KeyCorp (KEY) 10-Q 5 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 03, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	KEYCORP /NEW/
Trading Symbol	KEY
Entity Central Index Key	91,576
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,096,107,344

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
ASSETS
Cash and due from banks	$ 549	$ 677
Short-term investments	2,525	2,775
Trading account assets	921	867
Securities available for sale	18,431	20,212
Held-to-maturity securities (fair value: $9,954 and $10,007)	10,186	10,232
Other investments	689	738
Loans, net of unearned income	86,125	86,038
Less: Allowance for loan and lease losses	(870)	(858)
Net loans	85,255	85,180
Loans held for sale	1,384	1,104
Premises and equipment	935	978
Operating lease assets	563	540
Goodwill	2,427	2,446
Other intangible assets	362	384
Corporate-owned life insurance	4,087	4,068
Derivative assets	578	803
Accrued income and other assets	4,064	3,864
Discontinued assets (including $3 and $3 of portfolio loans at fair value, see Note 12)	1,520	1,585
Total assets	134,476	136,453
Deposits in domestic offices:
NOW and money market deposit accounts	55,095	54,590
Savings deposits	6,306	6,491
Certificates of deposit ($100,000 or more)	5,859	5,483
Other time deposits	4,694	4,698
Total interest-bearing deposits	71,954	71,262
Noninterest-bearing deposits	32,028	32,825
Total deposits	103,982	104,087
Federal funds purchased and securities sold under repurchase agreements	442	1,502
Bank notes and other short-term borrowings	943	808
Derivative liabilities	255	636
Accrued expense and other liabilities	1,552	1,796
Long-term debt	12,324	12,384
Total liabilities	119,498	121,213
EQUITY
Preferred stock	1,025	1,665
Common shares, $1 par value; authorized 1,400,000,000 shares; issued 1,256,702,081, and 1,256,702,081 shares	1,257	1,257
Capital surplus	6,287	6,385
Retained earnings	9,584	9,378
Treasury stock, at cost (159,223,419 and 177,388,429 shares)	(2,623)	(2,904)
Accumulated other comprehensive income (loss)	(554)	(541)
Key shareholders’ equity	14,976	15,240
Noncontrolling interests	2	0
Total equity	14,978	15,240
Total liabilities and equity	$ 134,476	$ 136,453

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Loans held for sale	$ 1,384	$ 1,104
Held-to-maturity securities, fair value	9,954	10,007
Unearned income on loans	783	826
Loan securitization trust VIEs	3	3
Aggregate amount of certificates of deposit, denominations	$ 100,000	$ 100,000
Common shares, par value (in usd per share)	$ 1	$ 1
Common shares, shares authorized (in shares)	1,400,000,000	1,400,000,000
Common shares, shares issued (in shares)	1,256,702,081	1,256,702,081
Treasury stock, shares (in shares)	159,223,419	177,388,429
Residential Mortgage [Member]
Loans held for sale	$ 62	$ 62

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
INTEREST INCOME
Loans		$ 877	$ 562
Loans held for sale		13	8
Securities available for sale		95	75
Held-to-maturity securities		51	24
Trading account assets		7	7
Short-term investments		3	4
Other investments		4	3
Total interest income		1,050	683
INTEREST EXPENSE
Deposits		58	31
Federal funds purchased and securities sold under repurchase agreements		1	0
Bank notes and other short-term borrowings		5	2
Long-term debt		68	46
Total interest expense		132	79
NET INTEREST INCOME		918	604
Provision for credit losses		63	89
Net interest income after provision for credit losses		855	515
NONINTEREST INCOME
Trust and investment services income		135	109
Investment banking and debt placement fees		127	71
Service charges on deposit accounts		87	65
Operating lease income and other leasing gains		23	17
Corporate services income		54	50
Cards and payments income		65	46
Corporate-owned life insurance income		30	28
Consumer mortgage income		6	2
Mortgage servicing fees		18	12
Net gains (losses) from principal investing		1	0
Other income	[1]	31	31
Total noninterest income		577	431
NONINTEREST EXPENSE
Personnel		556	404
Net occupancy		87	61
Computer processing		60	43
Business services and professional fees		46	41
Equipment		27	21
Operating lease expense		19	13
Marketing		21	12
FDIC assessment		20	9
Intangible asset amortization		22	8
OREO expense, net		2	1
Other expense		153	90
Total noninterest expense		1,013	703
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES		419	243
Income taxes		94	56
INCOME (LOSS) FROM CONTINUING OPERATIONS		325	187
Income (loss) from discontinued operations, net of taxes $0 and $0 (see Note 12)		0	1
NET INCOME (LOSS)		325	188
Less: Net income (loss) attributable to noncontrolling interests		1	0
NET INCOME (LOSS) ATTRIBUTABLE TO KEY		324	188
Income (loss) from continuing operations attributable to Key common shareholders		296	182
Net income (loss) attributable to Key common shareholders		$ 296	$ 183
Per common share:
Income (loss) from continuing operations attributable to Key common shareholders (in usd per share)		$ 0.28	$ 0.22
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[2]	0.28	0.22
Per common share — assuming dilution:
Income (loss) from continuing operations attributable to Key common shareholders (in usd per share)		0.27	0.22
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[2]	0.27	0.22
Cash dividends declared per common share (in usd per share)		$ 0.085	$ 0.075
Weighted-average common shares outstanding (in shares)		1,068,609	827,381
Effect of convertible preferred stock (in shares)		0	0
Effect of common share options and other stock awards (in shares)		17,931	7,679
Weighted-average common shares and potential common shares outstanding (in shares)	[3]	1,086,540	835,060
[1]	For the three months ended March 31, 2017, net securities gains totaled $1 million. For the three months ended March 31, 2016, net securities gains (losses) totaled less than $1 million. For the three months ended March 31, 2017, and March 31, 2016, we did not have any impairment losses related to securities.
[2]	EPS may not foot due to rounding.
[3]	Assumes conversion of common share options and other stock awards and/or convertible preferred stock, as applicable.

Consolidated Statements of Inc5

Consolidated Statements of Income (Parenthetical) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net tax effect on income (loss) from discontinued operations	$ 0	$ 0
Net securities gains (losses) (less than for 2015)	1,000,000	1,000,000
Impaired losses related to securities	$ 0	$ 0

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 325	$ 188
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on securities available for sale, net of income taxes of $4 and $76	6	128
Net unrealized gains (losses) on derivative financial instruments, net of income taxes of ($15) and $34	(24)	58
Foreign currency translation adjustments, net of income taxes of $1 and $3	1	5
Net pension and postretirement benefit costs, net of income taxes of $2 and $4	4	1
Total other comprehensive income (loss), net of tax	(13)	192
Comprehensive income (loss)	312	380
Less: Comprehensive income attributable to noncontrolling interests	1	0
Comprehensive income (loss) attributable to Key	$ 311	$ 380

Consolidated Statements of Com7

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Income taxes effect on net unrealized (losses) gains on securities available for sale	$ 4	$ 76
Income taxes effect on net unrealized gains (losses) on derivative financial instruments	(15)	34
Income taxes effect on foreign currency translation adjustments	1	3
Income taxes effect on net pension and postretirement benefit costs	$ 2	$ 4

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Series C Preferred Stock [Member]	Series D Preferred Stock [Member]	Series E Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Retained Earnings [Member]Series A Preferred Stock [Member]	Retained Earnings [Member]Series C Preferred Stock [Member]	Retained Earnings [Member]Series D Preferred Stock [Member]	Retained Earnings [Member]Series E Preferred Stock [Member]	Treasury Stock, at Cost [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning Balance, Preferred Shares at Dec. 31, 2015					2,900,000
Beginning Balance, Common Shares at Dec. 31, 2015						835,751,000
Beginning Balance at Dec. 31, 2015					$ 290	$ 1,017	$ 3,922	$ 8,922					$ (3,000)	$ (405)	$ 13
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 188							188
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	128													128
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	58													58
Foreign currency translation adjustments, net of income taxes	5													5
Net pension and postretirement benefit costs, net of income taxes	1													1
Deferred compensation							(6)
Cash dividends declared on common shares								(63)
Cash dividends declared on Noncumulative Series A Preferred Stock									$ (5)
Redemption of Series C Preferred Stock	$ 0
Common shares reissued (returned) for stock options and other employee benefit plans, shares						6,539,000
Common shares reissued (returned) for stock options and other employee benefit plans							(98)						112
Net contribution from (distribution to) noncontrolling interests															(8)
Ending Balance, Preferred Shares at Mar. 31, 2016					2,900,000
Ending Balance, Common Shares at Mar. 31, 2016						842,290,000
Ending Balance at Mar. 31, 2016					$ 290	$ 1,017	3,818	9,042					(2,888)	(213)	5
Beginning Balance, Preferred Shares at Dec. 31, 2015					2,900,000
Beginning Balance, Common Shares at Dec. 31, 2015						835,751,000
Beginning Balance at Dec. 31, 2015					$ 290	$ 1,017	3,922	8,922					(3,000)	(405)	13
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)								324
Ending Balance, Preferred Shares at Dec. 31, 2016	2,900,234	14,000,000	21,000	500,000	17,421,000
Ending Balance, Common Shares at Dec. 31, 2016						1,079,314,000
Ending Balance at Dec. 31, 2016	$ 15,240				$ 1,665	$ 1,257	6,385	9,378					(2,904)	(541)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	325														1
Other comprehensive income (loss):
Net unrealized gains (losses) on securities available for sale, net of income taxes	6													6
Net unrealized gains (losses) on derivative financial instruments, net of income taxes	(24)													(24)
Foreign currency translation adjustments, net of income taxes	1													1
Net pension and postretirement benefit costs, net of income taxes	4													4
Deferred compensation							3
Cash dividends declared on common shares								(90)
Cash dividends declared on Noncumulative Series A Preferred Stock									$ (6)	$ (7)	$ (7)	$ (8)
Open market common share repurchases, shares						(5,844,000)
Common shares repurchased													(107)
Employee equity compensation program common share repurchase, shares						(2,829,000)
Employee equity compensation program common share repurchases													(53)
Series A Preferred Stock exchanged for common shares, shares					2,900,000	20,568,000
Series A Preferred Stock exchanged for common shares					$ (290)		(49)						338
Redemption of Series C Preferred Stock, shares					(14,000,000)
Redemption of Series C Preferred Stock	350				$ (350)
Common shares reissued (returned) for stock options and other employee benefit plans, shares						6,270,000
Common shares reissued (returned) for stock options and other employee benefit plans							(52)						103
Net contribution from (distribution to) noncontrolling interests															1
Ending Balance, Preferred Shares at Mar. 31, 2017		14,000,000	21,000	500,000	521,000
Ending Balance, Common Shares at Mar. 31, 2017						1,097,479,000
Ending Balance at Mar. 31, 2017	$ 14,978				$ 1,025	$ 1,257	$ 6,287	$ 9,584					$ (2,623)	$ (554)	$ 2

Consolidated Statements of Cha9

Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income taxes effect on net unrealized (losses) gains on securities available for sale	$ 4	$ 76
Income taxes effect on net unrealized gains (losses) on derivative financial instruments	(15)	34
Income taxes effect on foreign currency translation adjustments	1	3
Income taxes effect on net pension and postretirement benefit costs	$ 2	$ 4
Cash dividends declared on common shares (in usd per share)	$ 0.085	$ 0.075
Series A Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	1.9375	$ 1.9375
Series C Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	0.539063
Series D Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	12.50
Series E Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	$ 0.395573

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES
Net income (loss)	$ 325	$ 188
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Provision for credit losses	63	89
Depreciation and amortization expense, net	100	62
Accretion of acquired loans	43	0
Increase in cash surrender value of corporate-owned life insurance	(28)	(25)
Stock-based compensation expense	27	19
FDIC reimbursement (payments), net of FDIC expense	(2)	1
Deferred income taxes (benefit)	137	50
Proceeds from sales of loans held for sale	2,334	1,110
Originations of loans held for sale, net of repayments	(2,562)	(1,153)
Net losses (gains) on sales of loans held for sale	(35)	(2)
Net losses (gains) from principal investing	(1)	0
Net losses (gains) and writedown on OREO	1	1
Net losses (gains) on leased equipment	(2)	0
Net securities losses (gains)	(1)	(1)
Net losses (gains) on sales of fixed assets	12	1
Net decrease (increase) in trading account assets	(54)	23
Other operating activities, net	(762)	9
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	(405)	373
INVESTING ACTIVITIES
Net decrease (increase) in short-term investments, excluding acquisitions	250	(2,729)
Purchases of securities available for sale	(195)	(610)
Proceeds from sales of securities available for sale	912	0
Proceeds from prepayments and maturities of securities available for sale	1,061	722
Proceeds from prepayments and maturities of held-to-maturity securities	456	251
Purchases of held-to-maturity securities	(411)	(358)
Purchases of other investments	(2)	(18)
Proceeds from sales of other investments	51	24
Proceeds from prepayments and maturities of other investments	1	0
Net decrease (increase) in loans, excluding acquisitions, sales and transfers	(255)	(663)
Proceeds from sales of portfolio loans	37	40
Proceeds from corporate-owned life insurance	9	9
Purchases of premises, equipment, and software	(2)	(8)
Proceeds from sales of premises and equipment	0	0
Proceeds from sales of OREO	11	3
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	1,923	(3,337)
FINANCING ACTIVITIES
Net increase (decrease) in deposits, excluding acquisitions	(105)	2,336
Net increase (decrease) in short-term borrowings	(925)	84
Net proceeds from issuance of long-term debt	0	976
Payments on long-term debt	(10)	(498)
Open market common share repurchases	(107)	0
Employee equity compensation program common share repurchases	(53)	0
Redemption of Preferred Stock Series C	(350)	0
Net proceeds from reissuance of common shares	22	1
Cash dividends paid	(118)	(68)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	(1,646)	2,831
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	(128)	(133)
CASH AND DUE FROM BANKS AT BEGINNING OF PERIOD	677	607
CASH AND DUE FROM BANKS AT END OF PERIOD	549	474
Additional disclosures relative to cash flows:
Interest paid	151	108
Income taxes paid (refunded)	(11)	13
Noncash items:
Reduction of secured borrowing and related collateral	13	21
Loans transferred to portfolio from held for sale	8	0
Loans transferred to held for sale from portfolio	25	0
Loans transferred to OREO	$ 11	$ 4

Basis of Presentation and Accou

Basis of Presentation and Accounting Policies	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Accounting Policies	1. Basis of Presentation and Accounting Policies As used in these Notes, references to “Key,” “we,” “our,” “us,” and similar terms refer to the consolidated entity consisting of KeyCorp and its subsidiaries. KeyCorp refers solely to the parent holding company, and KeyBank refers to KeyCorp’s subsidiary, KeyBank National Association and its subsidiaries. The acronyms and abbreviations identified below are used in the Notes to Consolidated Financial Statements (Unaudited) as well as in the Management’s Discussion & Analysis of Financial Condition & Results of Operations. You may find it helpful to refer back to this page as you read this report. References to our “ 2016 Form 10-K” refer to our Form 10-K for the year ended December 31, 2016 , which was filed with the U.S. Securities and Exchange Commission and is available on its website (www.sec.gov) and on our website (www.key.com/ir). AICPA: American Institute of Certified Public Accountants. KCDC: Key Community Development Corporation. ALCO: Asset/Liability Management Committee. KEF: Key Equipment Finance. ALLL: Allowance for loan and lease losses. KPP: Key Principal Partners. A/LM: Asset/liability management. KREEC: Key Real Estate Equity Capital, Inc. AOCI: Accumulated other comprehensive income (loss). LCR: Liquidity coverage ratio. APBO: Accumulated postretirement benefit obligation. LIBOR: London Interbank Offered Rate. Austin: Austin Capital Management, Ltd. LIHTC: Low-income housing tax credit. BHCs: Bank holding companies. LTV: Loan-to-value. Board: KeyCorp Board of Directors. Moody’s: Moody’s Investor Services, Inc. CCAR: Comprehensive Capital Analysis and Review. MRM: Market Risk Management group. CMBS: Commercial mortgage-backed securities. N/A: Not applicable. CME: Chicago Mercantile Exchange. NASDAQ: The NASDAQ Stock Market LLC. CMO: Collateralized mortgage obligation. NAV: Net asset value. Common Shares: KeyCorp common shares, $1 par value. N/M: Not meaningful. DIF: Deposit Insurance Fund of the FDIC. NOW: Negotiable Order of Withdrawal. Dodd-Frank Act: Dodd-Frank Wall Street Reform and NPR: Notice of proposed rulemaking. Consumer Protection Act of 2010. NYSE: New York Stock Exchange. EBITDA: Earnings before interest, taxes, depreciation, and OCC: Office of the Comptroller of the Currency. amortization. OCI: Other comprehensive income (loss). EPS: Earnings per share. OREO: Other real estate owned. ERISA: Employee Retirement Income Security Act of 1974. OTTI: Other-than-temporary impairment. ERM: Enterprise risk management. PBO: Projected benefit obligation. EVE: Economic value of equity. PCI: Purchased credit impaired. FASB: Financial Accounting Standards Board. S&P: Standard and Poor’s Ratings Services, a Division FDIC: Federal Deposit Insurance Corporation. of The McGraw-Hill Companies, Inc. Federal Reserve: Board of Governors of the Federal Reserve SEC: U.S. Securities and Exchange Commission. System. Series A Preferred Stock: KeyCorp’s 7.750% FHLB: Federal Home Loan Bank of Cincinnati. Noncumulative Perpetual Convertible Preferred Stock, FHLMC: Federal Home Loan Mortgage Corporation. Series A. FICO: Fair Isaac Corporation SIFIs: Systemically important financial institutions First Niagara: First Niagara Financial Group, Inc. including BHCs with total consolidated assets of at least (NASDAQ: FNFG). $50 billion and nonbank financial companies designated FNMA: Federal National Mortgage Association, or Fannie Mae. by FSOC for supervision by the Federal Reserve. FSOC: Financial Stability Oversight Council. TDR: Troubled debt restructuring. GAAP: U.S. generally accepted accounting principles. TE: Taxable-equivalent. GNMA: Government National Mortgage Association, or Ginnie U.S. Treasury: United States Department of the Treasury. Mae. VaR: Value at risk. ISDA: International Swaps and Derivatives Association. VEBA: Voluntary Employee Beneficiary Association. KAHC: Key Affordable Housing Corporation. VIE: Variable interest entity. KCC: Key Capital Corporation. The consolidated financial statements include the accounts of KeyCorp and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Some previously reported amounts have been reclassified to conform to current reporting practices. The consolidated financial statements include any voting rights entities in which we have a controlling financial interest. In accordance with the applicable accounting guidance for consolidations, we consolidate a VIE if we have: (i) a variable interest in the entity; (ii) the power to direct activities of the VIE that most significantly affect the entity’s economic performance; and (iii) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE (i.e., we are considered to be the primary beneficiary). Variable interests can include equity interests, subordinated debt, derivative contracts, leases, service agreements, guarantees, standby letters of credit, loan commitments, and other contracts, agreements, and financial instruments. See Note 10 (“ Variable Interest Entities ”) for information on our involvement with VIEs. We use the equity method to account for unconsolidated investments in voting rights entities or VIEs if we have significant influence over the entity’s operating and financing decisions (usually defined as a voting or economic interest of 20% to 50% , but not controlling). Unconsolidated investments in voting rights entities or VIEs in which we have a voting or economic interest of less than 20% generally are carried at cost. Investments held by our registered broker-dealer and investment company subsidiaries (principal investing entities and Real Estate Capital line of business) are carried at fair value. We believe that the unaudited consolidated interim financial statements reflect all adjustments of a normal recurring nature and disclosures that are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim period are not necessarily indicative of the results of operations to be expected for the full year. The interim financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in our 2016 Form 10-K. In preparing these financial statements, subsequent events were evaluated through the time the financial statements were issued. Financial statements are considered issued when they are widely distributed to all shareholders and other financial statement users, or filed with the SEC. Accounting Guidance Adopted in 2017 Consolidation. In October 2016, the FASB issued new accounting guidance that amends the previous consolidation guidance issued in February 2015, to require a decision maker that holds an interest in a VIE through an entity under common control to only consider its proportionate indirect interest in the VIE in determining whether the decision maker is the VIE’s primary beneficiary. This new guidance eliminates the requirement that a decision maker treat the common control party’s interest in the VIE as if the decision maker held the interest itself, an approach referred to as “full attribution.” The new guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) on a retrospective basis. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Stock-based compensation. In March 2016, the FASB issued new accounting guidance that simplifies the accounting for several aspects of share-based payment transactions, including the related income tax consequences, the classification of awards as either equity or liabilities, and the presentation on the statement of cash flows. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us). The method of transition was dependent upon the particular amendment within the new guidance. During the three months ended March 31, 2017 , we recognized $18 million in excess tax benefits within “income taxes” on our income statement that pertained to share-based payment arrangements. In prior periods, such excess tax benefits were recorded within “capital surplus” on our balance sheet. Under the new guidance, generally, if our share price increases over an award’s vesting period, the resulting tax windfall will decrease “income taxes.” In a like manner, if our share price decreases over an award’s vesting period, the resulting tax shortfall will increase “income taxes.” This change also removed the impact of the excess tax benefits and deficiencies from the calculation of diluted EPS and is required to be applied on a prospective basis. The adoption of this accounting standard did not materially affect our statement of cash flows, nor did it affect retained earnings as of the beginning of the period of adoption. We elected to retain our existing accounting policy of estimating award forfeitures upon the award’s grant date. Equity method investments. In March 2016, the FASB issued new accounting guidance that simplifies the transition to equity method accounting by eliminating the requirement for an investor to make retroactive adjustments to the investment, results of operations, and retained earnings on a step-by-step basis when an investment becomes qualified for equity method accounting. Instead, when an investment qualifies for the equity method due to an increase in ownership or degree of influence, an equity method investor is required to add the cost of acquiring the additional interest to the current basis of the previously held interest, and to adopt the equity method of accounting as of the date the investment becomes qualified for the equity method. This accounting guidance became effective prospectively for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us). Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. This guidance will only affect our financial condition or results of operations if there is an applicable change in an investment resulting in the investment’s qualifying for equity method accounting. Derivatives and hedging. In March 2016, the FASB issued new accounting guidance that requires an entity to use a four-step decision model when assessing contingent call (put) options that can accelerate the payment of principal on debt instruments to determine whether they are clearly and closely related to their debt hosts. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) on a modified retrospective basis. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Derivatives and hedging . In March 2016, the FASB issued new accounting guidance that clarifies that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument does not, by itself, require dedesignation, but all other hedge accounting criteria must be met. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) and was implemented using a prospective method. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Accounting Guidance Pending Adoption at March 31, 2017 Receivables. In March 2017, the FASB issued new accounting guidance that shortens the amortization period to the earliest call date for certain callable debt securities held at a premium. Securities held at a discount will continue to be amortized to maturity. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2018 (effective January 1, 2019, for us). The guidance should be applied on a modified retrospective basis using a cumulative-effect adjustment. Early adoption is permitted. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Compensation. In March 2017, the FASB issued new accounting guidance that requires service cost to be included in the same line item as certain other compensation costs related to services rendered by employees. We record compensation costs under personnel expense on the income statement. Other elements of net benefit cost should be presented separately. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). The guidance should be applied on a retrospective basis. Early adoption is permitted within the first interim period if the entity issues interim financial statements. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Other income. In February 2017, the FASB issued new accounting guidance that clarifies the scope of asset derecognition guidance and accounting for partial sales of nonfinancial assets. The guidance clarifies that financial assets may be within scope of the derecognition guidance if they are promised to a counterparty in a contract and substantially all the fair value of the assets in the contract are concentrated in nonfinancial assets, which are collectively referred to as in substance nonfinancial assets. The guidance requires entities to derecognize a nonfinancial asset or in substance nonfinancial asset when a counterparty obtains controls of it, and in a partial sale transaction when it does not have a controlling financial interest in the legal entity that holds the asset and when it transfers control of the asset. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). The guidance may be applied on a retrospective or modified retrospective basis. Early adoption is permitted for interim and annual reporting periods beginning after December 15, 2016. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Goodwill and Other Intangibles. In January 2017, the FASB issued new accounting guidance that simplifies the test for goodwill impairment by eliminating the second step of the current two-step method. Under the new guidance, entities will compare the fair value of a reporting unit with its carrying amount. If the carrying amount exceeds the reporting unit’s fair value, the entity is required to recognize an impairment charge for this amount. Current guidance requires an entity to proceed to a second step, whereby the entity would determine the fair value of its assets and liabilities. The new method applies to all reporting units. The option to perform a qualitative assessment is still allowable. This accounting guidance is effective prospectively for interim and annual reporting periods beginning after December 15, 2019 (effective January 1, 2020, for us). Early adoption is permitted. The adoption of this accounting guidance is not expected to have a material effect on our financial condition or results of operations. Business combinations. In January 2017, the FASB issued accounting guidance that clarifies the definition of a business and removes the requirement for a market participant to consider whether it could replace missing elements in an integrated set of assets and activities. The guidance states that if substantially all of the fair value of the assets acquired or disposed of is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a prospective approach. Early application is allowed for transactions for which the acquisition date occurs before the issuance date or effective date of the amendments, as long as the transaction has not been reported in financial statements that have been issued or made available for issuance, and for transactions in which a subsidiary is deconsolidated or a group of assets is derecognized that occurs before the issuance date or effective date of the amendments, as long as the transaction has not been reported in financial statements that have been issued or made available for issuance. This guidance will not affect our financial condition or results of operations unless we acquire or dispose of a business subsequent to the date of adoption. Statement of cash flows. In November 2016, the FASB issued accounting guidance requiring restricted cash and restricted cash equivalents to be included with other cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts presented on the statement of cash flows. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a retrospective approach. Early adoption is permitted. The adoption of this accounting guidance may affect the presentation in our Consolidated Statements of Cash Flows. Income taxes. In October 2016, the FASB issued accounting guidance requiring an entity to recognize any deferred taxes from an intra-entity transfer of an asset other than inventory when the transfer occurs. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a modified retrospective approach. Early adoption is permitted but only as of the beginning of an annual reporting period for which financial statements have not yet been issued. The adoption of this accounting guidance is not expected to have a material effect on our financial condition or results of operations. Statement of cash flows. In August 2016, the FASB issued new accounting guidance that clarifies how cash receipts and cash payments in certain specific transactions should be presented and classified in the statement of cash flows. These specific transactions include, but are not limited to, debt prepayment or extinguishment costs, contingent considerations made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, and distributions from equity method investees. This guidance also clarifies that in instances of cash flows with multiple aspects that cannot be separately identified, classification should be based on the activity that is likely to be the predominant source of or use of cash flow. This accounting guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a retrospective approach. Early adoption is permitted. The adoption of this accounting guidance may affect the presentation in our Consolidated Statements of Cash Flows. Financial instruments. In June 2016, the FASB issued new accounting guidance that changes the methodology for recognizing credit losses related to financial instruments. Under current GAAP, a credit loss is not recognized until it is probable that the loss has been incurred. The new accounting guidance eliminates that threshold and expands the information required for an entity to consider when developing an estimate of expected credit losses, including the use of forecast information. Entities will be required to present financial assets measured on an amortized cost basis at the net amount that is expected to be collected. This new guidance will impact the accounting for our loans, debt securities available for sale, and liability for credit losses on unfunded lending-related commitments, as well as purchased financial assets with a more-than-insignificant amount of credit deterioration since origination. This accounting guidance will be effective for interim and annual reporting periods beginning after December 15, 2019 (effective January 1, 2020, for us). Early adoption is permitted but only for interim and annual reporting periods beginning after December 15, 2018. This guidance must be implemented using a modified retrospective basis except that a prospective approach must be used for debt securities for which an other-than-temporary impairment had been recognized before the effective date. A prospective transition approach also should be used for purchased financial assets with credit deterioration. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations and related disclosures. Leases. In February 2016, the FASB issued new accounting guidance that requires a lessee to recognize a liability to make lease payments, and a right-of-use asset representing its right to use an underlying asset during the lease term for both finance and operating leases. The definition of a lease was modified to exemplify the concept of control over an asset identified in the lease. Lease classification criteria remain substantially similar to criteria in current lease guidance. The guidance defines which payments can be used in determining lease classification. For short-term leases with a term of 12 months or less, lessees can make a policy election not to recognize lease assets and lease liabilities. Lessor accounting is largely unchanged. Leveraged leases that commenced before the effective date of the new guidance are grandfathered. New disclosures are required, and certain practical expedients are allowed upon adoption. This accounting and disclosure guidance will be effective for interim and annual reporting periods beginning after December 15, 2018 (effective January 1, 2019, for us) and should be implemented using the modified retrospective approach. Early adoption is permitted. We are currently in the early stages of implementation and are working to identify our complete lease population, including potential embedded leases. We expect the adoption of this standard to result in additional assets and liabilities, as we will be required to recognize operating leases on our Consolidated Balance Sheet. Other implementation matters to be addressed include, but are not limited to, the determination of effects on our financial and capital ratios and the quantification of the impacts that this accounting guidance may have on our financial condition or results of operations. Financial instruments. In January 2016, the FASB issued new accounting guidance that requires equity investments, except those accounted for under the equity method of accounting or consolidated, to be measured at fair value with changes recognized in net income. If there is no readily determinable fair value, the guidance allows entities the ability to measure investments at cost less impairment, whereby impairment is based on a qualitative assessment. The guidance eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost and changes the presentation of financial assets and financial liabilities on the balance sheet or in the footnotes. If an entity has elected the fair value option to measure liabilities, the new accounting guidance requires the portion of the change in the fair value of a liability resulting from credit risk to be presented in OCI. We have not elected to measure any of our liabilities at fair value, and therefore, this aspect of the guidance is not applicable to us. This accounting and disclosure guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). For the guidance that is applicable to us, the accounting will be implemented on a modified retrospective basis though a cumulative-effect adjustment to the balance sheet, except for the guidance related to equity securities without readily determinable fair values, which should be applied on a prospective basis. Except under certain instances, early adoption is not permitted. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Revenue recognition. In May 2014, the FASB issued new accounting guidance that revises the criteria for determining when to recognize revenue from contracts with customers and expands disclosure requirements. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides a five-step model to be followed in making this determination. This accounting guidance can be implemented using either a retrospective method or a cumulative-effect approach. In August 2015, the FASB issued an update that defers the effective date of the revenue recognition guidance by one year. This new guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). Early adoption is permitted but only for interim and annual reporting periods beginning after December 15, 2016. We have elected to implement this new accounting guidance using a cumulative-effect approach. We have already identified the revenue line items within scope of the new guidance and are currently in the process of performing an in-depth assessment, though our preliminary analysis suggests that the adoption of this accounting guidance is not expected to have a material effect on our financial condition nor results of operations. We are also evaluating the related disclosures. There are many aspects of this new accounting guidance that are still being interpreted, and the FASB has issued updates to certain aspects of the guidance to address implementation issues. For example, the FASB issued accounting guidance in March 2016 to clarify principal-versus-agent considerations, and additional guidance in April 2016 to clarify the identification of performance obligations and the licensing implementation guidance. In May 2016, the FASB issued narrow-scope improvements related to collectability, sales tax and noncash consideration, and practical expedients for contract modifications and completed contracts. In December 2016, the FASB issued additional technical corrections and improvements. While certain implementation issues relevant to the industry are still pending resolution, including trade date versus settlement date recognition for broker-dealers and the applicability of interchange revenues for card-issuing banks, our preliminary conclusions reached as to the application of the new guidance are not expected to be significantly affected. We will continue to evaluate any impact as additional guidance is issued and as our internal assessment progresses.

