Comerica (CMA) 10-Q 30 Oct 17 2017 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 24, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
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	2,017
Document Fiscal Period Focus	Q3
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		173,915,038
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks		$ 1,351	$ 1,249
Interest-bearing deposits with banks		4,853	5,969
Other short-term investments		92	92
Investment securities available-for-sale	[1]	10,998	10,787
Investment securities held-to-maturity		1,344	1,582
Commercial loans		31,062	30,994
Real estate construction loans		3,018	2,869
Commercial mortgage loans		8,985	8,931
Lease financing		475	572
International loans		1,159	1,258
Residential mortgage loans		1,999	1,942
Consumer loans		2,511	2,522
Total loans		49,209	49,088
Less allowance for loan losses		(712)	(730)
Net loans		48,497	48,358
Premises and equipment		467	501
Accrued income and other assets		4,415	4,440
Total assets		72,017	72,978
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing deposits		32,391	31,540
Money market and interest-bearing checking deposits		20,869	22,556
Savings deposits		2,147	2,064
Customer certificates of deposit		2,342	2,806
Foreign office time deposits		70	19
Total interest-bearing deposits		25,428	27,445
Total deposits		57,819	58,985
Short-term borrowings		509	25
Accrued expenses and other liabilities		1,018	1,012
Medium- and long-term debt		4,637	5,160
Total liabilities		63,983	65,182
Common stock - $5 par value: Authorized - 325,000,000 shares; Issued - 228,164,824 shares		1,141	1,141
Capital surplus		2,112	2,135
Accumulated other comprehensive loss		(359)	(383)
Retained earnings		7,746	7,331
Less cost of common stock in treasury - 53,835,135 shares at 9/30/17 and 52,851,156 shares at 12/31/16		(2,606)	(2,428)
Total shareholders' equity		8,034	7,796
Total liabilities and shareholders' equity		$ 72,017	$ 72,978
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
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	53,835,135	52,851,156

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
INTEREST INCOME
Interest and fees on loans	$ 500	$ 411	$ 1,374	$ 1,223
Interest on investment securities	62	61	186	185
Interest on short-term investments	17	8	44	17
Total interest income	579	480	1,604	1,425
INTEREST EXPENSE
Interest on deposits	11	10	29	30
Interest on short-term borrowings	3	0	3	0
Interest on medium- and long-term debt	19	20	56	53
Total interest expense	33	30	88	83
Net interest income	546	450	1,516	1,342
Provision for credit losses	24	16	57	213
Net interest income after provision for credit losses	522	434	1,459	1,129
NONINTEREST INCOME
Card fees	85	76	242	224
Service charges on deposit accounts	57	55	172	165
Fiduciary income	48	47	148	142
Commercial lending fees	21	26	63	68
Letter of credit fees	11	12	34	38
Bank-owned life insurance	12	12	31	30
Foreign exchange income	11	10	33	31
Brokerage fees	6	5	17	14
Net securities losses	(1)	0	(3)	(3)
Other noninterest income	25	29	85	75
Total noninterest income	275	272	822	784
NONINTEREST EXPENSES
Salaries and benefits expense	225	247	677	742
Outside processing fee expense	92	86	267	247
Net occupancy expense	38	40	114	117
Equipment expense	12	13	34	40
Restructuring charges	7	20	32	73
Software expense	35	31	95	90
FDIC insurance expense	13	14	38	39
Advertising expense	8	5	19	15
Litigation-related expense	0	0	(2)	0
Other noninterest expenses	33	37	103	106
Total noninterest expenses	463	493	1,377	1,469
Income before income taxes	334	213	904	444
Provision for income taxes	108	64	273	131
Net Income	226	149	631	313
Less income allocated to participating securities	2	1	5	3
Net income attributable to common shares	$ 224	$ 148	$ 626	$ 310
Basic earnings per common share	$ 1.29	$ 0.87	$ 3.58	$ 1.80
Diluted earnings per common share	$ 1.26	$ 0.84	$ 3.50	$ 1.76
Comprehensive income	$ 228	$ 152	$ 655	$ 450
Cash dividends declared on common stock	$ 53	$ 40	$ 141	$ 115
Cash dividends declared per common share	$ 0.30	$ 0.23	$ 0.79	$ 0.66

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 at Dec. 31, 2015	$ 7,560	$ 1,141	$ 2,173	$ (429)	$ 7,084	$ (2,409)
BALANCE (in shares) at Dec. 31, 2015		175.7
Net income	313				313
Other comprehensive income, net of tax	137			137
Cash dividends declared on common stock	(115)				(115)
Purchase of common stock	(211)					(211)
Purchase of common stock (in shares)		(5)
Net issuance of common stock under employee stock plans	13		(29)		(20)	62
Net issuance of common stock under employee stock plans (in shares)		1.4
Share-based compensation	30		30
BALANCE at Sep. 30, 2016	7,727	$ 1,141	2,174	(292)	7,262	(2,558)
BALANCE (in shares) at Sep. 30, 2016		172.1
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	631				631
Other comprehensive income, net of tax	24			24
Cash dividends declared on common stock	(141)				(141)
Purchase of common stock	(396)					(396)
Purchase of common stock (in shares)		(5.7)
Net issuance of common stock under employee stock plans	90		(26)		(22)	138
Net issuance of common stock under employee stock plans (in shares)		3
Net issuance of common stock for warrants	0		(28)		(51)	79
Net issuance of common stock for warrants (in shares)		1.7
Share-based compensation	29		29
Other	0		(1)			1
Other (in shares)		0
BALANCE at Sep. 30, 2017	$ 8,034	$ 1,141	$ 2,112	$ (359)	$ 7,746	$ (2,606)
BALANCE (in shares) at Sep. 30, 2017		174.3

Consolidated Statements Of Cha6

Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Cash dividends declared on common stock, per share	$ 0.30	$ 0.23	$ 0.79	$ 0.66

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES
Net income	$ 631	$ 313
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	57	213
Benefit for deferred income taxes	(48)	(74)
Depreciation and amortization	91	91
Net periodic defined (credit) benefit cost	(14)	11
Share-based compensation expense	29	30
Net amortization of securities	5	7
Accretion of loan purchase discount	(3)	(4)
Net gains on sales of foreclosed property	(2)	(3)
Net change in accrued income receivable	(21)	(8)
Net change in accrued expenses payable	28	71
Other, net	105	(245)
Net cash provided by operating activities	858	402
INVESTING ACTIVITIES
Maturities and redemptions of investment securities available-for-sale	1,198	1,259
Sales of investment securities available-for-sale	1,259	0
Purchases of investment securities available-for-sale	(2,655)	(1,396)
Maturities and redemptions of investment securities held-to-maturity	241	288
Net change in loans	(193)	(290)
Proceeds from sales of foreclosed property	18	15
Net increase in premises and equipment	(43)	(71)
Purchases of Federal Home Loan Bank stock	(42)	(115)
Redemptions of Federal Home Loan Bank stock	21	0
Other, net	2	3
Net cash used in investing activities	(194)	(307)
FINANCING ACTIVITIES
Net change in deposits	(1,208)	(686)
Net change in short-term borrowings	484	(11)
Maturities of medium- and long-term debt	(500)	0
Issuances of medium- and long-term debt	0	2,800
Terminations of medium- and long-term debt	(16)	0
Repurchases of common stock	(404)	(215)
Cash dividends paid on common stock	(128)	(112)
Issuances of common stock under employee stock plans	98	25
Other, net	(4)	(3)
Net cash (used in) provided by financing activities	(1,678)	1,798
Net (decrease) increase in cash and cash equivalents	(1,014)	1,893
Cash and cash equivalents at beginning of period	7,218	6,147
Cash and cash equivalents at end of period	6,204	8,040
Interest paid	89	75
Income tax paid	247	111
Noncash investing and financing activities:
Loans transferred to other real estate	6	21
Loans transferred from held-for-sale to portfolio	$ 0	$ 17

