging.

Derivative And Credit-Related59

Derivative And Credit-Related Financial Instruments (Schedule Of Weighted Average Maturity And Interest Rates On Risk Management Interest Rate Swaps) (Details) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2018	Dec. 31, 2017
Notional Amount	[1]	$ 20,897	$ 20,545
Cumulative hedging adjustments		16	56
Cumulative hedging adjustments on discontinued hedging relationship		8	9
Risk management purposes
Notional Amount	[1]	2,568	2,425
Medium- and long-term debt | Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Notional Amount		1,775	1,775
Carrying Value of Hedged Item	[2]	$ 1,783	$ 1,822
Weighted Average Remaining Maturity		4 years 1 month 20 days	4 years 7 months 17 days
Weighted Average Receive Rate		3.26%	3.26%
Weighted Average Pay Rate	[3]	3.06%	2.35%
[1]	Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Balance Sheets.
[2]	Included $16 million and $56 million of cumulative hedging adjustments at June 30, 2018 and December 31, 2017, respectively, which included $8 million and $9 million, respectively, of hedging adjustment on a discontinued hedging relationship.
[3]	Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at June 30, 2018 and December 31, 2017.

Derivative And Credit-Related60

Derivative And Credit-Related Financial Instruments (Schedule Of Net Gains Recognized In Income On Customer-Initiated Derivatives) (Details) - Customer-initiated and other activities - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 19	$ 19	$ 35	$ 36
Interest rate contracts | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	7	7	11	13
Energy contracts | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	0	1	0	1
Foreign exchange contracts | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 12	$ 11	$ 24	$ 22

Derivative And Credit-Related61

Derivative And Credit-Related Financial Instruments (Schedule Of Financial Instruments With Off-Balance Sheet Credit Risk) (Details) - Maximum - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	$ (26,361)	$ (25,469)
Commercial And Other | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	(23,424)	(22,636)
Bankcard, Revolving Check Credit And Home Equity Loan Commitments | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	(2,937)	(2,833)
Standby Letters Of Credit
Loss contingency, estimate of possible loss, maximum	(3,236)	(3,228)
Commercial Letters Of Credit
Loss contingency, estimate of possible loss, maximum	$ (48)	$ (39)

Derivative And Credit-Related62

Derivative And Credit-Related Financial Instruments (Summary Of Internally Classified Watch List Letters Of Credit) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Total criticized standby and commercial letters of credit	$ 83	$ 88
As a percentage of total outstanding standby and commercial letters of credit	2.50%	2.70%

Variable Interest Entities (V63

Variable Interest Entities (VIEs) (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Variable Interest Entity
Unfunded commitments to fund tax credit entities	$ 150
Amount of financial or other support not contractually required provided by the Corporation to VIEs	0	$ 0
Low Income Housing Tax Credit Entities
Variable Interest Entity
Exposure to loss as a result of involvement with VIEs	409
Other Tax Credit Entities
Variable Interest Entity
Exposure to loss as a result of involvement with VIEs	$ 7

Variable Interest Entities (V64

Variable Interest Entities (VIEs) (Impact Of VIEs On The Consolidated Statements Of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Variable Interest Entity
Other noninterest income	$ 22	$ 29	$ 44	$ 58
Provision for income taxes	93	99	147	165
Variable Interest Entity
Variable Interest Entity
Other noninterest income	1	0	2	1
Provision for income taxes, amortization of LIHTC investments	16	16	31	32
Provision for income taxes	(3)	(6)	(6)	(11)
Low income housing tax credits | Variable Interest Entity
Variable Interest Entity
Provision for income taxes, affordable housing tax credits and other tax benefits	(15)	(16)	(30)	(31)
Other tax benefits related to tax credit entities | Variable Interest Entity
Variable Interest Entity
Provision for income taxes, affordable housing tax credits and other tax benefits	$ (4)	$ (6)	$ (7)	$ (12)