Business Combination

Business Combination	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Business Combination	2. Business Combination First Niagara On August 1, 2016 (the “Acquisition Date”), we acquired all of the outstanding common shares of First Niagara, the parent company of First Niagara Bank, for total consideration of approximately $4.0 billion and thereby acquired First Niagara Bank’s approximately 390 branch locations across New York, Pennsylvania, Connecticut, and Massachusetts. The merger with First Niagara enabled us to expand in the New England market and into the Pennsylvania market, improve our core deposit base, and add additional scale in our banking operations. The results of First Niagara’s operations are included in our consolidated financial statements from the Acquisition Date. Under the terms of the merger agreement, each outstanding share of First Niagara common stock was converted into the right to receive 0.680 KeyCorp Common Shares and $2.30 in cash, for a total per-share value of $10.26 , based on the $11.70 closing price of KeyCorp’s stock on July 29, 2016. In the aggregate, First Niagara stockholders received 240 million shares of KeyCorp common stock. Also under the terms of the merger agreement, First Niagara employee stock options and restricted stock awards converted into options to purchase and receive KeyCorp common stock. These options and restricted stock awards had a fair value of $26 million on the Acquisition Date. Our methodology for valuing employee stock options is disclosed in Note 16 (“Stock-Based Compensation”) under the heading “Stock Options” on page 179 of our 2016 Form 10-K. Our methodology for valuing restricted stock awards is disclosed in Note 16 (“Stock-Based Compensation”) under the heading “Long-Term Incentive Compensation Program” on page 180 of our 2016 Form 10-K. In addition, at the time of the merger, each share of First Niagara preferred stock, Series B, was converted into the right to receive a share of KeyCorp preferred stock, Series C, a newly created series of KeyCorp preferred stock. Additional information on this series of preferred stock is provided in Note 18 (“ Shareholders' Equity ”) of this report. On October 7, 2016, First Niagara Bank merged with and into KeyBank, with KeyBank as the surviving entity. Systems and client conversion also occurred during the fourth quarter of 2016 in connection with the bank merger. The acquisition of First Niagara constituted a business combination and was accounted for under the acquisition method of accounting. Accordingly, the assets acquired, the liabilities assumed, and the consideration paid were recorded at their estimated fair value as of the Acquisition Date. These fair value estimates are considered preliminary and are subject to change for up to one year after the Acquisition Date as additional information becomes available. The following table provides the purchase price calculation as of the Acquisition Date and the identifiable assets purchased and the liabilities assumed at their estimated fair value. These fair value measurements are based on internal and third-party valuations. in millions Consideration paid: KeyCorp common stock issued $ 2,831 Cash payments to First Niagara stockholders 811 Exchange of First Niagara preferred stock for KeyCorp preferred stock 350 Total consideration paid $ 3,992 Statement of Net Assets Acquired at Fair Value: ASSETS Cash and due from banks and short-term investments $ 620 Investment securities 9,012 Other investments 297 Loans 23,645 Premises and equipment 245 Other intangible assets 385 Accrued income and other assets 1,449 Total assets $ 35,653 LIABILITIES Deposits $ 28,994 Bank notes and other short-term borrowings 2,698 Accrued expense and other liabilities 490 Long-term debt 846 Total liabilities $ 33,028 Net identifiable assets acquired 2,625 Goodwill $ 1,367 Measurement Period Adjustments We estimated the fair value of loans acquired from First Niagara by utilizing the discounted cash flow method within the income approach. This methodology aggregates the purchased loans by category and risk rating. Cash flows for each category were determined by estimating future credit losses and the rate of prepayments. Projected monthly cash flows were then discounted to present value based on a market rate for similar loans. There was no carryover of First Niagara’s ALLL associated with the loans we acquired. The valuation of the acquired loans was not final prior to December 31, 2016, due to the relatively short time frame in which we had to complete the acquisition as well as the complexity involved in valuing loans. An estimate was recorded during the third quarter of 2016 based on the results of a valuation exercise conducted as of December 31, 2015, and applied to the August 1, 2016, balance of loans acquired from First Niagara. During the fourth quarter of 2016, and the first quarter of 2017, we continued to analyze the valuations assigned to the acquired assets and assumed liabilities. Our third-party valuation firm provided revised valuations for loans based on the August 1, 2016 balances, which affected the valuation estimates for loans and unfunded lending-related commitments. Due to the complexity in valuing the loans and the significant amount of data inputs required, the valuation of the loans, including unfunded lending-related commitments, is not yet final. As a result of revising the loan valuation, including unfunded commitments, the purchase accounting accretion and unfunded commitment amortization amounts are also subject to change. We anticipate finalizing the valuation during the second quarter of 2017. In addition, adjustments were made to certain tax balances based on new information resulting in the revised fair values displayed below. Based on the revised valuations and new information, we updated our estimated fair values of these items within our Consolidated Balance Sheet with a corresponding adjustment to goodwill. These changes are reflected in the following table: in millions Acquired Asset or Liability Balance Sheet Line Item Provisional Estimate Revised Estimate Increase (Decrease) Tax adjustment on previous fair value measurements (a) Accrued income and other assets $ 175 $ 194 $ 19 (a) The tax adjustment on previous fair value measurements did not have any impact on the income statement for the three months ended March 31, 2017. The following table presents the PCI loans receivable balance at the First Niagara Acquisition Date: in millions PCI Contractual required payments receivable $ 1,378 Nonaccretable difference 189 Expected cash flows 1,189 Accretable yield 205 Fair value $ 984 At the First Niagara Acquisition Date, the contractually-required payments receivable on the purchased performing loans totaled $22.6 billion , with a corresponding estimated fair value of $22.2 billion . The estimated cash flows not expected to be collected at the Acquisition Date were $399 million . These amounts do not include loans held for sale and the loans that were divested as part of the 18 First Niagara Bank branches that were sold on September 9, 2016. Intangible assets consisted of the core deposit intangible, the commercial purchased credit card relationships, the consumer purchased credit card relationships, and other intangible assets. The core deposit intangible asset of $356 million recognized as part of the First Niagara merger is being amortized over its estimated useful life of approximately ten years utilizing an accelerated method. The commercial purchased credit card relationships recognized as part of the First Niagara merger are being amortized over their estimated useful life of approximately six years utilizing an accelerated method. The consumer purchased credit card relationships recognized as part of the First Niagara merger are being amortized over their estimated useful life of approximately nine years utilizing an accelerated method. Goodwill of $1.4 billion was recorded as a result of the transaction and is not amortized for book purposes. Of this total, $1.1 billion of goodwill was assigned to our Key Community Bank segment and $273 million of goodwill was assigned to our Key Corporate Bank segment. The goodwill recorded is not deductible for tax purposes. The following table shows the changes in the carrying amount of goodwill by reporting unit. Key Key Community Corporate in millions Bank Bank Total BALANCE AT DECEMBER 31, 2015 $ 979 $ 81 $ 1,060 Acquisition of First Niagara 1,109 277 1,386 BALANCE AT DECEMBER 31, 2016 2,088 358 2,446 Tax adjustment on previous fair value measurements (15 ) (4 ) (19 ) BALANCE AT MARCH 31, 2017 $ 2,073 $ 354 $ 2,427 Certificates of deposit were valued by projecting out the expected cash flows based on the contractual terms of the certificates of deposit. The fair values of savings and transaction deposit accounts acquired from First Niagara were assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. These cash flows were discounted based on a market rate for a certificate of deposit with a corresponding maturity. Direct acquisition costs related to the First Niagara acquisition were expensed as incurred and amounted to less than $1 million for the three months ended March 31, 2017. These direct acquisition costs are part of our total merger-related charges. The following table presents unaudited pro forma information as if the acquisition of First Niagara had occurred on January 1, 2015. This pro forma information gives effect to certain adjustments, including purchase accounting fair value adjustments, amortization of core deposit and other intangibles, and related income tax effects. Merger-related charges related to the First Niagara merger that we incurred during the three months ended March 31, 2016, are not reflected in the unaudited pro forma amounts. The pro forma information does not necessarily reflect the results of operations that would have occurred had KeyCorp merged with First Niagara at the beginning of 2015. Cost savings are also not reflected in the unaudited pro forma amounts for the three months ended March 31, 2016. Pro forma in millions Three months ended March 31, 2016 Net interest income (TE) $ 886 Noninterest income 506 Net income (loss) attributable to common shareholders 245

Earnings Per Common Share

Earnings Per Common Share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Common Share	3. Earnings Per Common Share Basic earnings per share is the amount of earnings (adjusted for dividends declared on our preferred stock) available to each common share outstanding during the reporting periods. Diluted earnings per share is the amount of earnings available to each common share outstanding during the reporting periods adjusted to include the effects of potentially dilutive common shares. Potentially dilutive common shares include stock options and other stock-based awards. Potentially dilutive common shares are excluded from the computation of diluted earnings per share in the periods where the effect would be antidilutive. On March 20, 2017, all outstanding Series A Preferred Stock was converted into KeyCorp common shares. Prior to this conversion, for diluted earnings per share, net income available to common shareholders could have been affected by the conversion of our convertible Series A Preferred Stock. Where the effect of this conversion would have been dilutive, net income available to common shareholders was adjusted by the amount of preferred dividends associated with our Series A Preferred Stock. Our basic and diluted earnings per common share are calculated as follows: Three months ended March 31, dollars in millions, except per share amounts 2017 2016 EARNINGS Income (loss) from continuing operations $ 325 $ 187 Less: Net income (loss) attributable to noncontrolling interests 1 — Income (loss) from continuing operations attributable to Key 324 187 Less: Dividends on Preferred Stock 28 5 Income (loss) from continuing operations attributable to Key common shareholders 296 182 Income (loss) from discontinued operations, net of taxes (a) — 1 Net income (loss) attributable to Key common shareholders $ 296 $ 183 WEIGHTED-AVERAGE COMMON SHARES Weighted-average common shares outstanding (000) 1,068,609 827,381 Effect of convertible preferred stock — — Effect of common share options and other stock awards 17,931 7,679 Weighted-average common shares and potential common shares outstanding (000) (b) 1,086,540 835,060 EARNINGS PER COMMON SHARE Income (loss) from continuing operations attributable to Key common shareholders $ .28 $ .22 Income (loss) from discontinued operations, net of taxes (a) — — Net income (loss) attributable to Key common shareholders (c) .28 .22 Income (loss) from continuing operations attributable to Key common shareholders — assuming dilution $ .27 $ .22 Income (loss) from discontinued operations, net of taxes (a) — — Net income (loss) attributable to Key common shareholders — assuming dilution (c) .27 .22 (a) In September 2009, we decided to discontinue the education lending business conducted through Key Education Resources, the education payment and financing unit of KeyBank. As a result of this decision, we have accounted for this business as a discontinued operation. For further discussion regarding the income (loss) from discontinued operations, see Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”). (b) Assumes conversion of common share options and other stock awards and/or convertible preferred stock, as applicable. (c) EPS may not foot due to rounding.

Loans and Loans Held for Sale

Loans and Loans Held for Sale	3 Months Ended
	Mar. 31, 2017
Loans Receivables [Abstract]
Loans and Loans Held for Sale	4. Loans and Loans Held for Sale in millions March 31, 2017 December 31, 2016 Commercial and industrial (a) $ 40,112 $ 39,768 Commercial real estate: Commercial mortgage 15,260 15,111 Construction 2,270 2,345 Total commercial real estate loans 17,530 17,456 Commercial lease financing (b) 4,665 4,685 Total commercial loans 62,307 61,909 Residential — prime loans: Real estate — residential mortgage 5,507 5,547 Home equity loans 12,541 12,674 Total residential — prime loans 18,048 18,221 Consumer direct loans 1,735 1,788 Credit cards 1,037 1,111 Consumer indirect loans 2,998 3,009 Total consumer loans 23,818 24,129 Total loans (c), (d) $ 86,125 $ 86,038 (a) Loan balances include $114 million and $116 million of commercial credit card balances at March 31, 2017 , and December 31, 2016 , respectively. (b) Commercial lease financing includes receivables held as collateral for a secured borrowing of $55 million and $68 million at March 31, 2017 , and December 31, 2016 , respectively. Principal reductions are based on the cash payments received from these related receivables. Additional information pertaining to this secured borrowing is included in Note 19 (“ Long-Term Debt ”) beginning on page 191 of our 2016 Form 10-K. (c) At March 31, 2017 , total loans include purchased loans of $19 billion of which $812 million were PCI loans. At December 31, 2016 , total loans include purchased loans of $21 billion , of which $865 million were PCI loans. (d) Total loans exclude loans of $1.5 billion at March 31, 2017 , and $1.6 billion at December 31, 2016 , related to the discontinued operations of the education lending business. Additional information pertaining to these loans is provided in Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”). Our loans held for sale are summarized as follows: in millions March 31, 2017 December 31, 2016 Commercial and industrial $ 171 $ 19 Real estate — commercial mortgage 1,150 1,022 Real estate — construction — 1 Commercial lease financing 1 — Real estate — residential mortgage (a) 62 62 Total loans held for sale $ 1,384 $ 1,104 (a) Real estate — residential mortgage loans held for sale are held at fair value at March 31, 2017 , and December 31, 2016 . The fair value option was elected for real estate — residential mortgage loans held for sale during the third quarter of 2016 with the First Niagara acquisition. The contractual amount due on these loans totaled $62 million at March 31, 2017 , and December 31, 2016 . Changes in fair value are recorded in “Consumer mortgage income” on the income statement. Additional information regarding residential mortgage loans held for sale fair value methodology is provided in Note 6 (“ Fair Value Measurements ”). Our quarterly summary of changes in loans held for sale is provided below: in millions March 31, 2017 December 31, 2016 Balance at beginning of the period $ 1,104 $ 1,137 New originations 2,563 2,846 Transfers from (to) held to maturity, net 17 11 Loan sales (2,299 ) (2,889 ) Loan draws (payments), net (1 ) (1 ) Balance at end of period (a) $ 1,384 $ 1,104 (a) Total loans held for sale include real estate — residential mortgage loans held for sale at fair value of $62 million at March 31, 2017 , and December 31, 2016 .