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	9 Months Ended
	Sep. 30, 2017
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 nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 . 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, 2016 . Share-Based Compensation Effective January 1, 2016, the Corporation adopted the provisions of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payments Accounting” (ASU 2016-09). ASU 2016-09 provides for the election of an accounting policy as to the timing of when stock award forfeitures are recognized in compensation expense. The Corporation elected to account for forfeitures as they occur, rather than account for compensation cost based on an estimate of the number of awards that are expected to vest. The prior period effect of this policy election as of the beginning of the year was reported as "cumulative effect of change in accounting principle" in the accompanying Consolidated Statements of Changes in Shareholders’ Equity (unaudited). In addition, ASU 2016-09 requires excess tax benefits and deficiencies resulting from employee stock awards to be prospectively recognized as a component of income taxes. Previously, excess tax benefits and deficiencies were recognized in "capital surplus" in the Consolidated Statements of Changes in Shareholders' Equity. Net excess tax benefits for awards that vested, were exercised or expired included in the "provision for income taxes" totaled $2 million and $ 31 million for the three- and nine-month periods ended September 30, 2017 , respectively. The Corporation also retrospectively adopted certain changes to the statement of cash flows in accordance with ASU 2016-09. Excess tax benefits must be classified as an operating activity, and cash paid to a tax authority by the Corporation when withholding shares from an employee’s award for tax-withholding purposes must be classified as a financing activity. Accordingly, in the Consolidated Statements of Cash Flows (unaudited), net cash provided by operating activities increased $5 million and net cash provided by financing activities decreased by a corresponding amount for the nine months ended September 30, 2016 . Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” (ASU 2014-09), which is intended to improve and converge the financial reporting requirements for revenue contracts with customers. Previous GAAP comprised broad revenue recognition concepts along with numerous industry-specific requirements. The new guidance establishes a five-step model which entities must follow to recognize revenue and removes inconsistencies in existing guidance. The guidance under ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2017 and must be retrospectively applied. The Corporation expects to adopt ASU 2014-09 in the first quarter 2018 using the modified retrospective approach, which includes presenting the cumulative effect of initial application along with supplementary disclosures. The identification of revenue streams within the scope of Topic 606 is complete, resulting in less than 30 percent of total revenues in scope of the new guidance. The accounting analysis to determine potential changes to identified performance obligations, timing of revenue recognition and presentation as a result of implementing the new guidance is in its final stages. Under the new guidance, card fee revenue from certain products will generally be presented net of network costs (including interchange costs, surcharge fees and assessment fees), as opposed to the current presentation of associated network costs in "outside processing fees." Network costs impacted by the new guidance were approximately $97 million for the year ended December 31, 2016. The Corporation currently defers recognition of certain treasury management fees in "service charges on deposit accounts" in the consolidated statements of comprehensive income until the amount of compensation is considered fixed and determinable. Under the new guidance, a portion of these fees will be recognized as services are rendered. As a result of this earlier recognition, the Corporation expects to record a receivable of approximately $15 million to $18 million with a corresponding adjustment to retained earnings and deferred tax liability upon adoption of ASU 2014-09. The annual amount of treasury management fees reflected in the Corporation’s results of operations is not expected to significantly change. While no other material changes to the financial condition or results of operations have been identified to date, conclusions are preliminary as the Corporation finalizes its evaluation of the guidance. The Corporation continues to evaluate changes that may be required to applicable disclosures. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities," (ASU 2016-01), which makes targeted amendments to the guidance for recognition, measurement, presentation and disclosure of financial instruments. The guidance under ASU 2016-01 is effective for annual and interim periods beginning after December 15, 2017. 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. As of September 30, 2017, the Corporation classified approximately $45 million of auction-rate securities as available for sale equity securities. At adoption, any cumulative change in the fair value of these auction-rate securities previously recognized in accumulated other comprehensive income will be recorded as an adjustment to the opening balance of retained earnings, and any further changes to their fair value will be recorded in net income. The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operation. ASU 2016-01 also emphasizes the existing requirement to use exit prices to measure fair value for disclosure purposes and clarifies that entities should not make use of a practicability exception in determining the fair value of loans. Accordingly, the Corporation will refine the calculation used to determine the disclosed fair value of its held-for-investment loan portfolio as part of adopting the standard. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” (ASU 2016-15), which reduces diversity in the presentation of several categories of transactions in the cash flow statement. Among other things, the update clarifies the appropriate classification for proceeds from settlement of bank owned life insurance (BOLI) policies. The Corporation expects to change the classification of proceeds from settlement of BOLI policies from operating activities to investing activities. Proceeds from settlement of BOLI policies totaled $8 million and $16 million for the nine-month period ended September 30, 2017 and year ended December 31, 2016, respectively. Other changes in classification resulting from this update are not expected to be significant. ASU 2016-15 is effective for the Corporation on January 1, 2018 and must be applied using the retrospective approach. In March 2017, the FASB issued 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), which requires employers to report service cost as part of compensation expense and the other components of net benefit cost separately from service cost on the statement of income. Further, only the service cost component will be eligible for capitalization in deferred loan costs. The Corporation currently includes all components of net benefit cost in "salaries and benefits expense" in the consolidated statements of comprehensive income. Upon adoption of ASU 2017-07, only service cost will remain in salaries and benefits expense, and the other components (interest cost, expected return on assets, amortization of prior service cost or credit and amortization of net actuarial gains or losses) will be included in "other noninterest expenses." The other components of net benefit cost were a benefit of $36 million and $28 million for the nine months ended September 30, 2017 and the year ended December 31, 2016, respectively. ASU 2017-07 is effective for the Corporation on January 1, 2018. The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operations. In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” (ASU 2017-12), which better aligns the accounting and reporting of hedging relationships with the economics of risk management activities. ASU 2017-12 provides administrative reliefs to simplify the application of hedge accounting. The amendment is effective for the Corporation on January 1, 2019 and early adoption is permitted. The Corporation is considering early adoption of the guidance on January 1, 2018. ASU 2017-12 requires an adjustment to opening retained earnings for the cumulative effect of changes to the measurement methodology on the basis of hedged items at transition. The Corporation’s derivative instruments used for risk management predominately comprise swaps converting fixed-rate long-term debt to variable rates. These hedges have been highly effective, with no ineffectiveness net gains or losses recognized for the three- and nine-month periods ended September 30, 2017. An ineffectiveness net loss of $2 million was included in “other noninterest income” in the consolidated statements of income for the year ended December 31, 2016. Under the amendment, gains or losses relating to hedge ineffectiveness will prospectively be included in “net interest income” rather than “other noninterest income." The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operations.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
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. Trading securities, investment securities available-for-sale, derivatives and deferred compensation plan 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, 2016 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 LIABLILITIES 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 September 30, 2017 and December 31, 2016 . (in millions) Total Level 1 Level 2 Level 3 September 30, 2017 Trading securities: Deferred compensation plan assets $ 89 $ 89 $ — $ — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,770 2,770 — — Residential mortgage-backed securities (a) 8,137 — 8,137 — State and municipal securities 5 — — 5 (b) Equity and other non-debt securities 86 41 — 45 (b) Total investment securities available-for-sale 10,998 2,811 8,137 50 Derivative assets: Interest rate contracts 79 — 65 14 Energy derivative contracts 63 — 63 — Foreign exchange contracts 46 — 46 — Warrants 2 — — 2 Total derivative assets 190 — 174 16 Total assets at fair value $ 11,277 $ 2,900 $ 8,311 $ 66 Derivative liabilities: Interest rate contracts $ 45 $ — $ 45 Energy derivative contracts 60 — 60 — Foreign exchange contracts 44 — 44 — Total derivative liabilities 149 — 149 — Deferred compensation plan liabilities 89 89 — — Total liabilities at fair value $ 238 $ 89 $ 149 $ — (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Auction-rate securities. (in millions) Total Level 1 Level 2 Level 3 December 31, 2016 Trading securities: Deferred compensation plan assets $ 87 $ 87 $ — $ — Equity and other non-debt securities 1 1 — — Total trading securities 88 88 — — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,779 2,779 — — Residential mortgage-backed securities (a) 7,872 — 7,872 — State and municipal securities 7 — — 7 (b) Equity and other non-debt securities 129 82 — 47 (b) Total investment securities available-for-sale 10,787 2,861 7,872 54 Derivative assets: Interest rate contracts 223 — 212 11 Energy derivative contracts 146 — 146 — Foreign exchange contracts 38 — 38 — Warrants 3 — — 3 Total derivative assets 410 — 396 14 Total assets at fair value $ 11,285 $ 2,949 $ 8,268 $ 68 Derivative liabilities: Interest rate contracts $ 81 $ — $ 81 $ — Energy derivative contracts 144 — 144 — Foreign exchange contracts 29 — 29 — Total derivative liabilities 254 — 254 — Deferred compensation plan liabilities 87 87 — — Total liabilities at fair value $ 341 $ 87 $ 254 $ — (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 nine-month periods ended September 30, 2017 and 2016 . The following table summarizes the changes in Level 3 assets and liabilities measured at fair value on a recurring basis for the three- and nine-month periods ended September 30, 2017 and 2016 . Net Realized/Unrealized Gains (Losses) (Pretax) Balance at Beginning of Period Recorded in Earnings Recorded in Other Comprehensive Income Balance at End of Period (in millions) Realized Unrealized Redemptions Sales Three Months Ended September 30, 2017 Investment securities available-for-sale: State and municipal securities (a) $ 5 $ — $ — $ — $ — $ — $ 5 Equity and other non-debt securities (a) 46 — (1 ) — — 45 Total investment securities available-for-sale 51 — — (1 ) — — 50 Derivative assets: Interest rate contracts 13 — 1 (b) — — 14 Warrants 2 — — — — — 2 Three Months Ended September 30, 2016 Investment securities available-for-sale: State and municipal securities (a) $ 8 $ — $ — $ — $ — $ — $ 8 Corporate debt securities (a) 1 — — — (1 ) — — Equity and other non-debt securities (a) 48 — — 1 (3 ) — 46 Total investment securities available-for-sale 57 — — 1 (4 ) — 54 Derivative assets: Interest rate contracts 27 — — — — — 27 Warrants 2 3 (b) — — — (3 ) 2 Nine Months Ended September 30, 2017 Investment securities available-for-sale: State and municipal securities (a) $ 7 $ — $ — $ — $ (2 ) $ — $ 5 Equity and other non-debt securities (a) 47 — — (1 ) (1 ) — 45 Total investment securities available-for-sale 54 — — (1 ) (3 ) — 50 Derivative assets: Interest rate contracts 11 — 3 (b) — — — 14 Warrants 3 5 (b) (1 ) (b) — — (5 ) 2 Nine Months Ended September 30, 2016 Investment securities available-for-sale: State and municipal securities (a) $ 9 $ — $ — $ — $ (1 ) $ — $ 8 Corporate debt securities (a) 1 — — — (1 ) — — Equity and other non-debt securities (a) 67 — — (3 ) (18 ) — 46 Total investment securities available-for-sale 77 — — (3 ) (20 ) — 54 Derivative assets: Interest rate contracts 9 — 18 (b) — — — 27 Warrants 2 4 (b) — — — (4 ) 2 (a) Auction-rate securities. (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. ASSETS AND LIABILITIES RECORDED AT FAIR VALUE ON A NONRECURRING BASIS The Corporation may be required, from time to time, 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 that were recognized at fair value below cost at the end of the period. The following table presents assets recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 . No liabilities were recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 . (in millions) Level 3 September 30, 2017 Loans: Commercial $ 131 Commercial mortgage 9 International 2 Total assets at fair value $ 142 December 31, 2016 Loans: Commercial $ 256 Commercial mortgage 15 International 11 Total loans 282 Other real estate 1 Total assets at fair value $ 283 Level 3 assets recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 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. The following table presents quantitative information related to the significant unobservable inputs utilized in the Corporation's Level 3 recurring fair value measurement as of September 30, 2017 and December 31, 2016 . The Corporation's Level 3 recurring fair value measurements primarily include auction-rate securities where fair value is determined using an income approach based on a discounted cash flow model and certain interest rate derivative contracts where credit valuation adjustments are significant to the overall fair value of the derivative. The inputs in the table below reflect management's expectation of continued illiquidity in the secondary auction-rate securities market due to a lack of market activity for the issuers remaining in the portfolio, a lack of market incentives for issuer redemptions, and the expectation for a continuing low interest rate environment. The workout periods reflect management's expectation of the pace at which short-term interest rates could rise at each respective period. Discounted Cash Flow Model Unobservable Input Fair Value (in millions) Discount Rate Workout Period (in years) September 30, 2017 State and municipal securities (a) $ 5 5% - 7% 1 - 3 Equity and other non-debt securities (a) 45 7% - 10% 1 - 2 December 31, 2016 State and municipal securities (a) $ 7 4% - 6% 1 - 2 Equity and other non-debt securities (a) 47 7% - 9% 1 - 2 (a) Auction-rate securities. 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 September 30, 2017 Assets Cash and due from banks $ 1,351 $ 1,351 $ 1,351 $ — $ — Interest-bearing deposits with banks 4,853 4,853 4,853 — — Investment securities held-to-maturity 1,344 1,339 — 1,339 — Loans held-for-sale 3 3 — 3 — Total loans, net of allowance for loan losses (a) 48,497 48,296 — — 48,296 Customers’ liability on acceptances outstanding 2 2 2 — — Restricted equity investments 228 228 228 — — Nonmarketable equity securities (b) 6 9 Liabilities Demand deposits (noninterest-bearing) 32,391 32,391 — 32,391 — Interest-bearing deposits 23,086 23,086 — 23,086 — Customer certificates of deposit 2,342 2,309 — 2,309 — Total deposits 57,819 57,786 — 57,786 — Short-term borrowings 509 509 509 — — Acceptances outstanding 2 2 2 — — Medium- and long-term debt 4,637 4,642 — 4,642 — Credit-related financial instruments (70 ) (70 ) — — (70 ) December 31, 2016 Assets Cash and due from banks $ 1,249 $ 1,249 $ 1,249 $ — $ — Interest-bearing deposits with banks 5,969 5,969 5,969 — — Investment securities held-to-maturity 1,582 1,576 — 1,576 — Loans held-for-sale 4 4 — 4 — Total loans, net of allowance for loan losses (a) 48,358 48,250 — — 48,250 Customers’ liability on acceptances outstanding 5 5 5 — — Restricted equity investments 207 207 207 — — Nonmarketable equity securities (b) 11 16 Liabilities Demand deposits (noninterest-bearing) 31,540 31,540 — 31,540 — Interest-bearing deposits 24,639 24,639 — 24,639 — Customer certificates of deposit 2,806 2,731 — 2,731 — Total deposits 58,985 58,910 — 58,910 — Short-term borrowings 25 25 25 — — Acceptances outstanding 5 5 5 — — Medium- and long-term debt 5,160 5,132 — 5,132 — Credit-related financial instruments (73 ) (73 ) — — (73 ) (a) Included $142 million and $282 million of impaired loans recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 , 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	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,763 $ 8 $ 1 $ 2,770 Residential mortgage-backed securities (a) 8,168 44 75 8,137 State and municipal securities 5 — — 5 Equity and other non-debt securities 86 2 2 86 Total investment securities available-for-sale (b) $ 11,022 $ 54 $ 78 $ 10,998 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,344 $ 1 $ 6 $ 1,339 December 31, 2016 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,772 $ 8 $ 1 $ 2,779 Residential mortgage-backed securities (a) 7,921 48 97 7,872 State and municipal securities 7 — — 7 Equity and other non-debt securities 129 1 1 129 Total investment securities available-for-sale (b) $ 10,829 $ 57 $ 99 $ 10,787 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,582 $ 1 $ 7 $ 1,576 (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 $52 million and $50 million , respectively as of September 30, 2017 and $55 million and $54 million , respectively, as of December 31, 2016 . (c) The amortized cost of investment securities held-to-maturity included net unrealized losses of $9 million at September 30, 2017 and $12 million at December 31, 2016 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss. A summary of the Corporation’s investment securities in an unrealized loss position as of September 30, 2017 and December 31, 2016 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 September 30, 2017 U.S. Treasury and other U.S. government agency securities $ 486 $ 1 $ — $ — $ 486 $ 1 Residential mortgage-backed securities (a) 4,111 55 1,446 36 5,557 91 State and municipal securities (b) — — 5 — (c) 5 — (c) Equity and other non-debt securities (b) — — 45 2 45 2 Total temporarily impaired securities $ 4,597 $ 56 $ 1,496 $ 38 $ 6,093 $ 94 December 31, 2016 U.S. Treasury and other U.S. government agency securities $ 527 $ 1 $ — $ — $ 527 $ 1 Residential mortgage-backed securities (a) 4,992 87 1,177 32 6,169 119 State and municipal securities (b) — — 7 — (c) 7 — (c) Equity and other non-debt securities (b) 36 — (c) 11 — (c) 47 — (c) Total temporarily impaired securities $ 5,555 $ 88 $ 1,195 $ 32 $ 6,750 $ 120 (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 September 30, 2017 , the Corporation had 240 securities in an unrealized loss position with no credit impairment, including 6 U.S. Treasury securities, 193 residential mortgage-backed securities, 28 equity and other non-debt auction-rate preferred securities and 13 state and municipal auction-rate securities. As of September 30, 2017 , approximately 96 percent of the aggregate par value of auction-rate securities have been redeemed or sold since acquisition, of which approximately 90 percent were redeemed at or above cost. The unrealized losses for these securities resulted from changes in market interest rates and liquidity. 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 September 30, 2017 . Sales, calls and write-downs of investment securities available-for-sale resulted in the following gains and losses recorded in “net securities gains (losses)” on the consolidated statements of comprehensive income, computed based on the adjusted cost of the specific security. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Securities gains $ — $ — $ 1 $ — Securities losses (a) (1 ) — (4 ) (3 ) Net securities losses $ (1 ) $ — $ (3 ) $ (3 ) (a) Primarily charges related to a derivative contract tied to the conversion rate of Visa Class B shares. 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) Available-for-sale Held-to-maturity September 30, 2017 Amortized Cost Fair Value Amortized Cost Fair Value Contractual maturity Within one year $ 20 $ 20 $ — $ — After one year through five years 2,947 2,953 — — After five years through ten years 1,744 1,770 19 19 After ten years 6,225 6,169 1,325 1,320 Subtotal 10,936 10,912 1,344 1,339 Equity and other non-debt securities 86 86 — — Total investment securities $ 11,022 $ 10,998 $ 1,344 $ 1,339 Included in the contractual maturity distribution in the table above were residential mortgage-backed securities available-for-sale with total amortized cost of $8.2 billion and fair value of $8.1 billion , and residential mortgage-backed securities held-to-maturity with a total amortized cost and fair value of $1.3 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 September 30, 2017 , investment securities with a carrying value of $950 million were pledged where permitted or required by law to secure $700 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	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Business loans: Commercial $ 52 $ 31 $ 7 $ 90 $ 345 $ 30,627 $ 31,062 Real estate construction: Commercial Real Estate business line (a) — — — — — 2,709 2,709 Other business lines (b) 11 — — 11 — 298 309 Total real estate construction 11 — — 11 — 3,007 3,018 Commercial mortgage: Commercial Real Estate business line (a) 20 — — 20 9 1,702 1,731 Other business lines (b) 18 10 3 31 26 7,197 7,254 Total commercial mortgage 38 10 3 51 35 8,899 8,985 Lease financing — — — — 8 467 475 International 11 — 2 13 6 1,140 1,159 Total business loans 112 41 12 165 394 44,140 44,699 Retail loans: Residential mortgage 14 9 — 23 28 1,948 1,999 Consumer: Home equity 5 1 — 6 22 1,762 1,790 Other consumer 1 1 — 2 — 719 721 Total consumer 6 2 — 8 22 2,481 2,511 Total retail loans 20 11 — 31 50 4,429 4,510 Total loans $ 132 $ 52 $ 12 $ 196 $ 444 $ 48,569 $ 49,209 December 31, 2016 Business loans: Commercial $ 30 $ 12 $ 14 $ 56 $ 445 $ 30,493 $ 30,994 Real estate construction: Commercial Real Estate business line (a) — — — — — 2,485 2,485 Other business lines (b) — — — — — 384 384 Total real estate construction — — — — — 2,869 2,869 Commercial mortgage: Commercial Real Estate business line (a) 5 — — 5 9 2,004 2,018 Other business lines (b) 58 5 5 68 37 6,808 6,913 Total commercial mortgage 63 5 5 73 46 8,812 8,931 Lease financing — — — — 6 566 572 International 1 — — 1 14 1,243 1,258 Total business loans 94 17 19 130 511 43,983 44,624 Retail loans: Residential mortgage 7 3 — 10 39 1,893 1,942 Consumer: Home equity 4 3 — 7 28 1,765 1,800 Other consumer 1 — — 1 4 717 722 Total consumer 5 3 — 8 32 2,482 2,522 Total retail loans 12 6 — 18 71 4,375 4,464 Total loans $ 106 $ 23 $ 19 $ 148 $ 582 $ 48,358 $ 49,088 (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 September 30, 2017 Business loans: Commercial $ 29,187 $ 617 $ 913 $ 345 $ 31,062 Real estate construction: Commercial Real Estate business line (e) 2,658 51 — — 2,709 Other business lines (f) 305 4 — — 309 Total real estate construction 2,963 55 — — 3,018 Commercial mortgage: Commercial Real Estate business line (e) 1,660 20 42 9 1,731 Other business lines (f) 7,000 111 117 26 7,254 Total commercial mortgage 8,660 131 159 35 8,985 Lease financing 442 24 1 8 475 International 1,082 53 18 6 1,159 Total business loans 42,334 880 1,091 394 44,699 Retail loans: Residential mortgage 1,962 9 — 28 1,999 Consumer: Home equity 1,759 1 8 22 1,790 Other consumer 720 1 — — 721 Total consumer 2,479 2 8 22 2,511 Total retail loans 4,441 11 8 50 4,510 Total loans $ 46,775 $ 891 $ 1,099 $ 444 $ 49,209 December 31, 2016 Business loans: Commercial $ 28,616 $ 944 $ 989 $ 445 $ 30,994 Real estate construction: Commercial Real Estate business line (e) 2,485 — — — 2,485 Other business lines (f) 381 — 3 — 384 Total real estate construction 2,866 — 3 — 2,869 Commercial mortgage: Commercial Real Estate business line (e) 1,970 19 20 9 2,018 Other business lines (f) 6,645 109 122 37 6,913 Total commercial mortgage 8,615 128 142 46 8,931 Lease financing 550 11 5 6 572 International 1,200 22 22 14 1,258 Total business loans 41,847 1,105 1,161 511 44,624 Retail loans: Residential mortgage 1,900 3 — 39 1,942 Consumer: Home equity 1,767 1 4 28 1,800 Other consumer 718 — — 4 722 Total consumer 2,485 1 4 32 2,522 Total retail loans 4,385 4 4 71 4,464 Total loans $ 46,232 $ 1,109 $ 1,165 $ 582 $ 49,088 (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. (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 page F-56 in the Corporation's 2016 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) September 30, 2017 December 31, 2016 Nonaccrual loans $ 444 $ 582 Reduced-rate loans (a) 8 8 Total nonperforming loans 452 590 Foreclosed property (b) 6 17 Total nonperforming assets $ 458 $ 607 (a) There were no reduced-rate business loans at both September 30, 2017 and December 31, 2016 . Reduced-rate retail loans were $8 million at both September 30, 2017 and December 31, 2016 . (b) Included $5 million and $3 million of foreclosed residential real estate properties at September 30, 2017 and December 31, 2016 , respectively. There were no retail loans secured by residential real estate properties in process of foreclosure included in nonaccrual loans at both September 30, 2017 and December 31, 2016 . Allowance for Credit Losses The following table details the changes in the allowance for loan losses and related loan amounts. 2017 2016 (in millions) Business Loans Retail Loans Total Business Loans Retail Loans Total Three Months Ended September 30 Allowance for loan losses: Balance at beginning of period $ 661 $ 44 $ 705 $ 682 $ 47 $ 729 Loan charge-offs (36 ) (1 ) (37 ) (34 ) (1 ) (35 ) Recoveries on loans previously charged-off 10 2 12 18 1 19 Net loan (charge-offs) recoveries (26 ) 1 (25 ) (16 ) — (16 ) Provision for loan losses 21 10 31 12 2 14 Foreign currency translation adjustment 1 — 1 — — — Balance at end of period $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 Nine Months Ended September 30 Allowance for loan losses: Balance at beginning of period $ 682 $ 48 $ 730 $ 579 $ 55 $ 634 Loan charge-offs (115 ) (5 ) (120 ) (161 ) (5 ) (166 ) Recoveries on loans previously charged-off 39 5 44 53 3 56 Net loan charge-offs (76 ) — (76 ) (108 ) (2 ) (110 ) Provision for loan losses 50 7 57 206 (4 ) 202 Foreign currency translation adjustment 1 — 1 1 — 1 Balance at end of period $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 As a percentage of total loans 1.47 % 1.23 % 1.45 % 1.51 % 1.10 % 1.48 % September 30 Allowance for loan losses: Individually evaluated for impairment $ 90 $ — $ 90 $ 115 $ 1 $ 116 Collectively evaluated for impairment 567 55 622 563 48 611 Total allowance for loan losses $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 Loans: Individually evaluated for impairment $ 501 $ 37 $ 538 $ 677 $ 29 $ 706 Collectively evaluated for impairment 44,198 4,473 48,671 44,182 4,386 48,568 Total loans evaluated for impairment $ 44,699 $ 4,510 $ 49,209 $ 44,859 $ 4,415 $ 49,274 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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 48 $ 43 $ 41 $ 45 Charge-offs on lending-related commitments (a) — — — (11 ) Provision for credit losses on lending-related commitments (7 ) 2 — 11 Balance at end of period $ 41 $ 45 $ 41 $ 45 (a) Charge-offs result from the sale of unfunded lending-related commitments. 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 September 30, 2017 Business loans: Commercial $ 111 $ 311 $ 422 $ 543 $ 85 Commercial mortgage: Commercial Real Estate business line (a) 36 7 43 52 1 Other business lines (b) 3 27 30 36 3 Total commercial mortgage 39 34 73 88 4 International — 6 6 17 1 Total business loans 150 351 501 648 90 Retail loans: Residential mortgage 22 — 22 28 — Consumer: Home equity 12 — 12 12 — Other consumer 3 — 3 5 — Total consumer 15 — 15 17 — Total retail loans (c) 37 — 37 45 — Total individually evaluated impaired loans $ 187 $ 351 $ 538 $ 693 $ 90 December 31, 2016 Business loans: Commercial $ 90 $ 423 $ 513 $ 608 $ 80 Commercial mortgage: Commercial Real Estate business line (a) — 7 7 15 1 Other business lines (b) 2 30 32 40 3 Total commercial mortgage 2 37 39 55 4 International 3 11 14 20 2 Total business loans 95 471 566 683 86 Retail loans: Residential mortgage 19 9 28 30 2 Consumer: Home equity 15 — 15 19 — Other consumer 2 3 5 6 1 Total consumer 17 3 20 25 1 Total retail loans (c) 36 12 48 55 3 Total individually evaluated impaired loans $ 131 $ 483 $ 614 $ 738 $ 89 (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. Interest income recognized for the period primarily related to performing restructured loans. Individually Evaluated Impaired Loans 2017 2016 (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 September 30 Business loans: Commercial $ 442 $ 2 $ 606 $ 2 Commercial mortgage: Commercial Real Estate business line (a) 25 1 7 — Other business lines (b) 32 — 30 — Total commercial mortgage 57 1 37 — International 6 — 19 — Total business loans 505 3 662 2 Retail loans: Residential mortgage 24 — 11 — Consumer loans: Home equity 12 — 12 — Other consumer 3 — 4 — Total consumer 15 — 16 — Total retail loans 39 — 27 — Total individually evaluated impaired loans $ 544 $ 3 $ 689 $ 2 Nine Months Ended September 30 Business loans: Commercial $ 470 $ 6 $ 559 $ 8 Commercial mortgage: Commercial Real Estate business line (a) 16 1 9 — Other business lines (b) 33 — 31 — Total commercial mortgage 49 1 40 — International 9 — 19 — Total business loans 528 7 618 8 Retail loans: Residential mortgage 26 — 12 — Consumer: Home equity 13 — 12 — Other consumer 3 — 4 — Total consumer 16 — 16 — Total retail loans 42 — 28 — Total individually evaluated impaired loans $ 570 $ 7 $ 646 $ 8 (a) Primarily loans to real estate developers. (b) Primarily loans secured by owner-occupied real estate. Troubled Debt Restructurings The following tables detail the recorded balance at September 30, 2017 and 2016 of loans considered to be troubled debt restructurings (TDRs) that were restructured during the three- and nine-month periods ended September 30, 2017 and 2016 , 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. 2017 2016 Type of Modification Type of Modification (in millions) Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Three Months Ended September 30 Business loans: Commercial $ 22 $ — $ — $ 22 $ 70 $ — $ 40 $ 110 Commercial mortgage: Commercial Real Estate business line (c) 36 — — 36 — — — — International 2 — — 2 — — — — Total business loans 60 — — 60 70 — 40 110 Retail loans: Consumer: Home equity (d) 1 — — 1 — — — — Total retail loans 1 — — 1 — — — — Total loans $ 61 $ — $ — $ 61 $ 70 $ — $ 40 $ 110 Nine Months Ended September 30 Business loans: Commercial $ 95 $ — $ 31 $ 126 $ 150 $ — $ 49 $ 199 Commercial mortgage: Commercial Real Estate business line (c) 36 — — 36 — — — — Other business lines (e) 3 — — 3 2 — — 2 Total commercial mortgage 39 — — 39 2 — — 2 International 2 — — 2 — — 3 3 Total business loans 136 — 31 167 152 — 52 204 Retail loans: Consumer: Home equity (d) 1 2 — 3 1 1 — 2 Total retail loans 1 2 — 3 1 1 — 2 Total loans $ 137 $ 2 $ 31 $ 170 $ 153 $ 1 $ 52 $ 206 (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 real estate developers. (d) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt. (e) Primarily loans secured by owner-occupied real estate. Commitments to lend additional funds to borrowers whose terms have been modified in TDRs were $25 million at September 30, 2017 and $24 million at December 31, 2016 . The majority of the modifications considered to be TDRs that occurred during the nine months ended September 30, 2017 and 2016 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 nine months ended September 30, 2017 and 2016 were insignificant. On an ongoing basis, the Corporation monitors the performance of modified loans to their restructured terms. In the event of a subsequent default, 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 September 30, 2017 and 2016 of loans modified by principal deferral during the twelve-month periods ended September 30, 2017 and 2016 , and those principal deferrals which experienced a subsequent default during the three- and nine-month periods ended September 30, 2017 and 2016 . 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. 2017 2016 (in millions) Balance at September 30 Subsequent Default in the Three Months Ended September 30 Subsequent Default in the Nine Months Ended September 30 Balance at September 30 Subsequent Default in the Three Months Ended September 30 Subsequent Default in the Nine Months Ended September 30 Principal deferrals: Business loans: Commercial $ 127 $ 4 $ 4 $ 229 $ — $ 13 Commercial mortgage: Commercial Real Estate business line (a) 37 — — — — — Other business lines (b) 7 — 4 4 — 1 Total commercial mortgage 44 — 4 4 — 1 International 2 — — — — — Total business loans 173 4 8 233 — 14 Retail loans: Consumer: Home equity (c) 1 — — 1 — — Total principal deferrals $ 174 $ 4 $ 8 $ 234 $ — $ 14 (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. During the twelve-month periods ended September 30, 2017 and 2016 , loans with a carrying value of $2 million and $4 million , respectively, were modified by interest rate reduction, and loans with a carrying value of $31 million and $52 million , respectively, were restructured into two notes (AB note restructures). For reduced-rate loans 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 payment defaults of reduced-rate loans or AB note restructures during the three- and nine-month periods ended September 30, 2017 and 2016 .

Derivative And Credit-Related F

Derivative And Credit-Related Financial Instruments	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 , counterparties with bilateral collateral agreements had pledged $4 million of marketable investment securities and deposited $20 million of cash with the Corporation to secure the fair value of contracts in an unrealized gain position, and the Corporation had pledged $26 million of marketable investment securities and posted $8 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 September 30, 2017 . 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 September 30, 2017 and December 31, 2016 . The table excludes commitments and warrants accounted for as derivatives. September 30, 2017 December 31, 2016 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 (b) $ 1,775 $ — $ — $ 2,275 $ 92 $ 4 Derivatives used as economic hedges Foreign exchange contracts: Spot, forwards and swaps 663 — 2 717 2 2 Total risk management purposes 2,438 — 2 2,992 94 6 Customer-initiated and other activities Interest rate contracts: Caps and floors written 590 — — 436 — 1 Caps and floors purchased 590 — — 436 1 — Swaps (b) 12,905 79 45 12,451 130 76 Total interest rate contracts 14,085 79 45 13,323 131 77 Energy contracts: Caps and floors written 222 — 12 419 1 31 Caps and floors purchased 222 12 — 419 31 1 Swaps 1,352 51 48 1,389 114 112 Total energy contracts 1,796 63 60 2,227 146 144 Foreign exchange contracts: Spot, forwards, options and swaps 2,147 46 42 1,509 36 27 Total customer-initiated and other activities 18,028 188 147 17,059 313 248 Total gross derivatives $ 20,466 $ 188 $ 149 $ 20,051 $ 407 $ 254 Amounts offset in the consolidated balance sheets: Netting adjustment - Offsetting derivative assets/liabilities (49 ) (49 ) (84 ) (84 ) Netting adjustment - Cash collateral received/posted (19 ) (6 ) (47 ) (45 ) Net derivatives included in the consolidated balance sheets (c) 120 94 276 125 Amounts not offset in the consolidated balance sheets: Marketable securities pledged under bilateral collateral agreements (4 ) (24 ) (19 ) (8 ) Net derivatives after deducting amounts not offset in the consolidated balance sheets $ 116 $ 70 $ 257 $ 117 (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) Due to clearinghouse rule changes, beginning January 1, 2017, variation margin payments are treated as settlements of derivative exposure rather than as collateral. As a result, these payments are now considered in determining the fair value of centrally cleared derivatives, resulting in centrally cleared derivatives having a fair value of approximately zero. (c) 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 $6 million and $5 million at September 30, 2017 and December 31, 2016 , 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. These instruments generated net interest income of $7 million and $15 million for the three months ended September 30, 2017 and 2016 , respectively, and $27 million and $48 million for the nine months ended September 30, 2017 and 2016 , respectively. These hedges have been highly effective, with no ineffectiveness net gains or losses recognized for both the three- and nine-month periods ended September 30, 2017 . Ineffectiveness net gains of $1 million and $4 million were included in ''other noninterest income" in the consolidated statements of income for the three- and nine-month periods ended September 30, 2016 , respectively. The following table summarizes the expected weighted average remaining maturity of the notional amount of risk management interest rate swaps and the weighted average interest rates associated with amounts expected to be received or paid on interest rate swap agreements as of September 30, 2017 and December 31, 2016 . Weighted Average (dollar amounts in millions) Notional Amount Remaining Maturity (in years) Receive Rate Pay Rate (a) September 30, 2017 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt designation $ 1,775 4.9 3.26 % 2.21 % December 31, 2016 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt designation 2,275 4.5 3.69 1.80 (a) Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at September 30, 2017 and December 31, 2016 . 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 nine-month periods ended September 30, 2017 , respectively, and no net gains for the three months ended September 30, 2016 , and $1 million of net gains for the nine months ended September 30, 2016 . 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 September 30, Nine Months Ended September 30, (in millions) Location of Gain 2017 2016 2017 2016 Interest rate contracts Other noninterest income $ 5 $ 6 $ 18 $ 14 Energy contracts Other noninterest income 1 — 2 1 Foreign exchange contracts Foreign exchange income 11 11 33 30 Total $ 17 $ 17 $ 53 $ 45 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) September 30, 2017 December 31, 2016 Unused commitments to extend credit: Commercial and other $ 23,542 $ 24,333 Bankcard, revolving check credit and home equity loan commitments 2,865 2,658 Total unused commitments to extend credit $ 26,407 $ 26,991 Standby letters of credit $ 3,372 $ 3,623 Commercial letters of credit 43 46 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” on the consolidated balance sheets, was $41 million at both September 30, 2017 and December 31, 2016 . 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 $26 million and $29 million at September 30, 2017 and December 31, 2016 , 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 2023 . 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 $208 million and $255 million , respectively, of the $3.4 billion and $3.7 billion standby and commercial letters of credit outstanding at September 30, 2017 and December 31, 2016 , respectively. The carrying value of the Corporation’s standby and commercial letters of credit, included in “accrued expenses and other liabilities” on the consolidated balance sheets, totaled $44 million at September 30, 2017 , including $29 million in deferred fees and $15 million in the allowance for credit losses on lending-related commitments. At December 31, 2016 , the comparable amounts were $44 million , $32 million and $12 million , respectively. The following table presents a summary of criticized standby and commercial letters of credit at September 30, 2017 and December 31, 2016 . 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) September 30, 2017 December 31, 2016 Total criticized standby and commercial letters of credit $ 79 $ 135 As a percentage of total outstanding standby and commercial letters of credit 2.3 % 3.7 % 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 September 30, 2017 and December 31, 2016 , the total notional amount of the credit risk participation agreements was approximately $544 million and $458 million , respectively, and the fair value, included in customer-initiated interest rate contracts recorded in "accrued expenses and other liabilities" on the consolidated balance sheets, 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 approximately $1 million and $3 million at September 30, 2017 and December 31, 2016 , respectively. 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 September 30, 2017 , the weighted average remaining maturity of outstanding credit risk participation agreements was 2.3 years.