Medium- And Long-Term Debt (Nar

Medium- And Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Feb. 07, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 4		$ 5
Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank Advances	3,800		2,800
Blanket lien on real estate-related loans securing FHLB advances	16,000
Potential FHLB borrowing capacity	5,500
Floating-rate based on FHLB auction rate due 2026 | Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank Advances	$ 2,800		2,800
Weighted-average interest rate	2.06%
Floating-rate based on FHLB auction rate due 2028 | Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank Advances	$ 1,000	$ 1,000	$ 0
Weighted-average interest rate	2.06%

Medium- And Long-Term Debt (Sch

Medium- And Long-Term Debt (Schedule Of Medium- And Long-Term Debt) (Details) - USD ($) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2018	Dec. 31, 2017	Feb. 07, 2018
Debt Instrument [Line Items]
Total medium- and long-term debt		$ 5,583	$ 4,622
Parent Company
Debt Instrument [Line Items]
Total medium- and long-term debt		591	602
Subsidiaries
Debt Instrument [Line Items]
Subordinated notes		533	555
Long-term Federal Home Loan Bank Advances		3,800	2,800
Total medium- and long-term debt		4,992	4,020
3.80% subordinated notes due 2026 | Parent Company
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 245	$ 255
Stated interest rate		3.80%	3.80%
Maturity date		Jul. 22, 2026	Jul. 22, 2026
2.125% notes due 2019 | Parent Company
Debt Instrument [Line Items]
Medium-term notes	[1]	$ 346	$ 347
Stated interest rate		2.125%	2.125%
Maturity date		May 23, 2019	May 23, 2019
4.00% subordinated notes due 2025 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 335	$ 347
Stated interest rate		4.00%	4.00%
Maturity date		Jul. 27, 2025	Jul. 27, 2025
7.875% subordinated notes due 2026 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 198	$ 208
Stated interest rate		7.875%	7.875%
Maturity date		Sep. 15, 2026	Sep. 15, 2026
2.50% notes due 2020 | Subsidiaries
Debt Instrument [Line Items]
Medium-term notes	[1]	$ 659	$ 665
Stated interest rate		2.50%	2.50%
Maturity date		Jun. 2, 2020	Jun. 2, 2020
Floating-rate based on FHLB auction rate due 2026 | Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank Advances		$ 2,800	$ 2,800
Weighted-average interest rate		2.06%
Floating-rate based on FHLB auction rate due 2026 | Subsidiaries | Maximum
Debt Instrument [Line Items]
Maturity date		May 20, 2026
Floating-rate based on FHLB auction rate due 2026 | Subsidiaries | Minimum
Debt Instrument [Line Items]
Maturity date		Mar. 4, 2026
Floating-rate based on FHLB auction rate due 2028 | Subsidiaries
Debt Instrument [Line Items]
Long-term Federal Home Loan Bank Advances		$ 1,000	$ 0	$ 1,000
Maturity date		Jan. 26, 2028
Weighted-average interest rate		2.06%
[1]	The fixed interest rates on these notes have been swapped to a variable rate and designated in a hedging relationship. Accordingly, carrying value has been adjusted to reflect the change in the fair value of the debt as a result of changes in the benchmark rate.

Accumulated Other Comprehensi67

Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Investment securities, Balance at beginning of period, net of tax	$ (101)	$ (33)
Cumulative effect of change in accounting principle	1	0
Investment securities, Net unrealized holding (losses) gains arising during the period	(197)	21
Investment securities, Less: (Benefit) provision for income taxes	(46)	8
Investment securities, Net unrealized holding (losses) gains arising during the period, net of tax	(151)	13
Investment securities, Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax	0	(1)
Investment securities, Change in net unrealized (losses) gains on investment securities, net of tax	(151)	14
Investment securities, Balance at end of period, net of tax	(251)	(19)
Benefit plans, Balance at beginning of period, net of tax	(350)	(350)
Benefit plans, Amortization of actuarial net loss	30	25
Benefit plans, Amortization of prior service credit	(14)	(13)
Benefit plans, Amounts recognized in other noninterest expense	16	12
Benefit plans, Less: Provision for income taxes	4	4
Benefit plans, Change in defined benefit pension and other postretirement plans adjustment, net of tax	12	8
Benefit plans, Balance at end of period, net of tax	(338)	(342)
Total accumulated other comprehensive loss at end of period, net of tax	$ (589)	$ (361)	$ (451)