Asset Quality

Asset Quality	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Asset Quality	5. Asset Quality We assess the credit quality of the loan portfolio by monitoring net credit losses, levels of nonperforming assets, delinquencies, and credit quality ratings as defined by management. Nonperforming loans are loans for which we do not accrue interest income, and include commercial and consumer loans and leases, as well as current year TDRs and nonaccruing TDR loans from prior years. Nonperforming assets include nonperforming loans, nonperforming loans held for sale, OREO, and other nonperforming assets. Nonimpaired acquired loans are placed on nonaccrual status and reported as nonperforming or past due using the same criteria applied to the originated portfolio. PCI loans cannot be classified as nonperforming loans or TDRs. Our nonperforming assets and past due loans were as follows: in millions March 31, 2017 December 31, 2016 Total nonperforming loans (a) $ 573 $ 625 OREO (b) 49 51 Other nonperforming assets 1 — Total nonperforming assets $ 623 $ 676 Nonperforming assets from discontinued operations—education lending (c) $ 4 $ 5 TDRs included in nonperforming loans 161 141 TDRs with an allocated specific allowance (d) 84 59 Specifically allocated allowance for restructured loans (e) 30 27 Accruing loans past due 90 days or more $ 79 $ 87 Accruing loans past due 30 through 89 days 312 404 (a) Nonperforming loan balances exclude $812 million and $865 million of PCI loans at March 31, 2017 , and December 31, 2016 , respectively. (b) Includes carrying value of foreclosed residential real estate of approximately $31 million and $29 million at March 31, 2017 and December 31, 2016 , respectively. (c) Restructured loans of approximately $23 million and $22 million are included in discontinued operations at March 31, 2017 , and December 31, 2016 , respectively. See Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”) for further discussion. (d) Included in individually impaired loans allocated a specific allowance. (e) Included in allowance for individually evaluated impaired loans. We evaluate purchased loans for impairment in accordance with the applicable accounting guidance. Purchased loans that have evidence of deterioration in credit quality since origination and for which it is probable, at acquisition, that all contractually required payments will not be collected are deemed PCI. Several factors are considered when evaluating whether a loan is considered a PCI loan, including the delinquency status of the loan, updated borrower credit status, geographic information, and updated LTV ratios. In accordance with ASC 310-30, excluded from the purchased impaired loans are leases, revolving credit arrangements, and loans held for sale. We estimated the fair value of loans acquired from First Niagara by utilizing the discounted cash flow method within the income approach. See Note 2 (“ Business Combination ”) for further discussion of the fair value methodology used. There was no carryover of First Niagara’s ALLL associated with the loans we acquired. The excess of a PCI loan’s contractually required payments over the amount of its undiscounted cash flows expected to be collected is referred to as the nonaccretable difference. The nonaccretable difference, which is not accreted into income, reflects estimated future credit losses and uncollectible contractual interest expected to be incurred over the life of the PCI loan or pool. The excess of cash flows expected to be collected over the carrying amount of the PCI loans or pools is referred to as the accretable yield. This amount is accreted into interest income over the remaining life of the PCI loans or pools using the level yield method. Over the life of PCI loans or pools, Key evaluates the remaining contractually required payments receivable and estimates cash flows expected to be collected. Contractually required payments receivable may increase or decrease for a variety of reasons, such as, when the contractual terms of the loan agreement are modified, when interest rates on variable rate loans change, or when principal and/or interest payments are received. Cash flows expected to be collected on PCI loans are estimated by incorporating several primary assumptions similar to the initial estimate of fair value. These primary assumptions include probability of default, loss given default, and the amount of actual prepayments after the Acquisition Date. Increases in expected cash flows of PCI loans or pools subsequent to acquisition are recognized prospectively through adjustment of the yield on the loans or pools over its remaining life, while decreases in expected cash flows are recognized as impairment through a provision for credit losses and an increase in the ALLL. The difference between the fair value of a nonimpaired acquired loan and contractual amounts due at the Acquisition Date is accreted into income over the estimated life of the loan or pool. Contractually required payments represent the total undiscounted amount of all uncollected principal and interest payments. The following table presents the PCI loans receivable balance at the First Niagara Acquisition Date: August 1, 2016 PCI in millions Contractual required payments receivable $ 1,378 Nonaccretable difference 189 Expected cash flows 1,189 Accretable yield 205 Fair value $ 984 At the First Niagara Acquisition Date, the contractual required payments receivable on the purchased non-impaired loans totaled $22.6 billion , with a corresponding estimated fair value of $22.2 billion . The estimated cash flows not expected to be collected at the Acquisition Date were $399 million . These amounts do not include loans held for sale and the loans that were divested as part of the 18 branches that were sold on September 9, 2016. In addition to the PCI loans acquired with the First Niagara acquisition in the third quarter of 2016, Key has PCI loans from an earlier acquisition in 2012. At the 2012 acquisition date, the estimated gross contractual amount receivable of all PCI loans totaled $41 million . The estimated cash flows not expected to be collected (the nonaccretable amount) were $11 million , and the accretable amount was approximately $5 million . The following tables present the roll-forward of the accretable yield and the beginning and ending outstanding unpaid principal balance and carrying amount of all PCI loans for the three months ended March 31, 2017 , and the twelve months ended December 31, 2016 . Three months ended March 31, Twelve months ended December 31, 2017 2016 in millions Accretable Yield Carrying Amount Outstanding Unpaid Principal Balance Accretable Yield Carrying Amount Outstanding Unpaid Principal Balance Balance at beginning of period $ 197 $ 865 $ 1,002 $ 5 $ 11 $ 17 Additions — 205 Accretion (19 ) (29 ) Net reclassifications from nonaccretable to accretable 25 35 Payments received, net (11 ) (19 ) Disposals — — Balance at end of period $ 192 $ 812 $ 930 $ 197 $ 865 $ 1,002 At March 31, 2017 , the approximate carrying amount of our commercial nonperforming loans outstanding represented 75% of their original contractual amount owed, total nonperforming loans outstanding represented 79% of their original contractual amount owed, and nonperforming assets in total were carried at 79% of their original contractual amount owed. At March 31, 2017 , our 20 largest nonperforming loans totaled $228 million , representing 40% of total loans on nonperforming status. Nonperforming loans and loans held for sale reduced expected interest income by $6 million for the three months ended March 31, 2017 , and $5 million for the three months ended March 31, 2016 . The following tables set forth a further breakdown of individually impaired loans as of March 31, 2017 , and December 31, 2016 : March 31, 2017 Recorded Investment (a) Unpaid Principal Balance (b) Specific Allowance in millions With no related allowance recorded: Commercial and industrial $ 152 $ 217 — Commercial real estate: Commercial mortgage 1 3 — Total commercial real estate loans 1 3 — Total commercial loans 153 220 — Real estate — residential mortgage 20 20 — Home equity loans 60 60 — Consumer indirect loans 2 2 — Total consumer loans 82 82 — Total loans with no related allowance recorded 235 302 — With an allowance recorded: Commercial and industrial 85 90 $ 16 Commercial real estate: Commercial mortgage 15 15 3 Total commercial real estate loans 15 15 3 Total commercial loans 100 105 19 Real estate — residential mortgage 30 30 2 Home equity loans 64 64 17 Consumer direct loans 3 3 — Credit cards 3 3 — Consumer indirect loans 33 33 1 Total consumer loans 133 133 20 Total loans with an allowance recorded 233 238 39 Total $ 468 $ 540 $ 39 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet. (b) The Unpaid Principal Balance represents the customer’s legal obligation to us. December 31, 2016 Recorded Investment (a) Unpaid Principal Balance (b) Specific Allowance in millions With no related allowance recorded: Commercial and industrial $ 222 $ 301 — Commercial real estate: Commercial mortgage 2 3 — Total commercial real estate loans 2 3 — Total commercial loans 224 304 — Real estate — residential mortgage 20 20 — Home equity loans 61 61 — Consumer indirect loans 1 1 — Total consumer loans 82 82 — Total loans with no related allowance recorded 306 386 — With an allowance recorded: Commercial and industrial 62 73 $ 17 Commercial real estate: Commercial mortgage 4 4 — Total commercial real estate loans 4 4 — Total commercial loans 66 77 17 Real estate — residential mortgage 31 31 2 Home equity loans 64 64 18 Consumer direct loans 2 3 — Credit cards 3 3 — Consumer indirect loans 29 29 1 Total consumer loans 129 130 21 Total loans with an allowance recorded 195 207 38 Total $ 501 $ 593 $ 38 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet. (b) The Unpaid Principal Balance represents the customer’s legal obligation to us. The following table sets forth a further breakdown of the average recorded investment for individually impaired loans reported by Key: Average Recorded Investment (a) Three Months Ended March 31, in millions 2017 2016 Commercial and industrial $ 260 $ 215 Commercial real estate: Commercial mortgage 10 9 Construction — 6 Total commercial real estate loans 10 15 Total commercial loans 270 230 Real estate — residential mortgage 51 55 Home equity loans 125 129 Consumer direct loans 3 1 Credit cards 2 3 Consumer indirect loans 33 39 Total consumer loans 214 227 Total $ 484 $ 457 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet. For the three months ended March 31, 2017 , and March 31, 2016 , interest income recognized on the outstanding balances of accruing impaired loans totaled $3 million and $4 million , respectively. At March 31, 2017 , aggregate restructured loans (accrual and nonaccrual loans) totaled $302 million , compared to $280 million at December 31, 2016 . During the first three months of 2017, we added $47 million in restructured loans, which were partially offset by $25 million in payments and charge-offs. During 2016 , we added $107 million in restructured loans, which were offset by $107 million in payments and charge-offs. A further breakdown of TDRs included in nonperforming loans by loan category as of March 31, 2017 , follows: March 31, 2017 Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment dollars in millions LOAN TYPE Nonperforming: Commercial and industrial 20 $ 100 $ 66 Commercial real estate: Commercial mortgage 7 5 4 Total commercial real estate loans 7 5 4 Total commercial loans 27 105 70 Real estate — residential mortgage 267 16 16 Home equity loans 1,186 72 64 Consumer direct loans 40 1 1 Credit cards 288 2 1 Consumer indirect loans 522 10 9 Total consumer loans 2,303 101 91 Total nonperforming TDRs 2,330 206 161 Prior-year accruing: (a) Commercial and industrial 4 29 16 Total commercial loans 4 29 16 Real estate — residential mortgage 526 35 35 Home equity loans 1,240 75 61 Consumer direct loans 32 2 1 Credit cards 440 3 1 Consumer indirect loans 365 55 27 Total consumer loans 2,603 170 125 Total prior-year accruing TDRs 2,607 199 141 Total TDRs 4,937 $ 405 $ 302 (a) All TDRs that were restructured prior to January 1, 2017 , and are fully accruing. A further breakdown of TDRs included in nonperforming loans by loan category as of December 31, 2016 , follows: December 31, 2016 Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment dollars in millions LOAN TYPE Nonperforming: Commercial and industrial 18 $ 91 $ 50 Commercial real estate: Commercial mortgage 7 2 1 Total commercial real estate loans 7 2 1 Total commercial loans 25 93 51 Real estate — residential mortgage 264 16 16 Home equity loans 1,199 77 69 Consumer direct loans 32 1 — Credit cards 336 2 2 Consumer indirect loans 124 4 3 Total consumer loans 1,955 100 90 Total nonperforming TDRs 1,980 193 141 Prior-year accruing: (a) Commercial and Industrial 5 30 16 Total commercial loans 5 30 16 Real estate — residential mortgage 477 35 35 Home equity loans 1,231 70 57 Consumer direct loans 35 2 2 Credit cards 410 3 1 Consumer indirect loans 377 56 28 Total consumer loans 2,530 166 123 Total prior-year accruing TDRs 2,535 196 139 Total TDRs 4,515 $ 389 $ 280 (a) All TDRs that were restructured prior to January 1, 2016 , and are fully accruing. We classify loan modifications as TDRs when a borrower is experiencing financial difficulties and we have granted a concession without commensurate financial, structural, or legal consideration. Acquired loans that were previously modified in a TDR are no longer classified as TDRs at the Acquisition Date. An acquired loan may only be classified as a TDR if a modification meeting the above TDR criteria is performed after the Acquisition Date. PCI loans cannot be classified as TDRs. All commercial and consumer loan TDRs, regardless of size, are individually evaluated for impairment to determine the probable loss content and are assigned a specific loan loss allowance. This designation has the effect of moving the loan from the general reserve methodology (i.e., collectively evaluated) to the specific reserve methodology (i.e., individually evaluated) and may impact the ALLL through a charge-off or increased loan loss provision. These components affect the ultimate allowance level. Additional information regarding TDRs for discontinued operations is provided in Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”). Commercial loan TDRs are considered defaulted when principal and interest payments are 90 days past due . Consumer loan TDRs are considered defaulted when principal and interest payments are more than 60 days past due . During the three months ended March 31, 2017 , there were no commercial loan TDRs and 3 consumer loan TDRs with a combined recorded investment of less than $1 million that experienced payment defaults after modifications resulting in TDR status during 2016 . During the three months ended March 31, 2016 , there were no commercial loan TDRs and 51 consumer loan TDRs with a combined recorded investment of $3 million that experienced payment defaults from modifications resulting in TDR status during 2015 . As TDRs are individually evaluated for impairment under the specific reserve methodology, subsequent defaults do not generally have a significant additional impact on the ALLL. Commitments outstanding to lend additional funds to borrowers whose loan terms have been modified in TDRs are $15 million and $14 million at March 31, 2017 and December 31, 2016 , respectively. Our loan modifications are handled on a case-by-case basis and are negotiated to achieve mutually agreeable terms that maximize loan collectability and meet the borrower’s financial needs. Our concession types are primarily interest rate reductions, forgiveness of principal, and other modifications. The commercial TDR other concession category includes modification of loan terms, covenants, or conditions. The consumer TDR other concession category primarily includes those borrowers’ debts that are discharged through Chapter 7 bankruptcy and have not been formally re-affirmed. At March 31, 2017 , and December 31, 2016 , the recorded investment of consumer residential mortgage loans in the process of foreclosure was approximately $140 million and $141 million , respectively. The following table shows the post-modification outstanding recorded investment by concession type for our commercial and consumer accruing and nonaccruing TDRs that occurred during the three months ended March 31, 2017, and March 31, 2016. Three Months Ended March 31, in millions 2017 2016 Commercial loans: Interest rate reduction $ 7 — Other 21 $ 3 Total $ 28 $ 3 Consumer loans: Interest rate reduction $ 3 $ 2 Forgiveness of principal — 12 Other 12 2 Total $ 15 $ 16 Total commercial and consumer TDRs $ 43 $ 19 Total loans 86,125 60,438 Our policies for determining past due loans, placing loans on nonaccrual, applying payments on nonaccrual loans, and resuming accrual of interest for our commercial and consumer loan portfolios are disclosed in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Nonperforming Loans” beginning on page 108 of our 2016 Form 10-K. The following aging analysis of past due and current loans as of March 31, 2017 , and December 31, 2016 , provides further information regarding Key’s credit exposure. Aging Analysis of Loan Portfolio (a) March 31, 2017 Current 30-59 Days Past Due (b) 60-89 Days Past Due (b) 90 and Greater Days Past Due (b) Non-performing Loans Total Past Due and Non-performing Loans Purchased Credit Impaired Total Loans (c), (d) in millions LOAN TYPE Commercial and industrial $ 39,621 $ 60 $ 47 $ 24 $ 258 $ 389 $ 102 $ 40,112 Commercial real estate: Commercial mortgage 14,891 25 10 11 32 78 291 15,260 Construction 2,242 — — — 2 2 26 2,270 Total commercial real estate loans 17,133 25 10 11 34 80 317 17,530 Commercial lease financing 4,634 12 8 6 5 31 — 4,665 Total commercial loans $ 61,388 $ 97 $ 65 $ 41 $ 297 $ 500 $ 419 $ 62,307 Real estate — residential mortgage $ 5,065 $ 16 $ 7 $ 4 $ 54 $ 81 $ 361 $ 5,507 Home equity loans 12,225 42 27 14 207 290 26 12,541 Consumer direct loans 1,709 8 4 5 3 20 6 1,735 Credit cards 1,011 7 5 11 3 26 — 1,037 Consumer indirect loans 2,951 27 7 4 9 47 — 2,998 Total consumer loans $ 22,961 $ 100 $ 50 $ 38 $ 276 $ 464 $ 393 $ 23,818 Total loans $ 84,349 $ 197 $ 115 $ 79 $ 573 $ 964 $ 812 $ 86,125 (a) Amounts in table represent recorded investment and exclude loans held for sale. Recorded investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. (b) Past due loan amounts exclude PCI, even if contractually past due (or if we do not expect to collect principal or interest in full based on the original contractual terms), as we are currently accreting income over the remaining term of the loans. (c) Net of unearned income, net deferred loan fees and costs, and unamortized discounts and premiums. (d) Future accretable yield related to PCI loans is not included in the analysis of the loan portfolio. December 31, 2016 Current 30-59 Days Past Due (b) 60-89 Days Past Due (b) 90 and Greater Days Past Due (b) Non-performing Loans Total Past Due and Non-performing Loans Purchased Credit Impaired Total Loans (c), (d) in millions LOAN TYPE Commercial and industrial $ 39,242 $ 58 $ 28 $ 31 $ 297 $ 414 112 $ 39,768 Commercial real estate: Commercial mortgage 14,655 93 9 6 26 134 322 15,111 Construction 2,314 — — 2 3 5 26 2,345 Total commercial real estate loans 16,969 93 9 8 29 139 348 17,456 Commercial lease financing 4,641 28 3 5 8 44 — 4,685 Total commercial loans $ 60,852 $ 179 $ 40 $ 44 $ 334 $ 597 460 $ 61,909 Real estate — residential mortgage $ 5,098 $ 17 $ 5 $ 3 $ 56 $ 81 $ 368 $ 5,547 Home equity loans 12,327 49 29 16 223 317 30 12,674 Consumer direct loans 1,705 44 15 11 6 76 7 1,788 Credit cards 1,082 9 6 12 2 29 — 1,111 Consumer indirect loans 2,993 7 4 1 4 16 — 3,009 Total consumer loans $ 23,205 $ 126 $ 59 $ 43 $ 291 $ 519 $ 405 $ 24,129 Total loans $ 84,057 $ 305 $ 99 $ 87 $ 625 $ 1,116 $ 865 $ 86,038 (a) Amounts in table represent recorded investment and exclude loans held for sale. Recorded investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. (b) Past due loan amounts exclude purchased impaired loans, even if contractually past due (or if we do not expect to collect principal or interest in full based on the original contractual terms), as we are currently accreting income over the remaining term of the loans. (c) Net of unearned income, net deferred loan fees and costs, and unamortized discounts and premiums. (d) Future accretable yield related to purchased credit impaired loans is not included in the analysis of the loan portfolio. The prevalent risk characteristic for both commercial and consumer loans is the risk of loss arising from an obligor’s inability or failure to meet contractual payment or performance terms. Evaluation of this risk is stratified and monitored by the loan risk rating grades assigned for the commercial loan portfolios and the refreshed FICO score assigned for the consumer loan portfolios. Most extensions of credit are subject to loan grading or scoring. Loan grades are assigned at the time of origination, verified by credit risk management, and periodically re-evaluated thereafter. This risk rating methodology blends our judgment with quantitative modeling. Commercial loans generally are assigned two internal risk ratings. The first rating reflects the probability that the borrower will default on an obligation; the second rating reflects expected recovery rates on the credit facility. Default probability is determined based on, among other factors, the financial strength of the borrower, an assessment of the borrower’s management, the borrower’s competitive position within its industry sector, and our view of industry risk in the context of the general economic outlook. Types of exposure, transaction structure, and collateral, including credit risk mitigants, affect the expected recovery assessment. Commercial Credit Exposure — Excluding PCI Credit Risk Profile by Creditworthiness Category (a), (b) in millions Commercial and industrial RE — Commercial RE — Construction Commercial lease Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, RATING 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 Pass $ 38,268 $ 37,845 $ 14,536 $ 14,308 $ 2,199 $ 2,287 $ 4,602 $ 4,632 $ 59,605 $ 59,072 Criticized (Accruing) 1,484 1,514 401 455 43 30 58 45 1,986 2,044 Criticized (Nonaccruing) 258 297 32 26 2 2 5 8 297 333 Total $ 40,010 $ 39,656 $ 14,969 $ 14,789 $ 2,244 $ 2,319 $ 4,665 $ 4,685 $ 61,888 $ 61,449 (a) Credit quality indicators are updated on an ongoing basis and reflect credit quality information as of the dates indicated. (b) The term criticized refers to those loans that are internally classified by Key as special mention or worse, which are asset quality categories defined by regulatory authorities. These assets have an elevated level of risk and may have a high probability of default or total loss. Pass rated refers to all loans not classified as criticized. Consumer Credit Exposure — Excluding PCI Non-PCI Loans by Refreshed FICO Score (a) in millions Residential — Prime Consumer direct loans Credit cards Consumer indirect loans Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 750 and above $ 9,935 $ 9,818 $ 472 $ 498 $ 408 $ 453 $ 1,263 $ 1,266 $ 12,078 $ 12,035 660 to 749 5,821 5,266 644 661 498 525 1,190 1,195 8,153 7,647 Less than 660 1,665 1,617 199 194 131 132 545 543 2,540 2,486 No Score 240 1,122 414 428 — 1 — 5 654 1,556 Total $ 17,661 $ 17,823 $ 1,729 $ 1,781 $ 1,037 $ 1,111 $ 2,998 $ 3,009 $ 23,425 $ 23,724 (a) Borrower FICO scores provide information about the credit quality of our consumer loan portfolio as they provide an indication as to the likelihood that a debtor will repay its debts. The scores are obtained from a nationally recognized consumer rating agency and are presented in the above table at the dates indicated. Commercial Credit Exposure — PCI Credit Risk Profile by Creditworthiness Category (a), (b) in millions Commercial and Industrial RE — Commercial RE — Construction Commercial Lease Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, RATING 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 Pass $ 26 $ 12 $ 118 $ 139 $ 20 $ 21 — — $ 164 $ 172 Criticized 76 100 173 183 6 5 — — 255 288 Total $ 102 $ 112 $ 291 $ 322 $ 26 $ 26 — — $ 419 $ 460 (a) Credit quality indicators are updated on an ongoing basis and reflect credit quality information as of the dates indicated. (b) The term “criticized” refers to those loans that are internally classified by Key as special mention or worse, which are asset quality categories defined by regulatory authorities. These assets have an elevated level of risk and may have a high probability of default or total loss. Pass rated refers to all loans not classified as criticized. Consumer Credit Exposure — PCI PCI Loans by Refreshed FICO Score (a) in millions Residential — Prime Consumer direct loans Credit cards Consumer indirect loans Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 750 and above $ 136 $ 133 — — — — — — $ 136 $ 133 660 to 749 143 127 $ 2 $ 2 — — — — 145 129 Less than 660 103 133 3 4 — — — — 106 137 No Score 5 5 1 1 — — — — 6 6 Total $ 387 $ 398 $ 6 $ 7 — — — — $ 393 $ 405 (a) Borrower FICO scores provide information about the credit quality of our consumer loan portfolio as they provide an indication as to the likelihood that a debtor will repay its debts. The scores are obtained from a nationally recognized consumer rating agency and are presented in the above table at the dates indicated. We determine the appropriate level of the ALLL on at least a quarterly basis. The methodology for this determination is described in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Allowance for Loan and Lease Losses” beginning on page 109 of our 2016 Form 10-K. We apply expected loss rates to existing loans with similar risk characteristics and exercise judgment to assess the impact of qualitative factors such as changes in economic conditions, changes in credit policies or underwriting standards, and changes in the level of credit risk associated with specific industries and markets. For all commercial and consumer loan TDRs, regardless of size, as well as for impaired commercial loans with an outstanding balance of $2.5 million or greater, we conduct further analysis to determine the probable loss content and assign a specific allowance to the loan. We estimate the extent of the individual impairment for commercial loans and TDRs by comparing the recorded investment of the loan with the estimated present value of its future cash flows, the fair value of its underlying collateral, or the loan’s observable market price. Secured consumer loan TDRs that are discharged through Chapter 7 bankruptcy and not formally re-affirmed are adjusted to reflect the fair value of the underlying collateral, less costs to sell. Non-Chapter 7 consumer loan TDRs are combined in homogenous pools and assigned a specific allocation based on the estimated present value of future cash flows using the loan’s effective interest rate. A specific allowance also may be assigned, even when sources of repayment appear sufficient, if we remain uncertain about whether the loan will be repaid in full. On at least a quarterly basis, we evaluate the appropriateness of our loss estimation methods to reduce differences between estimated incurred losses and actual losses. Commercial loans are generally charged off in full or charged down to the fair value of the underlying collateral when the borrower’s payment is 180 days past due. Consumer loans are generally charged off when payments are 120 days past due. Home equity and residential mortgage loans are generally charged down to net realizable value when payment is 180 days past due. Credit card loans and similar unsecured products are charged off when payments are 180 days past due. The ALLL on the acquired non-impaired loan portfolio is estimated using the same methodology as is used for the originated portfolio, however, the estimated ALLL is compared to the remaining accretable yield to determine if any incremental ALLL must be recorded. For PCI loans, Key estimates cash flows expected to be collected quarterly. Decreases in expected cash flows are recognized as impairment through a provision for credit losses and an increase in the ALLL. The ALLL at March 31, 2017 , represents our best estimate of the probable credit losses inherent in the loan portfolio at that date. A summary of the changes in the ALLL for the periods indicated is presented in the table below: Three months ended March 31, in millions 2017 2016 Balance at beginning of period — continuing operations $ 858 $ 796 Charge-offs (77 ) (60 ) Recoveries 19 14 Net loans and leases charged off (58 ) (46 ) Provision for loan and lease losses from continuing operations 70 76 Balance at end of period — continuing operations $ 870 $ 826 The changes in the ALLL by loan category for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: Three months ended March 31, 2017 : in millions December 31, 2016 Provision Charge-offs Recoveries March 31, 2017 Commercial and Industrial $ 508 $ 31 $ (32 ) $ 5 $ 512 Commercial real estate: Real estate — commercial mortgage 144 2 — — 146 Real estate — construction 22 6 — 1 29 Total commercial real estate loans 166 8 — 1 175 Commercial lease financing 42 3 (7 ) 2 40 Total commercial loans 716 42 (39 ) 8 727 Real estate — residential mortgage 17 (3 ) 2 2 18 Home equity loans 54 4 (8 ) 3 53 Consumer direct loans 24 9 (10 ) 1 24 Credit cards 38 10 (11 ) 1 38 Consumer indirect loans 9 8 (11 ) 4 10 Total consumer loans 142 28 (38 ) 11 143 Total ALLL — continuing operations 858 70 (a) (77 ) 19 870 Discontinued operations 24 3 (6 ) 2 23 Total ALLL — including discontinued operations $ 882 $ 73 $ (83 ) $ 21 $ 893 (a) Excludes a credit for losses on lending-related commitments of $7 million . Three months ended March 31, 2016 : in millions December 31, 2015 Provision Charge-offs Recoveries March 31, 2016 Commercial and Industrial $ 450 $ 50 $ (26 ) $ 3 $ 477 Commercial real estate: Real estate — commercial mortgage 134 — (1 ) 2 135 Real estate — construction 25 (3 ) — 1 $ 23 Total commercial real estate loans 159 (3 ) (1 ) 3 158 Commercial lease financing 47 (1 ) (3 ) — 43 Total commercial loans 656 46 (30 ) 6 678 Real estate — residential mortgage 18 2 (2 ) 2 20 Home equity loans 57 14 (10 ) 3 64 Consumer direct loans 20 5 (6 ) 1 20 Credit cards 32 6 (8 ) 1 31 Consumer indirect loans 13 3 (4 ) 1 13 Total consumer loans 140 30 (30 ) 8 148 Total ALLL — continuing operations 796 76 (a) (60 ) 14 826 Discontinued operations 28 2 (9 ) 3 24 Total ALLL — including discontinued operations $ 824 $ 78 $ (69 ) $ 17 $ 850 (a) Excludes a provision for losses on lending-related commitments of $13 million . Our ALLL from continuing operations increased by $12 million , or 1.4% , from December 31, 2016 . Our allowance applies expected loss rates to our existing loans with simil