Variable Interest Entities (VIE

Variable Interest Entities (VIEs)	9 Months Ended
	Sep. 30, 2017
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. 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 September 30, 2017 was limited to approximately $421 million . Ownership interests in other community development projects which generate similar tax credits to investors (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 September 30, 2017 was limited to approximately $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 ( $170 million at September 30, 2017 ). 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 nine months ended September 30, 2017 and 2016 . 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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Other noninterest income: Amortization of other tax credit investments $ — $ (1 ) $ 1 $ (1 ) Provision for income taxes: Amortization of LIHTC investments 17 17 49 49 Low income housing tax credits (16 ) (16 ) (47 ) (47 ) Other tax benefits related to tax credit entities (6 ) (7 ) (18 ) (19 ) Total provision for income taxes $ (5 ) $ (6 ) $ (16 ) $ (17 ) For further information on the Corporation’s consolidation policy, see note 1 to the consolidated financial statements in the Corporation's 2016 Annual Report.

Medium- And Long-Term Debt

Medium- And Long-Term Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Medium- And Long-Term Debt	MEDIUM- AND LONG-TERM DEBT Medium- and long-term debt is summarized as follows: (in millions) September 30, 2017 December 31, 2016 Parent company Subordinated notes: 3.80% subordinated notes due 2026 (a) $ 257 $ 256 Medium-term notes: 2.125% notes due 2019 (a) 349 348 Total parent company 606 604 Subsidiaries Subordinated notes: 5.20% subordinated notes due 2017 (a) — 511 4.00% subordinated notes due 2025 (a) 350 347 7.875% subordinated notes due 2026 (a) 211 215 Total subordinated notes 561 1,073 Medium-term notes: 2.50% notes due 2020 (a) 670 667 Federal Home Loan Bank (FHLB) advances: Floating-rate based on FHLB auction rate due 2026 2,800 2,800 Other notes: 6.0% - 6.4% fixed-rate notes due 2018 to 2020 — 16 Total subsidiaries 4,031 4,556 Total medium- and long-term debt $ 4,637 $ 5,160 (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. The interest rate on each FHLB advance resets every four weeks, based on the FHLB auction rate, with the reset date of each note scheduled at one-week intervals. At September 30, 2017 , the weighted-average rate on these advances was 1.17% . 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 September 30, 2017 , $15.5 billion of real estate-related loans were pledged to the FHLB as blanket collateral for current and potential future borrowings of approximately $4.5 billion . Unamortized debt issuance costs deducted from the carrying amount of medium- and long-term debt totaled $5 million at September 30, 2017 and $7 million at December 31, 2016 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2017
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 nine months ended September 30, 2017 and 2016 , including the amount of income tax expense (benefit) allocated to each component of other comprehensive income (loss). Nine Months Ended September 30, (in millions) 2017 2016 Accumulated net unrealized (losses) gains on investment securities: Balance at beginning of period, net of tax $ (33 ) $ 9 Net unrealized holding gains arising during the period 18 140 Less: Provision for income taxes 7 51 Net unrealized holding gains arising during the period, net of tax 11 89 Less: Net losses realized as a yield adjustment in interest on investment securities (3 ) (2 ) Less: Benefit for income taxes (1 ) (1 ) Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax (2 ) (1 ) Change in net unrealized gains on investment securities, net of tax 13 90 Balance at end of period, net of tax $ (20 ) $ 99 Accumulated defined benefit pension and other postretirement plans adjustment: Balance at beginning of period, net of tax $ (350 ) $ (438 ) Actuarial loss arising during the period — (191 ) Prior service credit arising during the period — 235 Net defined benefit pension and other postretirement adjustment arising during the period — 44 Less: Provision for income taxes — 16 Net defined benefit pension and other postretirement plans adjustment arising during the period, net of tax — 28 Amortization of actuarial net loss 38 29 Amortization of prior service credit (20 ) — Amounts recognized in salaries and benefits expense 18 29 Less: Provision for income taxes 7 10 Adjustment for amounts recognized as components of net periodic benefit cost during the period, net of tax 11 19 Change in defined benefit pension and other postretirement plans adjustment, net of tax 11 47 Balance at end of period, net of tax $ (339 ) $ (391 ) Total accumulated other comprehensive loss at end of period, net of tax $ (359 ) $ (292 )

Net Income Per Common Share

Net Income Per Common Share	9 Months Ended
	Sep. 30, 2017
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 September 30, Nine Months Ended September 30, (in millions, except per share data) 2017 2016 2017 2016 Basic and diluted Net income $ 226 $ 149 $ 631 $ 313 Less: Income allocated to participating securities 2 1 5 3 Net income attributable to common shares $ 224 $ 148 $ 626 $ 310 Basic average common shares 174 171 175 173 Basic net income per common share $ 1.29 $ 0.87 $ 3.58 $ 1.80 Basic average common shares 174 171 175 173 Dilutive common stock equivalents: Net effect of the assumed exercise of stock options 2 2 3 1 Net effect of the assumed exercise of warrants 1 3 1 2 Diluted average common shares 177 176 179 176 Diluted net income per common share $ 1.26 $ 0.84 $ 3.50 $ 1.76 The following average shares related to outstanding options to purchase shares of common stock were not included in the computation of diluted net income per common share because the options were anti-dilutive for the period. There were no anti-dilutive options for both the three- and nine-month periods ended September 30, 2017 . (shares in millions) Three Months Ended September 30, 2016 Nine Months Ended September 30, 2016 Average outstanding options 2.6 4.0 Range of exercise prices $46.68 - $59.86 $37.26 - $59.86

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Net periodic benefit costs are charged to "employee benefits expense" on the consolidated statements of comprehensive income. The components of net periodic benefit cost 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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Service cost $ 7 $ 8 $ 21 $ 24 Interest cost 19 23 58 69 Expected return on plan assets (39 ) (39 ) (118 ) (120 ) Amortization of prior service (credit) cost (5 ) 1 (14 ) 3 Amortization of net loss 11 7 32 23 Net periodic defined benefit credit $ (7 ) $ — $ (21 ) $ (1 ) Non-Qualified Defined Benefit Pension Plan Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Service cost $ — $ — $ 1 $ 2 Interest cost 2 3 6 8 Amortization of prior service credit (2 ) (1 ) (6 ) (3 ) Amortization of net loss 2 2 6 5 Net periodic defined benefit cost $ 2 $ 4 $ 7 $ 12 Postretirement Benefit Plan Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Interest cost $ 1 $ — $ 2 $ 2 Expected return on plan assets (1 ) (1 ) (2 ) (3 ) Amortization of net loss — 1 — 1 Net periodic postretirement benefit cost $ — $ — $ — $ — For further information on the Corporation's employee benefit plans, refer to note 17 to the consolidated financial statements in the Corporation's 2016 Annual Report.

Income Taxes And Tax-Related It

Income Taxes And Tax-Related Items	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes and Tax-Related Items	INCOME TAXES AND TAX-RELATED ITEMS Net unrecognized tax benefits were $11 million at September 30, 2017 , compared to $15 million at December 31, 2016 . The decrease in unrecognized tax benefits of $4 million was primarily due to the recognition of federal settlements partially offset by an increase to established reserves. The Corporation anticipates it is reasonably possible the final settlement of state tax issues will result in a decrease in net unrecognized tax benefits of $1 million within the next twelve months. Included in "accrued expense and other liabilities" on the consolidated balance sheets was a $9 million liability for tax-related interest and penalties at September 30, 2017 compared to $7 million at December 31, 2016 . Net deferred tax assets were $252 million at September 30, 2017 , compared to $217 million at December 31, 2016 . The increase of $35 million in net deferred tax assets resulted primarily from a decrease in deferred tax liabilities related to lease financing transactions, partially offset by decreases in unrealized losses on investment securities available-for-sale and deferred compensation. Included in deferred tax assets at both September 30, 2017 and December 31, 2016 were $4 million of state net operating loss carryforwards, which expire between 2017 and 2026 . 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 September 30, 2017 and December 31, 2016 . The determination regarding valuation allowance was based on evidence of loss carryback capacity, projected future reversals of existing taxable temporary differences to absorb the deferred tax assets and assumptions made regarding future events. 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	9 Months Ended
	Sep. 30, 2017
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, 2016 and Forms 10-Q for the quarters ended March 31, 2017 and June 30, 2017 , 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. A ruling is not expected for some time. Management believes that 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 that 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, consolidated results of operations or consolidated cash flows. Legal fees of $4 million were included in "other noninterest expenses" on the consolidated statements of income for each of the three-month periods ended September 30, 2017 and 2016 , and $14 million for each of the nine-month periods ended September 30, 2017 and 2016 . 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 $28 million at September 30, 2017 . 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 that an estimate can currently be made. The Corporation’s estimate involves significant judgment, given the varying stages of the proceedings (including the fact that 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 that the ultimate resolution of these matters, if unfavorable, may be material to the Corporation's consolidated financial condition, consolidated results of operations or consolidated cash flows. For information regarding income tax contingencies, refer to note 11 .

Restructuring Charges

Restructuring Charges	9 Months Ended
	Sep. 30, 2017
Restructuring and Related Activities [Abstract]
Restructuring Charges	RESTRUCTURING CHARGES The Corporation approved and launched an initiative in the second quarter 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 38 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 September 30, 2017 Balance at beginning of period $ 6 $ — $ 3 $ 2 $ 11 Restructuring charges 1 — 5 1 7 Payments (1 ) — (4 ) (1 ) (6 ) Balance at end of period $ 6 $ — $ 4 $ 2 $ 12 Three Months Ended September 30, 2016 Balance at beginning of period $ 46 $ — $ — $ 4 $ 50 Restructuring charges 4 5 — 11 20 Payments (12 ) (1 ) — (8 ) (21 ) Adjustments for non-cash charges (a) 2 (4 ) — — (2 ) Balance at end of period $ 40 $ — $ — $ 7 $ 47 Nine Months Ended September 30, 2017 Balance at beginning of period $ 10 $ 4 $ — $ 4 $ 18 Restructuring charges 5 5 17 5 32 Payments (9 ) (9 ) (8 ) (7 ) (33 ) Adjustments for non-cash charges (a) — — (5 ) — (5 ) Balance at end of period $ 6 $ — $ 4 $ 2 $ 12 Nine Months Ended September 30, 2016 Balance at beginning of period $ — $ — $ — $ — $ — Restructuring charges 50 5 — 18 73 Payments (12 ) (1 ) — (11 ) (24 ) Adjustments for non-cash charges (a) 2 (4 ) — — (2 ) Balance at end of period $ 40 $ — $ — $ 7 $ 47 Total restructuring charges incurred to date $ 57 $ 20 $ 17 $ 31 $ 125 Total expected restructuring charges (b) 65 - 70 30 55 - 60 35 185 - 195 (a) Adjustments for non-cash charges primarily include the benefit from forfeitures of nonvested stock compensation in Employee Costs, accelerated depreciation expense in Facilities Costs and 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 23 to the consolidated financial statements in the Corporation's 2016 Annual Report. Total restructuring charges assigned to the Business Bank, Retail Bank and Wealth Management were $4 million , $2 million and $1 million , respectively, for the three months ended September 30, 2017 and $17 million , $10 million and $5 million , respectively, for the nine months ended September 30, 2017 . Total restructuring charges assigned to the Business Bank, Retail Bank and Wealth Management were $10 million , $8 million and $2 million , respectively, for the three months ended September 30, 2016 and $36 million , $27 million , and $10 million , respectively, for the nine months ended September 30, 2016 . 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	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 . 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 discontinued operations, 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 2016 Annual Report. Business segment financial results are as follows: (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended September 30, 2017 Earnings summary: Net interest income (expense) $ 356 $ 165 $ 45 $ (30 ) $ 10 $ 546 Provision for credit losses 16 (1 ) 10 — (1 ) 24 Noninterest income 148 49 63 13 2 275 Noninterest expenses 199 184 70 (1 ) 11 463 Provision (benefit) for income taxes 99 10 10 (10 ) (1 ) (a) 108 Net income (loss) $ 190 $ 21 $ 18 $ (6 ) $ 3 $ 226 Net credit-related charge-offs (recoveries) $ 28 $ (1 ) $ (2 ) $ — $ — $ 25 Selected average balances: Assets $ 38,917 $ 6,455 $ 5,416 $ 13,996 $ 6,467 $ 71,251 Loans 37,559 5,834 5,270 — — 48,663 Deposits 28,115 23,918 4,054 270 136 56,493 Statistical data: Return on average assets (b) 1.94 % 0.33 % 1.28 % N/M N/M 1.25 % Efficiency ratio (c) 39.32 85.51 65.23 N/M N/M 56.24 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 356 $ 156 $ 41 $ (109 ) $ 6 $ 450 Provision for credit losses 2 10 (1 ) — 5 16 Noninterest income 145 50 61 13 3 272 Noninterest expenses 215 195 75 (1 ) 9 493 Provision (benefit) for income taxes 95 — 10 (37 ) (4 ) 64 Net income (loss) $ 189 $ 1 $ 18 $ (58 ) $ (1 ) $ 149 Net credit-related charge-offs (recoveries) $ 14 $ 3 $ (1 ) $ — $ — $ 16 Selected average balances: Assets $ 39,618 $ 6,544 $ 5,283 $ 14,144 $ 7,320 $ 72,909 Loans 38,243 5,871 5,092 — — 49,206 Deposits 30,019 23,654 4,030 98 264 58,065 Statistical data: Return on average assets (b) 1.90 % — % 1.35 % N/M N/M 0.82 % Efficiency ratio (c) 42.77 95.08 73.64 N/M N/M 68.15 (a) Includes tax benefit of $2 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Nine Months Ended September 30, 2017 Earnings summary: Net interest income (expense) $ 1,025 $ 487 $ 127 $ (150 ) $ 27 $ 1,516 Provision for credit losses 39 16 6 — (4 ) 57 Noninterest income 445 144 191 34 8 822 Noninterest expenses 592 543 211 (3 ) 34 1,377 Provision (benefit) for income taxes 291 25 37 (51 ) (29 ) (a) 273 Net income (loss) $ 548 $ 47 $ 64 $ (62 ) $ 34 $ 631 Net credit-related charge-offs (recoveries) $ 67 $ 13 $ (4 ) $ — $ — $ 76 Selected average balances: Assets $ 38,632 $ 6,489 $ 5,418 $ 13,959 $ 6,972 $ 71,470 Loans 37,301 5,864 5,266 — — 48,431 Deposits 28,831 23,883 4,046 190 178 57,128 Statistical data: Return on average assets (b) 1.89 % 0.26 % 1.58 % N/M N/M 1.18 % Efficiency ratio (c) 40.26 85.43 66.28 N/M N/M 58.74 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Nine Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 1,064 $ 462 $ 125 $ (326 ) $ 17 $ 1,342 Provision for credit losses 200 13 (3 ) — 3 213 Noninterest income 426 141 182 33 2 784 Noninterest expenses 643 579 229 (2 ) 20 1,469 Provision (benefit) for income taxes 214 3 29 (112 ) (3 ) 131 Net income (loss) $ 433 $ 8 $ 52 $ (179 ) $ (1 ) $ 313 Net credit-related charge-offs $ 113 $ 6 $ 2 $ — $ — $ 121 Selected average balances: Assets $ 39,589 $ 6,548 $ 5,220 $ 13,955 $ 5,630 $ 70,942 Loans 38,126 5,872 5,025 — — 49,023 Deposits 29,195 23,438 4,137 81 251 57,102 Statistical data: Return on average assets (b) 1.46 % 0.05 % 1.33 % N/M N/M 0.59 % Efficiency ratio (c) 43.11 95.30 74.64 N/M N/M 68.88 (a) Includes tax benefit of $31 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). 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 September 30, 2017 . 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 September 30, 2017 Earnings summary: Net interest income (expense) $ 172 $ 184 $ 123 $ 87 $ (20 ) $ 546 Provision for credit losses 8 24 (22 ) 15 (1 ) 24 Noninterest income 79 41 33 107 15 275 Noninterest expenses 144 103 92 114 10 463 Provision (benefit) for income taxes 34 37 31 17 (11 ) (a) 108 Net income (loss) $ 65 $ 61 $ 55 $ 48 $ (3 ) $ 226 Net credit-related charge-offs $ 2 $ 10 $ 9 $ 4 $ — $ 25 Selected average balances: Assets $ 13,367 $ 18,170 $ 10,435 $ 8,816 $ 20,463 $ 71,251 Loans 12,612 17,916 9,959 8,176 — 48,663 Deposits 21,641 17,316 9,400 7,730 406 56,493 Statistical data: Return on average assets (b) 1.14 % 1.32 % 2.05 % 2.15 % N/M 1.25 % Efficiency ratio (c) 57.15 45.59 58.74 58.79 N/M 56.24 (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 168 $ 179 $ 117 $ 89 $ (103 ) $ 450 Provision for credit losses 13 (4 ) (3 ) 5 5 16 Noninterest income 82 44 33 97 16 272 Noninterest expenses 161 110 102 112 8 493 Provision (benefit) for income taxes 26 43 18 18 (41 ) 64 Net income (loss) $ 50 $ 74 $ 33 $ 51 $ (59 ) $ 149 Net credit-related charge-offs $ 1 $ — $ 10 $ 5 $ — $ 16 Selected average balances: Assets $ 13,019 $ 18,088 $ 11,014 $ 9,324 $ 21,464 $ 72,909 Loans 12,332 17,793 10,566 8,515 — 49,206 Deposits 21,907 17,711 9,860 8,225 362 58,065 Statistical data: Return on average assets (b) 0.87 % 1.58 % 1.13 % 2.19 % N/M 0.82 % Efficiency ratio (c) 64.64 48.93 68.12 60.18 N/M 68.15 (a) Includes tax benefit of $2 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful (dollar amounts in millions) Michigan California Texas Other Finance Total Nine Months Ended September 30, 2017 Earnings summary: Net interest income (expense) $ 510 $ 531 $ 350 $ 248 $ (123 ) $ 1,516 Provision for credit losses 3 70 (45 ) 33 (4 ) 57 Noninterest income 242 128 98 312 42 822 Noninterest expenses 439 297 280 330 31 1,377 Provision (benefit) for income taxes 110 111 78 54 (80 ) (a) 273 Net income (loss) $ 200 $ 181 $ 135 $ 143 $ (28 ) $ 631 Net credit-related charge-offs (recoveries) $ (2 ) $ 28 $ 36 $ 14 $ — $ 76 Selected average balances: Assets $ 13,331 $ 18,201 $ 10,490 $ 8,517 $ 20,931 $ 71,470 Loans 12,637 17,930 10,028 7,836 — 48,431 Deposits 21,827 17,301 9,712 7,920 368 57,128 Statistical data: Return on average assets (b) 1.18 % 1.33 % 1.64 % 2.20 % N/M 1.18 % Efficiency ratio (c) 58.22 44.87 62.54 58.86 N/M 58.74 (dollar amounts in millions) Michigan California Texas Other Finance Total Nine Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 503 $ 532 $ 355 $ 261 $ (309 ) $ 1,342 Provision for credit losses 10 8 199 (7 ) 3 213 Noninterest income 239 121 96 293 35 784 Noninterest expenses 470 334 316 331 18 1,469 Provision (benefit) for income taxes 88 115 (21 ) 64 (115 ) 131 Net income (loss) $ 174 $ 196 $ (43 ) $ 166 $ (180 ) $ 313 Net credit-related charge-offs $ 6 $ 25 $ 88 $ 2 $ — $ 121 Selected average balances: Assets $ 13,135 $ 17,980 $ 11,198 $ 9,044 $ 19,585 $ 70,942 Loans 12,484 17,700 10,722 8,117 — 49,023 Deposits 21,699 17,121 10,096 7,854 332 57,102 Statistical data: Return on average assets (b) 1.03 % 1.44 % (0.49 )% 2.46 % N/M 0.59 % Efficiency ratio (c) 63.09 51.02 70.00 59.70 N/M 68.88 (a) Includes tax benefit of $31 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful

Basis of Presentation and Acc22

Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Share-Based Compensation	Share-Based Compensation Effective January 1, 2016, the Corporation adopted the provisions of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payments Accounting” (ASU 2016-09). ASU 2016-09 provides for the election of an accounting policy as to the timing of when stock award forfeitures are recognized in compensation expense. The Corporation elected to account for forfeitures as they occur, rather than account for compensation cost based on an estimate of the number of awards that are expected to vest. The prior period effect of this policy election as of the beginning of the year was reported as "cumulative effect of change in accounting principle" in the accompanying Consolidated Statements of Changes in Shareholders’ Equity (unaudited). In addition, ASU 2016-09 requires excess tax benefits and deficiencies resulting from employee stock awards to be prospectively recognized as a component of income taxes. Previously, excess tax benefits and deficiencies were recognized in "capital surplus" in the Consolidated Statements of Changes in Shareholders' Equity. Net excess tax benefits for awards that vested, were exercised or expired included in the "provision for income taxes" totaled $2 million and $ 31 million for the three- and nine-month periods ended September 30, 2017 , respectively. The Corporation also retrospectively adopted certain changes to the statement of cash flows in accordance with ASU 2016-09. Excess tax benefits must be classified as an operating activity, and cash paid to a tax authority by the Corporation when withholding shares from an employee’s award for tax-withholding purposes must be classified as a financing activity. Accordingly, in the Consolidated Statements of Cash Flows (unaudited), net cash provided by operating activities increased $5 million and net cash provided by financing activities decreased by a corresponding amount for the nine months ended September 30, 2016 .
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” (ASU 2014-09), which is intended to improve and converge the financial reporting requirements for revenue contracts with customers. Previous GAAP comprised broad revenue recognition concepts along with numerous industry-specific requirements. The new guidance establishes a five-step model which entities must follow to recognize revenue and removes inconsistencies in existing guidance. The guidance under ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2017 and must be retrospectively applied. The Corporation expects to adopt ASU 2014-09 in the first quarter 2018 using the modified retrospective approach, which includes presenting the cumulative effect of initial application along with supplementary disclosures. The identification of revenue streams within the scope of Topic 606 is complete, resulting in less than 30 percent of total revenues in scope of the new guidance. The accounting analysis to determine potential changes to identified performance obligations, timing of revenue recognition and presentation as a result of implementing the new guidance is in its final stages. Under the new guidance, card fee revenue from certain products will generally be presented net of network costs (including interchange costs, surcharge fees and assessment fees), as opposed to the current presentation of associated network costs in "outside processing fees." Network costs impacted by the new guidance were approximately $97 million for the year ended December 31, 2016. The Corporation currently defers recognition of certain treasury management fees in "service charges on deposit accounts" in the consolidated statements of comprehensive income until the amount of compensation is considered fixed and determinable. Under the new guidance, a portion of these fees will be recognized as services are rendered. As a result of this earlier recognition, the Corporation expects to record a receivable of approximately $15 million to $18 million with a corresponding adjustment to retained earnings and deferred tax liability upon adoption of ASU 2014-09. The annual amount of treasury management fees reflected in the Corporation’s results of operations is not expected to significantly change. While no other material changes to the financial condition or results of operations have been identified to date, conclusions are preliminary as the Corporation finalizes its evaluation of the guidance. The Corporation continues to evaluate changes that may be required to applicable disclosures. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities," (ASU 2016-01), which makes targeted amendments to the guidance for recognition, measurement, presentation and disclosure of financial instruments. The guidance under ASU 2016-01 is effective for annual and interim periods beginning after December 15, 2017. 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. As of September 30, 2017, the Corporation classified approximately $45 million of auction-rate securities as available for sale equity securities. At adoption, any cumulative change in the fair value of these auction-rate securities previously recognized in accumulated other comprehensive income will be recorded as an adjustment to the opening balance of retained earnings, and any further changes to their fair value will be recorded in net income. The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operation. ASU 2016-01 also emphasizes the existing requirement to use exit prices to measure fair value for disclosure purposes and clarifies that entities should not make use of a practicability exception in determining the fair value of loans. Accordingly, the Corporation will refine the calculation used to determine the disclosed fair value of its held-for-investment loan portfolio as part of adopting the standard. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” (ASU 2016-15), which reduces diversity in the presentation of several categories of transactions in the cash flow statement. Among other things, the update clarifies the appropriate classification for proceeds from settlement of bank owned life insurance (BOLI) policies. The Corporation expects to change the classification of proceeds from settlement of BOLI policies from operating activities to investing activities. Proceeds from settlement of BOLI policies totaled $8 million and $16 million for the nine-month period ended September 30, 2017 and year ended December 31, 2016, respectively. Other changes in classification resulting from this update are not expected to be significant. ASU 2016-15 is effective for the Corporation on January 1, 2018 and must be applied using the retrospective approach. In March 2017, the FASB issued 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), which requires employers to report service cost as part of compensation expense and the other components of net benefit cost separately from service cost on the statement of income. Further, only the service cost component will be eligible for capitalization in deferred loan costs. The Corporation currently includes all components of net benefit cost in "salaries and benefits expense" in the consolidated statements of comprehensive income. Upon adoption of ASU 2017-07, only service cost will remain in salaries and benefits expense, and the other components (interest cost, expected return on assets, amortization of prior service cost or credit and amortization of net actuarial gains or losses) will be included in "other noninterest expenses." The other components of net benefit cost were a benefit of $36 million and $28 million for the nine months ended September 30, 2017 and the year ended December 31, 2016, respectively. ASU 2017-07 is effective for the Corporation on January 1, 2018. The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operations. In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities” (ASU 2017-12), which better aligns the accounting and reporting of hedging relationships with the economics of risk management activities. ASU 2017-12 provides administrative reliefs to simplify the application of hedge accounting. The amendment is effective for the Corporation on January 1, 2019 and early adoption is permitted. The Corporation is considering early adoption of the guidance on January 1, 2018. ASU 2017-12 requires an adjustment to opening retained earnings for the cumulative effect of changes to the measurement methodology on the basis of hedged items at transition. The Corporation’s derivative instruments used for risk management predominately comprise swaps converting fixed-rate long-term debt to variable rates. These hedges have been highly effective, with no ineffectiveness net gains or losses recognized for the three- and nine-month periods ended September 30, 2017. An ineffectiveness net loss of $2 million was included in “other noninterest income” in the consolidated statements of income for the year ended December 31, 2016. Under the amendment, gains or losses relating to hedge ineffectiveness will prospectively be included in “net interest income” rather than “other noninterest income." The Corporation does not expect the new guidance to have a material impact on its financial condition or results of operations.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 and December 31, 2016 . (in millions) Total Level 1 Level 2 Level 3 September 30, 2017 Trading securities: Deferred compensation plan assets $ 89 $ 89 $ — $ — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,770 2,770 — — Residential mortgage-backed securities (a) 8,137 — 8,137 — State and municipal securities 5 — — 5 (b) Equity and other non-debt securities 86 41 — 45 (b) Total investment securities available-for-sale 10,998 2,811 8,137 50 Derivative assets: Interest rate contracts 79 — 65 14 Energy derivative contracts 63 — 63 — Foreign exchange contracts 46 — 46 — Warrants 2 — — 2 Total derivative assets 190 — 174 16 Total assets at fair value $ 11,277 $ 2,900 $ 8,311 $ 66 Derivative liabilities: Interest rate contracts $ 45 $ — $ 45 Energy derivative contracts 60 — 60 — Foreign exchange contracts 44 — 44 — Total derivative liabilities 149 — 149 — Deferred compensation plan liabilities 89 89 — — Total liabilities at fair value $ 238 $ 89 $ 149 $ — (a) Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises. (b) Auction-rate securities. (in millions) Total Level 1 Level 2 Level 3 December 31, 2016 Trading securities: Deferred compensation plan assets $ 87 $ 87 $ — $ — Equity and other non-debt securities 1 1 — — Total trading securities 88 88 — — Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities 2,779 2,779 — — Residential mortgage-backed securities (a) 7,872 — 7,872 — State and municipal securities 7 — — 7 (b) Equity and other non-debt securities 129 82 — 47 (b) Total investment securities available-for-sale 10,787 2,861 7,872 54 Derivative assets: Interest rate contracts 223 — 212 11 Energy derivative contracts 146 — 146 — Foreign exchange contracts 38 — 38 — Warrants 3 — — 3 Total derivative assets 410 — 396 14 Total assets at fair value $ 11,285 $ 2,949 $ 8,268 $ 68 Derivative liabilities: Interest rate contracts $ 81 $ — $ 81 $ — Energy derivative contracts 144 — 144 — Foreign exchange contracts 29 — 29 — Total derivative liabilities 254 — 254 — Deferred compensation plan liabilities 87 87 — — Total liabilities at fair value $ 341 $ 87 $ 254 $ — (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 nine-month periods ended September 30, 2017 and 2016 . Net Realized/Unrealized Gains (Losses) (Pretax) Balance at Beginning of Period Recorded in Earnings Recorded in Other Comprehensive Income Balance at End of Period (in millions) Realized Unrealized Redemptions Sales Three Months Ended September 30, 2017 Investment securities available-for-sale: State and municipal securities (a) $ 5 $ — $ — $ — $ — $ — $ 5 Equity and other non-debt securities (a) 46 — (1 ) — — 45 Total investment securities available-for-sale 51 — — (1 ) — — 50 Derivative assets: Interest rate contracts 13 — 1 (b) — — 14 Warrants 2 — — — — — 2 Three Months Ended September 30, 2016 Investment securities available-for-sale: State and municipal securities (a) $ 8 $ — $ — $ — $ — $ — $ 8 Corporate debt securities (a) 1 — — — (1 ) — — Equity and other non-debt securities (a) 48 — — 1 (3 ) — 46 Total investment securities available-for-sale 57 — — 1 (4 ) — 54 Derivative assets: Interest rate contracts 27 — — — — — 27 Warrants 2 3 (b) — — — (3 ) 2 Nine Months Ended September 30, 2017 Investment securities available-for-sale: State and municipal securities (a) $ 7 $ — $ — $ — $ (2 ) $ — $ 5 Equity and other non-debt securities (a) 47 — — (1 ) (1 ) — 45 Total investment securities available-for-sale 54 — — (1 ) (3 ) — 50 Derivative assets: Interest rate contracts 11 — 3 (b) — — — 14 Warrants 3 5 (b) (1 ) (b) — — (5 ) 2 Nine Months Ended September 30, 2016 Investment securities available-for-sale: State and municipal securities (a) $ 9 $ — $ — $ — $ (1 ) $ — $ 8 Corporate debt securities (a) 1 — — — (1 ) — — Equity and other non-debt securities (a) 67 — — (3 ) (18 ) — 46 Total investment securities available-for-sale 77 — — (3 ) (20 ) — 54 Derivative assets: Interest rate contracts 9 — 18 (b) — — — 27 Warrants 2 4 (b) — — — (4 ) 2 (a) Auction-rate securities. (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.
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 September 30, 2017 and December 31, 2016 . No liabilities were recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 . (in millions) Level 3 September 30, 2017 Loans: Commercial $ 131 Commercial mortgage 9 International 2 Total assets at fair value $ 142 December 31, 2016 Loans: Commercial $ 256 Commercial mortgage 15 International 11 Total loans 282 Other real estate 1 Total assets at fair value $ 283
Quantitative Information About Level 3 Measurements	The Corporation's Level 3 recurring fair value measurements primarily include auction-rate securities where fair value is determined using an income approach based on a discounted cash flow model and certain interest rate derivative contracts where credit valuation adjustments are significant to the overall fair value of the derivative. The inputs in the table below reflect management's expectation of continued illiquidity in the secondary auction-rate securities market due to a lack of market activity for the issuers remaining in the portfolio, a lack of market incentives for issuer redemptions, and the expectation for a continuing low interest rate environment. The workout periods reflect management's expectation of the pace at which short-term interest rates could rise at each respective period. Discounted Cash Flow Model Unobservable Input Fair Value (in millions) Discount Rate Workout Period (in years) September 30, 2017 State and municipal securities (a) $ 5 5% - 7% 1 - 3 Equity and other non-debt securities (a) 45 7% - 10% 1 - 2 December 31, 2016 State and municipal securities (a) $ 7 4% - 6% 1 - 2 Equity and other non-debt securities (a) 47 7% - 9% 1 - 2 (a) Auction-rate securities.
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 September 30, 2017 Assets Cash and due from banks $ 1,351 $ 1,351 $ 1,351 $ — $ — Interest-bearing deposits with banks 4,853 4,853 4,853 — — Investment securities held-to-maturity 1,344 1,339 — 1,339 — Loans held-for-sale 3 3 — 3 — Total loans, net of allowance for loan losses (a) 48,497 48,296 — — 48,296 Customers’ liability on acceptances outstanding 2 2 2 — — Restricted equity investments 228 228 228 — — Nonmarketable equity securities (b) 6 9 Liabilities Demand deposits (noninterest-bearing) 32,391 32,391 — 32,391 — Interest-bearing deposits 23,086 23,086 — 23,086 — Customer certificates of deposit 2,342 2,309 — 2,309 — Total deposits 57,819 57,786 — 57,786 — Short-term borrowings 509 509 509 — — Acceptances outstanding 2 2 2 — — Medium- and long-term debt 4,637 4,642 — 4,642 — Credit-related financial instruments (70 ) (70 ) — — (70 ) December 31, 2016 Assets Cash and due from banks $ 1,249 $ 1,249 $ 1,249 $ — $ — Interest-bearing deposits with banks 5,969 5,969 5,969 — — Investment securities held-to-maturity 1,582 1,576 — 1,576 — Loans held-for-sale 4 4 — 4 — Total loans, net of allowance for loan losses (a) 48,358 48,250 — — 48,250 Customers’ liability on acceptances outstanding 5 5 5 — — Restricted equity investments 207 207 207 — — Nonmarketable equity securities (b) 11 16 Liabilities Demand deposits (noninterest-bearing) 31,540 31,540 — 31,540 — Interest-bearing deposits 24,639 24,639 — 24,639 — Customer certificates of deposit 2,806 2,731 — 2,731 — Total deposits 58,985 58,910 — 58,910 — Short-term borrowings 25 25 25 — — Acceptances outstanding 5 5 5 — — Medium- and long-term debt 5,160 5,132 — 5,132 — Credit-related financial instruments (73 ) (73 ) — — (73 ) (a) Included $142 million and $282 million of impaired loans recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016 , 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)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,763 $ 8 $ 1 $ 2,770 Residential mortgage-backed securities (a) 8,168 44 75 8,137 State and municipal securities 5 — — 5 Equity and other non-debt securities 86 2 2 86 Total investment securities available-for-sale (b) $ 11,022 $ 54 $ 78 $ 10,998 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,344 $ 1 $ 6 $ 1,339 December 31, 2016 Investment securities available-for-sale: U.S. Treasury and other U.S. government agency securities $ 2,772 $ 8 $ 1 $ 2,779 Residential mortgage-backed securities (a) 7,921 48 97 7,872 State and municipal securities 7 — — 7 Equity and other non-debt securities 129 1 1 129 Total investment securities available-for-sale (b) $ 10,829 $ 57 $ 99 $ 10,787 Investment securities held-to-maturity (c): Residential mortgage-backed securities (a) $ 1,582 $ 1 $ 7 $ 1,576 (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 $52 million and $50 million , respectively as of September 30, 2017 and $55 million and $54 million , respectively, as of December 31, 2016 . (c) The amortized cost of investment securities held-to-maturity included net unrealized losses of $9 million at September 30, 2017 and $12 million at December 31, 2016 related to securities transferred from available-for-sale, 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 September 30, 2017 and December 31, 2016 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 September 30, 2017 U.S. Treasury and other U.S. government agency securities $ 486 $ 1 $ — $ — $ 486 $ 1 Residential mortgage-backed securities (a) 4,111 55 1,446 36 5,557 91 State and municipal securities (b) — — 5 — (c) 5 — (c) Equity and other non-debt securities (b) — — 45 2 45 2 Total temporarily impaired securities $ 4,597 $ 56 $ 1,496 $ 38 $ 6,093 $ 94 December 31, 2016 U.S. Treasury and other U.S. government agency securities $ 527 $ 1 $ — $ — $ 527 $ 1 Residential mortgage-backed securities (a) 4,992 87 1,177 32 6,169 119 State and municipal securities (b) — — 7 — (c) 7 — (c) Equity and other non-debt securities (b) 36 — (c) 11 — (c) 47 — (c) Total temporarily impaired securities $ 5,555 $ 88 $ 1,195 $ 32 $ 6,750 $ 120 (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.
Summary of Net Securities Gains (Losses)	Sales, calls and write-downs of investment securities available-for-sale resulted in the following gains and losses recorded in “net securities gains (losses)” on the consolidated statements of comprehensive income, computed based on the adjusted cost of the specific security. Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Securities gains $ — $ — $ 1 $ — Securities losses (a) (1 ) — (4 ) (3 ) Net securities losses $ (1 ) $ — $ (3 ) $ (3 ) (a) Primarily charges related to a derivative contract tied to the conversion rate of Visa Class B shares.
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) Available-for-sale Held-to-maturity September 30, 2017 Amortized Cost Fair Value Amortized Cost Fair Value Contractual maturity Within one year $ 20 $ 20 $ — $ — After one year through five years 2,947 2,953 — — After five years through ten years 1,744 1,770 19 19 After ten years 6,225 6,169 1,325 1,320 Subtotal 10,936 10,912 1,344 1,339 Equity and other non-debt securities 86 86 — — Total investment securities $ 11,022 $ 10,998 $ 1,344 $ 1,339