Net Income Per Common Share (Na

Net Income Per Common Share (Narrative) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Average outstanding options	0	0	0	0

Net Income Per Common Share (Ba

Net Income Per Common Share (Basic And Diluted Net Income Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 326	$ 203	$ 607	$ 405
Income allocated to participating securities	2	1	4	3
Net income attributable to common shares	$ 324	$ 202	$ 603	$ 402
Basic average common shares	171	175	171	175
Basic net income per common share	$ 1.90	$ 1.15	$ 3.52	$ 2.30
Basic average common shares	171	175	171	175
Net effect of the assumed exercise of stock options	2	3	2	3
Net effect of the assumed exercise of warrants	1	1	1	2
Diluted average common shares	174	179	174	180
Diluted net income per common share	$ 1.87	$ 1.13	$ 3.46	$ 2.24

Employee Benefit Plans Employee

Employee Benefit Plans Employee Benefit Plans (Net Periodic Defined Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Net periodic defined benefit (credit) cost			$ (10)	$ (9)
Qualified Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Total other components of net benefit (credit) cost	$ (15)	$ (14)	(29)	(28)
Net periodic defined benefit (credit) cost	(7)	(7)	(14)	(14)
Qualified Defined Benefit Pension Plan | Component recognized in salaries and benefits expense
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	7	15	14
Qualified Defined Benefit Pension Plan | Component recognized in noninterest expense
Defined Benefit Plan Disclosure [Line Items]
Interest cost	18	19	37	39
Expected return on plan assets	(41)	(39)	(82)	(79)
Amortization of prior service credit	(4)	(4)	(9)	(9)
Amortization of net loss	12	10	25	21
Non-Qualified Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Total other components of net benefit (credit) cost	2	2	4	4
Net periodic defined benefit (credit) cost	3	2	5	5
Non-Qualified Defined Benefit Pension Plan | Component recognized in salaries and benefits expense
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	0	1	1
Non-Qualified Defined Benefit Pension Plan | Component recognized in noninterest expense
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2	2	4	4
Amortization of prior service credit	(3)	(2)	(5)	(4)
Amortization of net loss	3	2	5	4
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Net periodic defined benefit (credit) cost	1	0	1	0
Postretirement Benefit Plan | Component recognized in noninterest expense
Defined Benefit Plan Disclosure [Line Items]
Interest cost	0	0	1	1
Expected return on plan assets	$ (1)	$ 0	$ (2)	$ (1)

Income Taxes And Tax-Related 71

Income Taxes And Tax-Related Items Income Taxes And Tax-Related Items (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Unrecognized tax benefits	$ 10	$ 10
Reasonably possible decrease in unrecognized tax benefits in next 12 months	1
Tax-related interest and penalties payable	10	10
Net deferred tax assets	169	141
Increase in net deferred tax assets	28
State net operating loss carryforwards	4	4
Valuation allowance for deferred tax assets	$ 3	$ 3
Minimum
Years state net operating loss carryforwards expire	Dec. 31, 2018
Maximum
Years state net operating loss carryforwards expire	Dec. 31, 2027