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements Fair Value Determination As defined in the applicable accounting guidance, fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants in our principal market. We have established and documented our process for determining the fair values of our assets and liabilities, where applicable. Fair value is based on quoted market prices, when available, for identical or similar assets or liabilities. In the absence of quoted market prices, we determine the fair value of our assets and liabilities using valuation models or third-party pricing services. Both of these approaches rely on market-based parameters, when available, such as interest rate yield curves, option volatilities, and credit spreads, or on unobservable inputs. Unobservable inputs may be based on our judgment, assumptions, and estimates related to credit quality, liquidity, interest rates, and other relevant inputs. Valuation adjustments, such as those pertaining to counterparty and our own credit quality and liquidity, may be necessary to ensure that assets and liabilities are recorded at fair value. Credit valuation adjustments are made when market pricing does not accurately reflect the counterparty’s or our own credit quality. We make liquidity valuation adjustments to the fair value of certain assets to reflect the uncertainty in the pricing and trading of the instruments when we are unable to observe recent market transactions for identical or similar instruments. Liquidity valuation adjustments are based on the following factors: • the amount of time since the last relevant valuation; • whether there is an actual trade or relevant external quote available at the measurement date; and • volatility associated with the primary pricing components. We ensure that our fair value measurements are accurate and appropriate by relying upon various controls, including: • an independent review and approval of valuation models and assumptions; • recurring detailed reviews of profit and loss; and • a validation of valuation model components against benchmark data and similar products, where possible. We recognize transfers between levels of the fair value hierarchy at the end of the reporting period. Quarterly, we review any changes to our valuation methodologies to ensure they are appropriate and justified, and refine our valuation methodologies if more market-based data becomes available. The Fair Value Committee, which is governed by ALCO, oversees the valuation process. Various working groups that report to the Fair Value Committee analyze and approve the underlying assumptions and valuation adjustments. Changes in valuation methodologies for Level 1 and Level 2 instruments are presented to the Accounting Policy group for approval. Changes in valuation methodologies for Level 3 instruments are presented to the Fair Value Committee for approval. The working groups are discussed in more detail in the qualitative disclosures within this note. Formal documentation of the fair valuation methodologies is prepared by the lines of business and support areas as appropriate. The documentation details the asset or liability class and related general ledger accounts, valuation techniques, fair value hierarchy level, market participants, accounting methods, valuation methodology, group responsible for valuations, and valuation inputs. Additional information regarding our accounting policies for determining fair value is provided in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Fair Value Measurements” beginning on page 110 of our 2016 Form 10-K. Qualitative Disclosures of Valuation Techniques Loans . Most loans recorded as trading account assets are valued based on market spreads for similar assets since they are actively traded. Therefore, these loans are classified as Level 2 because the fair value recorded is based on observable market data for similar assets. Securities (trading and available for sale) . We own several types of securities, requiring a range of valuation methods: • Securities are classified as Level 1 when quoted market prices are available in an active market for the identical securities. Level 1 instruments include exchange-traded equity securities. • Securities are classified as Level 2 if quoted prices for identical securities are not available, and fair value is determined using pricing models (either by a third-party pricing service or internally) or quoted prices of similar securities. These instruments include municipal bonds, bonds backed by the U.S. government, corporate bonds, agency residential and CMBS, securities issued by the U.S. Treasury, money markets, and certain agency and corporate CMOs. Inputs to the pricing models include standard inputs (i.e. yields, benchmark securities, bids, and offers), actual trade data (i.e., spreads, credit ratings, and interest rates) for comparable assets, spread tables, matrices, high-grade scales, and option-adjusted spreads. • Securities are classified as Level 3 when there is limited activity in the market for a particular instrument. To determine fair value in such cases, depending on the complexity of the valuations required, we use internal models based on certain assumptions or a third-party valuation service. At March 31, 2017 , our Level 3 instruments consist of two convertible preferred securities. Our Corporate Strategy group is responsible for reviewing the valuation model and determining the fair value of these investments on a quarterly basis. The securities are valued using a cash flow analysis of the associated private company issuers. The valuations of the securities are negatively affected by projected net losses of the associated private companies and positively affected by projected net gains. The fair values of our Level 2 securities available for sale are determined by a third-party pricing service. The valuations provided by the third-party pricing service are based on observable market inputs, which include benchmark yields, reported trades, issuer spreads, benchmark securities, bids, offers, and reference data obtained from market research publications. Inputs used by the third-party pricing service in valuing CMOs and other mortgage-backed securities also include new issue data, monthly payment information, whole loan collateral performance, and “To Be Announced” prices. In valuations of securities issued by state and political subdivisions, inputs used by the third-party pricing service also include material event notices. On a monthly basis, we validate the pricing methodologies utilized by our third-party pricing service to ensure that the fair value determination is consistent with the applicable accounting guidance and that our assets are properly classified in the fair value hierarchy. To perform this validation, we: • review documentation received from our third-party pricing service regarding the inputs used in their valuations and determine a level assessment for each category of securities; • substantiate actual inputs used for a sample of securities by comparing the actual inputs used by our third-party pricing service to comparable inputs for similar securities; and • substantiate the fair values determined for a sample of securities by comparing the fair values provided by our third-party pricing service to prices from other independent sources for the same and similar securities. We analyze variances and conduct additional research with our third-party pricing service and take appropriate steps based on our findings. Private equity and mezzanine investments . Private equity and mezzanine investments consist of investments in debt and equity securities through our Real Estate Capital line of business. They include direct investments made in specific properties, as well as indirect investments made in funds that pool assets of many investors to invest in properties. There is no active market for these investments, so we employ other valuation methods. The portion of our Real Estate Capital line of business involved with private equity and mezzanine investments is accounted for as an investment company in accordance with the applicable accounting guidance, whereby all investments are recorded at fair value. Direct private equity and mezzanine investments are classified as Level 3 assets since there is a certain amount of subjectivity and use of unobservable inputs surrounding our determination of fair value. Our Fund Management, Asset Management, and Accounting groups are responsible for reviewing the valuation models and determining the fair value of these investments on a quarterly basis. Direct investments in properties are initially valued based upon the transaction price. This amount is then adjusted to fair value based on current market conditions using the discounted cash flow method based on the expected investment exit date. The fair values of the assets are reviewed and adjusted quarterly. There were no significant direct equity and mezzanine investments at March 31, 2017 , nor at December 31, 2016 . The fair value of our indirect investments is based on the most recent value of the capital accounts as reported by the general partners of the funds in which we invest. The calculation to determine the investment’s fair value is based on our percentage ownership in the fund multiplied by the net asset value of the fund, as provided by the fund manager. Under the requirements of the Volcker Rule, we will be required to dispose of some or all of our indirect investments. The Federal Reserve extended the conformance period with respect to covered funds to July 21, 2017, for all banking entities. On January 13, 2017, Key filed for an additional extension for illiquid funds, to retain certain indirect investments until the earlier of the date on which the investment is conformed or is expected to mature, or July 21, 2022. The application for an extension was approved on February 14, 2017. As of March 31, 2017 , we have not committed to a plan to sell these investments. Therefore, these investments continue to be valued using the net asset value per share methodology. For more information about the Volcker Rule, see the discussion under the heading “Other Regulatory Developments under the Dodd-Frank Act — ‘Volcker Rule’” in the section entitled “Supervision and Regulation” beginning on page 16 of our 2016 Form 10-K. Investments in real estate private equity funds are included within private equity and mezzanine investments. The main purpose of these funds is to acquire a portfolio of real estate investments that provides attractive, risk-adjusted returns and current income for investors. Certain of these investments do not have readily determinable fair values and represent our ownership interest in an entity that follows measurement principles under investment company accounting. The following table presents the fair value of our indirect investments and related unfunded commitments at March 31, 2017 . We did not provide any financial support to investees related to our direct and indirect investments for the three months ended March 31, 2017 , and March 31, 2016 . March 31, 2017 Fair Value Unfunded Commitments in millions INVESTMENT TYPE Indirect investments Passive funds (a) (measured at NAV) $ 2 $ 1 Total $ 2 $ 1 (a) We invest in passive funds, which are multi-investor private equity funds. These investments can never be redeemed. Instead, distributions are received through the liquidation of the underlying investments in the funds. Some funds have no restrictions on sale, while others require investors to remain in the fund until maturity. The funds will be liquidated over a period of one to three years. The purpose of KREEC’s funding is to allow funds to make additional investments and keep a certain market value threshold in the funds. KREEC is obligated to provide financial support, as all investors are required, to the funds based on its ownership percentage, as noted in the Limited Partnership Agreements. Principal investments . Principal investments consist of investments in equity and debt instruments made by our principal investing entities. They include direct investments (investments made in a particular company) and indirect investments (investments made through funds that include other investors). Our principal investing entities are accounted for as investment companies in accordance with the applicable accounting guidance, whereby each investment is adjusted to fair value with any net realized or unrealized gain/loss recorded in the current period’s earnings. This process is a coordinated and documented effort by the Principal Investing Entities Deal Team (individuals from one of the independent investment managers who oversee these instruments), accounting staff, and the Investment Committee (individual employees and one of the independent investment managers). This process involves an in-depth review of the condition of each investment depending on the type of investment. Our direct investments include investments in debt and equity instruments of both private and public companies. When quoted prices are available in an active market for the identical direct investment, we use the quoted prices in the valuation process, and the related investments are classified as Level 1 assets. In most cases, quoted market prices are not available for our direct investments, and we must perform valuations using other methods. These direct investment valuations are an in-depth analysis of the condition of each investment and are based on the unique facts and circumstances related to each individual investment. There is a certain amount of subjectivity surrounding the valuation of these investments due to the combination of quantitative and qualitative factors that are used in the valuation models. Therefore, these direct investments are classified as Level 3 assets. The specific inputs used in the valuations of each type of direct investment are described below. Interest-bearing securities (i.e., loans) are valued on a quarterly basis. Valuation adjustments are determined by the Principal Investing Entities Deal Team and are subject to approval by the Investment Committee. Valuations of debt instruments are based on the Principal Investing Entities Deal Team’s knowledge of the current financial status of the subject company, which is regularly monitored throughout the term of the investment. Significant, unobservable inputs used in the valuations of these investments include the company’s payment history, adequacy of cash flows from operations, and current operating results, including market multiples and historical and forecast EBITDA. Inputs can also include the seniority of the debt, the nature of any pledged collateral, the extent to which the security interest is perfected, and the net liquidation value of collateral. Valuations of equity instruments of private companies, which are prepared on a quarterly basis, are based on current market conditions and the current financial status of each company. A valuation analysis is performed to value each investment. The valuation analysis is reviewed by the Principal Investing Entities Deal Team Member, and reviewed and approved by the Chief Administrative Officer of one of the independent investment managers. Significant unobservable inputs used in these valuations include adequacy of the company’s cash flows from operations, any significant change in the company’s performance since the prior valuation, and any significant equity issuances by the company. Equity instruments of public companies are valued using quoted prices in an active market for the identical security. If the instrument is restricted, the fair value is determined considering the number of shares traded daily, the number of the company’s total restricted shares, and price volatility. Our indirect investments include primary and secondary investments in private equity funds engaged mainly in venture- and growth-oriented investing. These investments do not have readily determinable fair values. Indirect investments are valued using a methodology that is consistent with accounting guidance allowing us to estimate fair value based upon net asset value per share (or its equivalent, such as member units or an ownership interest in partners’ capital to which a proportionate share of net assets is attributed). On January 13, 2017, Key filed for an additional extension for illiquid funds, to retain certain indirect investments until the earlier of the date on which the investment is conformed or is expected to mature, or July 21, 2022. The application for an extension was approved on February 14, 2017. As of March 31, 2017 , we have not committed to a plan to sell these investments. Therefore, these investments continue to be valued using the net asset value per share methodology. For indirect investments, management may make adjustments it deems appropriate to the net asset value if it is determined that the net asset value does not properly reflect fair value. In determining the need for an adjustment to net asset value, management performs an analysis of the private equity funds based on the independent fund manager’s valuations as well as management’s own judgment. Management also considers whether the independent fund manager adequately marks down an impaired investment, maintains financial statements in accordance with GAAP, or follows a practice of holding all investments at cost. The following table presents the fair value of our direct and indirect principal investments and related unfunded commitments at March 31, 2017 , as well as financial support provided for the three months ended March 31, 2017 , and March 31, 2016 . Financial support provided Three months ended March 31, March 31, 2017 2017 2016 in millions Fair Value Unfunded Commitments Funded Commitments Funded Other Funded Commitments Funded Other INVESTMENT TYPE Direct investments (a) $ 21 — — — — $ 13 Indirect investments (b) (measured at NAV) 155 $ 37 $ 1 — $ 1 — Total $ 176 $ 37 $ 1 — $ 1 $ 13 (a) Our direct investments consist of equity and debt investments directly in independent business enterprises. Operations of the business enterprises are handled by management of the portfolio company. The purpose of funding these enterprises is to provide financial support for business development and acquisition strategies. We infuse equity capital based on an initial contractual cash contribution and later from additional requests on behalf of the companies’ management. (b) Our indirect investments consist of buyout funds, venture capital funds, and fund of funds. These investments are generally not redeemable. Instead, distributions are received through the liquidation of the underlying investments of the fund. An investment in any one of these funds typically can be sold only with the approval of the fund’s general partners. We estimate that the underlying investments of the funds will be liquidated over a period of one to eight years. The purpose of funding our capital commitments to these investments is to allow the funds to make additional follow-on investments and pay fund expenses until the fund dissolves. We, and all other investors in the fund, are obligated to fund the full amount of our respective capital commitments to the fund based on our and their respective ownership percentages, as noted in the applicable Limited Partnership Agreement. Loans Held for Sale. As of August 1, 2016, we account for our residential mortgage loans held for sale at fair value on a recurring basis. The election of the fair value option aligns the accounting for the residential mortgages held for sale with the related forward mortgage loan sale commitments. Additionally, we have elected to account for loans repurchased due to breaches of representations and warranties at fair value. Residential mortgage loans are valued based on quoted market prices, where available, prices for other traded mortgage loans with similar characteristics, and purchase commitments and bid information received from market participants. The prices are adjusted as necessary to include the embedded servicing value in the loans and to take into consideration the specific characteristics of certain loans that are priced based on the pricing of similar loans. These adjustments represent unobservable inputs to the valuation but are not considered significant given the relative insensitivity of the value to changes in these inputs to the fair value of the loans. Accordingly, the majority of residential mortgage loans held for sale are classified as Level 2. This category also includes repurchased and temporarily unsalable residential mortgage loans that are included in “Loans, net of unearned income” on the balance sheet. These loans are repurchased due to a breach of representations and warranties in the loan sales agreement and typically occur after the loan is in default. The temporarily unsalable loans have an origination defect that makes them currently unable to be sold into the performing loan sales market. Because transaction details regarding sales of this type of loan are often unavailable, unobservable bid information from brokers and investors is heavily relied upon. Accordingly, based on the significance of unobservable inputs, these loans are classified as Level 3. Derivatives . Exchange-traded derivatives are valued using quoted prices and, therefore, are classified as Level 1 instruments. However, only a few types of derivatives are exchange-traded. The majority of our derivative positions are valued using internally developed models, based on market convention, that use observable market inputs, such as interest rate curves, yield curves, LIBOR and Overnight Index Swap discount rates and curves, index pricing curves, foreign currency curves, and volatility surfaces (a three-dimensional graph of implied volatility against strike price and maturity), as well as current prices for mortgage securities and investor supplied prices. These derivative contracts, which are classified as Level 2 instruments, include interest rate swaps, certain options, cross-currency swaps, credit default swaps, and forward mortgage loan sale commitments. We have several customized derivative instruments and risk participations that are classified as Level 3 instruments. These derivative positions are valued using internally developed models, with inputs consisting of available market data, such as bond spreads and asset values, as well as unobservable, internally derived assumptions, such as loss probabilities and internal risk ratings of customers. These derivatives are priced monthly by our MRM group using a credit valuation adjustment methodology. Swap details with the customer and our related participation percentage, if applicable, are obtained from our derivatives accounting system, which is the system of record. Applicable customer rating information is obtained from the particular loan system and represents an unobservable input to this valuation process. Using these various inputs, a valuation of these Level 3 derivatives is performed using a model that was acquired from a third party. In summary, the fair value represents an estimate of the amount that the risk participation counterparty would need to pay/receive as of the measurement date based on the probability of customer default on the swap transaction and the fair value of the underlying customer swap. Therefore, a higher loss probability and a lower credit rating would negatively affect the fair value of the risk participations and a lower loss probability and higher credit rating would positively affect the fair value of the risk participations. As a result of the First Niagara acquisition, we acquired First Niagara’s residential mortgage business, which included interest rate lock commitments. These instruments are accounted for as a derivative and valued using models containing unobservable significant inputs. For valuation purposes, the loan amount associated with each interest rate lock commitment is adjusted by its modeled pull-through (an unobservable input) defined as the percentage of loans that will close prior to the expiration of the rate lock commitment, as adjusted for approved changes to the terms. Based on the significance of unobservable inputs, these instruments are classified as Level 3. Market convention implies a credit rating of “AA” equivalent in the pricing of derivative contracts, which assumes that all counterparties have the same creditworthiness. To reflect the actual exposure on our derivative contracts related to both counterparty and our own creditworthiness, we record a fair value adjustment in the form of a credit valuation adjustment. The credit component is determined by individual counterparty based on the probability of default and considers master netting and collateral agreements. The credit valuation adjustment is classified as Level 3. Our MRM group is responsible for the valuation policies and procedures related to this credit valuation adjustment. A weekly reconciliation process is performed to ensure that all applicable derivative positions are covered in the calculation, which includes transmitting customer exposures and reserve reports to trading management, derivative traders and marketers, derivatives middle office, and accounting personnel. On a quarterly basis, MRM prepares the credit valuation adjustment calculation, which includes a detailed reserve comparison with the previous quarter, an analysis for change in reserve, and a reserve forecast to ensure that the credit valuation adjustment recorded at period end is sufficient. Other assets and liabilities. The value of our short positions is driven by the valuation of the underlying securities. If quoted prices for identical securities are not available, fair value is determined by using pricing models or quoted prices of similar securities, resulting in a Level 2 classification. For interest rate-driven products, such as government bonds, U.S. Treasury bonds and other products backed by the U.S. government, inputs include spreads, credit ratings, and interest rates. For credit-driven products, such as corporate bonds and mortgage-backed securities, inputs include actual trade data for comparable assets and bids and offers. Assets and Liabilities Measured at Fair Value on a Recurring Basis Certain assets and liabilities are measured at fair value on a recurring basis in accordance with GAAP. The following tables present these assets and liabilities at March 31, 2017 , and December 31, 2016 . March 31, 2017 Level 1 Level 2 Level 3 Total in millions ASSETS MEASURED ON A RECURRING BASIS Trading account assets: U.S. Treasury, agencies and corporations — $ 586 — $ 586 States and political subdivisions — 47 — 47 Collateralized mortgage obligations — — — — Other mortgage-backed securities — 248 — 248 Other securities $ 1 35 — 36 Total trading account securities 1 916 — 917 Commercial loans — 4 — 4 Total trading account assets 1 920 — 921 Securities available for sale: U.S. Treasury, agencies and corporations — 185 — 185 States and political subdivisions — 11 — 11 Agency residential collateralized mortgage obligations (a) — 14,563 — 14,563 Agency residential mortgage-backed securities (a) — 1,742 — 1,742 Agency commercial mortgage-backed securities — 1,910 — 1,910 Other securities 3 — $ 17 20 Total securities available for sale 3 18,411 17 18,431 Other investments: Principal investments: Direct — — 21 21 Indirect (measured at NAV) (b) — — — 155 Total principal investments — — 21 176 Equity and mezzanine investments: Indirect (measured at NAV) (b) — — — 2 Total equity and mezzanine investments — — — 2 Total other investments — — 21 178 Loans, net of unearned income — — — — Loans held for sale — 62 — 62 Derivative assets: Interest rate — 777 5 782 Foreign exchange 91 7 — 98 Commodity — 150 — 150 Credit — 2 1 3 Other — 5 4 9 Derivative assets 91 941 10 1,042 Netting adjustments (c) — — — (464 ) Total derivative assets 91 941 10 578 Accrued income and other assets — — — — Total assets on a recurring basis at fair value $ 95 $ 20,334 $ 48 $ 20,170 LIABILITIES MEASURED ON A RECURRING BASIS Bank notes and other short-term borrowings: Short positions $ 214 $ 729 — $ 943 Derivative liabilities: Interest rate — 531 — 531 Foreign exchange 78 8 — 86 Commodity — 140 — 140 Credit — 6 — 6 Other — 16 — 16 Derivative liabilities 78 701 — 779 Netting adjustments (c) — — — (524 ) Total derivative liabilities 78 701 — 255 Accrued expense and other liabilities — — — — Total liabilities on a recurring basis at fair value $ 292 $ 1,430 — $ 1,198 (a) “Collateralized mortgage obligations” and “Other mortgage-back securities” were renamed to “Agency residential collateralized mortgage obligations” and “Agency residential mortgage-backed securities”, respectively, in September 2016. There was no reclassification of previously reported balances. (b) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (c) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The net basis takes into account the impact of bilateral collateral and master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Total derivative assets and liabilities include these netting adjustments. December 31, 2016 Level 1 Level 2 Level 3 Total in millions ASSETS MEASURED ON A RECURRING BASIS Trading account assets: U.S. Treasury, agencies and corporations — $ 655 — $ 655 States and political subdivisions — 8 — 8 Collateralized mortgage obligations — — — — Other mortgage-backed securities — 113 — 113 Other securities — 73 — 73 Total trading account securities — 849 — 849 Commercial loans — 18 — 18 Total trading account assets — 867 — 867 Securities available for sale: U.S. Treasury, agencies and corporations — 184 — 184 States and political subdivisions — 11 — 11 Agency residential collateralized mortgage obligations (a) — 16,408 — 16,408 Agency residential mortgage-backed securities (a) — 1,846 — 1,846 Agency commercial mortgage-backed securities — 1,743 — 1,743 Other securities $ 3 — $ 17 20 Total securities available for sale 3 20,192 17 20,212 Other investments: Principal investments: Direct — — 27 27 Indirect (measured at NAV) (b) — — — 158 Total principal investments — — 27 185 Equity and mezzanine investments: Indirect (measured at NAV) (b) — — — 6 Total equity and mezzanine investments — — — 6 Total other investments — — 27 191 Loans, net of unearned income — — — — Loans held for sale — 62 — 62 Derivative assets: Interest rate — 923 7 930 Foreign exchange 114 9 — 123 Commodity — 176 — 176 Credit — — 1 1 Other — 2 2 4 Derivative assets 114 1,110 10 1,234 Netting adjustments (c) — — — (431 ) Total derivative assets 114 1,110 10 803 Accrued income and other assets — 8 — 8 Total assets on a recurring basis at fair value $ 117 $ 22,239 $ 54 $ 22,143 LIABILITIES MEASURED ON A RECURRING BASIS Bank notes and other short-term borrowings: Short positions $ 192 $ 616 — $ 808 Derivative liabilities: Interest rate — 737 — 737 Foreign exchange 102 11 — 113 Commodity — 165 — 165 Credit — 4 — 4 Other — 1 — 1 Derivative liabilities 102 918 — 1,020 Netting adjustments (c) — — — (384 ) Total derivative liabilities 102 918 — 636 Accrued expense and other liabilities — 14 — 14 Total liabilities on a recurring basis at fair value $ 294 $ 1,548 — $ 1,458 (a) “Collateralized mortgage obligations” and “Other mortgage-back securities” were renamed to “Agency residential collateralized mortgage obligations” and “Agency residential mortgage-backed securities”, respectively, in September 2016. There was no reclassification of previously reported balances. (b) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented

Securities

Securities	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Securities	7. Securities Securities available for sale. These are securities that we intend to hold for an indefinite period of time but that may be sold in response to changes in interest rates, prepayment risk, liquidity needs, or other factors. Securities available for sale are reported at fair value. Unrealized gains and losses (net of income taxes) deemed temporary are recorded in equity as a component of AOCI on the balance sheet. Unrealized losses on equity securities deemed to be “other-than-temporary,” and realized gains and losses resulting from sales of securities using the specific identification method, are included in “other income” on the income statement. “Other securities” held in the available-for-sale portfolio consist primarily of convertible preferred stock issued by privately held companies. Unrealized losses on debt securities deemed to be “other-than-temporary” are included in “other income” on the income statement or in AOCI on the balance sheet in accordance with the applicable accounting guidance related to the recognition of OTTI of debt securities. Held-to-maturity securities. These are debt securities that we have the intent and ability to hold until maturity. Debt securities are carried at cost and adjusted for amortization of premiums and accretion of discounts using the interest method. This method produces a constant rate of return on the adjusted carrying amount. “Other securities” held in the held-to-maturity portfolio consists primarily of foreign bonds. Unrealized losses on equity securities deemed to be “other-than-temporary,” and realized gains and losses resulting from sales of securities using the specific identification method, are included in “other income” on the income statement. Unrealized losses on debt securities deemed to be “other-than-temporary” are included in “other income” on the income statement or in AOCI on the balance sheet in accordance with the applicable accounting guidance related to the recognition of OTTI of debt securities. The amortized cost, unrealized gains and losses, and approximate fair value of our securities available for sale and held-to-maturity securities are presented in the following tables. Gross unrealized gains and losses represent the difference between the amortized cost and the fair value of securities on the balance sheet as of the dates indicated. Accordingly, the amount of these gains and losses may change in the future as market conditions change. March 31, 2017 in millions Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE U.S. Treasury, agencies, and corporations $ 188 — $ 3 $ 185 States and political subdivisions 11 — — 11 Agency residential collateralized mortgage obligations 14,790 $ 29 256 14,563 Agency residential mortgage-backed securities 1,751 5 14 1,742 Agency commercial mortgage-backed securities 1,956 — 46 1,910 Other securities 21 — 1 20 Total securities available for sale $ 18,717 $ 34 $ 320 $ 18,431 HELD TO MATURITY SECURITIES Agency residential collateralized mortgage obligations $ 7,973 $ 2 $ 188 $ 7,787 Agency residential mortgage-backed securities 605 — 5 600 Agency commercial mortgage-backed securities 1,593 3 44 1,552 Other securities 15 — — 15 Total held-to-maturity securities $ 10,186 $ 5 $ 237 $ 9,954 December 31, 2016 in millions Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE U.S. Treasury, agencies, and corporations $ 188 — $ 4 $ 184 States and political subdivisions 11 — — 11 Agency residential collateralized mortgage obligations 16,652 $ 31 275 16,408 Agency residential mortgage-backed securities 1,857 6 17 1,846 Agency commercial mortgage-backed securities 1,778 — 35 1,743 Other securities 21 — 1 20 Total securities available for sale $ 20,507 $ 37 $ 332 $ 20,212 HELD TO MATURITY SECURITIES Agency residential collateralized mortgage obligations $ 8,404 $ 1 $ 173 $ 8,232 Agency residential mortgage-backed securities 629 — 5 624 Agency commercial mortgage-backed securities 1,184 1 49 1,136 Other securities 15 — — 15 Total held-to-maturity securities $ 10,232 $ 2 $ 227 $ 10,007 The following table summarizes our securities that were in an unrealized loss position as of March 31, 2017 , and December 31, 2016 . Duration of Unrealized Loss Position Less than 12 Months 12 Months or Longer Total in millions Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses March 31, 2017 Securities available for sale: U.S Treasury, agencies, and corporations $ 185 $ 3 — — $ 185 $ 3 Agency residential collateralized mortgage obligations 10,573 205 $ 1,507 $ 51 12,080 256 Agency residential mortgage-backed securities 1,527 14 — — 1,527 14 Agency commercial mortgage-backed securities 1,910 46 — — 1,910 46 Other securities (a) — — 3 1 3 1 Held-to-maturity: Agency residential collateralized mortgage obligations $ 6,634 $ 169 $ 521 $ 19 $ 7,155 $ 188 Agency residential mortgage-backed securities (a) 525 5 — — 525 5 Agency commercial mortgage-backed securities 1,001 44 — — 1,001 44 Other securities (b) 4 — — — 4 — Total temporarily impaired securities $ 22,359 $ 486 $ 2,031 $ 71 $ 24,390 $ 557 December 31, 2016 Securities available for sale: U.S. Treasury, agencies, and corporations $ 182 $ 4 — — $ 182 $ 4 Agency residential collateralized mortgage obligations 12,345 231 $ 1,410 $ 44 13,755 275 Agency residential mortgage-backed securities 1,452 17 — — 1,452 17 Agency commercial mortgage-backed securities 1,482 35 — — 1,482 35 Other securities (a) 2 — 3 1 5 1 Held-to-maturity: Agency residential collateralized mortgage obligations 7,028 156 518 17 7,546 173 Agency residential mortgage-backed securities 547 5 — — 547 5 Agency commercial mortgage-backed securities 996 49 — — 996 49 Other securities (b) 4 — — — 4 — Total temporarily impaired securities $ 24,038 $ 497 $ 1,931 $ 62 $ 25,969 $ 559 (a) Gross unrealized losses totaled less than $1 million for other securities available for sale at March 31, 2017 , and December 31, 2016 . (b) Gross unrealized losses totaled less than $1 million for other securities held to maturity at March 31, 2017 , and December 31, 2016 . At March 31, 2017 , we had $256 million of gross unrealized losses related to 367 fixed-rate agency residential CMOs that we invested in as part of our overall A/LM strategy. These securities had a weighted-average maturity of 4.19 years at March 31, 2017 . We also had $14 million of gross unrealized losses related to 234 agency residential mortgage-backed securities positions, which had a weighted-average maturity of 3.85 years at March 31, 2017 . Because these securities have a fixed interest rate, their fair value is sensitive to movements in market interest rates. These unrealized losses are considered temporary since we expect to collect all contractually due amounts from these securities. Accordingly, these investments were reduced to their fair value through OCI, not through earnings. We regularly assess our securities portfolio for OTTI. The assessments are based on the nature of the securities, the underlying collateral, the financial condition of the issuer, the extent and duration of the loss, our intent related to the individual securities, and the likelihood that we will have to sell securities prior to expected recovery. The debt securities identified as OTTI are written down to their current fair value. For those debt securities that we intend to sell, or more likely than not will be required to sell prior to the expected recovery of the amortized cost, the entire impairment (i.e., the difference between amortized cost and the fair value) is recognized in earnings. For those debt securities that we do not intend to sell, or more likely than not will not be required to sell prior to expected recovery, the credit portion of OTTI is recognized in earnings, while the remaining OTTI is recognized in equity as a component of AOCI on the balance sheet. As shown in the following table, we did not have any impairment losses recognized in earnings for the three months ended March 31, 2017 . Three months ended March 31, 2017 in millions Balance at December 31, 2016 $ 4 Impairment recognized in earnings — Balance at March 31, 2017 $ 4 For the three months ended March 31, 2017 , net realized securities gains totaled $1 million . At March 31, 2017 , securities available for sale and held-to-maturity securities totaling $8.9 billion were pledged to secure securities sold under repurchase agreements, to secure public and trust deposits, to facilitate access to secured funding, and for other purposes required or permitted by law. The following table shows our securities by remaining maturity. CMOs and other mortgage-backed securities (both of which are included in the securities available-for-sale portfolio) as well as the CMOs in the held-to-maturity portfolio are presented based on their expected average lives. The remaining securities, in both the available-for-sale and held-to-maturity portfolios, are presented based on their remaining contractual maturity. Actual maturities may differ from expected or contractual maturities since borrowers have the right to prepay obligations with or without prepayment penalties. Securities Available for Sale Held to Maturity Securities March 31, 2017 Amortized Cost Fair Value Amortized Cost Fair Value in millions Due in one year or less $ 177 $ 179 $ 55 $ 56 Due after one through five years 16,595 16,354 6,935 6,798 Due after five through ten years 1,737 1,693 2,936 2,862 Due after ten years 208 205 260 238 Total $ 18,717 $ 18,431 $ 10,186 $ 9,954