Credit Quality And Allowance 25

Credit Quality And Allowance For Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Business loans: Commercial $ 52 $ 31 $ 7 $ 90 $ 345 $ 30,627 $ 31,062 Real estate construction: Commercial Real Estate business line (a) — — — — — 2,709 2,709 Other business lines (b) 11 — — 11 — 298 309 Total real estate construction 11 — — 11 — 3,007 3,018 Commercial mortgage: Commercial Real Estate business line (a) 20 — — 20 9 1,702 1,731 Other business lines (b) 18 10 3 31 26 7,197 7,254 Total commercial mortgage 38 10 3 51 35 8,899 8,985 Lease financing — — — — 8 467 475 International 11 — 2 13 6 1,140 1,159 Total business loans 112 41 12 165 394 44,140 44,699 Retail loans: Residential mortgage 14 9 — 23 28 1,948 1,999 Consumer: Home equity 5 1 — 6 22 1,762 1,790 Other consumer 1 1 — 2 — 719 721 Total consumer 6 2 — 8 22 2,481 2,511 Total retail loans 20 11 — 31 50 4,429 4,510 Total loans $ 132 $ 52 $ 12 $ 196 $ 444 $ 48,569 $ 49,209 December 31, 2016 Business loans: Commercial $ 30 $ 12 $ 14 $ 56 $ 445 $ 30,493 $ 30,994 Real estate construction: Commercial Real Estate business line (a) — — — — — 2,485 2,485 Other business lines (b) — — — — — 384 384 Total real estate construction — — — — — 2,869 2,869 Commercial mortgage: Commercial Real Estate business line (a) 5 — — 5 9 2,004 2,018 Other business lines (b) 58 5 5 68 37 6,808 6,913 Total commercial mortgage 63 5 5 73 46 8,812 8,931 Lease financing — — — — 6 566 572 International 1 — — 1 14 1,243 1,258 Total business loans 94 17 19 130 511 43,983 44,624 Retail loans: Residential mortgage 7 3 — 10 39 1,893 1,942 Consumer: Home equity 4 3 — 7 28 1,765 1,800 Other consumer 1 — — 1 4 717 722 Total consumer 5 3 — 8 32 2,482 2,522 Total retail loans 12 6 — 18 71 4,375 4,464 Total loans $ 106 $ 23 $ 19 $ 148 $ 582 $ 48,358 $ 49,088 (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 September 30, 2017 Business loans: Commercial $ 29,187 $ 617 $ 913 $ 345 $ 31,062 Real estate construction: Commercial Real Estate business line (e) 2,658 51 — — 2,709 Other business lines (f) 305 4 — — 309 Total real estate construction 2,963 55 — — 3,018 Commercial mortgage: Commercial Real Estate business line (e) 1,660 20 42 9 1,731 Other business lines (f) 7,000 111 117 26 7,254 Total commercial mortgage 8,660 131 159 35 8,985 Lease financing 442 24 1 8 475 International 1,082 53 18 6 1,159 Total business loans 42,334 880 1,091 394 44,699 Retail loans: Residential mortgage 1,962 9 — 28 1,999 Consumer: Home equity 1,759 1 8 22 1,790 Other consumer 720 1 — — 721 Total consumer 2,479 2 8 22 2,511 Total retail loans 4,441 11 8 50 4,510 Total loans $ 46,775 $ 891 $ 1,099 $ 444 $ 49,209 December 31, 2016 Business loans: Commercial $ 28,616 $ 944 $ 989 $ 445 $ 30,994 Real estate construction: Commercial Real Estate business line (e) 2,485 — — — 2,485 Other business lines (f) 381 — 3 — 384 Total real estate construction 2,866 — 3 — 2,869 Commercial mortgage: Commercial Real Estate business line (e) 1,970 19 20 9 2,018 Other business lines (f) 6,645 109 122 37 6,913 Total commercial mortgage 8,615 128 142 46 8,931 Lease financing 550 11 5 6 572 International 1,200 22 22 14 1,258 Total business loans 41,847 1,105 1,161 511 44,624 Retail loans: Residential mortgage 1,900 3 — 39 1,942 Consumer: Home equity 1,767 1 4 28 1,800 Other consumer 718 — — 4 722 Total consumer 2,485 1 4 32 2,522 Total retail loans 4,385 4 4 71 4,464 Total loans $ 46,232 $ 1,109 $ 1,165 $ 582 $ 49,088 (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. (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 page F-56 in the Corporation's 2016 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) September 30, 2017 December 31, 2016 Nonaccrual loans $ 444 $ 582 Reduced-rate loans (a) 8 8 Total nonperforming loans 452 590 Foreclosed property (b) 6 17 Total nonperforming assets $ 458 $ 607 (a) There were no reduced-rate business loans at both September 30, 2017 and December 31, 2016 . Reduced-rate retail loans were $8 million at both September 30, 2017 and December 31, 2016 . (b) Included $5 million and $3 million of foreclosed residential real estate properties at September 30, 2017 and December 31, 2016 , 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. 2017 2016 (in millions) Business Loans Retail Loans Total Business Loans Retail Loans Total Three Months Ended September 30 Allowance for loan losses: Balance at beginning of period $ 661 $ 44 $ 705 $ 682 $ 47 $ 729 Loan charge-offs (36 ) (1 ) (37 ) (34 ) (1 ) (35 ) Recoveries on loans previously charged-off 10 2 12 18 1 19 Net loan (charge-offs) recoveries (26 ) 1 (25 ) (16 ) — (16 ) Provision for loan losses 21 10 31 12 2 14 Foreign currency translation adjustment 1 — 1 — — — Balance at end of period $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 Nine Months Ended September 30 Allowance for loan losses: Balance at beginning of period $ 682 $ 48 $ 730 $ 579 $ 55 $ 634 Loan charge-offs (115 ) (5 ) (120 ) (161 ) (5 ) (166 ) Recoveries on loans previously charged-off 39 5 44 53 3 56 Net loan charge-offs (76 ) — (76 ) (108 ) (2 ) (110 ) Provision for loan losses 50 7 57 206 (4 ) 202 Foreign currency translation adjustment 1 — 1 1 — 1 Balance at end of period $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 As a percentage of total loans 1.47 % 1.23 % 1.45 % 1.51 % 1.10 % 1.48 % September 30 Allowance for loan losses: Individually evaluated for impairment $ 90 $ — $ 90 $ 115 $ 1 $ 116 Collectively evaluated for impairment 567 55 622 563 48 611 Total allowance for loan losses $ 657 $ 55 $ 712 $ 678 $ 49 $ 727 Loans: Individually evaluated for impairment $ 501 $ 37 $ 538 $ 677 $ 29 $ 706 Collectively evaluated for impairment 44,198 4,473 48,671 44,182 4,386 48,568 Total loans evaluated for impairment $ 44,699 $ 4,510 $ 49,209 $ 44,859 $ 4,415 $ 49,274
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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Balance at beginning of period $ 48 $ 43 $ 41 $ 45 Charge-offs on lending-related commitments (a) — — — (11 ) Provision for credit losses on lending-related commitments (7 ) 2 — 11 Balance at end of period $ 41 $ 45 $ 41 $ 45 (a) Charge-offs result from the sale of unfunded lending-related commitments.
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 September 30, 2017 Business loans: Commercial $ 111 $ 311 $ 422 $ 543 $ 85 Commercial mortgage: Commercial Real Estate business line (a) 36 7 43 52 1 Other business lines (b) 3 27 30 36 3 Total commercial mortgage 39 34 73 88 4 International — 6 6 17 1 Total business loans 150 351 501 648 90 Retail loans: Residential mortgage 22 — 22 28 — Consumer: Home equity 12 — 12 12 — Other consumer 3 — 3 5 — Total consumer 15 — 15 17 — Total retail loans (c) 37 — 37 45 — Total individually evaluated impaired loans $ 187 $ 351 $ 538 $ 693 $ 90 December 31, 2016 Business loans: Commercial $ 90 $ 423 $ 513 $ 608 $ 80 Commercial mortgage: Commercial Real Estate business line (a) — 7 7 15 1 Other business lines (b) 2 30 32 40 3 Total commercial mortgage 2 37 39 55 4 International 3 11 14 20 2 Total business loans 95 471 566 683 86 Retail loans: Residential mortgage 19 9 28 30 2 Consumer: Home equity 15 — 15 19 — Other consumer 2 3 5 6 1 Total consumer 17 3 20 25 1 Total retail loans (c) 36 12 48 55 3 Total individually evaluated impaired loans $ 131 $ 483 $ 614 $ 738 $ 89 (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. Interest income recognized for the period primarily related to performing restructured loans. Individually Evaluated Impaired Loans 2017 2016 (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 September 30 Business loans: Commercial $ 442 $ 2 $ 606 $ 2 Commercial mortgage: Commercial Real Estate business line (a) 25 1 7 — Other business lines (b) 32 — 30 — Total commercial mortgage 57 1 37 — International 6 — 19 — Total business loans 505 3 662 2 Retail loans: Residential mortgage 24 — 11 — Consumer loans: Home equity 12 — 12 — Other consumer 3 — 4 — Total consumer 15 — 16 — Total retail loans 39 — 27 — Total individually evaluated impaired loans $ 544 $ 3 $ 689 $ 2 Nine Months Ended September 30 Business loans: Commercial $ 470 $ 6 $ 559 $ 8 Commercial mortgage: Commercial Real Estate business line (a) 16 1 9 — Other business lines (b) 33 — 31 — Total commercial mortgage 49 1 40 — International 9 — 19 — Total business loans 528 7 618 8 Retail loans: Residential mortgage 26 — 12 — Consumer: Home equity 13 — 12 — Other consumer 3 — 4 — Total consumer 16 — 16 — Total retail loans 42 — 28 — Total individually evaluated impaired loans $ 570 $ 7 $ 646 $ 8 (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 tables detail the recorded balance at September 30, 2017 and 2016 of loans considered to be troubled debt restructurings (TDRs) that were restructured during the three- and nine-month periods ended September 30, 2017 and 2016 , 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. 2017 2016 Type of Modification Type of Modification (in millions) Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Principal Deferrals (a) Interest Rate Reductions AB Note Restructures (b) Total Modifications Three Months Ended September 30 Business loans: Commercial $ 22 $ — $ — $ 22 $ 70 $ — $ 40 $ 110 Commercial mortgage: Commercial Real Estate business line (c) 36 — — 36 — — — — International 2 — — 2 — — — — Total business loans 60 — — 60 70 — 40 110 Retail loans: Consumer: Home equity (d) 1 — — 1 — — — — Total retail loans 1 — — 1 — — — — Total loans $ 61 $ — $ — $ 61 $ 70 $ — $ 40 $ 110 Nine Months Ended September 30 Business loans: Commercial $ 95 $ — $ 31 $ 126 $ 150 $ — $ 49 $ 199 Commercial mortgage: Commercial Real Estate business line (c) 36 — — 36 — — — — Other business lines (e) 3 — — 3 2 — — 2 Total commercial mortgage 39 — — 39 2 — — 2 International 2 — — 2 — — 3 3 Total business loans 136 — 31 167 152 — 52 204 Retail loans: Consumer: Home equity (d) 1 2 — 3 1 1 — 2 Total retail loans 1 2 — 3 1 1 — 2 Total loans $ 137 $ 2 $ 31 $ 170 $ 153 $ 1 $ 52 $ 206 (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 real estate developers. (d) Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt. (e) Primarily loans secured by owner-occupied real estate.
Troubled Debt Restructuring Subsequent Default	The following table presents information regarding the recorded balance at September 30, 2017 and 2016 of loans modified by principal deferral during the twelve-month periods ended September 30, 2017 and 2016 , and those principal deferrals which experienced a subsequent default during the three- and nine-month periods ended September 30, 2017 and 2016 . 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. 2017 2016 (in millions) Balance at September 30 Subsequent Default in the Three Months Ended September 30 Subsequent Default in the Nine Months Ended September 30 Balance at September 30 Subsequent Default in the Three Months Ended September 30 Subsequent Default in the Nine Months Ended September 30 Principal deferrals: Business loans: Commercial $ 127 $ 4 $ 4 $ 229 $ — $ 13 Commercial mortgage: Commercial Real Estate business line (a) 37 — — — — — Other business lines (b) 7 — 4 4 — 1 Total commercial mortgage 44 — 4 4 — 1 International 2 — — — — — Total business loans 173 4 8 233 — 14 Retail loans: Consumer: Home equity (c) 1 — — 1 — — Total principal deferrals $ 174 $ 4 $ 8 $ 234 $ — $ 14 (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-Related26

Derivative And Credit-Related Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 and December 31, 2016 . The table excludes commitments and warrants accounted for as derivatives. September 30, 2017 December 31, 2016 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 (b) $ 1,775 $ — $ — $ 2,275 $ 92 $ 4 Derivatives used as economic hedges Foreign exchange contracts: Spot, forwards and swaps 663 — 2 717 2 2 Total risk management purposes 2,438 — 2 2,992 94 6 Customer-initiated and other activities Interest rate contracts: Caps and floors written 590 — — 436 — 1 Caps and floors purchased 590 — — 436 1 — Swaps (b) 12,905 79 45 12,451 130 76 Total interest rate contracts 14,085 79 45 13,323 131 77 Energy contracts: Caps and floors written 222 — 12 419 1 31 Caps and floors purchased 222 12 — 419 31 1 Swaps 1,352 51 48 1,389 114 112 Total energy contracts 1,796 63 60 2,227 146 144 Foreign exchange contracts: Spot, forwards, options and swaps 2,147 46 42 1,509 36 27 Total customer-initiated and other activities 18,028 188 147 17,059 313 248 Total gross derivatives $ 20,466 $ 188 $ 149 $ 20,051 $ 407 $ 254 Amounts offset in the consolidated balance sheets: Netting adjustment - Offsetting derivative assets/liabilities (49 ) (49 ) (84 ) (84 ) Netting adjustment - Cash collateral received/posted (19 ) (6 ) (47 ) (45 ) Net derivatives included in the consolidated balance sheets (c) 120 94 276 125 Amounts not offset in the consolidated balance sheets: Marketable securities pledged under bilateral collateral agreements (4 ) (24 ) (19 ) (8 ) Net derivatives after deducting amounts not offset in the consolidated balance sheets $ 116 $ 70 $ 257 $ 117 (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) Due to clearinghouse rule changes, beginning January 1, 2017, variation margin payments are treated as settlements of derivative exposure rather than as collateral. As a result, these payments are now considered in determining the fair value of centrally cleared derivatives, resulting in centrally cleared derivatives having a fair value of approximately zero. (c) 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 $6 million and $5 million at September 30, 2017 and December 31, 2016 , respectively.
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 and the weighted average interest rates associated with amounts expected to be received or paid on interest rate swap agreements as of September 30, 2017 and December 31, 2016 . Weighted Average (dollar amounts in millions) Notional Amount Remaining Maturity (in years) Receive Rate Pay Rate (a) September 30, 2017 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt designation $ 1,775 4.9 3.26 % 2.21 % December 31, 2016 Swaps - fair value - receive fixed/pay floating rate Medium- and long-term debt designation 2,275 4.5 3.69 1.80 (a) Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at September 30, 2017 and December 31, 2016 .
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 September 30, Nine Months Ended September 30, (in millions) Location of Gain 2017 2016 2017 2016 Interest rate contracts Other noninterest income $ 5 $ 6 $ 18 $ 14 Energy contracts Other noninterest income 1 — 2 1 Foreign exchange contracts Foreign exchange income 11 11 33 30 Total $ 17 $ 17 $ 53 $ 45
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) September 30, 2017 December 31, 2016 Unused commitments to extend credit: Commercial and other $ 23,542 $ 24,333 Bankcard, revolving check credit and home equity loan commitments 2,865 2,658 Total unused commitments to extend credit $ 26,407 $ 26,991 Standby letters of credit $ 3,372 $ 3,623 Commercial letters of credit 43 46
Summary Of Criticized Letters Of Credit	The following table presents a summary of criticized standby and commercial letters of credit at September 30, 2017 and December 31, 2016 . 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) September 30, 2017 December 31, 2016 Total criticized standby and commercial letters of credit $ 79 $ 135 As a percentage of total outstanding standby and commercial letters of credit 2.3 % 3.7 %

Variable Interest Entities (V27

Variable Interest Entities (VIEs) (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Other noninterest income: Amortization of other tax credit investments $ — $ (1 ) $ 1 $ (1 ) Provision for income taxes: Amortization of LIHTC investments 17 17 49 49 Low income housing tax credits (16 ) (16 ) (47 ) (47 ) Other tax benefits related to tax credit entities (6 ) (7 ) (18 ) (19 ) Total provision for income taxes $ (5 ) $ (6 ) $ (16 ) $ (17 )

Medium- And Long-Term Debt (Tab

Medium- And Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule Of Medium- And Long-Term Debt	Medium- and long-term debt is summarized as follows: (in millions) September 30, 2017 December 31, 2016 Parent company Subordinated notes: 3.80% subordinated notes due 2026 (a) $ 257 $ 256 Medium-term notes: 2.125% notes due 2019 (a) 349 348 Total parent company 606 604 Subsidiaries Subordinated notes: 5.20% subordinated notes due 2017 (a) — 511 4.00% subordinated notes due 2025 (a) 350 347 7.875% subordinated notes due 2026 (a) 211 215 Total subordinated notes 561 1,073 Medium-term notes: 2.50% notes due 2020 (a) 670 667 Federal Home Loan Bank (FHLB) advances: Floating-rate based on FHLB auction rate due 2026 2,800 2,800 Other notes: 6.0% - 6.4% fixed-rate notes due 2018 to 2020 — 16 Total subsidiaries 4,031 4,556 Total medium- and long-term debt $ 4,637 $ 5,160 (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 Comprehensi29

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2017
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 nine months ended September 30, 2017 and 2016 , including the amount of income tax expense (benefit) allocated to each component of other comprehensive income (loss). Nine Months Ended September 30, (in millions) 2017 2016 Accumulated net unrealized (losses) gains on investment securities: Balance at beginning of period, net of tax $ (33 ) $ 9 Net unrealized holding gains arising during the period 18 140 Less: Provision for income taxes 7 51 Net unrealized holding gains arising during the period, net of tax 11 89 Less: Net losses realized as a yield adjustment in interest on investment securities (3 ) (2 ) Less: Benefit for income taxes (1 ) (1 ) Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax (2 ) (1 ) Change in net unrealized gains on investment securities, net of tax 13 90 Balance at end of period, net of tax $ (20 ) $ 99 Accumulated defined benefit pension and other postretirement plans adjustment: Balance at beginning of period, net of tax $ (350 ) $ (438 ) Actuarial loss arising during the period — (191 ) Prior service credit arising during the period — 235 Net defined benefit pension and other postretirement adjustment arising during the period — 44 Less: Provision for income taxes — 16 Net defined benefit pension and other postretirement plans adjustment arising during the period, net of tax — 28 Amortization of actuarial net loss 38 29 Amortization of prior service credit (20 ) — Amounts recognized in salaries and benefits expense 18 29 Less: Provision for income taxes 7 10 Adjustment for amounts recognized as components of net periodic benefit cost during the period, net of tax 11 19 Change in defined benefit pension and other postretirement plans adjustment, net of tax 11 47 Balance at end of period, net of tax $ (339 ) $ (391 ) Total accumulated other comprehensive loss at end of period, net of tax $ (359 ) $ (292 )

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, Nine Months Ended September 30, (in millions, except per share data) 2017 2016 2017 2016 Basic and diluted Net income $ 226 $ 149 $ 631 $ 313 Less: Income allocated to participating securities 2 1 5 3 Net income attributable to common shares $ 224 $ 148 $ 626 $ 310 Basic average common shares 174 171 175 173 Basic net income per common share $ 1.29 $ 0.87 $ 3.58 $ 1.80 Basic average common shares 174 171 175 173 Dilutive common stock equivalents: Net effect of the assumed exercise of stock options 2 2 3 1 Net effect of the assumed exercise of warrants 1 3 1 2 Diluted average common shares 177 176 179 176 Diluted net income per common share $ 1.26 $ 0.84 $ 3.50 $ 1.76
Schedule of Average Shares Excluded From Diluted Net Income Per Common Share Computation	The following average shares related to outstanding options to purchase shares of common stock were not included in the computation of diluted net income per common share because the options were anti-dilutive for the period. There were no anti-dilutive options for both the three- and nine-month periods ended September 30, 2017 . (shares in millions) Three Months Ended September 30, 2016 Nine Months Ended September 30, 2016 Average outstanding options 2.6 4.0 Range of exercise prices $46.68 - $59.86 $37.26 - $59.86

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Components of Net Periodic Benefit Cost	The components of net periodic benefit cost 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 September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Service cost $ 7 $ 8 $ 21 $ 24 Interest cost 19 23 58 69 Expected return on plan assets (39 ) (39 ) (118 ) (120 ) Amortization of prior service (credit) cost (5 ) 1 (14 ) 3 Amortization of net loss 11 7 32 23 Net periodic defined benefit credit $ (7 ) $ — $ (21 ) $ (1 ) Non-Qualified Defined Benefit Pension Plan Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Service cost $ — $ — $ 1 $ 2 Interest cost 2 3 6 8 Amortization of prior service credit (2 ) (1 ) (6 ) (3 ) Amortization of net loss 2 2 6 5 Net periodic defined benefit cost $ 2 $ 4 $ 7 $ 12 Postretirement Benefit Plan Three Months Ended September 30, Nine Months Ended September 30, (in millions) 2017 2016 2017 2016 Interest cost $ 1 $ — $ 2 $ 2 Expected return on plan assets (1 ) (1 ) (2 ) (3 ) Amortization of net loss — 1 — 1 Net periodic postretirement benefit cost $ — $ — $ — $ —

Restructuring Charges (Tables)

Restructuring Charges (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Balance at beginning of period $ 6 $ — $ 3 $ 2 $ 11 Restructuring charges 1 — 5 1 7 Payments (1 ) — (4 ) (1 ) (6 ) Balance at end of period $ 6 $ — $ 4 $ 2 $ 12 Three Months Ended September 30, 2016 Balance at beginning of period $ 46 $ — $ — $ 4 $ 50 Restructuring charges 4 5 — 11 20 Payments (12 ) (1 ) — (8 ) (21 ) Adjustments for non-cash charges (a) 2 (4 ) — — (2 ) Balance at end of period $ 40 $ — $ — $ 7 $ 47 Nine Months Ended September 30, 2017 Balance at beginning of period $ 10 $ 4 $ — $ 4 $ 18 Restructuring charges 5 5 17 5 32 Payments (9 ) (9 ) (8 ) (7 ) (33 ) Adjustments for non-cash charges (a) — — (5 ) — (5 ) Balance at end of period $ 6 $ — $ 4 $ 2 $ 12 Nine Months Ended September 30, 2016 Balance at beginning of period $ — $ — $ — $ — $ — Restructuring charges 50 5 — 18 73 Payments (12 ) (1 ) — (11 ) (24 ) Adjustments for non-cash charges (a) 2 (4 ) — — (2 ) Balance at end of period $ 40 $ — $ — $ 7 $ 47 Total restructuring charges incurred to date $ 57 $ 20 $ 17 $ 31 $ 125 Total expected restructuring charges (b) 65 - 70 30 55 - 60 35 185 - 195 (a) Adjustments for non-cash charges primarily include the benefit from forfeitures of nonvested stock compensation in Employee Costs, accelerated depreciation expense in Facilities Costs and 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)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 Earnings summary: Net interest income (expense) $ 356 $ 165 $ 45 $ (30 ) $ 10 $ 546 Provision for credit losses 16 (1 ) 10 — (1 ) 24 Noninterest income 148 49 63 13 2 275 Noninterest expenses 199 184 70 (1 ) 11 463 Provision (benefit) for income taxes 99 10 10 (10 ) (1 ) (a) 108 Net income (loss) $ 190 $ 21 $ 18 $ (6 ) $ 3 $ 226 Net credit-related charge-offs (recoveries) $ 28 $ (1 ) $ (2 ) $ — $ — $ 25 Selected average balances: Assets $ 38,917 $ 6,455 $ 5,416 $ 13,996 $ 6,467 $ 71,251 Loans 37,559 5,834 5,270 — — 48,663 Deposits 28,115 23,918 4,054 270 136 56,493 Statistical data: Return on average assets (b) 1.94 % 0.33 % 1.28 % N/M N/M 1.25 % Efficiency ratio (c) 39.32 85.51 65.23 N/M N/M 56.24 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Three Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 356 $ 156 $ 41 $ (109 ) $ 6 $ 450 Provision for credit losses 2 10 (1 ) — 5 16 Noninterest income 145 50 61 13 3 272 Noninterest expenses 215 195 75 (1 ) 9 493 Provision (benefit) for income taxes 95 — 10 (37 ) (4 ) 64 Net income (loss) $ 189 $ 1 $ 18 $ (58 ) $ (1 ) $ 149 Net credit-related charge-offs (recoveries) $ 14 $ 3 $ (1 ) $ — $ — $ 16 Selected average balances: Assets $ 39,618 $ 6,544 $ 5,283 $ 14,144 $ 7,320 $ 72,909 Loans 38,243 5,871 5,092 — — 49,206 Deposits 30,019 23,654 4,030 98 264 58,065 Statistical data: Return on average assets (b) 1.90 % — % 1.35 % N/M N/M 0.82 % Efficiency ratio (c) 42.77 95.08 73.64 N/M N/M 68.15 (a) Includes tax benefit of $2 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Nine Months Ended September 30, 2017 Earnings summary: Net interest income (expense) $ 1,025 $ 487 $ 127 $ (150 ) $ 27 $ 1,516 Provision for credit losses 39 16 6 — (4 ) 57 Noninterest income 445 144 191 34 8 822 Noninterest expenses 592 543 211 (3 ) 34 1,377 Provision (benefit) for income taxes 291 25 37 (51 ) (29 ) (a) 273 Net income (loss) $ 548 $ 47 $ 64 $ (62 ) $ 34 $ 631 Net credit-related charge-offs (recoveries) $ 67 $ 13 $ (4 ) $ — $ — $ 76 Selected average balances: Assets $ 38,632 $ 6,489 $ 5,418 $ 13,959 $ 6,972 $ 71,470 Loans 37,301 5,864 5,266 — — 48,431 Deposits 28,831 23,883 4,046 190 178 57,128 Statistical data: Return on average assets (b) 1.89 % 0.26 % 1.58 % N/M N/M 1.18 % Efficiency ratio (c) 40.26 85.43 66.28 N/M N/M 58.74 (dollar amounts in millions) Business Retail Wealth Management Finance Other Total Nine Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 1,064 $ 462 $ 125 $ (326 ) $ 17 $ 1,342 Provision for credit losses 200 13 (3 ) — 3 213 Noninterest income 426 141 182 33 2 784 Noninterest expenses 643 579 229 (2 ) 20 1,469 Provision (benefit) for income taxes 214 3 29 (112 ) (3 ) 131 Net income (loss) $ 433 $ 8 $ 52 $ (179 ) $ (1 ) $ 313 Net credit-related charge-offs $ 113 $ 6 $ 2 $ — $ — $ 121 Selected average balances: Assets $ 39,589 $ 6,548 $ 5,220 $ 13,955 $ 5,630 $ 70,942 Loans 38,126 5,872 5,025 — — 49,023 Deposits 29,195 23,438 4,137 81 251 57,102 Statistical data: Return on average assets (b) 1.46 % 0.05 % 1.33 % N/M N/M 0.59 % Efficiency ratio (c) 43.11 95.30 74.64 N/M N/M 68.88 (a) Includes tax benefit of $31 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). 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 September 30, 2017 Earnings summary: Net interest income (expense) $ 172 $ 184 $ 123 $ 87 $ (20 ) $ 546 Provision for credit losses 8 24 (22 ) 15 (1 ) 24 Noninterest income 79 41 33 107 15 275 Noninterest expenses 144 103 92 114 10 463 Provision (benefit) for income taxes 34 37 31 17 (11 ) (a) 108 Net income (loss) $ 65 $ 61 $ 55 $ 48 $ (3 ) $ 226 Net credit-related charge-offs $ 2 $ 10 $ 9 $ 4 $ — $ 25 Selected average balances: Assets $ 13,367 $ 18,170 $ 10,435 $ 8,816 $ 20,463 $ 71,251 Loans 12,612 17,916 9,959 8,176 — 48,663 Deposits 21,641 17,316 9,400 7,730 406 56,493 Statistical data: Return on average assets (b) 1.14 % 1.32 % 2.05 % 2.15 % N/M 1.25 % Efficiency ratio (c) 57.15 45.59 58.74 58.79 N/M 56.24 (dollar amounts in millions) Michigan California Texas Other Finance Total Three Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 168 $ 179 $ 117 $ 89 $ (103 ) $ 450 Provision for credit losses 13 (4 ) (3 ) 5 5 16 Noninterest income 82 44 33 97 16 272 Noninterest expenses 161 110 102 112 8 493 Provision (benefit) for income taxes 26 43 18 18 (41 ) 64 Net income (loss) $ 50 $ 74 $ 33 $ 51 $ (59 ) $ 149 Net credit-related charge-offs $ 1 $ — $ 10 $ 5 $ — $ 16 Selected average balances: Assets $ 13,019 $ 18,088 $ 11,014 $ 9,324 $ 21,464 $ 72,909 Loans 12,332 17,793 10,566 8,515 — 49,206 Deposits 21,907 17,711 9,860 8,225 362 58,065 Statistical data: Return on average assets (b) 0.87 % 1.58 % 1.13 % 2.19 % N/M 0.82 % Efficiency ratio (c) 64.64 48.93 68.12 60.18 N/M 68.15 (a) Includes tax benefit of $2 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful (dollar amounts in millions) Michigan California Texas Other Finance Total Nine Months Ended September 30, 2017 Earnings summary: Net interest income (expense) $ 510 $ 531 $ 350 $ 248 $ (123 ) $ 1,516 Provision for credit losses 3 70 (45 ) 33 (4 ) 57 Noninterest income 242 128 98 312 42 822 Noninterest expenses 439 297 280 330 31 1,377 Provision (benefit) for income taxes 110 111 78 54 (80 ) (a) 273 Net income (loss) $ 200 $ 181 $ 135 $ 143 $ (28 ) $ 631 Net credit-related charge-offs (recoveries) $ (2 ) $ 28 $ 36 $ 14 $ — $ 76 Selected average balances: Assets $ 13,331 $ 18,201 $ 10,490 $ 8,517 $ 20,931 $ 71,470 Loans 12,637 17,930 10,028 7,836 — 48,431 Deposits 21,827 17,301 9,712 7,920 368 57,128 Statistical data: Return on average assets (b) 1.18 % 1.33 % 1.64 % 2.20 % N/M 1.18 % Efficiency ratio (c) 58.22 44.87 62.54 58.86 N/M 58.74 (dollar amounts in millions) Michigan California Texas Other Finance Total Nine Months Ended September 30, 2016 Earnings summary: Net interest income (expense) $ 503 $ 532 $ 355 $ 261 $ (309 ) $ 1,342 Provision for credit losses 10 8 199 (7 ) 3 213 Noninterest income 239 121 96 293 35 784 Noninterest expenses 470 334 316 331 18 1,469 Provision (benefit) for income taxes 88 115 (21 ) 64 (115 ) 131 Net income (loss) $ 174 $ 196 $ (43 ) $ 166 $ (180 ) $ 313 Net credit-related charge-offs $ 6 $ 25 $ 88 $ 2 $ — $ 121 Selected average balances: Assets $ 13,135 $ 17,980 $ 11,198 $ 9,044 $ 19,585 $ 70,942 Loans 12,484 17,700 10,722 8,117 — 49,023 Deposits 21,699 17,121 10,096 7,854 332 57,102 Statistical data: Return on average assets (b) 1.03 % 1.44 % (0.49 )% 2.46 % N/M 0.59 % Efficiency ratio (c) 63.09 51.02 70.00 59.70 N/M 68.88 (a) Includes tax benefit of $31 million from employee stock transactions. (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 (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses). N/M – not meaningful