Contingent Liabilities (Narrati

Contingent Liabilities (Narrative) (Details) - USD ($) $ in Millions	Jan. 17, 2014	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Loss Contingencies [Line Items]
Legal fees		$ 4	$ 5	$ 7	$ 10
Pending Litigation | Minimum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss		0		0
Pending Litigation | Maximum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss		$ 33		$ 33
Butte Local Development v. Masters Group v. Comerica Bank
Loss Contingencies [Line Items]
Amount of damages awarded by the jury	$ 52

Restructuring Charges (Narrativ

Restructuring Charges (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 11	$ 14	$ 27	$ 25
Business Bank
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6	7	15	13
Retail Bank
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4	4	9	8
Wealth Management
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1	$ 3	$ 3	$ 4

Restructuring Charges (Schedule

Restructuring Charges (Schedule of Changes in Restructuring Reserves) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		$ 19	$ 13	$ 15	$ 18
Restructuring charges		11	14	27	25
Payments		(15)	(14)	(27)	(27)
Adjustments for non-cash charges	[1]		(2)		(5)
Balance at end of period		15	11	15	11
Total restructuring charges incurred to date		165		$ 165
Expected completion date of restructuring activities				Dec. 31, 2018
Employee costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		10	7	$ 8	10
Restructuring charges		0	3	5	4
Payments		(6)	(4)	(9)	(8)
Adjustments for non-cash charges	[1]		0		0
Balance at end of period		4	6	4	6
Total restructuring charges incurred to date		67		67
Facilities costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		0	0	0	4
Restructuring charges		1	4	2	5
Payments		(1)	(4)	(2)	(9)
Adjustments for non-cash charges	[1]		0		0
Balance at end of period		0	0	0	0
Total restructuring charges incurred to date		19		19
Technology costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		9	3	6	0
Restructuring charges		10	6	20	12
Payments		(8)	(4)	(15)	(4)
Adjustments for non-cash charges	[1]		(2)		(5)
Balance at end of period		11	3	11	3
Total restructuring charges incurred to date		46		46
Other costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		0	3	1	4
Restructuring charges		0	1	0	4
Payments		0	(2)	(1)	(6)
Adjustments for non-cash charges	[1]		0		0
Balance at end of period		0	$ 2	0	$ 2
Total restructuring charges incurred to date		33		33
Minimum
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	185		185
Minimum | Employee costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	70		70
Minimum | Facilities costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	20		20
Minimum | Technology costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	60		60
Minimum | Other costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	35		35
Maximum
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	190		190
Maximum | Employee costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	70		70
Maximum | Facilities costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	20		20
Maximum | Technology costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	65		65
Maximum | Other costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	$ 35		$ 35
[1]	Adjustments for non-cash charges primarily relate to impairments of previously capitalized software costs in Technology Costs.
[2]	Restructuring activities are expected to be substantially completed by 12/31/2018.

Business Segment Information (N

Business Segment Information (Narrative) (Details)	6 Months Ended
	Jun. 30, 2018segmentsmarkets
Segment Reporting [Abstract]
Number of Major Business Segments | segments	3
Number of Primary Market Segments | markets	3