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	8. Derivatives and Hedging Activities We are a party to various derivative instruments, mainly through our subsidiary, KeyBank. Derivative instruments are contracts between two or more parties that have a notional amount and an underlying variable, require a small or no net investment, and allow for the net settlement of positions. A derivative’s notional amount serves as the basis for the payment provision of the contract and takes the form of units, such as shares or dollars. A derivative’s underlying variable is a specified interest rate, security price, commodity price, foreign exchange rate, index, or other variable. The interaction between the notional amount and the underlying variable determines the number of units to be exchanged between the parties and influences the fair value of the derivative contract. The primary derivatives that we use are interest rate swaps, caps, floors, and futures; foreign exchange contracts; commodity derivatives; and credit derivatives. Generally, these instruments help us manage exposure to interest rate risk, mitigate the credit risk inherent in our loan portfolio, hedge against changes in foreign currency exchange rates, and meet client financing and hedging needs. As further discussed in this note: • interest rate risk is the risk that the EVE or net interest income will be adversely affected by fluctuations in interest rates; • credit risk is the risk of loss arising from an obligor’s inability or failure to meet contractual payment or performance terms; and • foreign exchange risk is the risk that an exchange rate will adversely affect the fair value of a financial instrument. Derivative assets and liabilities are recorded at fair value on the balance sheet, after taking into account the effects of bilateral collateral and master netting agreements. These agreements allow us to settle all derivative contracts held with a single counterparty on a net basis and to offset net derivative positions with related cash collateral, where applicable. As a result, we may have derivative contracts with negative fair values included in derivative assets on the balance sheet and contracts with positive fair values included in derivative liabilities. At March 31, 2017 , after taking into account the effects of bilateral collateral and master netting agreements, we had $27 million of derivative assets and a positive $8 million of derivative liabilities that relate to contracts entered into for hedging purposes. Our hedging derivative liabilities are in an asset position largely because we have contracts with positive fair values as a result of master netting agreements. As of the same date, after taking into account the effects of bilateral collateral and master netting agreements and a reserve for potential future losses, we had derivative assets of $551 million and derivative liabilities of $263 million that were not designated as hedging instruments. Additional information regarding our accounting policies for derivatives is provided in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Derivatives” beginning on page 112 of our 2016 Form 10-K. Derivatives Designated in Hedge Relationships Net interest income and the EVE change in response to changes in the mix of assets, liabilities, and off-balance sheet instruments and the associated interest rates tied to each instrument. In addition, differences in the repricing and maturity characteristics of interest-earning assets and interest-bearing liabilities cause net interest income and the EVE to fluctuate. We utilize derivatives that have been designated as part of a hedge relationship in accordance with the applicable accounting guidance to manage net interest income and EVE to within our stated risk tolerances. The primary derivative instruments used to manage interest rate risk are interest rate swaps, which convert the contractual interest rate index of agreed-upon amounts of assets and liabilities (i.e., notional amounts) to another interest rate index. We designate certain “receive fixed/pay variable” interest rate swaps as fair value hedges. These contracts convert certain fixed-rate long-term debt into variable-rate obligations, thereby modifying our exposure to changes in interest rates. As a result, we receive fixed-rate interest payments in exchange for making variable-rate payments over the lives of the contracts without exchanging the notional amounts. Similarly, we designate certain “receive fixed/pay variable” interest rate swaps as cash flow hedges. These contracts effectively convert certain floating-rate loans into fixed-rate loans to reduce the potential adverse effect of interest rate decreases on future interest income. Again, we receive fixed-rate interest payments in exchange for making variable-rate payments over the lives of the contracts without exchanging the notional amounts. We also designate certain “pay fixed/receive variable” interest rate swaps as cash flow hedges. These swaps convert certain floating-rate debt into fixed-rate debt. We also use these swaps to manage the interest rate risk associated with anticipated sales of certain commercial real estate loans. The swaps protect against the possible short-term decline in the value of the loans that could result from changes in interest rates between the time they are originated and the time they are sold. We use foreign currency forward transactions to hedge the foreign currency exposure of our net investment in various foreign equipment finance entities. These entities are denominated in a non-U.S. currency. These swaps are designated as net investment hedges to mitigate the exposure of measuring the net investment at the spot foreign exchange rate. Derivatives Not Designated in Hedge Relationships On occasion, we enter into interest rate swap contracts to manage economic risks but do not designate the instruments in hedge relationships. Excluding contracts addressing customer exposures, the amount of derivatives hedging risks on an economic basis at March 31, 2017 , was not significant. Like other financial services institutions, we originate loans and extend credit, both of which activities expose us to credit risk. We actively manage our overall loan portfolio and the associated credit risk in a manner consistent with asset quality objectives and concentration risk tolerances to mitigate portfolio credit risk. Purchasing credit default swaps enables us to transfer to a third party a portion of the credit risk associated with a particular extension of credit, including situations where there is a forecast sale of loans. Beginning in the first quarter of 2014, we began purchasing credit default swaps to reduce the credit risk associated with the debt securities held in our trading portfolio. We may also sell credit derivatives to offset our purchased credit default swap position prior to maturity. Although we use credit default swaps for risk management purposes, they are not treated as hedging instruments. We also enter into derivative contracts for other purposes, including: • interest rate swap, cap, and floor contracts generally entered into to accommodate the needs of commercial loan clients; • energy and base metal swap and option contracts entered into to accommodate the needs of clients; • foreign exchange forward and option contracts entered into primarily to accommodate the needs of clients; and • futures contracts and positions with third parties that are intended to offset or mitigate the interest rate or market risk related to client positions discussed above. These contracts are not designated as part of hedge relationships. Fair Values, Volume of Activity, and Gain/Loss Information Related to Derivative Instruments The following table summarizes the fair values of our derivative instruments on a gross and net basis as of March 31, 2017 , and December 31, 2016 . The change in the notional amounts of these derivatives by type from December 31, 2016 , to March 31, 2017 , indicates the volume of our derivative transaction activity during the first three months of 2017 . The notional amounts are not affected by bilateral collateral and master netting agreements. The derivative asset and liability balances are presented on a gross basis, prior to the application of bilateral collateral and master netting agreements. Total derivative assets and liabilities are adjusted to take into account the impact of legally enforceable master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Where master netting agreements are not in effect or are not enforceable under bankruptcy laws, we do not adjust those derivative assets and liabilities with counterparties. Securities collateral related to legally enforceable master netting agreements is not offset on the balance sheet. Our derivative instruments are included in “derivative assets” or “derivative liabilities” on the balance sheet, as indicated in the following table: March 31, 2017 December 31, 2016 Fair Value Fair Value in millions Notional Amount Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedging instruments: Interest rate $ 24,917 $ 98 $ 20 $ 24,237 $ 189 $ 94 Foreign exchange 284 3 2 282 6 4 Total 25,201 101 22 24,519 195 98 Derivatives not designated as hedging instruments: Interest rate 58,963 684 511 55,315 741 643 Foreign exchange 6,897 95 84 6,230 117 109 Commodity 1,569 150 140 1,474 176 165 Credit 418 3 6 360 1 4 Other (a) 2,625 9 16 390 4 1 Total 70,472 941 757 63,769 1,039 922 Netting adjustments (b) — (464 ) (524 ) — (431 ) (384 ) Net derivatives in the balance sheet 95,673 578 255 88,288 803 636 Other collateral (c) — (11 ) (71 ) — (21 ) (97 ) Net derivative amounts $ 95,673 $ 567 $ 184 $ 88,288 $ 782 $ 539 (a) Other derivatives include interest rate lock commitments and forward sale commitments related to our residential mortgage banking activities, forward purchase and sales contracts consisting of contractual commitments associated with “to be announced” securities and when issued securities, and when-issued security transactions in connection with an “at-the-market” equity offering program. (b) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. (c) Other collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above. Fair value hedges. Instruments designated as fair value hedges are recorded at fair value and included in “derivative assets” or “derivative liabilities” on the balance sheet. The effective portion of a change in the fair value of an instrument designated as a fair value hedge is recorded in earnings at the same time as a change in fair value of the hedged item, resulting in no effect on net income. The ineffective portion of a change in the fair value of such a hedging instrument is recorded in “other income” on the income statement with no corresponding offset. During the three -month period ended March 31, 2017 , we did not exclude any portion of these hedging instruments from the assessment of hedge effectiveness. While there is some immaterial ineffectiveness in our hedging relationships, all of our fair value hedges remained “highly effective” as of March 31, 2017 . The following table summarizes the pre-tax net gains (losses) on our fair value hedges for the three -month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. Three months ended March 31, 2017 in millions Income Statement Location of Net Gains (Losses) on Derivative Net Gains (Losses) on Derivative Hedged Item Income Statement Location of Net Gains (Losses) on Hedged Item Net Gains (Losses) on Hedged Item Interest rate Other income $ (35 ) Long-term debt Other income $ 35 (a) Interest rate Interest expense — Long-term debt 18 Total $ (17 ) $ 35 Three months ended March 31, 2016 in millions Income Statement Location of Net Gains (Losses) on Derivative Net Gains (Losses) on Derivative Hedged Item Income Statement Location of Net Gains (Losses) on Hedged Item Net Gains (Losses) on Hedged Item Interest rate Other income $ 115 Long-term debt Other income $ (115 ) (a) Interest rate Interest expense — Long-term debt 27 Total $ 142 $ (115 ) (a) Net gains (losses) on hedged items represent the change in fair value caused by fluctuations in interest rates. Cash flow hedges. Instruments designated as cash flow hedges are recorded at fair value and included in “derivative assets” or “derivative liabilities” on the balance sheet. Initially, the effective portion of a gain or loss on a cash flow hedge is recorded as a component of AOCI on the balance sheet. This amount is subsequently reclassified into income when the hedged transaction affects earnings (e.g., when we pay variable-rate interest on debt, receive variable-rate interest on commercial loans, or sell commercial real estate loans). The ineffective portion of cash flow hedging transactions is included in “other income” on the income statement. During the three -month period ended March 31, 2017 , we did not exclude any portion of these hedging instruments from the assessment of hedge effectiveness. While there is some immaterial ineffectiveness in our hedging relationships, all of our cash flow hedges remained “highly effective” as of March 31, 2017 . Considering the interest rates, yield curves, and notional amounts as of March 31, 2017 , we would expect to reclassify an estimated $8 million of after-tax net gains on derivative instruments designated as cash flow hedges from AOCI to income during the next 12 months . In addition, we expect to reclassify approximately $3 million of net losses related to terminated cash flow hedges from AOCI to income during the next 12 months. As of March 31, 2017 , the maximum length of time over which we hedge forecast transactions is 11 years . Net investment hedges. We enter into foreign currency forward contracts to hedge our exposure to changes in the carrying value of our investments in foreign subsidiaries as a result of changes in the related foreign exchange rates. Instruments designated as net investment hedges are recorded at fair value and included in “derivative assets” or “derivative liabilities” on the balance sheet. Initially, the effective portion of a gain or loss on a net investment hedge is recorded as a component of AOCI on the balance sheet when the terms of the derivative match the notional and currency risk being hedged. The effective portion is subsequently reclassified into income when the hedged transaction affects earnings (e.g., when we dispose of or liquidate a foreign subsidiary). At March 31, 2017 , AOCI reflected unrecognized, after-tax gains totaling $38 million related to cumulative changes in the fair value of our net investment hedges, which offset the unrecognized, after-tax foreign currency losses on net investment balances. The ineffective portion of net investment hedging transactions is included in “other income” on the income statement, but there was no net investment hedge ineffectiveness as of March 31, 2017 . We did not exclude any portion of our hedging instruments from the assessment of hedge effectiveness during the three -month period ended March 31, 2017 . The following table summarizes the pre-tax net gains (losses) on our cash flow and net investment hedges for the three -month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. The table includes the effective portion of net gains (losses) recognized in OCI during the period, the effective portion of net gains (losses) reclassified from OCI into income during the current period, and the portion of net gains (losses) recognized directly in income, representing the amount of hedge ineffectiveness. Three months ended March 31, 2017 in millions Net Gains (Losses) Recognized in OCI (Effective Portion) Income Statement Location of Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Income Statement Location of Net Gains (Losses) Recognized in Income (Ineffective Portion) Net Gains (Losses) Recognized in Income (Ineffective Portion) Cash Flow Hedges Interest rate $ (22 ) Interest income — Loans $ 15 Other income — Interest rate — Interest expense — Long-term debt (1 ) Other income — Interest rate — Investment banking and debt placement fees — Other income — Net Investment Hedges Foreign exchange contracts (3 ) Other Income — Other income — Total $ (25 ) $ 14 — Three months ended March 31, 2016 in millions Net Gains (Losses) Recognized in OCI (Effective Portion) Income Statement Location of Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Income Statement Location of Net Gains (Losses) Recognized in Income (Ineffective Portion) Net Gains (Losses) Recognized in Income (Ineffective Portion) Cash Flow Hedges Interest rate $ 133 Interest income — Loans $ 23 Other income — Interest rate (4 ) Interest expense — Long-term debt (1 ) Other income — Interest rate (1 ) Investment banking and debt placement fees — Other income — Net Investment Hedges Foreign exchange contracts (14 ) Other Income — Other income — Total $ 114 $ 22 — The after-tax change in AOCI resulting from cash flow and net investment hedges is as follows: in millions December 31, 2016 2017 Hedging Activity Reclassification of Gains to Net Income March 31, 2017 AOCI resulting from cash flow and net investment hedges $ (14 ) $ (15 ) $ (9 ) $ (38 ) Nonhedging instruments. Our derivatives that are not designated as hedging instruments are recorded at fair value in “derivative assets” and “derivative liabilities” on the balance sheet. Adjustments to the fair values of these instruments, as well as any premium paid or received, are included in “corporate services income,” “consumer mortgage income,” and “other income” on the income statement. The following table summarizes the pre-tax net gains (losses) on our derivatives that are not designated as hedging instruments for the three-month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. Three months ended March 31, 2017 Three months ended March 31, 2016 in millions Corporate Services Income Consumer Mortgage Income (a) Other Income Total Corporate Services Income Other Income Total NET GAINS (LOSSES) Interest rate $ 6 — $ (1 ) $ 5 $ 6 $ (1 ) $ 5 Foreign exchange 11 — — 11 10 — 10 Commodity 2 — — 2 1 — 1 Credit 1 — (5 ) (4 ) 1 (2 ) (1 ) Other — $ (1 ) (1 ) (2 ) — — — Total net gains (losses) $ 20 $ (1 ) $ (7 ) $ 12 $ 18 $ (3 ) $ 15 (a) As a result of the First Niagara acquisition, we began recognizing net gains (losses) on other derivatives related to our residential mortgage banking activities in “consumer mortgage income” in December 2016. Counterparty Credit Risk Like other financial instruments, derivatives contain an element of credit risk. This risk is measured as the expected positive replacement value of the contracts. We use several means to mitigate and manage exposure to credit risk on derivative contracts. We generally enter into bilateral collateral and master netting agreements that provide for the net settlement of all contracts with a single counterparty in the event of default. Additionally, we monitor counterparty credit risk exposure on each contract to determine appropriate limits on our total credit exposure across all product types. We review our collateral positions on a daily basis and exchange collateral with our counterparties in accordance with standard ISDA documentation, central clearing rules, and other related agreements. We generally hold collateral in the form of cash and highly rated securities issued by the U.S. Treasury, government-sponsored enterprises, or GNMA. Cash collateral of $25 million was included in derivative assets on the balance sheet at March 31, 2017 , compared to $155 million of cash collateral netted against derivative assets at December 31, 2016 . The cash collateral netted against derivative liabilities totaled $35 million at March 31, 2017 , and $108 million at December 31, 2016 . Beginning in the first quarter of 2017, the relevant agreements that allow us to access the central clearing organizations to clear derivative transactions became qualified master netting agreements resulting in a change in how cash collateral is reflected in our balance sheet and related disclosures as of March 31, 2017. As of March 31, 2017, all cash collateral exchanged with central clearing organizations is netted against the related derivative contracts in our balance sheet and related disclosures. Cash collateral exchanged with central clearing organizations was included in “short-term investments” and “NOW and money market deposit accounts” on the balance sheet in all periods prior to March 31, 2017. At December 31, 2016 , we posted $448 million of cash collateral with clearing organizations and held $59 million of cash collateral from clearing organizations. Additionally, the CME amended its rulebook effective January 3, 2017, to legally characterize variation margin payments made to and received from the CME as settlement of derivatives, not collateral against derivative exposure. As a result, variation margin payments with the CME are presented in the balance sheet and related disclosures as part of the gross fair value of CME-cleared derivative assets and liabilities. At March 31, 2017 we had paid $194 million and received $68 million in variation margin to settle CME-cleared derivatives. In addition, under the CME’s settlement rulebook, CME-cleared derivative assets and liabilities are offset against one another to determine the gross asset or liability exposure of CME-cleared derivatives. Netting cash collateral exchanged with all central clearing organizations and applying variation margin payments as settlement to CME-cleared derivative transactions resulted in a reduction of net derivative assets on our balance sheet of $121 million and a reduction of net derivative liabilities on our balance sheet of $394 million as of March 31, 2017 , as compared to December 31, 2016 . The following table summarizes the fair value of our derivative assets by type at the dates indicated. These assets represent our gross exposure to potential loss after taking into account the effects of bilateral collateral and master netting agreements and other means used to mitigate risk. in millions March 31, 2017 December 31, 2016 Interest rate $ 452 $ 782 Foreign exchange 41 62 Commodity 50 110 Credit 1 — Other 9 4 Derivative assets before collateral 553 958 Less: Related collateral (25 ) 155 Total derivative assets $ 578 $ 803 We enter into derivative transactions with two primary groups: broker-dealers and banks, and clients. Given that these groups have different economic characteristics, we have different methods for managing counterparty credit exposure and credit risk. We enter into transactions with broker-dealers and banks for various risk management purposes. These types of transactions are generally high dollar volume. We generally enter into bilateral collateral and master netting agreements with these counterparties. We began clearing certain types of derivative transactions with these counterparties in June 2013, whereby the central clearing organizations become our counterparties subsequent to novation of the original derivative contracts. In addition, we began entering into derivative contracts through swap execution facilities during the first quarter of 2014. The swap clearing and swap trade execution requirements were mandated by the Dodd-Frank Act for the purpose of reducing counterparty credit risk and increasing transparency in the derivative market. At March 31, 2017 , we had gross exposure of $464 million to broker-dealers and banks. We had net exposure of $239 million after the application of master netting agreements and cash collateral, where such qualifying agreements exist. We had net exposure of $215 million after considering $24 million of additional collateral held in the form of securities. We enter into transactions with clients to accommodate their business needs. These types of transactions are generally low dollar volume. We generally enter into master netting agreements with these counterparties. In addition, we mitigate our overall portfolio exposure and market risk by buying and selling U.S. Treasuries and Eurodollar futures and entering into offsetting positions and other derivative contracts, sometimes with entities other than broker-dealers and banks. Due to the smaller size and magnitude of the individual contracts with clients, we generally do not exchange collateral in connection with these derivative transactions. To address the risk of default associated with the uncollateralized contracts, we have established a credit valuation adjustment (included in “derivative assets”) in the amount of $5 million at March 31, 2017 , which we estimate to be the potential future losses on amounts due from client counterparties in the event of default. At March 31, 2017 , we had gross exposure of $382 million to client counterparties and other entities that are not broker-dealers or banks for derivatives that have associated master netting agreements. We had net exposure of $339 million on our derivatives with these counterparties after the application of master netting agreements, collateral, and the related reserve. Credit Derivatives We are a buyer and, under limited circumstances, may be a seller of credit protection through the credit derivative market. We purchase credit derivatives to manage the credit risk associated with specific commercial lending and swap obligations as well as exposures to debt securities. We may also sell credit derivatives, mainly single-name credit default swaps, to offset our purchased credit default swap positions prior to maturity. The following table summarizes the fair value of our credit derivatives purchased and sold by type as of March 31, 2017 , and December 31, 2016 . The fair value of credit derivatives presented below does not take into account the effects of bilateral collateral or master netting agreements. March 31, 2017 December 31, 2016 in millions Purchased Sold Net Purchased Sold Net Single-name credit default swaps $ (2 ) — $ (2 ) $ (2 ) — $ (2 ) Traded credit default swap indices (1 ) — (1 ) (1 ) — (1 ) Other (a) — — — — $ — — Total credit derivatives $ (3 ) — $ (3 ) $ (3 ) $ — (3 ) (a) As of both March 31, 2017 , and December 31, 2016 , the fair value of other credit derivatives sold totaled less than $1 million . Single-name credit default swaps are bilateral contracts whereby the seller agrees, for a premium, to provide protection against the credit risk of a specific entity (the “reference entity”) in connection with a specific debt obligation. The protected credit risk is related to adverse credit events, such as bankruptcy, failure to make payments, and acceleration or restructuring of obligations, identified in the credit derivative contract. As the seller of a single-name credit derivative, we may settle in one of two ways if the underlying reference entity experiences a predefined credit event. We may be required to pay the purchaser the difference between the par value and the market price of the debt obligation (cash settlement) or receive the specified referenced asset in exchange for payment of the par value (physical settlement). If we effect a physical settlement and receive our portion of the related debt obligation, we will join other creditors in the liquidation process, which may enable us to recover a portion of the amount paid under the credit default swap contract. We also may purchase offsetting credit derivatives for the same reference entity from third parties that will permit us to recover the amount we pay should a credit event occur. A traded credit default swap index represents a position on a basket or portfolio of reference entities. As a seller of protection on a credit default swap index, we would be required to pay the purchaser if one or more of the entities in the index had a credit event. Upon a credit event, the amount payable is based on the percentage of the notional amount allocated to the specific defaulting entity. The majority of transactions represented by the “other” category shown in the above table are risk participation agreements. In these transactions, the lead participant has a swap agreement with a customer. The lead participant (purchaser of protection) then enters into a risk participation agreement with a counterparty (seller of protection), under which the counterparty receives a fee to accept a portion of the lead participant’s credit risk. If the customer defaults on the swap contract, the counterparty to the risk participation agreement must reimburse the lead participant for the counterparty’s percentage of the positive fair value of the customer swap as of the default date. If the customer swap has a negative fair value, the counterparty has no reimbursement requirements. If the customer defaults on the swap contract and the seller fulfills its payment obligations under the risk participation agreement, the seller is entitled to a pro rata share of the lead participant’s claims against the customer under the terms of the swap agreement. The following table provides information on the types of credit derivatives sold by us and held on the balance sheet at March 31, 2017 , and December 31, 2016 . The notional amount represents the maximum amount that the seller could be required to pay. The payment/performance risk assessment is based on the default probabilities for the underlying reference entities’ debt obligations using a Moody’s credit ratings matrix known as Moody’s “Idealized” Cumulative Default Rates. The payment/performance risk shown in the table represents a weighted-average of the default probabilities for all reference entities in the respective portfolios. These default probabilities are directly correlated to the probability that we will have to make a payment under the credit derivative contracts. March 31, 2017 December 31, 2016 dollars in millions Notional Amount Average Term (Years) Payment / Performance Risk Notional Amount Average Term (Years) Payment / Performance Risk Other $ 8 11.40 12.85 % $ 4 6.49 17.93 % Total credit derivatives sold $ 8 — — $ 4 — — Credit Risk Contingent Features We have entered into certain derivative contracts that require us to post collateral to the counterparties when these contracts are in a net liability position. The amount of collateral to be posted is based on the amount of the net liability and thresholds generally related to our long-term senior unsecured credit ratings with Moody’s and S&P. Collateral requirements also are based on minimum transfer amounts, which are specific to each Credit Support Annex (a component of the ISDA Master Agreement) that we have signed with the counterparties. In a limited number of instances, counterparties have the right to terminate their ISDA Master Agreements with us if our ratings fall below a certain level, usually investment-grade level (i.e., “Baa3” for Moody’s and “BBB-” for S&P). At March 31, 2017 , KeyBank’s rating was “ A3 ” with Moody’s and “ A- ” with S&P, and KeyCorp’s rating was “ Baa1 ” with Moody’s and “ BBB+ ” with S&P. As of March 31, 2017 , the aggregate fair value of all derivative contracts with credit risk contingent features (i.e., those containing collateral posting or termination provisions based on our ratings) held by KeyBank that were in a net liability position totaled $98 million , which comprised of $164 million in derivative assets and $262 million in derivative liabilities. We had $100 million in cash and securities collateral posted to cover those positions as