Basis of Presentation and Acc34

Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net excess tax benefits for awards that vested, were exercised or expired included in the provision for income taxes	$ 108	$ 64	$ 273	$ 131
Network costs to be presented net of card fee revenue	85	76	242	224
Gain (loss) on interest rate fair value hedge ineffectiveness	0	$ (1)	0	4
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net excess tax benefits for awards that vested, were exercised or expired included in the provision for income taxes	2		31
Net excess tax benefit and cash paid to tax authority reclassified to operating activities from financing activities				$ 5
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Network costs to be presented net of card fee revenue					$ 97
Accounting Standards Update 2014-09 | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Treasury management fee receivable						$ 15
Accounting Standards Update 2014-09 | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Treasury management fee receivable						$ 18
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Auction-rate securities reclassified as available for sale equity securities	45		45
Accounting Standards Update 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Proceeds from settlement of BOLI policies			8		16
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net benefit cost to be reclassified			36		28
Accounting Standards Update 2017-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain (loss) on interest rate fair value hedge ineffectiveness	$ 0		$ 0		$ 2

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Recurring
Transfers into or out of Level 1 or Level 2 or Level 3	$ 0	$ 0	$ 0	$ 0
Total liabilities at fair value	238		238		$ 341
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		Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[1]	$ 10,998	$ 10,787
Derivative assets		188	407
Derivative liabilities	[2]	94	125
Equity and other non-debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		86	129
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		2,770	2,779
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	[3]	8,137	7,872
State and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale		5	7
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			88
Investment securities available-for-sale		10,998	10,787
Derivative assets		190	410
Total assets at fair value		11,277	11,285
Derivative liabilities		149	254
Deferred compensation plan liabilities		89	87
Total liabilities at fair value		238	341
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			88
Investment securities available-for-sale		2,811	2,861
Derivative assets		0	0
Total assets at fair value		2,900	2,949
Derivative liabilities		0	0
Deferred compensation plan liabilities		89	87
Total liabilities at fair value		89	87
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			0
Investment securities available-for-sale		8,137	7,872
Derivative assets		174	396
Total assets at fair value		8,311	8,268
Derivative liabilities		149	254
Deferred compensation plan liabilities		0	0
Total liabilities at fair value		149	254
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			0
Investment securities available-for-sale		50	54
Derivative assets		16	14
Total assets at fair value		66	68
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		79	223
Derivative liabilities		45	81
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		65	212
Derivative liabilities		45	81
Recurring | Interest rate contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		14	11
Derivative liabilities			0
Recurring | Energy derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		63	146
Derivative liabilities		60	144
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		63	146
Derivative liabilities		60	144
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		46	38
Derivative liabilities		44	29
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		46	38
Derivative liabilities		44	29
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	3
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	3
Recurring | Deferred compensation plan assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		89	87
Recurring | Deferred compensation plan assets | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		89	87
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]
Trading securities			1
Investment securities available-for-sale		86	129
Recurring | Equity and other non-debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			1
Investment securities available-for-sale		41	82
Recurring | Equity and other non-debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities			0
Investment securities available-for-sale		0	0
Recurring | Equity and other non-debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading 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		2,770	2,779
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		2,770	2,779
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	[4]	8,137	7,872
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]	8,137	7,872
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	7
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	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	$ 0
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.
[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 $6 million and $5 million at September 30, 2017 and December 31, 2016, 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.

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				9 Months Ended
		Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Interest rate contracts
Balance at beginning of period		$ 13		$ 27		$ 11		$ 9
Realized gains (losses) recorded in earnings		0		0		0		0
Unrealized gains (losses) recorded in earnings		1	[1]	0		3	[1]	18	[1]
Gains (losses) recorded in other comprehensive income				0		0		0
Redemptions		0		0		0		0
Sales		0		0		0		0
Balance at end of period		14		27		14		27
Warrants
Balance at beginning of period		2		2		3		2
Realized gains (losses) recorded in earnings		0		3	[1]	5	[1]	4	[1]
Unrealized gains (losses) recorded in earnings		0		0		(1)	[1]	0
Gains (losses) recorded in other comprehensive income		0		0		0		0
Redemptions		0		0		0		0
Sales		0		(3)		(5)		(4)
Balance at end of period		2		2		2		2
Investment Securities Available-For-Sale
Balance at beginning of period		51		57		54		77
Realized gains (losses) recorded in earnings		0		0		0		0
Unrealized gains (losses) recorded in earnings		0		0		0		0
Gains (losses) recorded in other comprehensive income		(1)		1		(1)		(3)
Redemptions		0		(4)		(3)		(20)
Sales		0		0		0		0
Balance at end of period		50		54		50		54
State and municipal securities | Investment Securities Available-For-Sale
Balance at beginning of period	[2]	5		8		7		9
Realized gains (losses) recorded in earnings	[2]	0		0		0		0
Unrealized gains (losses) recorded in earnings	[2]	0		0		0		0
Gains (losses) recorded in other comprehensive income	[2]	0		0		0		0
Redemptions	[2]	0		0		(2)		(1)
Sales	[2]	0		0		0		0
Balance at end of period	[2]	5		8		5		8
Corporate debt securities | Investment Securities Available-For-Sale
Balance at beginning of period	[2]			1				1
Realized gains (losses) recorded in earnings	[2]			0				0
Unrealized gains (losses) recorded in earnings	[2]			0				0
Gains (losses) recorded in other comprehensive income	[2]			0				0
Redemptions	[2]			(1)				(1)
Sales	[2]			0				0
Balance at end of period	[2]			0				0
Equity and other non-debt securities | Investment Securities Available-For-Sale
Balance at beginning of period	[2]	46		48		47		67
Realized gains (losses) recorded in earnings	[2]	0		0		0		0
Unrealized gains (losses) recorded in earnings	[2]			0		0		0
Gains (losses) recorded in other comprehensive income	[2]	(1)		1		(1)		(3)
Redemptions	[2]	0		(3)		(1)		(18)
Sales	[2]	0		0		0		0
Balance at end of period	[2]	$ 45		$ 46		$ 45		$ 46
[1]	Realized and unrealized gains and losses due to changes in fair value recorded in "other noninterest income" on the consolidated statements of comprehensive income.
[2]	Auction-rate securities.

Fair Value Measurements (Asse38

Fair Value Measurements (Assets And Liabilities Recorded At Fair Value On A Nonrecurring Basis) (Details) - Nonrecurring - Level 3 - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans		$ 282
Other real estate		1
Total assets at fair value	$ 142	283
Commercial borrower | Domestic loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	131	256
Commercial borrower | International loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	2	11
Commercial borrower | Commercial Mortgage Loans | Domestic loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 9	$ 15

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Information About Level 3 Measurements) (Details) - USD ($) $ in Millions		9 Months Ended		12 Months Ended
		Sep. 30, 2017		Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Investment securities available-for-sale	[1]	$ 10,998		$ 10,787
Recurring
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Investment securities available-for-sale		10,998		10,787
Recurring | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Investment securities available-for-sale		50		54
Recurring | State and municipal securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Investment securities available-for-sale	[2]	$ 5		$ 7
Recurring | State and municipal securities | Minimum | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	[3]	5.00%		4.00%
Unobservable input, workout period	[3]	1 year		1 year
Recurring | State and municipal securities | Maximum | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	[3]	7.00%		6.00%
Unobservable input, workout period	[3]	3 years		2 years
Recurring | Equity and other non-debt securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Investment securities available-for-sale	[2]	$ 45	[3]	$ 47
Recurring | Equity and other non-debt securities | Minimum | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	[3]	7.00%		7.00%
Unobservable input, workout period	[3]	1 year		1 year
Recurring | Equity and other non-debt securities | Maximum | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable input, discount rate	[3]	10.00%		9.00%
Unobservable input, workout period	[3]	2 years		2 years
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.
[2]	Auction-rate securities.
[3]	Auction-rate securities.

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		Sep. 30, 2017	Dec. 31, 2016
Cash and due from banks		$ 1,351	$ 1,249
Interest-bearing deposits with banks		4,853	5,969
Investment securities held-to-maturity		1,344	1,582
Total loans, net of allowance for loan losses		48,497	48,358
Demand deposits (noninterest-bearing)		32,391	31,540
Customer certificates of deposit		2,342	2,806
Total deposits		57,819	58,985
Short-term borrowings		509	25
Medium- and long-term debt		4,637	5,160
Carrying Amount
Cash and due from banks		1,351	1,249
Interest-bearing deposits with banks		4,853	5,969
Investment securities held-to-maturity		1,344	1,582
Loans held-for-sale		3	4
Total loans, net of allowance for loan losses	[1]	48,497	48,358
Customers' liability on acceptances outstanding		2	5
Restricted equity investments		228	207
Nonmarketable equity securities	[2]	6	11
Demand deposits (noninterest-bearing)		32,391	31,540
Interest-bearing deposits		23,086	24,639
Customer certificates of deposit		2,342	2,806
Total deposits		57,819	58,985
Short-term borrowings		509	25
Acceptances outstanding		2	5
Medium- and long-term debt		4,637	5,160
Credit-related financial instruments		(70)	(73)
Estimated Fair Value
Cash and due from banks		1,351	1,249
Interest-bearing deposits with banks		4,853	5,969
Investment securities held-to-maturity		1,339	1,576
Loans held-for-sale		3	4
Total loans, net of allowance for loan losses	[1]	48,296	48,250
Customers' liability on acceptances outstanding		2	5
Restricted equity investments		228	207
Nonmarketable equity securities	[2]	9	16
Demand deposits (noninterest-bearing)		32,391	31,540
Interest-bearing deposits		23,086	24,639
Customer certificates of deposit		2,309	2,731
Total deposits		57,786	58,910
Short-term borrowings		509	25
Acceptances outstanding		2	5
Medium- and long-term debt		4,642	5,132
Credit-related financial instruments		(70)	(73)
Level 1 | Estimated Fair Value
Cash and due from banks		1,351	1,249
Interest-bearing deposits with banks		4,853	5,969
Investment securities held-to-maturity		0	0
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	0	0
Customers' liability on acceptances outstanding		2	5
Restricted equity investments		228	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		509	25
Acceptances outstanding		2	5
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		1,339	1,576
Loans held-for-sale		3	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)		32,391	31,540
Interest-bearing deposits		23,086	24,639
Customer certificates of deposit		2,309	2,731
Total deposits		57,786	58,910
Short-term borrowings		0	0
Acceptances outstanding		0	0
Medium- and long-term debt		4,642	5,132
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	0
Loans held-for-sale		0	0
Total loans, net of allowance for loan losses	[1]	48,296	48,250
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		(70)	(73)
Nonrecurring
Total loans, net of allowance for loan losses		$ 142	$ 282
[1]	Included $142 million and $282 million of impaired loans recorded at fair value on a nonrecurring basis at September 30, 2017 and December 31, 2016, 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		9 Months Ended
		Sep. 30, 2017USD ($)Security	Dec. 31, 2016USD ($)
Securities with no credit impairment in unrealized loss position | Security		240
Investment securities available-for-sale, Amortized Cost	[1]	$ 11,022	$ 10,829
Investment securities available-for-sale, Fair Value	[1]	10,998	10,787
Investment securities held-to-maturity, Amortized Cost		1,344	1,582
Investment securities held-to-maturity, Fair Value		1,339
Carrying value of securities pledged		950
Liabilities secured by pledged collateral		$ 700
U.S. Treasury and other U.S. government agency securities
Securities with no credit impairment in unrealized loss position		6
Investment securities available-for-sale, Amortized Cost		$ 2,763	2,772
Investment securities available-for-sale, Fair Value		$ 2,770	2,779
Residential mortgage-backed securities
Securities with no credit impairment in unrealized loss position | Security		193
Investment securities available-for-sale, Amortized Cost	[2]	$ 8,168	7,921
Investment securities available-for-sale, Fair Value	[2]	8,137	7,872
Investment securities held-to-maturity, Amortized Cost	[2],[3]	1,344	1,582
Investment securities held-to-maturity, Fair Value	[2],[3]	$ 1,339	1,576
Auction Rate Preferred Securities
Securities with no credit impairment in unrealized loss position		28
Auction-Rate State And Municipal Securities
Securities with no credit impairment in unrealized loss position		13
Auction-rate securities
ARS portfolio redeemed or sold since acquisition		96.00%
ARS portfolio redeemed or sold since acquisition at or above cost		90.00%
Investment securities available-for-sale, Amortized Cost		$ 52	55
Investment securities available-for-sale, Fair Value		50	$ 54
Prepayment options | Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost		8,200
Investment securities available-for-sale, Fair Value		8,100
Investment securities held-to-maturity, Amortized Cost		1,300
Investment securities held-to-maturity, Fair Value		$ 1,300
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.
[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 September 30, 2017 and $12 million at December 31, 2016 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss.

Investment Securities (Summary

Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Investment securities available-for-sale, Amortized Cost	[1]	$ 11,022	$ 10,829
Investment securities available-for-sale securities, Gross Unrealized Gains	[1]	54	57
Investment securities available-for-sale securities, Gross Unrealized Losses	[1]	78	99
Investment securities available-for-sale, Fair Value	[1]	10,998	10,787
Investment securities held-to-maturity, Amortized Cost		1,344	1,582
Investment securities held-to-maturity, Fair Value		1,339
Net unrealized losses on available-for-sale securities transferred to held-to-maturity		(9)	12
U.S. Treasury and other U.S. government agency securities
Investment securities available-for-sale, Amortized Cost		2,763	2,772
Investment securities available-for-sale securities, Gross Unrealized Gains		8	8
Investment securities available-for-sale securities, Gross Unrealized Losses		1	1
Investment securities available-for-sale, Fair Value		2,770	2,779
Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	[2]	8,168	7,921
Investment securities available-for-sale securities, Gross Unrealized Gains	[2]	44	48
Investment securities available-for-sale securities, Gross Unrealized Losses	[2]	75	97
Investment securities available-for-sale, Fair Value	[2]	8,137	7,872
Investment securities held-to-maturity, Amortized Cost	[2],[3]	1,344	1,582
Investment securities held-to-maturity, Gross Unrealized Gains	[2],[3]	1	1
Investment securities held-to-maturity, Gross Unrealized Losses	[2],[3]	6	7
Investment securities held-to-maturity, Fair Value	[2],[3]	1,339	1,576
State and municipal securities
Investment securities available-for-sale, Amortized Cost		5	7
Investment securities available-for-sale securities, Gross Unrealized Gains		0	0
Investment securities available-for-sale securities, Gross Unrealized Losses		0	0
Investment securities available-for-sale, Fair Value		5	7
Equity and other non-debt securities
Investment securities available-for-sale, Amortized Cost		86	129
Investment securities available-for-sale securities, Gross Unrealized Gains		2	1
Investment securities available-for-sale securities, Gross Unrealized Losses		2	1
Investment securities available-for-sale, Fair Value		86	129
Auction-rate securities
Investment securities available-for-sale, Amortized Cost		52	55
Investment securities available-for-sale, Fair Value		$ 50	$ 54
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.
[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 September 30, 2017 and $12 million at December 31, 2016 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss.

Investment Securities (Summar43

Investment Securities (Summary Of Investment Securities Available-For-Sale In Unrealized Loss Positions) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Temporarily Impaired Less than 12 months, Fair Value		$ 4,597	$ 5,555
Temporarily Impaired Less than 12 Months, Unrealized Losses		56	88
Temporarily Impaired 12 months or more, Fair Value		1,496	1,195
Temporarily Impaired 12 Months or more, Unrealized Losses		38	32
Temporarily Impaired Total, Fair Value		6,093	6,750
Temporarily Impaired Total, Unrealized Losses		94	120
U.S. Treasury and other U.S. government agency securities
Temporarily Impaired Less than 12 months, Fair Value		486	527
Temporarily Impaired Less than 12 Months, Unrealized Losses		1	1
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		486	527
Temporarily Impaired Total, Unrealized Losses		1	1
Residential mortgage-backed securities
Temporarily Impaired Less than 12 months, Fair Value	[1]	4,111	4,992
Temporarily Impaired Less than 12 Months, Unrealized Losses	[1]	55	87
Temporarily Impaired 12 months or more, Fair Value	[1]	1,446	1,177
Temporarily Impaired 12 Months or more, Unrealized Losses	[1]	36	32
Temporarily Impaired Total, Fair Value	[1]	5,557	6,169
Temporarily Impaired Total, Unrealized Losses	[1]	91	119
State and municipal securities
Temporarily Impaired Less than 12 months, Fair Value	[2]	0	0
Temporarily Impaired Less than 12 Months, Unrealized Losses	[2]	0	0
Temporarily Impaired 12 months or more, Fair Value	[2]	5	7
Temporarily Impaired 12 Months or more, Unrealized Losses	[2],[3]	0	0
Temporarily Impaired Total, Fair Value	[2]	5	7
Temporarily Impaired Total, Unrealized Losses	[2],[3]	0	0
Equity and other non-debt securities
Temporarily Impaired Less than 12 months, Fair Value	[2]	0	36
Temporarily Impaired Less than 12 Months, Unrealized Losses	[2]	0	0	[3]
Temporarily Impaired 12 months or more, Fair Value	[2]	45	11
Temporarily Impaired 12 Months or more, Unrealized Losses	[2]	2	0	[3]
Temporarily Impaired Total, Fair Value	[2]	45	47
Temporarily Impaired Total, Unrealized Losses	[2]	$ 2	$ 0	[3]
[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 Investmen

Investment Securities Investment Securities (Gains and Losses on Available-For-Sale Securities) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Securities gains		$ 0	$ 0	$ 1	$ 0
Securities losses	[1]	(1)	0	(4)	(3)
Net securities losses		$ (1)	$ 0	$ (3)	$ (3)
[1]	Primarily charges related to a derivative contract tied to the conversion rate of Visa Class B shares.