Business Segment Information (B

Business Segment Information (Business Segment Financial Results) (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017		Jun. 30, 2018		Jun. 30, 2017
Net interest income (expense)		$ 590		$ 500		$ 1,139		$ 970
Provision for credit losses		(29)		17		(17)		33
Noninterest income		248		276		492		547
Noninterest expenses		448		457		894		914
Provision (benefit) for income taxes		(93)		(99)		(147)		(165)
Net income (loss)		326		203		607		405
Net credit-related charge-offs (recoveries)		(3)		18		25		51
Assets, average		70,520		71,346		70,423		71,581
Loans, average		49,225		48,723		48,825		48,313
Deposits, average		$ 55,830		$ 57,128		$ 55,959		$ 57,452
Return on average assets	[1]	1.85%		1.14%		1.74%		1.14%
Efficiency ratio	[2]	53.24%		58.70%		54.74%		60.17%
Tax benefits from employee stock transactions		$ 3		$ 5		$ 22		$ 29
Business Bank
Net interest income (expense)		341		336		671		668
Provision for credit losses		(17)		12		(7)		22
Noninterest income		126		152		247		296
Noninterest expenses		182		196		366		393
Provision (benefit) for income taxes		(68)		(100)		(127)		(192)
Net income (loss)		234		180		432		357
Net credit-related charge-offs (recoveries)		0		10		18		40
Assets, average		39,961		38,881		39,438		38,488
Loans, average		38,332		37,580		37,853		37,169
Deposits, average		$ 26,582		$ 28,748		$ 26,946		$ 29,196
Return on average assets	[1]	2.34%		1.85%		2.21%		1.87%
Efficiency ratio	[2]	39.00%		40.25%		39.85%		40.82%
Retail Bank
Net interest income (expense)		$ 169		$ 162		$ 334		$ 322
Provision for credit losses		(9)		5		(5)		17
Noninterest income		42		48		84		96
Noninterest expenses		178		180		355		359
Provision (benefit) for income taxes		(10)		(9)		(16)		(15)
Net income (loss)		32		16		52		27
Net credit-related charge-offs (recoveries)		(4)		9		8		14
Assets, average		6,412		6,487		6,420		6,506
Loans, average		5,766		5,865		5,786		5,880
Deposits, average		$ 24,161		$ 23,935		$ 24,112		$ 23,866
Return on average assets	[1]	0.52%		0.27%		0.42%		0.22%
Efficiency ratio	[2]	84.05%		84.80%		84.54%		85.40%
Wealth Management
Net interest income (expense)		$ 40		$ 42		$ 81		$ 83
Provision for credit losses		1		(2)		(3)		(3)
Noninterest income		67		64		135		128
Noninterest expenses		75		71		147		141
Provision (benefit) for income taxes		(7)		(14)		(17)		(27)
Net income (loss)		24		23		55		46
Net credit-related charge-offs (recoveries)		1		(1)		(1)		(3)
Assets, average		5,260		5,432		5,316		5,419
Loans, average		5,127		5,278		5,186		5,264
Deposits, average		$ 3,852		$ 4,106		$ 3,824		$ 4,042
Return on average assets	[1]	1.90%		1.76%		2.10%		1.73%
Efficiency ratio	[2]	69.03%		66.44%		68.06%		66.81%
Finance
Net interest income (expense)		$ 26		$ (49)		$ 27		$ (120)
Provision for credit losses		0		0		0		0
Noninterest income		12		10		23		21
Noninterest expenses		(1)		(1)		(2)		(2)
Provision (benefit) for income taxes		(6)		17		(7)		41
Net income (loss)		33		(21)		45		(56)
Net credit-related charge-offs (recoveries)		0		0		0		0
Assets, average		13,735		13,936		13,757		13,940
Loans, average		0		0		0		0
Deposits, average		1,093		156		959		149
Other
Net interest income (expense)		14		9		26		17
Provision for credit losses		(4)		2		(2)		(3)
Noninterest income		1		2		3		6
Noninterest expenses		14		11		28		23
Provision (benefit) for income taxes		(2)	[3]	7	[3]	20	[4]	28	[4]
Net income (loss)		3		5		23		31
Net credit-related charge-offs (recoveries)		0		0		0		0
Assets, average		5,152		6,610		5,492		7,228
Loans, average		0		0		0		0
Deposits, average		$ 142		$ 183		$ 118		$ 199
[1]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[2]	Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares.
[3]	Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively.
[4]	Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively.