Mortgage Servicing Assets

Mortgage Servicing Assets	3 Months Ended
	Mar. 31, 2017
Servicing Asset [Abstract]
Mortgage Servicing Assets	9. Mortgage Servicing Assets We originate and periodically sell commercial and residential mortgage loans but continue to service those loans for the buyers. We also may purchase the right to service commercial mortgage loans for other lenders. We record a servicing asset if we purchase or retain the right to service loans in exchange for servicing fees that exceed the going market servicing rate and are considered more than adequate compensation for servicing. Commercial and residential mortgage servicing assets are recorded as a component of “accrued income and other assets” on the balance sheet. Additional information pertaining to the accounting for mortgage and other servicing assets is included in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Servicing Assets.” Commercial Mortgage Servicing Changes in the carrying amount of commercial mortgage servicing assets are summarized as follows: Three months ended March 31, in millions 2017 2016 Balance at beginning of period $ 356 $ 321 Servicing retained from loan sales 28 7 Purchases 7 12 Amortization (22 ) (22 ) Balance at end of period $ 369 $ 318 Fair value at end of period $ 480 $ 408 The fair value of commercial mortgage servicing assets is determined by calculating the present value of future cash flows associated with servicing the loans. This calculation uses a number of assumptions that are based on current market conditions. The range and weighted average of the significant unobservable inputs used to determine the fair value of our commercial mortgage servicing assets at March 31, 2017 , and December 31, 2016 , along with the valuation techniques, are shown in the following table: March 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Commercial mortgage servicing assets Discounted cash flow Expected defaults 1.00 - 3.00% (1.30%) Residual cash flows discount rate 7.00 - 15.00% (8.60%) Escrow earn rate 1.20 - 3.20% (2.60%) Servicing cost $150 - $38,500 ($1,342) Loan assumption rate 0.00 - 3.00% (1.25%) Percentage late 0.00 - 2.00% (.31%) December 31, 2016 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Commercial mortgage servicing assets Discounted cash flow Expected defaults 1.00 - 3.00% (1.40%) Residual cash flows discount rate 7.00 - 12.00% (8.00%) Escrow earn rate 1.10 - 3.00% (2.40%) Servicing cost $150 - $2,700 ($1,124) Loan assumption rate 0.00 - 3.00% (1.13%) Percentage late 0.00 - 2.00% (.34%) If these economic assumptions change or prove incorrect, the fair value of commercial mortgage servicing assets may also change. Expected credit losses, escrow earning rates, and discount rates are critical to the valuation of commercial mortgage servicing assets. Estimates of these assumptions are based on how a market participant would view the respective rates, and reflect historical data associated with the commercial mortgage loans, industry trends, and other considerations. Actual rates may differ from those estimated due to changes in a variety of economic factors. A decrease in the value assigned to the escrow earning rates would cause a decrease in the fair value of our commercial mortgage servicing assets. An increase in the assumed default rates of commercial mortgage loans or an increase in the assigned discount rates would cause a decrease in the fair value of our commercial mortgage servicing assets. Prepayment activity on commercial serviced loans does not significantly affect the valuation of our commercial mortgage servicing assets. Unlike residential mortgages, commercial mortgages experience significantly lower prepayments due to certain contractual restrictions affecting the borrower’s ability to prepay the mortgage. We have elected to account for commercial servicing assets using the amortization method. The amortization of commercial servicing assets is determined in proportion to, and over the period of, the estimated net servicing income. The amortization of commercial servicing assets for each period, as shown in the table at the beginning of this note, is recorded as a reduction to contractual fee income. The contractual fee income from servicing commercial mortgage loans totaled $38 million for the three-month period ended March 31, 2017 , and $35 million for the three-month period ended March 31, 2016 . This fee income was offset by $22 million of amortization for the three-month period ended March 31, 2017 , and $23 million for the three-month period ended March 31, 2016 . Both the contractual fee income and the amortization are recorded, net, in “mortgage servicing fees” on the income statement. Additional information pertaining to the accounting for commercial mortgage and other servicing assets is included in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Servicing Assets” on page 113 of our 2016 Form 10-K. Residential Mortgage Servicing With the First Niagara acquisition, we acquired residential mortgage servicing assets with a fair value of $28 million as of the Acquisition Date. Changes in the carrying amount of residential mortgage servicing assets are summarized as follows: Three months ended March 31, 2017 in millions Balance at beginning of period $ 28 Servicing retained from loan sales 2 Amortization (1 ) Balance at end of period $ 29 Fair value at end of period $ 35 The fair value of mortgage servicing assets is determined by calculating the present value of future cash flows associated with servicing the loans. This calculation uses a number of assumptions that are based on current market conditions. The range and weighted-average of the significant unobservable inputs used to fair value our mortgage servicing assets at March 31, 2017 , along with the valuation techniques, are shown in the following table: March 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Residential mortgage servicing assets Discounted cash flow Prepayment speed 7.68 - 19.68% (9.24%) Discount rate 8.50 - 11.00% (8.55%) Servicing cost $76 - $3,335 ($83.03) If these economic assumptions change or prove incorrect, the fair value of residential mortgage servicing assets may also change. Prepayment speed, discount rates, and servicing cost are critical to the valuation of servicing assets. Estimates of these assumptions are based on how a market participant would view the respective rates, and reflect historical data associated with the loans, industry trends, and other considerations. Actual rates may differ from those estimated due to changes in a variety of economic factors. An increase in the prepayment speed, assigned discount rates, and servicing cost assumptions would also cause a negative impact on the fair value of our residential mortgage servicing assets. We have elected to account for residential servicing assets using the amortization method. The amortization of residential servicing assets is determined in proportion to, and over the period of, the estimated net residential servicing income. The amortization of servicing assets for March 31, 2017 , as shown in the table above, is recorded as a reduction to contractual fee income. The contractual fee income from servicing residential mortgage loans totaled $3 million for the three-month period ended March 31, 2017 . This fee income was offset by $1 million of amortization for the three-month period ended March 31, 2017 . Both the contractual fee income and the amortization are recorded, net, in “mortgage servicing fees” on the income statement.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	10. Variable Interest Entities A VIE is a partnership, limited liability company, trust, or other legal entity that meets any one of the following criteria: • The entity does not have sufficient equity to conduct its activities without additional subordinated financial support from another party. • The entity’s investors lack the power to direct the activities that most significantly affect the entity’s economic performance. • The entity’s equity at risk holders do not have the obligation to absorb losses or the right to receive residual returns. • The voting rights of some investors are not proportional to their economic interests in the entity, and substantially all of the entity’s activities involve, or are conducted on behalf of, investors with disproportionately few voting rights. Our significant VIEs are summarized below. We define a “significant interest” in a VIE as a subordinated interest that exposes us to a significant portion, but not the majority, of the VIE’s expected losses or residual returns, even though we do not have the power to direct the activities that most significantly affect the entity’s economic performance. KCC and KPP principal investments are newly assessed VIEs under the amended consolidation guidance. Additional information on the amended consolidation guidance is provided in Note 1 (“ Basis of Presentation and Accounting Policies ”). LIHTC investments. Through KCDC, we have made investments directly and indirectly in LIHTC operating partnerships formed by third parties. As a limited partner in these operating partnerships, we are allocated tax credits and deductions associated with the underlying properties. We have determined that we are not the primary beneficiary of these investments because the general partners have the power to direct the activities that most significantly influence the economic performance of their respective partnerships and have the obligation to absorb expected losses and the right to receive residual returns. As we are not the primary beneficiary of these investments, we do not include them in our corporate consolidation. Our maximum exposure to loss in connection with these partnerships consists of our unamortized investment balance plus any unfunded equity commitments and tax credits claimed but subject to recapture. We had $1.2 billion of investments in LIHTC operating partnerships at both March 31, 2017 , and December 31, 2016 . These investments are recorded in “accrued income and other assets” on our balance sheet. We do not have any loss reserves recorded related to these investments because we believe the likelihood of any loss to be remote. For all legally binding, unfunded equity commitments, we increase our recognized investment and recognize a liability. As of March 31, 2017 , and December 31, 2016 , we had liabilities of $439 million and $462 million , respectively, related to investments in qualified affordable housing projects, which are recorded in “accrued expenses and other liabilities” on our balance sheet. We continue to invest in these LIHTC operating partnerships. The assets and liabilities presented in the table below convey the size of KCDC’s direct and indirect investments at March 31, 2017 , and December 31, 2016 . As these investments represent unconsolidated VIEs, the assets and liabilities of the investments themselves are not recorded on our balance sheet. Unconsolidated VIEs in millions Total Assets Total Liabilities Maximum Exposure to Loss March 31, 2017 LIHTC investments $ 4,785 $ 1,972 $ 1,451 December 31, 2016 LIHTC investments $ 4,814 $ 2,003 $ 1,465 We amortize our LIHTC investments over the period that we expect to receive the tax benefits. During the first three months of 2017 , we recognized $40 million of amortization and $39 million of tax credits associated with these investments within “income taxes” on our income statement. During the first three months of 2016 , we recognized $33 million of amortization and $33 million of tax credits associated with these investments within “income taxes” on our income statement. Principal investments. Through our principal investing entity, KCC, we have made investments in private equity funds engaged in venture- and growth-oriented investing. As a limited partner to these funds, KCC records these investments at fair value and receives distributions from the funds in accordance with the funds’ partnership agreements. We are not the primary beneficiary of these investments as we do not hold the power to direct the activities that most significantly affect the funds’ economic performance. Such power rests with the funds’ general partners. In addition, we have neither the obligation to absorb the funds’ expected losses nor the right to receive their residual returns. Our voting rights are also disproportionate to our economic interests, and substantially all of the funds’ activities are conducted on behalf of investors with disproportionally few voting rights. Because we are not the primary beneficiary of these investments, we do not consolidate them. Our maximum exposure to loss associated with indirect principal investments consists of the investments’ fair value plus any unfunded equity commitments. The fair value of our indirect principal investments totaled $155 million and $158 million at March 31, 2017 , and December 31, 2016 , respectively. These investments are recorded in “other investments” on our balance sheet. Additional information on indirect principal investments is provided in Note 6 (“ Fair Value Measurements ”). The table below reflects the size of the private equity funds in which KCC was invested as well as our maximum exposure to loss in connection with these investments at March 31, 2017 . Unconsolidated VIEs in millions Total Assets Total Liabilities Maximum Exposure to Loss March 31, 2017 KCC indirect investments $ 19,029 $ 135 $ 192 December 31, 2016 KCC indirect investments $ 32,755 $ 201 $ 195 Other unconsolidated VIEs. We are involved with other various entities that we have determined to be VIEs in the normal course of business. We have determined that we are not the primary beneficiary of these partnerships because the general partners have the power to direct the activities that most significantly impact their economic performance. Our assets associated with these unconsolidated VIEs totaled $172 million at March 31, 2017 , and $178 million at December 31, 2016 , and primarily consisted of our investments in these entities. These assets are recorded in “accrued income and other assets,” “other investments,” and “securities available for sale” on our balance sheet. We had liabilities totaling $ 4 million associated with these unconsolidated VIEs at both March 31, 2017 , and December 31, 2016 . These liabilities are recorded in “accrued expenses and other liabilities” on our balance sheet. Consolidated VIEs. Through our principal investing entity, KPP, we have formed and funded operating entities that provide management and other related services to our investment company funds, which directly invest in portfolio companies. In return for providing services to our direct investment funds, these entities’ receive a minority equity interest in the funds. This minority equity ownership is recorded at fair value on the entities financial statements. Additional information on our direct principal investments is provided in Note 6 (“ Fair Value Measurements ”). While other equity investors manage the daily operations of these entities, we retain the power, through voting rights, to direct the activities of the entities that most significantly affect their economic performance. In addition, we have the obligation to absorb losses and the right to receive residual returns that could potentially be significant to these entities. As a result, we have determined that we are the primary beneficiary of these funds and have consolidated them since formation. The assets of these KPP entities that can only be used to settle the entities’ obligations totaled $3 million at March 31, 2017 , and $1 million at December 31, 2016 . These assets are recorded in “cash and due from banks” and “accrued income and other assets” on our balance sheet. The entities had no liabilities at March 31, 2017 , nor at December 31, 2016 , and other equity investors have no recourse to our general credit.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes Income Tax Provision In accordance with the applicable accounting guidance, the principal method established for computing the provision for income taxes in interim periods requires us to make our best estimate of the effective tax rate expected to be applicable for the full year. This estimated effective tax rate is then applied to interim consolidated pre-tax operating income to determine the interim provision for income taxes. The effective tax rate, which is the provision for income taxes as a percentage of income from continuing operations before income taxes, was 22.4% for the first quarter of 2017 and 23.0% for the first quarter of 2016 . The effective tax rates are below our combined federal and state statutory tax rate of 37.2% primarily due to income from investments in tax-advantaged assets such as corporate-owned life insurance and credits associated with renewable energy and low-income housing investments. The effective tax rates for the three months ended March 31, 2017, and March 31, 2016, were favorably affected by net discrete income tax benefits of 4.7% and 1% , respectively. The tax rate for the first quarter of 2017 was also significantly reduced due to merger-related charges of $81 million . Excluding those expenses, the tax rate for the first quarter of 2017 was 24.8% . Deferred Tax Asset At March 31, 2017 , from continuing operations we had a net deferred tax asset of $468 million , compared to a net deferred tax asset of $607 million at December 31, 2016 , included in “accrued income and other assets” on the balance sheet. At March 31, 2017 , deferred tax assets were affected by the First Niagara acquisition including certain purchase accounting adjustments and changes in market conditions that affect the mark-to-market deferred tax adjustment on securities. To determine the amount of deferred tax assets that are more likely than not to be realized, and therefore recorded, we conduct a quarterly assessment of all available evidence. This evidence includes, but is not limited to, taxable income in prior periods, projected future taxable income, and projected future reversals of deferred tax items. These assessments involve a degree of subjectivity and may undergo change. Based on these criteria, we had a valuation allowance of $26 million at March 31, 2017 , and $26 million at December 31, 2016 . The valuation allowance is associated with certain state net operating loss carryforwards, state credit carryforwards, and federal and state capital loss carryforwards. Unrecognized Tax Benefits As permitted under the applicable accounting guidance for income taxes, it is our policy to recognize interest and penalties related to unrecognized tax benefits in “income tax expense.” At March 31, 2017 , Key’s unrecognized tax benefits were $50 million . Pre-1988 Bank Reserves Acquired in a Business Combination As a result of the First Niagara acquisition, at March 31, 2017 , the retained earnings of KeyBank included approximately $92 million of allocated bad debt deductions for which no income taxes have been recorded. Under current federal law, these reserves are subject to recapture into taxable income if KeyBank, or any successor, fails to maintain its bank status under the Internal Revenue Code or makes non-dividend distributions or distributions greater than its accumulated earnings and profits. No deferred tax liability has been established as these events are not expected to occur in the foreseeable future.

Acquisition, Divestiture, and D

Acquisition, Divestiture, and Discontinued Operations	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Acquisition, Divestiture, and Discontinued Operations	12. Acquisition, Divestiture, and Discontinued Operations Acquisition First Niagara Financial Group, Inc. As previously disclosed, on October 30, 2015, KeyCorp entered into a definitive agreement and plan of merger (“Agreement”) to acquire all of the outstanding capital stock of First Niagara, headquartered in Buffalo, New York. On August 1, 2016, First Niagara merged with and into KeyCorp, with KeyCorp as the surviving entity. The total consideration for the transaction was approximately $4.0 billion . Under the terms of the Agreement, at the effective time of the merger, each share of First Niagara common stock was converted into the right to receive (i) 0.680 of a share of KeyCorp common stock and (ii) $2.30 in cash. The exchange ratio of KeyCorp stock for First Niagara stock was fixed per the Agreement and did not adjust based on changes in KeyCorp’s share trading price. First Niagara equity awards outstanding immediately prior to the effective time of the merger were converted into equity awards for KeyCorp common stock as provided in the Agreement. Each share of First Niagara’s Fixed-to-Floating Rate Perpetual Non-Cumulative Preferred Stock, Series B, was converted into a share of a newly created series of preferred stock of KeyCorp having substantially the same terms as First Niagara’s preferred stock. For more information on the acquisition, see Note 2 (“ Business Combination ”). On October 7, 2016, First Niagara Bank merged with and into KeyBank, with KeyBank as the surviving entity. Systems and client conversion also occurred during the fourth quarter of 2016 in connection with the bank merger. Divestiture On September 9, 2016, KeyCorp sold to Northwest Bank, a wholly-owned subsidiary of Northwest Bancshares, Inc., 18 First Niagara Bank branches in the Buffalo, New York market. The branches were divested in connection with the merger between First Niagara and KeyCorp and pursuant to an agreement with the United States Department of Justice and commitments to the Federal Reserve following a customary antitrust review in connection with the merger. The divestiture included $439 million of loans and $1.6 billion of deposits associated with the 18 branches. Discontinued operations Education lending. In September 2009, we decided to exit the government-guaranteed education lending business. As a result, we have accounted for this business as a discontinued operation. As of January 1, 2010, we consolidated our ten outstanding education lending securitization trusts, as we held the residual interests and are the master servicer with the power to direct the activities that most significantly influence the economic performance of the trusts. On September 30, 2014, we sold the residual interests in all of our outstanding education lending securitization trusts to a third party for $57 million . In selling the residual interests, we no longer have the obligation to absorb losses nor the right to receive benefits related to the securitization trusts. Therefore, in accordance with the applicable accounting guidance, we deconsolidated the securitization trusts and removed trust assets of $1.7 billion and trust liabilities of $1.6 billion from our balance sheet at September 30, 2014. We continue to service the securitized loans in eight of the securitization trusts and receive servicing fees, whereby we are adequately compensated, as well as remaining a counterparty to derivative contracts with three of the securitization trusts. We retained interests in the securitization trusts through our ownership of an insignificant percentage of certificates in two of the securitization trusts and two interest-only strips in one of the securitization trusts. These retained interests were remeasured at fair value on September 30, 2014, and their fair value of $1 million was recorded in “discontinued assets” on our balance sheet. These assets were valued using a similar approach and inputs that have been used to value the education loan securitization trust loans and securities, which are further discussed later in this note. “Income (loss) from discontinued operations, net of taxes” on the income statement includes (i) the changes in fair value of the portfolio loans at fair value (discussed later in this note), and (ii) the interest income and expense from the loans in portfolio at both amortized cost and fair value. These amounts are shown separately in the following table. Gains and losses attributable to changes in fair value are recorded as a component of “noninterest income” or “noninterest expense.” Interest income and interest expense related to the loans and securities are included as components of “net interest income.” The components of “income (loss) from discontinued operations, net of taxes” for the education lending business are as follows: Three months ended March 31, in millions 2017 2016 Net interest income $ 5 $ 7 Provision for credit losses 3 2 Net interest income after provision for credit losses 2 5 Noninterest income 2 1 Noninterest expense 4 5 Income (loss) before income taxes — 1 Income taxes — — Income (loss) from discontinued operations, net of taxes (a) — $ 1 (a) Includes after-tax charges of $6 million for each of the three-month periods ended March 31, 2017 , and March 31, 2016 , determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations. The discontinued assets of our education lending business included on the balance sheet are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Held-to-maturity securities $ 1 $ 1 Portfolio loans at fair value 3 3 Loans, net of unearned income (a) 1,497 1,562 Less: Allowance for loan and lease losses 23 24 Net loans 1,477 1,541 Accrued income and other assets 27 28 Total assets $ 1,505 $ 1,570 (a) At March 31, 2017 , and December 31, 2016 , unearned income was less than $1 million . The discontinued education lending business consisted of loans in portfolio recorded at fair value and loans in portfolio recorded at carrying value with appropriate valuation reserves. As of June 30, 2015, we decided to sell the portfolio loans that are recorded at fair value, which were subsequently sold during the fourth quarter of 2015. At March 31, 2017 , education loans included 2,316 TDRs with a recorded investment of approximately $23 million (pre-modification and post-modification). A specifically allocated allowance of $2 million was assigned to these loans as of March 31, 2017 . At December 31, 2016 , education loans included 2,163 TDRs with a recorded investment of approximately $22 million (pre-modification and post-modification). A specifically allocated allowance of $2 million was assigned to these loans as of December 31, 2016 . There have been no significant payment defaults. There are no significant commitments to lend additional funds to these borrowers outstanding. Additional information regarding TDR classification and ALLL methodology is provided in Note 5 (“ Asset Quality ”). In June 2015, we transferred $179 million of loans that were previously purchased from three of the outstanding securitization trusts pursuant to the legal terms of those particular trusts to held for sale and accounted for them at fair value. These portfolio loans held for sale were valued based on indicative bids to sell the loans. These loans were considered Level 3 assets since we relied on unobservable inputs when determining their fair value. Portfolio loans accounted for at fair value were $3 million at March 31, 2017 . The following table shows the significant unobservable inputs used to measure the fair value of the portfolio loans accounted for at fair value as of March 31, 2017 , and December 31, 2016 : March 31, 2017 Fair Value of Level 3 Assets and Liabilities Valuation Technique Significant Unobservable Input Range (Weighted-Average) dollars in millions Portfolio loans accounted for at fair value $ 3 Market approach Indicative bids 84.50-104.00% December 31, 2016 Fair Value of Level 3 Assets and Liabilities Valuation Technique Significant Unobservable Input Range (Weighted-Average) dollars in millions Portfolio loans accounted for at fair value $ 3 Market approach Indicative bids 84.50-104.00% The following table shows the principal and fair value amounts for our portfolio loans at carrying value at March 31, 2017 , and December 31, 2016 . Our policies for determining past due loans, placing loans on nonaccrual, applying payments on nonaccrual loans, and resuming accrual of interest are disclosed in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Nonperforming Loans” beginning on page 108 of our 2016 Form 10-K. March 31, 2017 December 31, 2016 in millions Principal Fair Value Principal Fair Value Portfolio loans at carrying value Accruing loans past due 90 days or more $ 20 N/A $ 22 N/A Loans placed on nonaccrual status 4 N/A 5 N/A The following table shows the portfolio loans at fair value and their related contractual amounts as of March 31, 2017 , and December 31, 2016 . March 31, 2017 December 31, 2016 in millions Contractual Amount Fair Value Contractual Amount Fair Value ASSETS Portfolio loans $ 3 $ 3 $ 3 $ 3 The following tables present the assets of the portfolio loans measured at fair value on a recurring basis at March 31, 2017 , and December 31, 2016 . March 31, 2017 in millions Level 1 Level 2 Level 3 Total ASSETS MEASURED ON A RECURRING BASIS Portfolio loans — — $ 3 $ 3 Total assets on a recurring basis at fair value — — $ 3 $ 3 December 31, 2016 in millions Level 1 Level 2 Level 3 Total ASSETS MEASURED ON A RECURRING BASIS Portfolio loans — — $ 3 $ 3 Total assets on a recurring basis at fair value — — $ 3 $ 3 The following table shows the change in the fair values of the Level 3 portfolio loans held for sale, portfolio loans, and consolidated education loan securitization trusts for the three-month periods ended March 31, 2017 , and March 31, 2016 . in millions Portfolio Student Loans Balance at December 31, 2016 $ 3 Settlements — Balance at March 31, 2017 (a) $ 3 Balance at December 31, 2015 $ 4 Settlements (1 ) Balance at March 31, 2016 (a) $ 3 (a) There were no purchases, sales, issuances, gains (losses) recognized in earnings, transfers into Level 3, or transfers out of Level 3 for the three -month period ended March 31, 2017 . There were no purchases, sales, issuances, gains (losses) recognized in earnings, transfers into Level 3, or transfers out of Level 3 for the three -month period ended March 31, 2016 . Austin Capital Management, Ltd. In April 2009, we decided to discontinue the operations of Austin, a subsidiary that specialized in managing hedge fund investments for institutional customers. As a result, we have accounted for this business as a discontinued operation. There was no income related to Austin for the three -month periods ended March 31, 2017 , and March 31, 2016 . The discontinued assets of Austin included on the balance sheet are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Cash and due from banks $ 15 $ 15 Total assets $ 15 $ 15 Combined discontinued operations. The combined results of the discontinued operations are as follows: Three months ended March 31, in millions 2017 2016 Net interest income $ 5 $ 7 Provision for credit losses 3 2 Net interest income after provision for credit losses 2 5 Noninterest income 2 1 Noninterest expense 4 5 Income (loss) before income taxes — 1 Income taxes — — Income (loss) from discontinued operations, net of taxes (a) — $ 1 (a) Includes after-tax charges of $6 million and for each of the three-month periods ended March 31, 2017 , and March 31, 2016 , determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations. The combined assets of the discontinued operations are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Cash and due from banks $ 15 $ 15 Held-to-maturity securities 1 1 Portfolio loans at fair value 3 3 Loans, net of unearned income (a) 1,497 1,562 Less: Allowance for loan and lease losses 23 24 Net loans 1,477 1,541 Accrued income and other assets 27 28 Total assets $ 1,520 $ 1,585 (a) At March 31, 2017 , and December 31, 2016 , unearned income was less than $1 million .

Securities Financing Activities

Securities Financing Activities	3 Months Ended
	Mar. 31, 2017
Banking and Thrift [Abstract]
Securities Financing Activities	13. Securities Financing Activities We enter into repurchase agreements to finance overnight customer sweep deposits. We also enter into repurchase and reverse repurchase agreements to settle other securities obligations. We account for these securities financing agreements as collateralized financing transactions. Repurchase and reverse repurchase agreements are recorded on the balance sheet at the amounts for which the securities will be subsequently sold or repurchased. Securities borrowed transactions are recorded on the balance sheet at the amounts of cash collateral advanced. While our securities financing agreements incorporate a right of set off, the assets and liabilities are reported on a gross basis. Reverse repurchase agreements and securities borrowed transactions are included in “short-term investments” on the balance sheet; repurchase agreements are included in “federal funds purchased and securities sold under repurchase agreements.” The following table summarizes our securities financing agreements at March 31, 2017 , and December 31, 2016 : March 31, 2017 in millions Gross Amount Presented in Balance Sheet Netting Adjustments (a) Collateral (b) Net Amounts Offsetting of financial assets: Reverse repurchase agreements $ 4 $ (3 ) $ (1 ) — Total $ 4 $ (3 ) $ (1 ) — Offsetting of financial liabilities: Repurchase agreements (c) $ 437 $ (3 ) $ (434 ) — Total $ 437 $ (3 ) $ (434 ) — December 31, 2016 in millions Gross Amount Presented in Balance Sheet Netting Adjustments (a) Collateral (b) Net Amounts Offsetting of financial assets: Reverse repurchase agreements $ 3 $ (3 ) — — Total $ 3 $ (3 ) — — Offsetting of financial liabilities: Repurchase agreements (c) $ 497 $ (3 ) $ (494 ) — Total $ 497 $ (3 ) $ (494 ) — (a) Netting adjustments take into account the impact of master netting agreements that allow us to settle with a single counterparty on a net basis. (b) These adjustments take into account the impact of bilateral collateral agreements that allow us to offset the net positions with the related collateral. The application of collateral cannot reduce the net position below zero. Therefore, excess collateral, if any, is not reflected above. (c) Repurchase agreements are collateralized by federal agency CMOs and U.S. Treasury securities and contracted on an overnight basis. These securities are reported in “securities available for sale” on our balance sheet. As of March 31, 2017 , the carrying amount of assets pledged as collateral against repurchase agreements totaled $569 million . Assets pledged as collateral are reported in “securities available for sale” and “held-to-maturity securities” on our balance sheet. At March 31, 2017 , the liabilities associated with collateral pledged were solely comprised of customer sweep financing activity and had a carrying value of $434 million . The collateral pledged under customer sweep repurchase agreements is posted to a third-party custodian and cannot be sold or repledged by the secured party. The risk related to a decline in the market value of collateral pledged is minimal given the collateral's high credit quality and the overnight duration of the repurchase agreements. Like other financing transactions, securities financing agreements contain an element of credit risk. To mitigate and manage credit risk exposure, we generally enter into master netting agreements and other collateral arrangements that give us the right, in the event of default, to liquidate collateral held and to offset receivables and payables with the same counterparty. Additionally, we establish and monitor limits on our counterparty credit risk exposure by product type. For the reverse repurchase agreements, we monitor the value of the underlying securities we received from counterparties and either request additional collateral or return a portion of the collateral based on the value of those securities. We generally hold collateral in the form of highly rated securities issued by the U.S. Treasury and fixed income securities. In addition, we may need to provide collateral to counterparties under our repurchase agreements. With the exception of collateral pledged against customer sweep repurchase agreements, the collateral we pledge and receive can generally be sold or repledged by the secured parties.