Investment Securities (Contract

Investment Securities (Contractual Maturity Distribution Of Debt Securities) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Available-for-sale, Within one year, Amortized Cost		$ 20
Available-for-sale, After one year through five years, Amortized Cost		2,947
Available-for-sale, After five years through ten years, Amortized Cost		1,744
Available-for-sale, After ten years, Amortized Cost		6,225
Available-for-sale, Subtotal, Amortized Cost		10,936
Available-for-sale, Within one year, Fair Value		20
Available-for-sale, After one year through five years, Fair Value		2,953
Available-for-sale, After five years through ten years, Fair Value		1,770
Available-for-sale, After ten years, Fair Value		6,169
Available-for-sale, Subtotal, Fair Value		10,912
Investment securities available-for-sale, Amortized Cost	[1]	11,022	$ 10,829
Investment securities available-for-sale, Fair Value	[1]	10,998	10,787
Held-to-maturity, Within one year, Amortized Cost		0
Held-to-maturity, After one year through five years, Amortized Cost		0
Held-to-maturity, After five years through ten years, Amortized Cost		19
Held-to-maturities, After ten years, Amortized Cost		1,325
Held-to-maturity Securities		1,344	1,582
Held-to-maturity, Within one year, Fair Value		0
Held-to-maturity Securities, After one year through five years, Fair Value		0
Held-to-maturity Securities, After five years through ten years, Fair Value		19
Held-to-maturity Securities, After ten years, Fair Value		1,320
Held-to-maturity Securities, Fair Value		1,339
Equity and other non-debt securities
Investment securities available-for-sale, Amortized Cost		86	129
Investment securities available-for-sale, Fair Value		$ 86	$ 129
[1]	Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.

Credit Quality And Allowance 46

Credit Quality And Allowance For Credit Losses (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Retail loans secured by residential real estate in process of foreclosure	$ 0		$ 0		$ 0
Commitments to lend additional funds to TDR borrowers	25		$ 25		$ 24
Interest Rate Reductions
Days past due defined as subsequent default			90 days	90 days
Balance	2	$ 4	$ 2	$ 4
Subsequent default during period	0	0	$ 0	$ 0
AB Note Restructures
Days past due defined as subsequent default			90 days	90 days
Balance	31	52	$ 31	$ 52
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		Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		$ 196	$ 148
Nonaccrual loans		444	582
Current loans		48,569	48,358
Total loans		49,209	49,088
30 to 59 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		132	106
60 to 89 days past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		52	23
90 days or more past due and still accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		12	19
Business loans | Commercial borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		165	130
Nonaccrual loans		394	511
Current loans		44,140	43,983
Total loans		44,699	44,624
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		112	94
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		41	17
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		12	19
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		90	56
Nonaccrual loans		345	445
Current loans		30,627	30,493
Total loans		31,062	30,994
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		52	30
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		31	12
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		7	14
Business loans | Commercial borrower | International loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		13	1
Nonaccrual loans		6	14
Current loans		1,140	1,243
Total loans		1,159	1,258
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		11	1
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		2	0
Business loans | Real estate construction | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		11	0
Nonaccrual loans		0	0
Current loans		3,007	2,869
Total loans		3,018	2,869
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		11	0
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]	0	0
Nonaccrual loans	[1]	0	0
Current loans	[1]	2,709	2,485
Total loans	[1],[2]	2,709	2,485
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]	0	0
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]	11	0
Nonaccrual loans	[3]	0	0
Current loans	[3]	298	384
Total loans	[3],[4]	309	384
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]	11	0
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		51	73
Nonaccrual loans		35	46
Current loans		8,899	8,812
Total loans		8,985	8,931
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		38	63
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		10	5
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		3	5
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]	20	5
Nonaccrual loans	[1]	9	9
Current loans	[1]	1,702	2,004
Total loans	[1],[2]	1,731	2,018
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]	20	5
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]	0	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]	31	68
Nonaccrual loans	[3]	26	37
Current loans	[3]	7,197	6,808
Total loans	[3],[4]	7,254	6,913
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]	18	58
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]	10	5
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]	3	5
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		8	6
Current loans		467	566
Total loans		475	572
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		31	18
Nonaccrual loans		50	71
Current loans		4,429	4,375
Total loans		4,510	4,464
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		20	12
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		11	6
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	0
Retail loans | Consumer borrower
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		8	8
Nonaccrual loans		22	32
Current loans		2,481	2,482
Total loans		2,511	2,522
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	5
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		2	3
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	0
Retail loans | Real estate mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due and still accruing		23	10
Nonaccrual loans		28	39
Current loans		1,948	1,893
Total loans		1,999	1,942
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		14	7
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		9	3
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		6	7
Nonaccrual loans		22	28
Current loans		1,762	1,765
Total loans		1,790	1,800
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		5	4
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	3
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	1
Nonaccrual loans		0	4
Current loans		719	717
Total loans		721	722
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		1	1
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		1	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	$ 0
[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		Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans		$ 49,209	$ 49,088
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	46,775	46,232
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	891	1,109
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	1,099	1,165
Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	444	582
Business loans | Commercial borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		44,699	44,624
Business loans | Commercial borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	42,334	41,847
Business loans | Commercial borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	880	1,105
Business loans | Commercial borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	1,091	1,161
Business loans | Commercial borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	394	511
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		31,062	30,994
Business loans | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	29,187	28,616
Business loans | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	617	944
Business loans | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	913	989
Business loans | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	345	445
Business loans | Commercial borrower | International loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		1,159	1,258
Business loans | Commercial borrower | International loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	1,082	1,200
Business loans | Commercial borrower | International loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	53	22
Business loans | Commercial borrower | International loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	18	22
Business loans | Commercial borrower | International loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	6	14
Business loans | Real estate construction | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		3,018	2,869
Business loans | Real estate construction | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	2,963	2,866
Business loans | Real estate construction | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	55	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	0	3
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]	2,709	2,485
Business loans | Real estate construction | Commercial borrower | Domestic loans | Commercial Real Estate business line | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[6]	2,658	2,485
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],[6]	51	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],[6]	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],[6]	0	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	[7],[8]	309	384
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[8]	305	381
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[8]	4	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[8]	0	3
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[8]	0	0
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		8,985	8,931
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	8,660	8,615
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	131	128
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	159	142
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	35	46
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Recorded Investment [Line Items]
Total loans	[5],[6]	1,731	2,018
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[6]	1,660	1,970
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],[6]	20	19
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[6]	42	20
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[6]	9	9
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	[7],[8]	7,254	6,913
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1],[8]	7,000	6,645
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2],[8]	111	109
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3],[8]	117	122
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4],[8]	26	37
Business loans | Lease financing | Commercial borrower | Domestic loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		475	572
Business loans | Lease financing | Commercial borrower | Domestic loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	442	550
Business loans | Lease financing | Commercial borrower | Domestic loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	24	11
Business loans | Lease financing | Commercial borrower | Domestic loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	1	5
Business loans | Lease financing | Commercial borrower | Domestic loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	8	6
Retail loans
Financing Receivable, Recorded Investment [Line Items]
Total loans		4,510	4,464
Retail loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	4,441	4,385
Retail loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	11	4
Retail loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	8	4
Retail loans | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	50	71
Retail loans | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		2,511	2,522
Retail loans | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	2,479	2,485
Retail loans | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	2	1
Retail loans | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	8	4
Retail loans | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	22	32
Retail loans | Real estate mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans		1,999	1,942
Retail loans | Real estate mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	1,962	1,900
Retail loans | Real estate mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	9	3
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]	28	39
Retail loans | Home equity | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		1,790	1,800
Retail loans | Home equity | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	1,759	1,767
Retail loans | Home equity | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	1	1
Retail loans | Home equity | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	8	4
Retail loans | Home equity | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	22	28
Retail loans | Other consumer | Consumer borrower
Financing Receivable, Recorded Investment [Line Items]
Total loans		721	722
Retail loans | Other consumer | Consumer borrower | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	[1]	720	718
Retail loans | Other consumer | Consumer borrower | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	[2]	1	0
Retail loans | Other consumer | Consumer borrower | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	[3]	0	0
Retail loans | Other consumer | Consumer borrower | Nonaccrual
Financing Receivable, Recorded Investment [Line Items]
Total loans	[4]	$ 0	$ 4
[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.
[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 page F-56 in the Corporation's 2016 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		Sep. 30, 2017	Dec. 31, 2016
Nonaccrual loans		$ 444	$ 582
Reduced-rate loans	[1]	8	8
Total nonperforming loans		452	590
Foreclosed property	[2]	6	17
Total nonperforming assets		458	607
Residential Real Estate
Foreclosed property		5	3
Business loans
Reduced-rate loans		0	0
Retail loans
Nonaccrual loans		50	71
Reduced-rate loans		$ 8	$ 8
[1]	There were no reduced-rate business loans at both September 30, 2017 and December 31, 2016. Reduced-rate retail loans were $8 million at both September 30, 2017 and December 31, 2016.
[2]	Included $5 million and $3 million of foreclosed residential real estate properties at September 30, 2017 and December 31, 2016, 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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for loan losses	$ 24	$ 16	$ 57	$ 213
Total loans					$ 49,209	$ 49,088
Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	705	729	730	634
Loan charge-offs	(37)	(35)	(120)	(166)
Recoveries on loans previously charged-off	12	19	44	56
Net loan charge-offs (recoveries)	(25)	(16)	(76)	(110)
Provision for loan losses	31	14	57	202
Foreign currency translation adjustment	1	0	1	1
Balance at end of period	712	727	712	727
As a percentage of total loans					1.45%		1.48%
Allowance for loan losses individually evaluated for impairment					$ 90		$ 116
Allowance for loan losses collectively evaluated for impairment					622		611
Total allowance for loan losses	705	729	730	634	712	730	727
Loans individually evaluated for impairment					538		706
Loans collectively evaluated for impairment					48,671		48,568
Total loans					$ 49,209		$ 49,274
Business loans | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	661	682	682	579
Loan charge-offs	(36)	(34)	(115)	(161)
Recoveries on loans previously charged-off	10	18	39	53
Net loan charge-offs (recoveries)	(26)	(16)	(76)	(108)
Provision for loan losses	21	12	50	206
Foreign currency translation adjustment	1	0	1	1
Balance at end of period	657	678	657	678
As a percentage of total loans					1.47%		1.51%
Allowance for loan losses individually evaluated for impairment					$ 90		$ 115
Allowance for loan losses collectively evaluated for impairment					567		563
Total allowance for loan losses	661	682	682	579	657	682	678
Loans individually evaluated for impairment					501		677
Loans collectively evaluated for impairment					44,198		44,182
Total loans					44,699		$ 44,859
Retail loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans					$ 4,510	4,464
Retail loans | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	44	47	48	55
Loan charge-offs	(1)	(1)	(5)	(5)
Recoveries on loans previously charged-off	2	1	5	3
Net loan charge-offs (recoveries)	1	0	0	(2)
Provision for loan losses	10	2	7	(4)
Foreign currency translation adjustment	0	0	0	0
Balance at end of period	55	49	55	49
As a percentage of total loans					1.23%		1.10%
Allowance for loan losses individually evaluated for impairment					$ 0		$ 1
Allowance for loan losses collectively evaluated for impairment					55		48
Total allowance for loan losses	$ 44	$ 47	$ 48	$ 55	55	$ 48	49
Loans individually evaluated for impairment					37		29
Loans collectively evaluated for impairment					4,473		4,386
Total loans					$ 4,510		$ 4,415

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		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses		$ 24	$ 16	$ 57	$ 213
Lending-related commitments
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period		48	43	41	45
Charge-offs on lending related commitments	[1]	0	0	0	(11)
Provision for credit losses		(7)	2	0	11
Balance at end of period		$ 41	$ 45	$ 41	$ 45
[1]	Charge-offs result from the sale of unfunded lending-related commitments.

Credit Quality And Allowance 52

Credit Quality And Allowance For Credit Losses (Individually Evaluated Impaired Loans) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		$ 187	$ 131
Recorded investment in impaired loans with related allowance		351	483
Recorded investment total impaired loans		538	614
Unpaid principal balance		693	738
Related allowance for loan losses		90	89
Business loans | Commercial borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		150	95
Recorded investment in impaired loans with related allowance		351	471
Recorded investment total impaired loans		501	566
Unpaid principal balance		648	683
Related allowance for loan losses		90	86
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		111	90
Recorded investment in impaired loans with related allowance		311	423
Recorded investment total impaired loans		422	513
Unpaid principal balance		543	608
Related allowance for loan losses		85	80
Business loans | Commercial borrower | International loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		0	3
Recorded investment in impaired loans with related allowance		6	11
Recorded investment total impaired loans		6	14
Unpaid principal balance		17	20
Related allowance for loan losses		1	2
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		39	2
Recorded investment in impaired loans with related allowance		34	37
Recorded investment total impaired loans		73	39
Unpaid principal balance		88	55
Related allowance for loan losses		4	4
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]	36	0
Recorded investment in impaired loans with related allowance	[1]	7	7
Recorded investment total impaired loans	[1]	43	7
Unpaid principal balance	[1]	52	15
Related allowance for loan losses	[1]	1	1
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]	3	2
Recorded investment in impaired loans with related allowance	[2]	27	30
Recorded investment total impaired loans	[2]	30	32
Unpaid principal balance	[2]	36	40
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]	37	36
Recorded investment in impaired loans with related allowance	[3]	0	12
Recorded investment total impaired loans	[3]	37	48
Unpaid principal balance	[3]	45	55
Related allowance for loan losses	[3]	0	3
Retail loans | Consumer borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		15	17
Recorded investment in impaired loans with related allowance		0	3
Recorded investment total impaired loans		15	20
Unpaid principal balance		17	25
Related allowance for loan losses		0	1
Retail loans | Real estate mortgage
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		22	19
Recorded investment in impaired loans with related allowance		0	9
Recorded investment total impaired loans		22	28
Unpaid principal balance		28	30
Related allowance for loan losses		0	2
Retail loans | Home equity | Consumer borrower
Financing Receivable, Impaired [Line Items]
Recorded investment in impaired loans with no related allowance		12	15
Recorded investment in impaired loans with related allowance		0	0
Recorded investment total impaired loans		12	15
Unpaid principal balance		12	19
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		3	2
Recorded investment in impaired loans with related allowance		0	3
Recorded investment total impaired loans		3	5
Unpaid principal balance		5	6
Related allowance for loan losses		$ 0	$ 1
[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		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		$ 544	$ 689	$ 570	$ 646
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		3	2	7	8
Business loans | Commercial borrower
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		505	662	528	618
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		3	2	7	8
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		442	606	470	559
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		2	2	6	8
Business loans | Commercial borrower | International loans
Financing Receivable, Impaired [Line Items]
Individually Evaluated Impaired Loans Average Balance for the Period		6	19	9	19
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		57	37	49	40
Individually Evaluated Impaired Loans Interest Income Recognized for the Period		1	0	1	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]	25	7	16	9
Individually Evaluated Impaired Loans Interest Income Recognized for the Period	[1]	1	0	1	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]	32	30	33	31
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		39	27	42	28
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		15	16	16	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		24	11	26	12
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		12	12	13	12
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		3	4	3	4
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		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		$ 61	$ 110	$ 170	$ 206
Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		60	110	167	204
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		22	110	126	199
Business loans | Commercial borrower | International loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		2	0	2	3
Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period				39	2
Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1]	36	0	36	0
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	[2]			3	2
Retail loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		1	0	3	2
Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3]	1	0	3	2
Principal Deferrals
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]	61	70	$ 137	$ 153
Minimum period loan terms were extended				90 days	90 days
Principal Deferrals | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]	60	70	$ 136	$ 152
Principal Deferrals | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]	22	70	95	150
Principal Deferrals | Business loans | Commercial borrower | International loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]	2	0	2	0
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]			39	2
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1],[4]	36	0	36	0
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	[2],[4]			3	2
Principal Deferrals | Retail loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[4]	1	0	1	1
Principal Deferrals | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3],[4]	1	0	1	1
Interest Rate Reductions
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		0	0	2	1
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 | Commercial borrower | International 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
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period				0	0
Interest Rate Reductions | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1]	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	[2]			0	0
Interest Rate Reductions | Retail loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period		0	0	2	1
Interest Rate Reductions | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[3]	0	0	2	1
AB Note Restructures
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]	0	40	31	52
AB Note Restructures | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]	0	40	31	52
AB Note Restructures | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]	0	40	31	49
AB Note Restructures | Business loans | Commercial borrower | International loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]	0	0	0	3
AB Note Restructures | Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]			0	0
AB Note Restructures | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[1],[5]	0	0	0	0
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	[2],[5]			0	0
AB Note Restructures | Retail loans
Financing Receivable, Modifications [Line Items]
Recorded balance of troubled debt restructuring modified during the period	[5]	0	0	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	[3],[5]	$ 0	$ 0	$ 0	$ 0
[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.
[4]	Primarily represents loan balances where terms were extended 90 days or more at or above contractual interest rates.
[5]	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		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Mortgage Loans in Process of Foreclosure, Amount		$ 0		$ 0		$ 0
Principal Deferrals
Financing Receivable, Modifications [Line Items]
Balance		174	$ 234	174	$ 234
Subsequent default during period		4	0	8	14
Principal Deferrals | Business loans | Commercial borrower
Financing Receivable, Modifications [Line Items]
Balance		173	233	173	233
Subsequent default during period		4	0	8	14
Principal Deferrals | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		127	229	127	229
Subsequent default during period		4	0	4	13
Principal Deferrals | Business loans | Commercial borrower | International loans
Financing Receivable, Modifications [Line Items]
Balance		2	0	2	0
Subsequent default during period		0	0	0	0
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans
Financing Receivable, Modifications [Line Items]
Balance		44	4	44	4
Subsequent default during period		0	0	4	1
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Commercial Real Estate business line
Financing Receivable, Modifications [Line Items]
Balance	[1]	37	0	37	0
Subsequent default during period	[1]	0	0	0	0
Principal Deferrals | Business loans | Real estate mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Modifications [Line Items]
Balance	[2]	7	4	7	4
Subsequent default during period	[2]	0	0	4	1
Principal Deferrals | Retail loans | Home equity | Consumer borrower
Financing Receivable, Modifications [Line Items]
Balance	[3]	1	1	1	1
Subsequent default during period	[3]	$ 0	$ 0	$ 0	$ 0
[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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of securities received as collateral for derivative assets	$ 26		$ 26
Cash received as collateral for derivative assets	20		20
Fair value of securities pledged as collateral for derivative liabilities	4		4
Cash posted as collateral for derivative liabilities	8		8
Aggregate fair value of all derivative instruments with credit-risk contingent features that were in a liability position	0		0
Net interest income generated by risk management fair value interest rate swaps	7	$ 15	27	$ 48
Net gain on interest rate fair value hedge ineffectiveness	0	1	0	(4)
Gain (loss) on foreign currency derivatives used as economic hedges	0	0	0
Net gain on open foreign currency positions	0	$ 0	0	$ 1
Allowance for credit losses on lending-related commitments					$ 41
Allowance for credit losses on lending-related commitments, amount related to unused commitments to extend credit	26		$ 26		29
Final year of expiration for outstanding letters of credit			2,023
Risk participation agreements covering standby and commercial letters of credit	208		$ 208		255
Standby and commercial letters of credit	3,400		3,400		3,700
Carrying value of standby and commercial letters of credit included in accrued expenses and other liabilities	44		44		44
Deferred fees on standby and commercial letters of credit included in accrued expenses and other liabilities	29		29		32
Allowance for credit losses on lending-related commitments, amount related to standby and commercial letters of credit	15		15		12
Notional amount of derivative credit risk participation agreements	544		544		458
Maximum estimated exposure to credit risk participation agreements assuming 100% default	$ 1		$ 1		$ 3
Weighted average remaining maturity of credit risk participation agreements, in years			2 years 4 months 6 days

Derivative And Credit-Related57

Derivative And Credit-Related Financial Instruments (Schedule Of Derivative Instruments) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	$ 20,466	$ 20,051
Fair Value of Gross Derivative Assets		188	407
Fair Value of Gross Derivative Liabilities		149	254
Derivative assets, Netting adjustment - Offsetting derivative liabilities		(49)	(84)
Derivative liabilities, Netting adjustment - Offsetting derivative assets		(49)	(84)
Derivative assets, Netting adjustment - Cash collateral received		(19)	(47)
Derivative liabilities, Netting adjustment, Cash collateral posted		(6)	(45)
Net derivative assets included in the consolidated balance sheets	[2]	120	276
Net derivative liabilities included in the consolidated balance sheets	[2]	94	125
Derivative asset, securities pledged as collateral		(4)	(19)
Derivative liability, securities pledged as collateral		(24)	(8)
Net derivative assets after deducting amounts not offset in the consolidated balance sheets		116	257
Net derivative liabilities after deducting amounts not offset in the consolidated balance sheets		70	117
Credit valuation adjustments for counterparty credit risk		6	5
Risk management purposes
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,438	2,992
Fair Value of Gross Derivative Assets		0	94
Fair Value of Gross Derivative Liabilities		2	6
Risk management purposes | Derivatives designated as hedging instruments | Fair Value Hedging | Interest rate swap
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1],[3]	1,775	2,275
Fair Value of Gross Derivative Assets	[3]	0	92
Fair Value of Gross Derivative Liabilities	[3]	0	4
Risk management purposes | Derivatives used as economic hedges | Foreign exchange spot, forwards and swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	663	717
Fair Value of Gross Derivative Assets		0	2
Fair Value of Gross Derivative Liabilities		2	2
Customer-initiated and other activities
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	18,028	17,059
Fair Value of Gross Derivative Assets		188	313
Fair Value of Gross Derivative Liabilities		147	248
Customer-initiated and other activities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	14,085	13,323
Fair Value of Gross Derivative Assets		79	131
Fair Value of Gross Derivative Liabilities		45	77
Customer-initiated and other activities | Interest rate caps and floors written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	590	436
Fair Value of Gross Derivative Assets		0	0
Fair Value of Gross Derivative Liabilities		0	1
Customer-initiated and other activities | Interest rate caps and floors purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	590	436
Fair Value of Gross Derivative Assets		0	1
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],[3]	12,905	12,451
Fair Value of Gross Derivative Assets	[3]	79	130
Fair Value of Gross Derivative Liabilities	[3]	45	76
Customer-initiated and other activities | Energy contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	1,796	2,227
Fair Value of Gross Derivative Assets		63	146
Fair Value of Gross Derivative Liabilities		60	144
Customer-initiated and other activities | Energy caps and floors written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	222	419
Fair Value of Gross Derivative Assets		0	1
Fair Value of Gross Derivative Liabilities		12	31
Customer-initiated and other activities | Energy caps and floors purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	222	419
Fair Value of Gross Derivative Assets		12	31
Fair Value of Gross Derivative Liabilities		0	1
Customer-initiated and other activities | Energy swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	1,352	1,389
Fair Value of Gross Derivative Assets		51	114
Fair Value of Gross Derivative Liabilities		48	112
Customer-initiated and other activities | Foreign exchange spot, options and swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,147	1,509
Fair Value of Gross Derivative Assets		46	36
Fair Value of Gross Derivative Liabilities		$ 42	$ 27
[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 $6 million and $5 million at September 30, 2017 and December 31, 2016, respectively.
[3]	Due to clearinghouse rule changes, beginning January 1, 2017, variation margin payments are treated as settlements of derivative exposure rather than as collateral. As a result, these payments are now considered in determining the fair value of centrally cleared derivatives, resulting in centrally cleared derivatives having a fair value of approximately zero.