Business Segment Information (M

Business Segment Information (Market Segment Financial Results) (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017		Jun. 30, 2018		Jun. 30, 2017
Net interest income (expense)		$ 590		$ 500		$ 1,139		$ 970
Provision for credit losses		(29)		17		(17)		33
Noninterest income		248		276		492		547
Noninterest expenses		448		457		894		914
Provision (benefit) for income taxes		(93)		(99)		(147)		(165)
Net income (loss)		326		203		607		405
Net credit-related charge-offs (recoveries)		(3)		18		25		51
Assets, average		70,520		71,346		70,423		71,581
Loans, average		49,225		48,723		48,825		48,313
Deposits, average		$ 55,830		$ 57,128		$ 55,959		$ 57,452
Return on average assets	[1]	1.85%		1.14%		1.74%		1.14%
Efficiency ratio	[2]	53.24%		58.70%		54.74%		60.17%
Tax benefits from employee stock transactions		$ 3		$ 5		$ 22		$ 29
Michigan
Net interest income (expense)		167		167		336		337
Provision for credit losses		1		(2)		34		(4)
Noninterest income		73		81		146		164
Noninterest expenses		144		145		288		295
Provision (benefit) for income taxes		(22)		(38)		(38)		(75)
Net income (loss)		73		67		122		135
Net credit-related charge-offs (recoveries)		0		(1)				(4)
Assets, average		13,427		13,371		13,411		13,313
Loans, average		12,641		12,712		12,623		12,650
Deposits, average		$ 20,904		$ 21,698		$ 21,064		$ 21,923
Return on average assets	[1]	1.37%		1.20%		1.13%		1.20%
Efficiency ratio	[2]	59.77%		58.18%		59.64%		58.79%
California
Net interest income (expense)		$ 183		$ 178		$ 363		$ 349
Provision for credit losses		(9)		24		(11)		45
Noninterest income		42		45		81		86
Noninterest expenses		105		98		211		194
Provision (benefit) for income taxes		(32)		(40)		(62)		(76)
Net income (loss)		97		61		182		120
Net credit-related charge-offs (recoveries)		0		8				18
Assets, average		18,697		18,474		18,639		18,217
Loans, average		18,435		18,194		18,391		17,938
Deposits, average		$ 16,642		$ 17,344		$ 16,865		$ 17,294
Return on average assets	[1]	2.06%		1.33%		1.96%		1.33%
Efficiency ratio	[2]	46.94%		43.85%		47.66%		44.53%
Texas
Net interest income (expense)		$ 117		$ 113		$ 226		$ 226
Provision for credit losses		(15)		(15)		(28)		(24)
Noninterest income		30		33		61		65
Noninterest expenses		92		94		184		188
Provision (benefit) for income taxes		(16)		(25)		(30)		(47)
Net income (loss)		54		42		101		80
Net credit-related charge-offs (recoveries)		3		5				27
Assets, average		10,439		10,481		10,406		10,518
Loans, average		9,862		10,015		9,846		10,062
Deposits, average		$ 8,967		$ 9,632		$ 9,077		$ 9,871
Return on average assets	[1]	2.08%		1.52%		1.96%		1.44%
Efficiency ratio	[2]	62.17%		64.39%		63.85%		64.59%
Other Markets
Net interest income (expense)		$ 83		$ 82		$ 161		$ 161
Provision for credit losses		(2)		8		(10)		19
Noninterest income		90		105		178		205
Noninterest expenses		94		110		185		216
Provision (benefit) for income taxes		(15)		(20)		(30)		(36)
Net income (loss)		66		49		134		95
Net credit-related charge-offs (recoveries)		(6)		6				10
Assets, average		9,070		8,474		8,718		8,365
Loans, average		8,287		7,802		7,965		7,663
Deposits, average		$ 8,082		$ 8,115		$ 7,876		$ 8,016
Return on average assets	[1]	2.93%		2.24%		3.11%		2.17%
Efficiency ratio	[2]	53.72%		58.59%		54.41%		59.01%
Finance & Other
Net interest income (expense)		$ 40		$ (40)		$ 53		$ (103)
Provision for credit losses		(4)		2		(2)		(3)
Noninterest income		13		12		26		27
Noninterest expenses		13		10		26		21
Provision (benefit) for income taxes		(8)	[3]	24	[3]	13	[4]	69	[4]
Net income (loss)		36		(16)		68		(25)
Net credit-related charge-offs (recoveries)		0						0
Assets, average		18,887		20,546		19,249		21,168
Loans, average		0		0		0		0
Deposits, average		$ 1,235		$ 339		$ 1,077		$ 348
[1]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[2]	Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net securities gains (losses) and a derivative contract tied to the conversion rate of Visa Class B shares.
[3]	Included tax benefits from employee stock transactions of $3 million and $5 million for the three months ended June 30, 2018 and 2017, respectively.
[4]	Included tax benefits from employee stock transactions of $22 million and $29 million for the six months ended June 30, 2018 and 2017, respectively.