Employee Benefits

Employee Benefits	3 Months Ended
	Mar. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Benefits	14. Employee Benefits Pension Plans Effective December 31, 2009, we amended our cash balance pension plan and other defined benefit plans to freeze all benefit accruals and close the plans to new employees. We will continue to credit participants’ existing account balances for interest until they receive their plan benefits. We changed certain pension plan assumptions after freezing the plans. As part of the acquisition of First Niagara, Key also obtained two frozen defined benefit plans sponsored by First Niagara, both of which provide benefits based upon length of service and compensation levels. Effective September 30, 2016, the two First Niagara plans merged into another defined benefit plan maintained by Key to form the KeyCorp Consolidated Cash Balance Plan. Effective December 31, 2016, our original cash balance pension plan merged into the KeyCorp Consolidated Cash Balance Plan. The components of net pension cost (benefit) for all funded and unfunded plans are as follows: Three months ended March 31, in millions 2017 2016 Interest cost on PBO $ 12 $ 10 Expected return on plan assets (17 ) (13 ) Amortization of losses 4 4 Net pension cost $ (1 ) $ 1 Other Postretirement Benefit Plans We sponsor a retiree healthcare plan in which all employees age 55 with 5 years of service (or employees age 50 with 15 years of service who are terminated under conditions that entitle them to a severance benefit) are eligible to participate. Participant contributions are adjusted annually. Key may provide a subsidy toward the cost of coverage for certain employees hired before 2001 with a minimum of 15 years of service at the time of termination. We use a separate VEBA trust to fund the retiree healthcare plan. Effective November 29, 2016, an unfunded retiree welfare plan previously sponsored by First Niagara merged into our current retiree healthcare plan. The components of net postretirement benefit cost for all funded and unfunded plans are as follows: Three months ended March 31, in millions 2017 2016 Interest cost on APBO — $ 1 Expected return on plan assets — (1 ) Net postretirement benefit cost — —

Trust Preferred Securities Issu

Trust Preferred Securities Issued by Unconsolidated Subsidiaries	3 Months Ended
	Mar. 31, 2017
Banking and Thrift [Abstract]
Trust Preferred Securities Issued by Unconsolidated Subsidiaries	15. Trust Preferred Securities Issued by Unconsolidated Subsidiaries We own the outstanding common stock of business trusts formed by us that issued corporation-obligated, mandatorily redeemable, trust preferred securities. The trusts used the proceeds from the issuance of their trust preferred securities and common stock to buy debentures issued by KeyCorp. These debentures are the trusts’ only assets; the interest payments from the debentures finance the distributions paid on the mandatorily redeemable trust preferred securities. The outstanding common stock of these business trusts is recorded in “other investments” on our balance sheet. We unconditionally guarantee the following payments or distributions on behalf of the trusts: • required distributions on the trust preferred securities; • the redemption price when a capital security is redeemed; and • the amounts due if a trust is liquidated or terminated. The Regulatory Capital Rules, discussed in “Supervision and regulation” in Item 2 of this report, implement a phase-out of trust preferred securities as Tier 1 capital, consistent with the requirements of the Dodd-Frank Act. For “standardized approach” banking organizations such as Key, the phase-out period began on January 1, 2015, and starting in 2016 requires us to treat our mandatorily redeemable, trust preferred securities as Tier 2 capital. During the quarter, we redeemed $9 million of trust preferred securities that were acquired in the First Niagara acquisition. The trust preferred securities, common stock, and related debentures are summarized as follows: dollars in millions Trust Preferred Securities, Net of Discount (a) Common Stock Principal Amount of Debentures, Net of Discount (b) Interest Rate of Trust Preferred Securities and Debentures (c) Maturity of Trust Preferred Securities and Debentures March 31, 2017 KeyCorp Capital I $ 155 $ 6 $ 161 1.738 % 2028 KeyCorp Capital II 105 4 109 6.875 2029 KeyCorp Capital III 138 4 142 7.750 2029 HNC Statutory Trust III 18 1 19 2.453 2035 Willow Grove Statutory Trust I 18 1 19 2.441 2036 HNC Statutory Trust IV 16 1 17 2.319 2037 Westbank Capital Trust II 7 — 7 3.342 2034 Westbank Capital Trust III 7 — 7 3.342 2034 Total $ 464 $ 17 $ 481 4.811 % — December 31, 2016 $ 475 $ 17 $ 492 4.845 % — (a) The trust preferred securities must be redeemed when the related debentures mature, or earlier if provided in the governing indenture. Each issue of trust preferred securities carries an interest rate identical to that of the related debenture. Certain trust preferred securities include basis adjustments related to fair value hedges totaling $58 million at March 31, 2017 , and $59 million at December 31, 2016 . See Note 8 (“ Derivatives and Hedging Activities ”) for an explanation of fair value hedges. (b) We have the right to redeem these debentures. If the debentures purchased by KeyCorp Capital I, HNC Statutory Trust III, Willow Grove Statutory Trust I, HNC Statutory Trust IV, Westbank Capital Trust II, or Westbank Capital Trust III are redeemed before they mature, the redemption price will be the principal amount, plus any accrued but unpaid interest. If the debentures purchased by KeyCorp Capital II or KeyCorp Capital III are redeemed before they mature, the redemption price will be the greater of: (i) the principal amount, plus any accrued but unpaid interest, or (ii) the sum of the present values of principal and interest payments discounted at the Treasury Rate (as defined in the applicable indenture), plus 20 basis points for KeyCorp Capital II or 25 basis points for KeyCorp Capital III, or 50 basis points in the case of redemption upon either a tax or a capital treatment event for either KeyCorp Capital II or KeyCorp Capital III, plus any accrued but unpaid interest. The principal amount of certain debentures includes basis adjustments related to fair value hedges totaling $58 million at March 31, 2017 , and $59 million at December 31, 2016 . See Note 8 for an explanation of fair value hedges. The principal amount of debentures, net of discounts, is included in “long-term debt” on the balance sheet. (c) The interest rates for the trust preferred securities issued by KeyCorp Capital II and KeyCorp Capital III are fixed. The trust preferred securities issued by KeyCorp Capital I have a floating interest rate, equal to three-month LIBOR plus 74 basis points, that reprices quarterly. The trust preferred securities issued by HNC Statutory Trust III have a floating interest rate, equal to three-month LIBOR plus 140 basis points, that reprices quarterly. The trust preferred securities issued by Willow Grove Statutory Trust I have a floating interest rate, equal to three-month LIBOR plus 131 basis points, that reprices quarterly. The trust preferred securities issued by HNC Statutory Trust IV have a floating interest rate, equal to three-month LIBOR plus 128 basis points, that reprices quarterly. The trust preferred securities issued by Westbank Capital Trust II and Westbank Capital Trust III each have a floating interest rate, equal to three-month LIBOR plus 219 basis points, that reprices quarterly. The total interest rates are weighted-average rates.

Contingent Liabilities and Guar

Contingent Liabilities and Guarantees	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities and Guarantees	16. Contingent Liabilities and Guarantees Legal Proceedings See Note 21 (“ Commitments, Contingent Liabilities, and Guarantees ”) under the heading “Legal Proceedings” on page 194 of our 2016 Form 10-K for a description of a proceeding styled In re: Checking Account Overdraft Litigation. Other litigation. From time to time, in the ordinary course of business, we and our subsidiaries are subject to various other litigation, investigations, and administrative proceedings. Private, civil litigations may range from individual actions involving a single plaintiff to putative class action lawsuits with potentially thousands of class members. Investigations may involve both formal and informal proceedings, by both government agencies and self-regulatory bodies. These other matters may involve claims for substantial monetary relief. At times, these matters may present novel claims or legal theories. Due to the complex nature of these various other matters, it may be years before some matters are resolved. While it is impossible to ascertain the ultimate resolution or range of financial liability, based on information presently known to us, we do not believe there is any other matter to which we are a party, or involving any of our properties that, individually or in the aggregate, would reasonably be expected to have a material adverse effect on our financial condition. We continually monitor and reassess the potential materiality of these other litigation matters. We note, however, that in light of the inherent uncertainty in legal proceedings there can be no assurance that the ultimate resolution will not exceed established reserves. As a result, the outcome of a particular matter, or a combination of matters, may be material to our results of operations for a particular period, depending upon the size of the loss or our income for that particular period. Guarantees We are a guarantor in various agreements with third parties. The following table shows the types of guarantees that we had outstanding at March 31, 2017 . Information pertaining to the basis for determining the liabilities recorded in connection with these guarantees is included in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Guarantees” beginning on page 115 of our 2016 Form 10-K. March 31, 2017 Maximum Potential Undiscounted Future Payments Liability Recorded in millions Financial guarantees: Standby letters of credit $ 11,779 $ 70 Recourse agreement with FNMA 2,664 5 Residential mortgage reserve 1,270 5 Return guarantee agreement with LIHTC investors 3 3 Written put options (a) 2,052 43 Total $ 17,768 $ 126 (a) The maximum potential undiscounted future payments represent notional amounts of derivatives qualifying as guarantees. We determine the payment/performance risk associated with each type of guarantee described below based on the probability that we could be required to make the maximum potential undiscounted future payments shown in the preceding table. We use a scale of low ( 0% to 30% probability of payment), moderate (greater than 30% to 70% probability of payment), or high (greater than 70% probability of payment) to assess the payment/performance risk, and have determined that the payment/performance risk associated with each type of guarantee outstanding at March 31, 2017 , is low. Standby letters of credit. KeyBank issues standby letters of credit to address clients’ financing needs. These instruments obligate us to pay a specified third party when a client fails to repay an outstanding loan or debt instrument or fails to perform some contractual nonfinancial obligation. Any amounts drawn under standby letters of credit are treated as loans to the client; they bear interest (generally at variable rates) and pose the same credit risk to us as a loan. At March 31, 2017 , our standby letters of credit had a remaining weighted-average life of two years , with remaining actual lives ranging from less than one year to as many as 18 years . Recourse agreement with FNMA. We participate as a lender in the FNMA Delegated Underwriting and Servicing program. FNMA delegates responsibility for originating, underwriting, and servicing mortgages, and we assume a limited portion of the risk of loss during the remaining term on each commercial mortgage loan that we sell to FNMA. We maintain a reserve for such potential losses in an amount that we believe approximates the fair value of our liability. At March 31, 2017 , the outstanding commercial mortgage loans in this program had a weighted-average remaining term of 7.5 years , and the unpaid principal balance outstanding of loans sold by us as a participant was $9.1 billion . The maximum potential amount of undiscounted future payments that we could be required to make under this program, as shown in the preceding table, is equal to approximately 29% of the principal balance of loans outstanding at March 31, 2017 . If we are required to make a payment, we would have an interest in the collateral underlying the related commercial mortgage loan; any loss we incur could be offset by the amount of any recovery from the collateral. Residential Mortgage Banking. We often originate and sell residential mortgage loans with servicing retained. Our loan sales activity is generally conducted through loan sales in a secondary market sponsored by FNMA and FHLMC. Subsequent to the sale of mortgage loans, we do not typically retain any interest in the underlying loans except through our relationship as the servicer of the loans. As is customary in the mortgage banking industry, we, or banks we have acquired, have made certain representations and warranties related to the sale of residential mortgage loans (including loans sold with servicing released) and to the performance of our obligations as servicer. The breach of any such representations or warranties could result in losses for us. Our maximum exposure to loss is equal to the outstanding principal balance of the sold loans; however, any loss would be reduced by any payments received on the loans or through the sale of collateral. At March 31, 2017 , the outstanding residential mortgage loans in this program had a weighted-average LTV ratio of 71% , and the unpaid principal balance outstanding of loans sold by us was $4.2 billion . The risk assessment is low for the residential mortgage product. The maximum potential amount of undiscounted future payments that we could be required to make under this program, as shown in the preceding table, is equal to approximately 30% of the principal balance of loans outstanding at March 31, 2017 . Our liability for estimated repurchase obligations on loans sold, which is included in other liabilities on our balance sheet, was $5 million at March 31, 2017 . Return guarantee agreement with LIHTC investors. KAHC, a subsidiary of KeyBank, offered limited partnership interests to qualified investors. Partnerships formed by KAHC invested in low-income residential rental properties that qualify for federal low-income housing tax credits under Section 42 of the Internal Revenue Code. In certain partnerships, investors paid a fee to KAHC for a guaranteed return that is based on the financial performance of the property and the property’s confirmed LIHTC status throughout a 15 -year compliance period. Typically, KAHC fulfills these guaranteed returns by distributing tax credits and deductions associated with the specific properties. If KAHC defaults on its obligation to provide the guaranteed return, KeyBank is obligated to make any necessary payments to investors. No recourse or collateral is available to offset our guarantee obligation other than the underlying income streams from the properties and the residual value of the operating partnership interests. As shown in the previous table, KAHC maintained a reserve in the amount of $3 million at March 31, 2017 , which is sufficient to cover estimated future obligations under the guarantees. The maximum exposure to loss reflected in the table represents undiscounted future payments due to investors for the return on and of their investments. These guarantees have expiration dates that extend through 2018 , but KAHC has not formed any new partnerships under this program since October 2003. Additional information regarding these partnerships is included in Note 10 (“ Variable Interest Entities ”). Written put options. In the ordinary course of business, we “write” put options for clients that wish to mitigate their exposure to changes in interest rates and commodity prices. At March 31, 2017 , our written put options had an average life of three years . These instruments are considered to be guarantees, as we are required to make payments to the counterparty (the client) based on changes in an underlying variable that is related to an asset, a liability, or an equity security that the client holds. We are obligated to pay the client if the applicable benchmark interest rate or commodity price is above or below a specified level (known as the “strike rate”). These written put options are accounted for as derivatives at fair value, as further discussed in Note 8 (“ Derivatives and Hedging Activities ”). We mitigate our potential future payment obligations by entering into offsetting positions with third parties. Written put options where the counterparty is a broker-dealer or bank are accounted for as derivatives at fair value but are not considered guarantees since these counterparties typically do not hold the underlying instruments. In addition, we are a purchaser and seller of credit derivatives, which are further discussed in Note 8 (“ Derivatives and Hedging Activities ”). Default guarantees. Some lines of business participate in guarantees that obligate us to perform if the debtor (typically a client) fails to satisfy all of its payment obligations to third parties. We generally undertake these guarantees for one of two possible reasons: (i) either the risk profile of the debtor should provide an investment return, or (ii) we are supporting our underlying investment in the debtor. We do not hold collateral for the default guarantees. If we were required to make a payment under a guarantee, we would receive a pro rata share should the third party collect some or all of the amounts due from the debtor. At March 31, 2017 , we had less than $1 million of default guarantees. Other Off-Balance Sheet Risk Other off-balance sheet risk stems from financial instruments that do not meet the definition of a guarantee as specified in the applicable accounting guidance, and from other relationships. Indemnifications provided in the ordinary course of business. We provide certain indemnifications, primarily through representations and warranties in contracts that we execute in the ordinary course of business in connection with loan and lease sales and other ongoing activities, as well as in connection with purchases and sales of businesses. We maintain reserves, when appropriate, with respect to liability that reasonably could arise as a result of these indemnities. Intercompany guarantees. KeyCorp, KeyBank, and certain of our affiliates are parties to various guarantees that facilitate the ongoing business activities of other affiliates. These business activities include issuing debt, assuming certain lease and insurance obligations, purchasing or issuing investments and securities, and engaging in certain leasing transactions involving clients.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income	17. Accumulated Other Comprehensive Income Our changes in AOCI for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: in millions Unrealized gains (losses) on securities available for sale Unrealized gains (losses) on derivative financial instruments Foreign currency translation adjustment Net pension and postretirement benefit costs Total Balance at December 31, 2016 $ (185 ) $ (14 ) $ (3 ) $ (339 ) $ (541 ) Other comprehensive income before reclassification, net of income taxes 6 (15 ) 1 1 (7 ) Amounts reclassified from accumulated other comprehensive income, net of income taxes (a) — (9 ) — 3 (6 ) Net current-period other comprehensive income, net of income taxes 6 (24 ) 1 4 (13 ) Balance at March 31, 2017 $ (179 ) $ (38 ) $ (2 ) $ (335 ) $ (554 ) Balance at December 31, 2015 $ (58 ) $ 20 $ (2 ) $ (365 ) $ (405 ) Other comprehensive income before reclassification, net of income taxes 128 72 5 (2 ) 203 Amounts reclassified from accumulated other comprehensive income, net of income taxes (a) — (14 ) — 3 (11 ) Net current-period other comprehensive income, net of income taxes 128 58 5 1 192 Balance at March 31, 2016 $ 70 $ 78 $ 3 $ (364 ) $ (213 ) (a) See table below for details about these reclassifications . Our reclassifications out of AOCI for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: Three months ended March 31, 2017 Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income is Presented in millions Unrealized gains (losses) on derivative financial instruments Interest rate $ 15 Interest income — Loans Interest rate (1 ) Interest expense — Long-term debt 14 Income (loss) from continuing operations before income taxes 5 Income taxes $ 9 Income (loss) from continuing operations Net pension and postretirement benefit costs Amortization of losses $ (4 ) Personnel expense Amortization of unrecognized prior service credit — Personnel expense (4 ) Income (loss) from continuing operations before income taxes (1 ) Income taxes $ (3 ) Income (loss) from continuing operations Three months ended March 31, 2016 Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income is Presented in millions Unrealized gains (losses) on derivative financial instruments Interest rate $ 23 Interest income — Loans Interest rate (1 ) Interest expense — Long-term debt 22 Income (loss) from continuing operations before income taxes 8 Income taxes $ 14 Income (loss) from continuing operations Net pension and postretirement benefit costs Amortization of losses $ (4 ) Personnel expense (4 ) Income (loss) from continuing operations before income taxes (1 ) Income taxes $ (3 ) Income (loss) from continuing operations

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Shareholder' Equity	18. Shareholders' Equity Comprehensive Capital Plan On June 29, 2016, the Federal Reserve announced that it did not object to our 2016 capital plan submitted as part of the annual CCAR process. Share repurchases of up to $350 million were included in the 2016 capital plan, which is effective through the second quarter of 2017. We completed $160 million of Common Share repurchases, including $107 million of Common Share repurchases in the open market and $53 million of Common Share repurchases related to employee equity compensation programs in the first quarter of 2017 under this authorization. Consistent with our 2016 capital plan, the Board declared a quarterly dividend of $.085 per Common Share for the first quarter of 2017 . Our 2016 capital plan proposed an increase in our quarterly Common Share dividend, up to $.095 per share, which will be considered by the Board for the second quarter of 2017. Preferred Stock On March 9, 2017, we announced that all of our 7.75% Noncumulative Perpetual Convertible Series A Preferred Stock would convert into KeyCorp Common Shares. On March 20, 2017, the conversion date, holders of the Series A Preferred Stock received 7.0922 Common Shares for each share of Series A Preferred Stock. Cash was paid in lieu of fractional shares. Prior to the conversion of the Series A Preferred Stock, we made a quarterly dividend payment of $1.9375 per share, or $6 million , on our Series A Preferred Stock during the first quarter of 2017 . We had $290 million of 7.75% Noncumulative Perpetual Convertible Series A Preferred Stock outstanding at December 31, 2016 . Our Series A Preferred Stock had a $1 par value and a $100 liquidation preference. There were 7,475,000 shares authorized and 2,900,234 shares outstanding at December 31, 2016 . As previously reported, on January 12, 2017, we provided notice of our intention to redeem all outstanding shares of the Series C Preferred Stock on February 15, 2017. On February 15, 2017, the Series C Preferred Stock was redeemed for cash at a redemption price of $25 per share. The redemption date was also a dividend payment date, and declared dividends of $.539063 per share, or $7 million , were also paid separately on February 15, 2017. The Series C Preferred Stock was initially issued in connection with the First Niagara acquisition to replace First Niagara’s outstanding preferred stock. Prior to the redemption, we had $350 million of Fixed-to-Floating Rate Perpetual Noncumulative Series C Preferred Stock. Our Series C Preferred Stock had a $1 par value with a $25 liquidation preference. There were 14,000,000 shares authorized and outstanding at December 31, 2016 . We have $525 million of depositary shares, each representing a 1/25 th ownership interest in a share of our Fixed-to-Floating Rate Perpetual Noncumulative Series D Preferred Stock outstanding at March 31, 2017 , and December 31, 2016 . Our Series D Preferred Stock has a $1 par value with a $25,000 liquidation preference. There are 21,000 shares authorized and outstanding at March 31, 2017 , and December 31, 2016 . We made payments of $12.50 per depository share on the depositary shares related to our Series D Preferred Stock during the first quarter of 2017 , for a total of $7 million . We have $500 million of depositary shares, each representing a 1/40th ownership interest in a share of our Fixed-to-Floating Rate Perpetual Noncumulative Series E Preferred Stock outstanding at March 31, 2017 , and December 31, 2016 . Our Series E Preferred Stock has a $1 par value with a $1,000 liquidation preference. There are 500,000 shares authorized and outstanding at March 31, 2017 , and December 31, 2016 . We made payments of $.395573 per depositary share on the depositary shares related to our Series E Preferred Stock during the first quarter of 2017 , for a total of $8 million .

Line of Business Results

Line of Business Results	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Line of Business Results	19. Line of Business Results The specific lines of business that constitute each of the major business segments (operating segments) are described below. Key Community Bank Key Community Bank serves individuals and small to mid-sized businesses primarily through its 15 -state branch network. Individuals are provided with branch-based deposit and investment products, personal finance services, and loans, including residential mortgages, home equity, credit card, and various types of installment loans. Key Community Bank offers personal property and casualty insurance, such as home, auto, renters, watercraft, and umbrella policies. Key Community Bank also purchases retail auto sales contracts via a network of auto dealerships. The auto dealerships finance the sale of automobiles as the initial lender and then assign the contracts to us pursuant to dealer agreements. In addition, financial, estate and retirement planning, asset management services, and Delaware Trust capabilities are offered to assist high net worth clients with their banking, trust, portfolio management, life insurance, charitable giving, and related needs. Small businesses are provided with deposit, investment and credit products, and business advisory services. Mid-sized businesses are provided with products and services, some of which are delivered by Key Corporate Bank, that include commercial lending, cash management, equipment leasing, investment, insurance including commercial property and casualty as well as captive insurance and employee benefit programs, succession planning, access to capital markets, derivatives, and foreign exchange. Key Corporate Bank Key Corporate Bank is a full-service corporate and investment bank focused principally on serving the needs of middle market clients in seven industry sectors: consumer, energy, healthcare, industrial, public sector, real estate, and technology. Key Corporate Bank delivers a broad suite of banking and capital markets products to its clients, including syndicated finance, debt and equity capital markets, commercial payments, equipment finance, commercial mortgage banking, derivatives, foreign exchange, financial advisory, and public finance. Key Corporate Bank is also a significant servicer of commercial mortgage loans and a significant special servicer of CMBS. Key Corporate Bank delivers many of its product capabilities to clients of Key Community Bank. Other Segments Other Segments consists of corporate treasury, our principal investing unit, and various exit portfolios. Reconciling Items Total assets included under “Reconciling Items” primarily represent the unallocated portion of nonearning assets of corporate support functions. Charges related to the funding of these assets are part of net interest income and are allocated to the business segments through noninterest expense. Reconciling Items also includes intercompany eliminations and certain items that are not allocated to the business segments because they do not reflect their normal operations, including merger-related charges. The information was derived from the internal financial reporting system that we use to monitor and manage our financial performance. GAAP guides financial accounting, but there is no authoritative guidance for “management accounting,” i.e., the way we apply judgment and experience to make reporting decisions. Consequently, the line of business results we report may not be comparable to line of business results presented by other companies. The selected financial data are based on internal accounting policies designed to compile results on a consistent basis and in a manner that reflects the underlying economics of the businesses. In accordance with our policies: • Net interest income is determined by assigning a standard cost for funds used or a standard credit for funds provided based on their assumed maturity, prepayment, and/or repricing characteristics; • Indirect expenses, such as computer servicing costs and corporate overhead, are allocated based on assumptions regarding the extent that each line of business actually uses the services; • The consolidated provision for credit losses is allocated among the lines of business primarily based on their actual net loan charge-offs, adjusted periodically for loan growth and changes in risk profile. The amount of the consolidated provision is based on the methodology that we use to estimate our consolidated ALLL. This methodology is described in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Allowance for Loan and Lease Losses” beginning on page 109 of our 2016 Form 10-K; • Income taxes are allocated based on the statutory federal income tax rate of 35% and a blended state income tax rate (net of the federal income tax benefit) of 2.2% ; and • Capital is assigned to each line of business based on economic equity. The development and application of the methodologies that we use to allocate items among our lines of business is a dynamic process. Accordingly, financial results may be revised periodically to reflect enhanced alignment of expense base allocation drivers, changes in the risk profile of a particular business, or changes in our organizational structure. The table on the following pages shows selected financial data for our major business segments for the three -month periods ended March 31, 2017 , and March 31, 2016 . Three months ended March 31, Key Community Bank Key Corporate Bank dollars in millions 2017 2016 2017 2016 SUMMARY OF OPERATIONS Net interest income (TE) $ 631 $ 399 $ 304 $ 218 Noninterest income 277 196 275 207 Total revenue (TE) (a) 908 595 579 425 Provision for credit losses 47 42 17 43 Depreciation and amortization expense 28 13 20 13 Other noninterest expense 599 423 283 224 Income (loss) from continuing operations before income taxes (TE) 234 117 259 145 Allocated income taxes and TE adjustments 87 43 78 27 Income (loss) from continuing operations 147 74 181 118 Income (loss) from discontinued operations, net of taxes — — — — Net income (loss) 147 74 181 118 Less: Net income (loss) attributable to noncontrolling interests — — — — Net income (loss) attributable to Key $ 147 $ 74 $ 181 $ 118 AVERAGE BALANCES (b) Loans and leases $ 47,036 $ 30,789 $ 37,737 $ 27,722 Total assets (a) 50,962 32,856 44,167 33,413 Deposits 79,393 52,803 21,003 18,074 OTHER FINANCIAL DATA Net loan charge-offs (b) $ 43 $ 23 $ 14 $ 18 Return on average allocated equity (b) 12.60 % 11.10 % 24.86 % 22.92 % Return on average allocated equity 12.60 11.10 24.86 22.92 Average full-time equivalent employees (c) 10,804 7,376 2,384 2,126 (a) Substantially all revenue generated by our major business segments is derived from clients that reside in the United States. Substantially all long-lived assets, including premises and equipment, capitalized software, and goodwill held by our major business segments, are located in the United States. (b) From continuing operations. (c) The number of average full-time equivalent employees was not adjusted for discontinued operations. Other Segments Total Segments Reconciling Items Key 2017 2016 2017 2016 2017 2016 2017 2016 $ (5 ) $ (9 ) $ 930 $ 608 $ (1 ) $ 4 $ 929 $ 612 33 30 585 433 (8 ) (2 ) 577 431 28 21 1,515 1,041 (9 ) 2 1,506 1,043 (1 ) 5 63 90 — (1 ) 63 89 1 1 49 27 44 37 93 64 10 9 892 656 28 (17 ) 920 639 18 6 511 268 (81 ) (17 ) 430 251 (5 ) (8 ) 160 62 (55 ) 2 105 64 23 14 351 206 (26 ) (19 ) 325 187 — — — — — 1 — 1 23 14 351 206 (26 ) (18 ) 325 188 2 (1 ) 2 (1 ) (1 ) 1 1 — $ 21 $ 15 $ 349 $ 207 $ (25 ) $ (19 ) $ 324 $ 188 $ 1,328 $ 1,603 $ 86,101 $ 60,114 $ 32 $ 42 $ 86,133 $ 60,156 36,549 27,729 131,678 93,998 1,063 479 132,741 94,477 2,030 756 102,426 71,633 (348 ) (35 ) 102,078 71,598 $ 1 $ 5 $ 58 $ 46 — — $ 58 $ 46 53.56 % 33.33 % 18.04 % 16.88 % (1.38 )% (1.34 )% 8.65 % 6.87 % 53.56 33.33 18.04 16.88 (1.38 ) (1.27 ) 8.65 6.90 3 8 13,191 9,510 5,195 3,893 18,386 13,403