Derivative And Credit-Related58

Derivative And Credit-Related Financial Instruments (Schedule Of Weighted Average Maturity And Interest Rates On Risk Management Interest Rate Swaps) (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Derivative assets credit valuation adjustments		$ 6	$ 5
Notional Amount	[1]	20,466	20,051
Risk management purposes
Notional Amount	[1]	2,438	2,992
Medium- and long-term debt | Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Notional Amount		$ 1,775	$ 2,275
Weighted Average Remaining Maturity		4 years 10 months 18 days	4 years 6 months 12 days
Weighted Average Receive Rate		3.26%	3.69%
Weighted Average Pay Rate	[2]	2.21%	1.80%
[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]	Variable rates paid on receive fixed swaps are based on six-month LIBOR rates in effect at September 30, 2017 and December 31, 2016.

Derivative And Credit-Related59

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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 17	$ 17	$ 53	$ 45
Interest rate contracts | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	5	6	18	14
Energy Related Derivative [Member] | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	1	0	2	1
Foreign exchange contracts | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 11	$ 11	$ 33	$ 30

Derivative And Credit-Related60

Derivative And Credit-Related Financial Instruments (Schedule Of Financial Instruments With Off-Balance Sheet Credit Risk) (Details) - Maximum - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	$ (26,407)	$ (26,991)
Commercial And Other | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	(23,542)	(24,333)
Bankcard, Revolving Check Credit And Home Equity Loan Commitments | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss, maximum	(2,865)	(2,658)
Standby Letters Of Credit
Loss contingency, estimate of possible loss, maximum	(3,372)	(3,623)
Commercial Letters Of Credit
Loss contingency, estimate of possible loss, maximum	$ (43)	$ (46)

Derivative And Credit-Related61

Derivative And Credit-Related Financial Instruments (Summary Of Internally Classified Watch List Letters Of Credit) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Total criticized standby and commercial letters of credit	$ 79	$ 135
As a percentage of total outstanding standby and commercial letters of credit	2.30%	3.70%

Variable Interest Entities (V62

Variable Interest Entities (VIEs) (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Variable Interest Entity
Unfunded commitments to fund tax credit entities	$ 170
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	421
Other Tax Credit Entities
Variable Interest Entity
Exposure to loss as a result of involvement with VIEs	$ 7

Variable Interest Entities (V63

Variable Interest Entities (VIEs) (Impact Of VIEs On The Consolidated Statements Of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Variable Interest Entity
Other noninterest income	$ 25	$ 29	$ 85	$ 75
Provision for income taxes	108	64	273	131
Variable Interest Entity
Variable Interest Entity
Other noninterest income	0	(1)	1	(1)
Provision for income taxes, amortization of LIHTC investments	17	17	49	49
Provision for income taxes	(5)	(6)	(16)	(17)
Low income housing tax credits | Variable Interest Entity
Variable Interest Entity
Provision for income taxes, affordable housing tax credits and other tax benefits	(16)	(16)	(47)	(47)
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	$ (6)	$ (7)	$ (18)	$ (19)

Medium- And Long-Term Debt (Nar

Medium- And Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 5	$ 7
Subsidiaries
Debt Instrument [Line Items]
Blanket lien on real estate-related loans securing FHLB advances	15,500
Potential FHLB borrowing capacity	$ 4,500
Floating-rate FHLB advances | Subsidiaries
Debt Instrument [Line Items]
Weighted-average interest rate	1.17%

Medium- And Long-Term Debt (Sch

Medium- And Long-Term Debt (Schedule Of Medium- And Long-Term Debt) (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total medium- and long-term debt		$ 4,637	$ 5,160
Parent Company
Debt Instrument [Line Items]
Total medium- and long-term debt		606	604
Subsidiaries
Debt Instrument [Line Items]
Subordinated notes		561	1,073
Total medium- and long-term debt		4,031	4,556
3.80% subordinated notes due 2026 | Parent Company
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 257	$ 256
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]	$ 349	$ 348
Stated interest rate		2.125%	2.125%
Maturity date		May 23, 2019	May 23, 2019
5.20% subordinated notes due 2017 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 0	$ 511
Stated interest rate		5.20%	5.20%
Maturity date		Aug. 22, 2017	Aug. 22, 2017
4.00% subordinated notes due 2025 | Subsidiaries
Debt Instrument [Line Items]
Subordinated notes	[1]	$ 350	$ 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]	$ 211	$ 215
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]	$ 670	$ 667
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]
Federal Home Loan Bank advances		$ 2,800	$ 2,800
Weighted-average interest rate		1.17%
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 2026 | Subsidiaries | Maximum
Debt Instrument [Line Items]
Maturity date		May 20, 2026
6.0% - 6.4% fixed-rate notes due 2020 | Subsidiaries
Debt Instrument [Line Items]
Other notes		$ 0	$ 16
Maturity date		Jun. 30, 2020	Jun. 30, 2020
6.0% - 6.4% fixed-rate notes due 2020 | Subsidiaries | Minimum
Debt Instrument [Line Items]
Stated interest rate		6.00%	6.00%
6.0% - 6.4% fixed-rate notes due 2020 | Subsidiaries | Maximum
Debt Instrument [Line Items]
Stated interest rate		6.40%	6.40%
[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 Comprehensi66

Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Investment securities, Balance at beginning of period, net of tax	$ (33)	$ 9
Investment securities, Net unrealized holding gains arising during the period	18	140
Investment securities, Less: Provision for income taxes	7	51
Investment securities, Net unrealized holding gains arising during the period, net of tax	11	89
Investment securities, Net losses realized as a yield adjustment in interest on investment securities	(3)	(2)
Investment securities, Less: Benefit for income taxes	(1)	(1)
Investment securities, Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax	(2)	(1)
Investment securities, Change in net unrealized gains on investment securities, net of tax	13	90
Investment securities, Balance at end of period, net of tax	(20)	99
Benefit plans, Balance at beginning of period, net of tax	(350)	(438)
Benefit plans, Actuarial loss arising during the period	0	(191)
Benefit plans, Prior service credit arising during the period	0	(235)
Benefit plans, Net defined benefit pension and other postretirement adjustment arising during the period	0	44
Benefit plans, Less: Provision for income taxes	0	16
Benefit plans, Net defined benefit pension and other postretirement plans adjustment arising during the period, net of tax	0	28
Benefit plans, Amortization of actuarial net loss	38	29
Benefit plans, Amortization of prior service credit	(20)	0
Benefit plans, Amounts recognized in salaries and benefits expense	18	29
Benefit plans, Less: Provision for income taxes	7	10
Benefit plans, Adjustment for amounts recognized as components of net periodic benefit cost during the period, net of tax	11	19
Benefit plans, Change in defined benefit pension and other postretirement plans adjustment, net of tax	11	47
Benefit plans, Balance at end of period, net of tax	(339)	(391)
Total accumulated other comprehensive loss at end of period, net of tax	$ (359)	$ (292)	$ (383)

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		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 226	$ 149	$ 631	$ 313
Income allocated to participating securities	2	1	5	3
Net income attributable to common shares	$ 224	$ 148	$ 626	$ 310
Basic average common shares	174	171	175	173
Basic net income per common share	$ 1.29	$ 0.87	$ 3.58	$ 1.80
Basic average common shares	174	171	175	173
Net effect of the assumed exercise of stock options	2	2	3	1
Net effect of the assumed exercise of warrants	1	3	1	2
Diluted average common shares	177	176	179	176
Diluted net income per common share	$ 1.26	$ 0.84	$ 3.50	$ 1.76

Net Income Per Common Share (Sc

Net Income Per Common Share (Schedule of Average Shares Excluded From Diluted Net Income Per Common Share Computation) (Details) - Stock Options - $ / shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Average outstanding options	0	2.6	0	4
Minimum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Range of exercise prices		$ 46.68		$ 37.26
Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Range of exercise prices		$ 59.86		$ 59.86

Employee Benefit Plans Employee

Employee Benefit Plans Employee Benefit Plans (Net Periodic Defined Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Net periodic defined benefit cost			$ (14)	$ 11
Qualified Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 7	$ 8	21	24
Interest cost	19	23	58	69
Expected return on plan assets	(39)	(39)	(118)	(120)
Amortization of prior service (credit) cost	(5)	1	(14)	3
Amortization of net loss	11	7	32	23
Net periodic defined benefit cost	(7)	0	(21)	(1)
Non-Qualified Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	2
Interest cost	2	3	6	8
Amortization of prior service (credit) cost	(2)	(1)	(6)	(3)
Amortization of net loss	2	2	6	5
Net periodic defined benefit cost	2	4	7	12
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	0	2	2
Expected return on plan assets	(1)	(1)	(2)	(3)
Amortization of net loss	0	1	0	1
Net periodic defined benefit cost	$ 0	$ 0	$ 0	$ 0

Income Taxes And Tax-Related 70

Income Taxes And Tax-Related Items Income Taxes And Tax-Related Items (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Unrecognized tax benefits	$ 11	$ 15
Unrecognized tax benefits decrease resulting from settlements with taxing authorities	4
Reasonably possible decrease in unrecognized tax benefits in next 12 months	1
Tax-related interest and penalties payable	9	7
Net deferred tax assets	252	217
Increase in net deferred tax assets	35
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, 2017
Maximum
Years state net operating loss carryforwards expire	Dec. 31, 2026

Contingent Liabilities (Narrati

Contingent Liabilities (Narrative) (Details) - USD ($) $ in Millions	Jan. 17, 2014	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Loss Contingencies [Line Items]
Legal fees		$ 4	$ 4	$ 14	$ 14
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		$ 28		$ 28
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) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Restructuring Cost and Reserve [Line Items]
Number of banking centers to be consolidated under restructuring plan	38
Restructuring charges	$ 7	$ 20	$ 32	$ 73
Business Bank
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4	10	17	36
Retail Bank
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2	8	10	27
Wealth Management
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1	$ 2	$ 5	$ 10

Restructuring Charges (Schedule

Restructuring Charges (Schedule of Changes in Restructuring Reserves) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		$ 11	$ 50	$ 18	$ 0
Restructuring charges		7	20	32	73
Payments		(6)	(21)	(33)	(24)
Adjustments for non-cash charges	[1]		(2)	(5)	(2)
Balance at end of period		12	47	12	47
Total restructuring charges incurred to date		125		$ 125
Expected completion date of restructuring activities				Dec. 31, 2018
Employee costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		6	46	$ 10	0
Restructuring charges		1	4	5	50
Payments		(1)	(12)	(9)	(12)
Adjustments for non-cash charges	[1]		2	0	2
Balance at end of period		6	40	6	40
Total restructuring charges incurred to date		57		57
Facilities costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		0	0	4	0
Restructuring charges		0	5	5	5
Payments		0	(1)	(9)	(1)
Adjustments for non-cash charges	[1]		(4)	0	(4)
Balance at end of period		0	0	0	0
Total restructuring charges incurred to date		20		20
Technology costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		3	0	0	0
Restructuring charges		5	0	17	0
Payments		(4)	0	(8)	0
Adjustments for non-cash charges	[1]		0	(5)	0
Balance at end of period		4	0	4	0
Total restructuring charges incurred to date		17		17
Other costs
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period		2	4	4	0
Restructuring charges		1	11	5	18
Payments		(1)	(8)	(7)	(11)
Adjustments for non-cash charges	[1]		0	0	0
Balance at end of period		2	$ 7	2	$ 7
Total restructuring charges incurred to date		31		31
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]	65		65
Minimum | Facilities costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	30		30
Minimum | Technology costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	55		55
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]	195		195
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]	30		30
Maximum | Technology costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	60		60
Maximum | Other costs
Restructuring Cost and Reserve [Line Items]
Total expected restructuring charges	[2]	$ 35		$ 35
[1]	Adjustments for non-cash charges primarily include the benefit from forfeitures of nonvested stock compensation in Employee Costs, accelerated depreciation expense in Facilities Costs and 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)	9 Months Ended
	Sep. 30, 2017segmentsmarkets
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			9 Months Ended
		Sep. 30, 2017		Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Net interest income (expense)		$ 546		$ 450	$ 1,516		$ 1,342
Provision for credit losses		24		16	57		213
Noninterest income		275		272	822		784
Noninterest expenses		463		493	1,377		1,469
Provision (benefit) for income taxes		(108)		(64)	(273)		(131)
Net income (loss)		226		149	631		313
Net credit-related charge-offs (recoveries)		25		16	76		121
Assets, average		71,251		72,909	71,470		70,942
Loans, average		48,663		49,206	48,431		49,023
Deposits, average		$ 56,493		$ 58,065	$ 57,128		$ 57,102
Return on average assets	[1],[2]	1.25%		0.82%	1.18%		0.59%
Efficiency ratio	[3],[4]	56.24%		68.15%	58.74%		68.88%
Business Bank
Net interest income (expense)		$ 356		$ 356	$ 1,025		$ 1,064
Provision for credit losses		16		2	39		200
Noninterest income		148		145	445		426
Noninterest expenses		199		215	592		643
Provision (benefit) for income taxes		(99)		(95)	(291)		(214)
Net income (loss)		190		189	548		433
Net credit-related charge-offs (recoveries)		28		14	67		113
Assets, average		38,917		39,618	38,632		39,589
Loans, average		37,559		38,243	37,301		38,126
Deposits, average		$ 28,115		$ 30,019	$ 28,831		$ 29,195
Return on average assets	[1]	1.94%		1.90%	1.89%		1.46%
Efficiency ratio	[3]	39.32%		42.77%	40.26%		43.11%
Retail Bank
Net interest income (expense)		$ 165		$ 156	$ 487		$ 462
Provision for credit losses		(1)		10	16		13
Noninterest income		49		50	144		141
Noninterest expenses		184		195	543		579
Provision (benefit) for income taxes		(10)		0	(25)		(3)
Net income (loss)		21		1	47		8
Net credit-related charge-offs (recoveries)		(1)		3	13		6
Assets, average		6,455		6,544	6,489		6,548
Loans, average		5,834		5,871	5,864		5,872
Deposits, average		$ 23,918		$ 23,654	$ 23,883		$ 23,438
Return on average assets	[1]	0.33%		0.00%	0.26%		0.05%
Efficiency ratio	[3]	85.51%		95.08%	85.43%		95.30%
Wealth Management
Net interest income (expense)		$ 45		$ 41	$ 127		$ 125
Provision for credit losses		10		(1)	6		(3)
Noninterest income		63		61	191		182
Noninterest expenses		70		75	211		229
Provision (benefit) for income taxes		(10)		(10)	(37)		(29)
Net income (loss)		18		18	64		52
Net credit-related charge-offs (recoveries)		(2)		(1)	(4)		2
Assets, average		5,416		5,283	5,418		5,220
Loans, average		5,270		5,092	5,266		5,025
Deposits, average		$ 4,054		$ 4,030	$ 4,046		$ 4,137
Return on average assets	[1]	1.28%		1.35%	1.58%		1.33%
Efficiency ratio	[3]	65.23%		73.64%	66.28%		74.64%
Finance
Net interest income (expense)		$ (30)		$ (109)	$ (150)		$ (326)
Provision for credit losses		0		0	0		0
Noninterest income		13		13	34		33
Noninterest expenses		(1)		(1)	(3)		(2)
Provision (benefit) for income taxes		10		37	51		112
Net income (loss)		(6)		(58)	(62)		(179)
Net credit-related charge-offs (recoveries)		0		0	0		0
Assets, average		13,996		14,144	13,959		13,955
Loans, average		0		0	0		0
Deposits, average		270		98	190		81
Other
Net interest income (expense)		10		6	27		17
Provision for credit losses		(1)		5	(4)		3
Noninterest income		2		3	8		2
Noninterest expenses		11		9	34		20
Provision (benefit) for income taxes		1	[5]	4	29	[6]	3
Net income (loss)		3		(1)	34		(1)
Net credit-related charge-offs (recoveries)		0		0	0		0
Assets, average		6,467		7,320	6,972		5,630
Loans, average		0		0	0		0
Deposits, average		136		$ 264	178		$ 251
Accounting Standards Update 2016-09
Provision (benefit) for income taxes		$ (2)			$ (31)
[1]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[2]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[3]	Noninterest expenses as a percentage of the sum of net interest income (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses).
[4]	Noninterest expenses as a percentage of the sum of net interest income (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses).
[5]	Includes tax benefit of $2 million from employee stock transactions.
[6]	Includes tax benefit of $31 million from employee stock transactions.

Business Segment Information (M

Business Segment Information (Market Segment Financial Results) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2017		Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Net interest income (expense)		$ 546		$ 450	$ 1,516		$ 1,342
Provision for credit losses		24		16	57		213
Noninterest income		275		272	822		784
Noninterest expenses		463		493	1,377		1,469
Provision (benefit) for income taxes		(108)		(64)	(273)		(131)
Net income (loss)		226		149	631		313
Net credit-related charge-offs (recoveries)		25		16	76		121
Assets, average		71,251		72,909	71,470		70,942
Loans, average		48,663		49,206	48,431		49,023
Deposits, average		$ 56,493		$ 58,065	$ 57,128		$ 57,102
Return on average assets	[1],[2]	1.25%		0.82%	1.18%		0.59%
Efficiency ratio	[3],[4]	56.24%		68.15%	58.74%		68.88%
Michigan
Net interest income (expense)		$ 172		$ 168	$ 510		$ 503
Provision for credit losses		8		13	3		10
Noninterest income		79		82	242		239
Noninterest expenses		144		161	439		470
Provision (benefit) for income taxes		(34)		(26)	(110)		(88)
Net income (loss)		65		50	200		174
Net credit-related charge-offs (recoveries)		2		1	(2)		6
Assets, average		13,367		13,019	13,331		13,135
Loans, average		12,612		12,332	12,637		12,484
Deposits, average		$ 21,641		$ 21,907	$ 21,827		$ 21,699
Return on average assets	[2]	1.14%		0.87%	1.18%		1.03%
Efficiency ratio	[4]	57.15%		64.64%	58.22%		63.09%
California
Net interest income (expense)		$ 184		$ 179	$ 531		$ 532
Provision for credit losses		24		(4)	70		8
Noninterest income		41		44	128		121
Noninterest expenses		103		110	297		334
Provision (benefit) for income taxes		(37)		(43)	(111)		(115)
Net income (loss)		61		74	181		196
Net credit-related charge-offs (recoveries)		10		0	28		25
Assets, average		18,170		18,088	18,201		17,980
Loans, average		17,916		17,793	17,930		17,700
Deposits, average		$ 17,316		$ 17,711	$ 17,301		$ 17,121
Return on average assets	[2]	1.32%		1.58%	1.33%		1.44%
Efficiency ratio	[4]	45.59%		48.93%	44.87%		51.02%
Texas
Net interest income (expense)		$ 123		$ 117	$ 350		$ 355
Provision for credit losses		(22)		(3)	(45)		199
Noninterest income		33		33	98		96
Noninterest expenses		92		102	280		316
Provision (benefit) for income taxes		(31)		(18)	(78)		21
Net income (loss)		55		33	135		(43)
Net credit-related charge-offs (recoveries)		9		10	36		88
Assets, average		10,435		11,014	10,490		11,198
Loans, average		9,959		10,566	10,028		10,722
Deposits, average		$ 9,400		$ 9,860	$ 9,712		$ 10,096
Return on average assets	[2]	2.05%		1.13%	1.64%		(0.49%)
Efficiency ratio	[4]	58.74%		68.12%	62.54%		70.00%
Other Markets
Net interest income (expense)		$ 87		$ 89	$ 248		$ 261
Provision for credit losses		15		5	33		(7)
Noninterest income		107		97	312		293
Noninterest expenses		114		112	330		331
Provision (benefit) for income taxes		(17)		(18)	(54)		(64)
Net income (loss)		48		51	143		166
Net credit-related charge-offs (recoveries)		4		5	14		2
Assets, average		8,816		9,324	8,517		9,044
Loans, average		8,176		8,515	7,836		8,117
Deposits, average		$ 7,730		$ 8,225	$ 7,920		$ 7,854
Return on average assets	[2]	2.15%		2.19%	2.20%		2.46%
Efficiency ratio	[4]	58.79%		60.18%	58.86%		59.70%
Finance & Other
Net interest income (expense)		$ (20)		$ (103)	$ (123)		$ (309)
Provision for credit losses		(1)		5	(4)		3
Noninterest income		15		16	42		35
Noninterest expenses		10		8	31		18
Provision (benefit) for income taxes		11	[5]	41	80	[6]	115
Net income (loss)		(3)		(59)	(28)		(180)
Net credit-related charge-offs (recoveries)		0		0	0		0
Assets, average		20,463		21,464	20,931		19,585
Loans, average		0		0	0		0
Deposits, average		406		$ 362	368		$ 332
Accounting Standards Update 2016-09
Provision (benefit) for income taxes		$ (2)			$ (31)
[1]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[2]	Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.
[3]	Noninterest expenses as a percentage of the sum of net interest income (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses).
[4]	Noninterest expenses as a percentage of the sum of net interest income (fully taxable equivalent basis) and noninterest income excluding net securities gains (losses).
[5]	Includes tax benefit of $2 million from employee stock transactions.
[6]	Includes tax benefit of $31 million from employee stock transactions.