Revenue from Contracts with C78

Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
Card fees		$ 60	[1]	$ 80	$ 119	[1]	$ 157
Service charges on deposit accounts		53	[1]	57	107	[1]	115
Fiduciary income		52		51	104		100
Commercial loan servicing fees	[2]	5		6	9		9
Brokerage fees		6		6	13		11
Other noninterest income	[3]	11		12	23		29
Total revenue from contracts with customers		187		212	375		421
Other sources of noninterest income		61		64	117		126
Total noninterest income		248		276	492		547
Business Bank
Card fees		47	[1]	65	94	[1]	129
Service charges on deposit accounts		28	[1]	30	58	[1]	62
Fiduciary income		0		0	0		0
Commercial loan servicing fees	[2]	5		6	9		9
Brokerage fees		0		0	0		0
Other noninterest income	[3]	3		2	6		6
Total revenue from contracts with customers		83		103	167		206
Other sources of noninterest income		43		49	80		90
Total noninterest income		126		152	247		296
Retail Bank
Card fees		12	[1]	14	23	[1]	26
Service charges on deposit accounts		23	[1]	25	46	[1]	50
Fiduciary income		0		0	0		0
Commercial loan servicing fees	[2]	0		0	0		0
Brokerage fees		0		0	0		0
Other noninterest income	[3]	3		7	8		15
Total revenue from contracts with customers		38		46	77		91
Other sources of noninterest income		4		2	7		5
Total noninterest income		42		48	84		96
Wealth Management
Card fees		1	[1]	1	2	[1]	2
Service charges on deposit accounts		2	[1]	2	3	[1]	3
Fiduciary income		52		51	104		100
Commercial loan servicing fees	[2]	0		0	0		0
Brokerage fees		6		6	13		11
Other noninterest income	[3]	5		3	9		8
Total revenue from contracts with customers		66		63	131		124
Other sources of noninterest income		1		1	4		4
Total noninterest income		67		64	135		128
Finance & Other
Card fees		0	[1]	0	0	[1]	0
Service charges on deposit accounts		0	[1]	0	0	[1]	0
Fiduciary income		0		0	0		0
Commercial loan servicing fees	[2]	0		0	0		0
Brokerage fees		0		0	0		0
Other noninterest income	[3]	0		0	0		0
Total revenue from contracts with customers		0		0	0		0
Other sources of noninterest income		13		12	26		27
Total noninterest income		13		12	26		27
Adoption of Topic 606 change in presentation
Card fees		37		$ 26	71		$ 51
Decrease in card fees due to change in presentation		37			71
Decrease in service charges on deposit accounts due to change in presentation		$ 1			$ 2
[1]	Adoption of Topic 606 resulted in a change in presentation which records certain costs in the same category as the associated revenues. The effect of this change was to reduce card fees by $37 million and $71 million and service charges on deposit accounts by $1 million and 2 million for three- and six-month periods ended June 30, 2018, respectively. Refer to note 1 for further information.
[2]	Included in commercial lending fees on the Consolidated Statements of Comprehensive Income.
[3]	Excludes derivative, warrant and other miscellaneous income.