Basis of Presentation and Acc30

Basis of Presentation and Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation	The consolidated financial statements include the accounts of KeyCorp and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Some previously reported amounts have been reclassified to conform to current reporting practices. The consolidated financial statements include any voting rights entities in which we have a controlling financial interest. In accordance with the applicable accounting guidance for consolidations, we consolidate a VIE if we have: (i) a variable interest in the entity; (ii) the power to direct activities of the VIE that most significantly affect the entity’s economic performance; and (iii) the obligation to absorb losses of the entity or the right to receive benefits from the entity that could potentially be significant to the VIE (i.e., we are considered to be the primary beneficiary). Variable interests can include equity interests, subordinated debt, derivative contracts, leases, service agreements, guarantees, standby letters of credit, loan commitments, and other contracts, agreements, and financial instruments. See Note 10 (“ Variable Interest Entities ”) for information on our involvement with VIEs. We use the equity method to account for unconsolidated investments in voting rights entities or VIEs if we have significant influence over the entity’s operating and financing decisions (usually defined as a voting or economic interest of 20% to 50% , but not controlling). Unconsolidated investments in voting rights entities or VIEs in which we have a voting or economic interest of less than 20% generally are carried at cost. Investments held by our registered broker-dealer and investment company subsidiaries (principal investing entities and Real Estate Capital line of business) are carried at fair value. We believe that the unaudited consolidated interim financial statements reflect all adjustments of a normal recurring nature and disclosures that are necessary for a fair presentation of the results for the interim periods presented. The results of operations for the interim period are not necessarily indicative of the results of operations to be expected for the full year. The interim financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in our 2016 Form 10-K.
Subsequent Events	In preparing these financial statements, subsequent events were evaluated through the time the financial statements were issued. Financial statements are considered issued when they are widely distributed to all shareholders and other financial statement users, or filed with the SEC.
Accounting Guidance Adopted and Pending Adoption	Accounting Guidance Adopted in 2017 Consolidation. In October 2016, the FASB issued new accounting guidance that amends the previous consolidation guidance issued in February 2015, to require a decision maker that holds an interest in a VIE through an entity under common control to only consider its proportionate indirect interest in the VIE in determining whether the decision maker is the VIE’s primary beneficiary. This new guidance eliminates the requirement that a decision maker treat the common control party’s interest in the VIE as if the decision maker held the interest itself, an approach referred to as “full attribution.” The new guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) on a retrospective basis. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Stock-based compensation. In March 2016, the FASB issued new accounting guidance that simplifies the accounting for several aspects of share-based payment transactions, including the related income tax consequences, the classification of awards as either equity or liabilities, and the presentation on the statement of cash flows. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us). The method of transition was dependent upon the particular amendment within the new guidance. During the three months ended March 31, 2017 , we recognized $18 million in excess tax benefits within “income taxes” on our income statement that pertained to share-based payment arrangements. In prior periods, such excess tax benefits were recorded within “capital surplus” on our balance sheet. Under the new guidance, generally, if our share price increases over an award’s vesting period, the resulting tax windfall will decrease “income taxes.” In a like manner, if our share price decreases over an award’s vesting period, the resulting tax shortfall will increase “income taxes.” This change also removed the impact of the excess tax benefits and deficiencies from the calculation of diluted EPS and is required to be applied on a prospective basis. The adoption of this accounting standard did not materially affect our statement of cash flows, nor did it affect retained earnings as of the beginning of the period of adoption. We elected to retain our existing accounting policy of estimating award forfeitures upon the award’s grant date. Equity method investments. In March 2016, the FASB issued new accounting guidance that simplifies the transition to equity method accounting by eliminating the requirement for an investor to make retroactive adjustments to the investment, results of operations, and retained earnings on a step-by-step basis when an investment becomes qualified for equity method accounting. Instead, when an investment qualifies for the equity method due to an increase in ownership or degree of influence, an equity method investor is required to add the cost of acquiring the additional interest to the current basis of the previously held interest, and to adopt the equity method of accounting as of the date the investment becomes qualified for the equity method. This accounting guidance became effective prospectively for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us). Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. This guidance will only affect our financial condition or results of operations if there is an applicable change in an investment resulting in the investment’s qualifying for equity method accounting. Derivatives and hedging. In March 2016, the FASB issued new accounting guidance that requires an entity to use a four-step decision model when assessing contingent call (put) options that can accelerate the payment of principal on debt instruments to determine whether they are clearly and closely related to their debt hosts. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) on a modified retrospective basis. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Derivatives and hedging . In March 2016, the FASB issued new accounting guidance that clarifies that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument does not, by itself, require dedesignation, but all other hedge accounting criteria must be met. This accounting guidance was effective for interim and annual reporting periods beginning after December 15, 2016 (effective January 1, 2017, for us) and was implemented using a prospective method. Early adoption was permitted. The adoption of this accounting guidance did not affect our financial condition or results of operations. Accounting Guidance Pending Adoption at March 31, 2017 Receivables. In March 2017, the FASB issued new accounting guidance that shortens the amortization period to the earliest call date for certain callable debt securities held at a premium. Securities held at a discount will continue to be amortized to maturity. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2018 (effective January 1, 2019, for us). The guidance should be applied on a modified retrospective basis using a cumulative-effect adjustment. Early adoption is permitted. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Compensation. In March 2017, the FASB issued new accounting guidance that requires service cost to be included in the same line item as certain other compensation costs related to services rendered by employees. We record compensation costs under personnel expense on the income statement. Other elements of net benefit cost should be presented separately. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). The guidance should be applied on a retrospective basis. Early adoption is permitted within the first interim period if the entity issues interim financial statements. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Other income. In February 2017, the FASB issued new accounting guidance that clarifies the scope of asset derecognition guidance and accounting for partial sales of nonfinancial assets. The guidance clarifies that financial assets may be within scope of the derecognition guidance if they are promised to a counterparty in a contract and substantially all the fair value of the assets in the contract are concentrated in nonfinancial assets, which are collectively referred to as in substance nonfinancial assets. The guidance requires entities to derecognize a nonfinancial asset or in substance nonfinancial asset when a counterparty obtains controls of it, and in a partial sale transaction when it does not have a controlling financial interest in the legal entity that holds the asset and when it transfers control of the asset. This accounting guidance is effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). The guidance may be applied on a retrospective or modified retrospective basis. Early adoption is permitted for interim and annual reporting periods beginning after December 15, 2016. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Goodwill and Other Intangibles. In January 2017, the FASB issued new accounting guidance that simplifies the test for goodwill impairment by eliminating the second step of the current two-step method. Under the new guidance, entities will compare the fair value of a reporting unit with its carrying amount. If the carrying amount exceeds the reporting unit’s fair value, the entity is required to recognize an impairment charge for this amount. Current guidance requires an entity to proceed to a second step, whereby the entity would determine the fair value of its assets and liabilities. The new method applies to all reporting units. The option to perform a qualitative assessment is still allowable. This accounting guidance is effective prospectively for interim and annual reporting periods beginning after December 15, 2019 (effective January 1, 2020, for us). Early adoption is permitted. The adoption of this accounting guidance is not expected to have a material effect on our financial condition or results of operations. Business combinations. In January 2017, the FASB issued accounting guidance that clarifies the definition of a business and removes the requirement for a market participant to consider whether it could replace missing elements in an integrated set of assets and activities. The guidance states that if substantially all of the fair value of the assets acquired or disposed of is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a prospective approach. Early application is allowed for transactions for which the acquisition date occurs before the issuance date or effective date of the amendments, as long as the transaction has not been reported in financial statements that have been issued or made available for issuance, and for transactions in which a subsidiary is deconsolidated or a group of assets is derecognized that occurs before the issuance date or effective date of the amendments, as long as the transaction has not been reported in financial statements that have been issued or made available for issuance. This guidance will not affect our financial condition or results of operations unless we acquire or dispose of a business subsequent to the date of adoption. Statement of cash flows. In November 2016, the FASB issued accounting guidance requiring restricted cash and restricted cash equivalents to be included with other cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts presented on the statement of cash flows. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a retrospective approach. Early adoption is permitted. The adoption of this accounting guidance may affect the presentation in our Consolidated Statements of Cash Flows. Income taxes. In October 2016, the FASB issued accounting guidance requiring an entity to recognize any deferred taxes from an intra-entity transfer of an asset other than inventory when the transfer occurs. This accounting guidance will be effective for annual and interim reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a modified retrospective approach. Early adoption is permitted but only as of the beginning of an annual reporting period for which financial statements have not yet been issued. The adoption of this accounting guidance is not expected to have a material effect on our financial condition or results of operations. Statement of cash flows. In August 2016, the FASB issued new accounting guidance that clarifies how cash receipts and cash payments in certain specific transactions should be presented and classified in the statement of cash flows. These specific transactions include, but are not limited to, debt prepayment or extinguishment costs, contingent considerations made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, and distributions from equity method investees. This guidance also clarifies that in instances of cash flows with multiple aspects that cannot be separately identified, classification should be based on the activity that is likely to be the predominant source of or use of cash flow. This accounting guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us) and should be implemented using a retrospective approach. Early adoption is permitted. The adoption of this accounting guidance may affect the presentation in our Consolidated Statements of Cash Flows. Financial instruments. In June 2016, the FASB issued new accounting guidance that changes the methodology for recognizing credit losses related to financial instruments. Under current GAAP, a credit loss is not recognized until it is probable that the loss has been incurred. The new accounting guidance eliminates that threshold and expands the information required for an entity to consider when developing an estimate of expected credit losses, including the use of forecast information. Entities will be required to present financial assets measured on an amortized cost basis at the net amount that is expected to be collected. This new guidance will impact the accounting for our loans, debt securities available for sale, and liability for credit losses on unfunded lending-related commitments, as well as purchased financial assets with a more-than-insignificant amount of credit deterioration since origination. This accounting guidance will be effective for interim and annual reporting periods beginning after December 15, 2019 (effective January 1, 2020, for us). Early adoption is permitted but only for interim and annual reporting periods beginning after December 15, 2018. This guidance must be implemented using a modified retrospective basis except that a prospective approach must be used for debt securities for which an other-than-temporary impairment had been recognized before the effective date. A prospective transition approach also should be used for purchased financial assets with credit deterioration. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations and related disclosures. Leases. In February 2016, the FASB issued new accounting guidance that requires a lessee to recognize a liability to make lease payments, and a right-of-use asset representing its right to use an underlying asset during the lease term for both finance and operating leases. The definition of a lease was modified to exemplify the concept of control over an asset identified in the lease. Lease classification criteria remain substantially similar to criteria in current lease guidance. The guidance defines which payments can be used in determining lease classification. For short-term leases with a term of 12 months or less, lessees can make a policy election not to recognize lease assets and lease liabilities. Lessor accounting is largely unchanged. Leveraged leases that commenced before the effective date of the new guidance are grandfathered. New disclosures are required, and certain practical expedients are allowed upon adoption. This accounting and disclosure guidance will be effective for interim and annual reporting periods beginning after December 15, 2018 (effective January 1, 2019, for us) and should be implemented using the modified retrospective approach. Early adoption is permitted. We are currently in the early stages of implementation and are working to identify our complete lease population, including potential embedded leases. We expect the adoption of this standard to result in additional assets and liabilities, as we will be required to recognize operating leases on our Consolidated Balance Sheet. Other implementation matters to be addressed include, but are not limited to, the determination of effects on our financial and capital ratios and the quantification of the impacts that this accounting guidance may have on our financial condition or results of operations. Financial instruments. In January 2016, the FASB issued new accounting guidance that requires equity investments, except those accounted for under the equity method of accounting or consolidated, to be measured at fair value with changes recognized in net income. If there is no readily determinable fair value, the guidance allows entities the ability to measure investments at cost less impairment, whereby impairment is based on a qualitative assessment. The guidance eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost and changes the presentation of financial assets and financial liabilities on the balance sheet or in the footnotes. If an entity has elected the fair value option to measure liabilities, the new accounting guidance requires the portion of the change in the fair value of a liability resulting from credit risk to be presented in OCI. We have not elected to measure any of our liabilities at fair value, and therefore, this aspect of the guidance is not applicable to us. This accounting and disclosure guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). For the guidance that is applicable to us, the accounting will be implemented on a modified retrospective basis though a cumulative-effect adjustment to the balance sheet, except for the guidance related to equity securities without readily determinable fair values, which should be applied on a prospective basis. Except under certain instances, early adoption is not permitted. We are currently evaluating the impact that this accounting guidance may have on our financial condition or results of operations. Revenue recognition. In May 2014, the FASB issued new accounting guidance that revises the criteria for determining when to recognize revenue from contracts with customers and expands disclosure requirements. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides a five-step model to be followed in making this determination. This accounting guidance can be implemented using either a retrospective method or a cumulative-effect approach. In August 2015, the FASB issued an update that defers the effective date of the revenue recognition guidance by one year. This new guidance will be effective for interim and annual reporting periods beginning after December 15, 2017 (effective January 1, 2018, for us). Early adoption is permitted but only for interim and annual reporting periods beginning after December 15, 2016. We have elected to implement this new accounting guidance using a cumulative-effect approach. We have already identified the revenue line items within scope of the new guidance and are currently in the process of performing an in-depth assessment, though our preliminary analysis suggests that the adoption of this accounting guidance is not expected to have a material effect on our financial condition nor results of operations. We are also evaluating the related disclosures. There are many aspects of this new accounting guidance that are still being interpreted, and the FASB has issued updates to certain aspects of the guidance to address implementation issues. For example, the FASB issued accounting guidance in March 2016 to clarify principal-versus-agent considerations, and additional guidance in April 2016 to clarify the identification of performance obligations and the licensing implementation guidance. In May 2016, the FASB issued narrow-scope improvements related to collectability, sales tax and noncash consideration, and practical expedients for contract modifications and completed contracts. In December 2016, the FASB issued additional technical corrections and improvements. While certain implementation issues relevant to the industry are still pending resolution, including trade date versus settlement date recognition for broker-dealers and the applicability of interchange revenues for card-issuing banks, our preliminary conclusions reached as to the application of the new guidance are not expected to be significantly affected. We will continue to evaluate any impact as additional guidance is issued and as our internal assessment progresses.

Business Combination (Tables)

Business Combination (Tables)	3 Months Ended
	Mar. 31, 2017
Business Acquisition [Line Items]
Information About Acquired Loan Portfolio as of Acquisition Date	The following table presents the PCI loans receivable balance at the First Niagara Acquisition Date: August 1, 2016 PCI in millions Contractual required payments receivable $ 1,378 Nonaccretable difference 189 Expected cash flows 1,189 Accretable yield 205 Fair value $ 984
Schedule of Changes in Goodwill by Reporting Unit	The following table shows the changes in the carrying amount of goodwill by reporting unit. Key Key Community Corporate in millions Bank Bank Total BALANCE AT DECEMBER 31, 2015 $ 979 $ 81 $ 1,060 Acquisition of First Niagara 1,109 277 1,386 BALANCE AT DECEMBER 31, 2016 2,088 358 2,446 Tax adjustment on previous fair value measurements (15 ) (4 ) (19 ) BALANCE AT MARCH 31, 2017 $ 2,073 $ 354 $ 2,427
First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Schedule of Purchase Price Calculation and Identifiable Assets Purchased and Liabilities Assumed	The following table provides the purchase price calculation as of the Acquisition Date and the identifiable assets purchased and the liabilities assumed at their estimated fair value. These fair value measurements are based on internal and third-party valuations. in millions Consideration paid: KeyCorp common stock issued $ 2,831 Cash payments to First Niagara stockholders 811 Exchange of First Niagara preferred stock for KeyCorp preferred stock 350 Total consideration paid $ 3,992 Statement of Net Assets Acquired at Fair Value: ASSETS Cash and due from banks and short-term investments $ 620 Investment securities 9,012 Other investments 297 Loans 23,645 Premises and equipment 245 Other intangible assets 385 Accrued income and other assets 1,449 Total assets $ 35,653 LIABILITIES Deposits $ 28,994 Bank notes and other short-term borrowings 2,698 Accrued expense and other liabilities 490 Long-term debt 846 Total liabilities $ 33,028 Net identifiable assets acquired 2,625 Goodwill $ 1,367 Based on the revised valuations and new information, we updated our estimated fair values of these items within our Consolidated Balance Sheet with a corresponding adjustment to goodwill. These changes are reflected in the following table: in millions Acquired Asset or Liability Balance Sheet Line Item Provisional Estimate Revised Estimate Increase (Decrease) Tax adjustment on previous fair value measurements (a) Accrued income and other assets $ 175 $ 194 $ 19 (a) The tax adjustment on previous fair value measurements did not have any impact on the income statement for the three months ended March 31, 2017.
Information About Acquired Loan Portfolio as of Acquisition Date	The following table presents the PCI loans receivable balance at the First Niagara Acquisition Date: in millions PCI Contractual required payments receivable $ 1,378 Nonaccretable difference 189 Expected cash flows 1,189 Accretable yield 205 Fair value $ 984
Schedule of Operations Included in Consolidated Statement of Income and Unaudited Pro Forma Information	The following table presents unaudited pro forma information as if the acquisition of First Niagara had occurred on January 1, 2015. This pro forma information gives effect to certain adjustments, including purchase accounting fair value adjustments, amortization of core deposit and other intangibles, and related income tax effects. Merger-related charges related to the First Niagara merger that we incurred during the three months ended March 31, 2016, are not reflected in the unaudited pro forma amounts. The pro forma information does not necessarily reflect the results of operations that would have occurred had KeyCorp merged with First Niagara at the beginning of 2015. Cost savings are also not reflected in the unaudited pro forma amounts for the three months ended March 31, 2016. Pro forma in millions Three months ended March 31, 2016 Net interest income (TE) $ 886 Noninterest income 506 Net income (loss) attributable to common shareholders 245

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Common Share	Our basic and diluted earnings per common share are calculated as follows: Three months ended March 31, dollars in millions, except per share amounts 2017 2016 EARNINGS Income (loss) from continuing operations $ 325 $ 187 Less: Net income (loss) attributable to noncontrolling interests 1 — Income (loss) from continuing operations attributable to Key 324 187 Less: Dividends on Preferred Stock 28 5 Income (loss) from continuing operations attributable to Key common shareholders 296 182 Income (loss) from discontinued operations, net of taxes (a) — 1 Net income (loss) attributable to Key common shareholders $ 296 $ 183 WEIGHTED-AVERAGE COMMON SHARES Weighted-average common shares outstanding (000) 1,068,609 827,381 Effect of convertible preferred stock — — Effect of common share options and other stock awards 17,931 7,679 Weighted-average common shares and potential common shares outstanding (000) (b) 1,086,540 835,060 EARNINGS PER COMMON SHARE Income (loss) from continuing operations attributable to Key common shareholders $ .28 $ .22 Income (loss) from discontinued operations, net of taxes (a) — — Net income (loss) attributable to Key common shareholders (c) .28 .22 Income (loss) from continuing operations attributable to Key common shareholders — assuming dilution $ .27 $ .22 Income (loss) from discontinued operations, net of taxes (a) — — Net income (loss) attributable to Key common shareholders — assuming dilution (c) .27 .22 (a) In September 2009, we decided to discontinue the education lending business conducted through Key Education Resources, the education payment and financing unit of KeyBank. As a result of this decision, we have accounted for this business as a discontinued operation. For further discussion regarding the income (loss) from discontinued operations, see Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”). (b) Assumes conversion of common share options and other stock awards and/or convertible preferred stock, as applicable. (c) EPS may not foot due to rounding.

Loans and Loans Held for Sale (

Loans and Loans Held for Sale (Tables)	3 Months Ended
	Mar. 31, 2017
Loans Receivables [Abstract]
Loans by Category	in millions March 31, 2017 December 31, 2016 Commercial and industrial (a) $ 40,112 $ 39,768 Commercial real estate: Commercial mortgage 15,260 15,111 Construction 2,270 2,345 Total commercial real estate loans 17,530 17,456 Commercial lease financing (b) 4,665 4,685 Total commercial loans 62,307 61,909 Residential — prime loans: Real estate — residential mortgage 5,507 5,547 Home equity loans 12,541 12,674 Total residential — prime loans 18,048 18,221 Consumer direct loans 1,735 1,788 Credit cards 1,037 1,111 Consumer indirect loans 2,998 3,009 Total consumer loans 23,818 24,129 Total loans (c), (d) $ 86,125 $ 86,038 (a) Loan balances include $114 million and $116 million of commercial credit card balances at March 31, 2017 , and December 31, 2016 , respectively. (b) Commercial lease financing includes receivables held as collateral for a secured borrowing of $55 million and $68 million at March 31, 2017 , and December 31, 2016 , respectively. Principal reductions are based on the cash payments received from these related receivables. Additional information pertaining to this secured borrowing is included in Note 19 (“ Long-Term Debt ”) beginning on page 191 of our 2016 Form 10-K. (c) At March 31, 2017 , total loans include purchased loans of $19 billion of which $812 million were PCI loans. At December 31, 2016 , total loans include purchased loans of $21 billion , of which $865 million were PCI loans. (d) Total loans exclude loans of $1.5 billion at March 31, 2017 , and $1.6 billion at December 31, 2016 , related to the discontinued operations of the education lending business. Additional information pertaining to these loans is provided in Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”).
Loans Held for Sale	Our loans held for sale are summarized as follows: in millions March 31, 2017 December 31, 2016 Commercial and industrial $ 171 $ 19 Real estate — commercial mortgage 1,150 1,022 Real estate — construction — 1 Commercial lease financing 1 — Real estate — residential mortgage (a) 62 62 Total loans held for sale $ 1,384 $ 1,104 (a) Real estate — residential mortgage loans held for sale are held at fair value at March 31, 2017 , and December 31, 2016 . The fair value option was elected for real estate — residential mortgage loans held for sale during the third quarter of 2016 with the First Niagara acquisition. The contractual amount due on these loans totaled $62 million at March 31, 2017 , and December 31, 2016 . Changes in fair value are recorded in “Consumer mortgage income” on the income statement. Additional information regarding residential mortgage loans held for sale fair value methodology is provided in Note 6 (“ Fair Value Measurements ”).
Summary of Changes in Loans Held for Sale	Our quarterly summary of changes in loans held for sale is provided below: in millions March 31, 2017 December 31, 2016 Balance at beginning of the period $ 1,104 $ 1,137 New originations 2,563 2,846 Transfers from (to) held to maturity, net 17 11 Loan sales (2,299 ) (2,889 ) Loan draws (payments), net (1 ) (1 ) Balance at end of period (a) $ 1,384 $ 1,104 (a) Total loans held for sale include real estate — residential mortgage loans held for sale at fair value of $62 million at March 31, 2017 , and December 31, 2016 .

Asset Quality (Tables)

Asset Quality (Tables)	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Nonperforming Assets and Past Due Loans	Our nonperforming assets and past due loans were as follows: in millions March 31, 2017 December 31, 2016 Total nonperforming loans (a) $ 573 $ 625 OREO (b) 49 51 Other nonperforming assets 1 — Total nonperforming assets $ 623 $ 676 Nonperforming assets from discontinued operations—education lending (c) $ 4 $ 5 TDRs included in nonperforming loans 161 141 TDRs with an allocated specific allowance (d) 84 59 Specifically allocated allowance for restructured loans (e) 30 27 Accruing loans past due 90 days or more $ 79 $ 87 Accruing loans past due 30 through 89 days 312 404 (a) Nonperforming loan balances exclude $812 million and $865 million of PCI loans at March 31, 2017 , and December 31, 2016 , respectively. (b) Includes carrying value of foreclosed residential real estate of approximately $31 million and $29 million at March 31, 2017 and December 31, 2016 , respectively. (c) Restructured loans of approximately $23 million and $22 million are included in discontinued operations at March 31, 2017 , and December 31, 2016 , respectively. See Note 12 (“ Acquisition, Divestiture, and Discontinued Operations ”) for further discussion. (d) Included in individually impaired loans allocated a specific allowance. (e) Included in allowance for individually evaluated impaired loans.
PCI and Non-Impaired Loans Receivable	The following table presents the PCI loans receivable balance at the First Niagara Acquisition Date: August 1, 2016 PCI in millions Contractual required payments receivable $ 1,378 Nonaccretable difference 189 Expected cash flows 1,189 Accretable yield 205 Fair value $ 984
Schedule of Changes in Outstanding Unpaid Principal Balance, Carrying Amount, and Accretable Yield for PCI Loans	The following tables present the roll-forward of the accretable yield and the beginning and ending outstanding unpaid principal balance and carrying amount of all PCI loans for the three months ended March 31, 2017 , and the twelve months ended December 31, 2016 . Three months ended March 31, Twelve months ended December 31, 2017 2016 in millions Accretable Yield Carrying Amount Outstanding Unpaid Principal Balance Accretable Yield Carrying Amount Outstanding Unpaid Principal Balance Balance at beginning of period $ 197 $ 865 $ 1,002 $ 5 $ 11 $ 17 Additions — 205 Accretion (19 ) (29 ) Net reclassifications from nonaccretable to accretable 25 35 Payments received, net (11 ) (19 ) Disposals — — Balance at end of period $ 192 $ 812 $ 930 $ 197 $ 865 $ 1,002
Breakdown of Individually Impaired Loans	The following tables set forth a further breakdown of individually impaired loans as of March 31, 2017 , and December 31, 2016 : March 31, 2017 Recorded Investment (a) Unpaid Principal Balance (b) Specific Allowance in millions With no related allowance recorded: Commercial and industrial $ 152 $ 217 — Commercial real estate: Commercial mortgage 1 3 — Total commercial real estate loans 1 3 — Total commercial loans 153 220 — Real estate — residential mortgage 20 20 — Home equity loans 60 60 — Consumer indirect loans 2 2 — Total consumer loans 82 82 — Total loans with no related allowance recorded 235 302 — With an allowance recorded: Commercial and industrial 85 90 $ 16 Commercial real estate: Commercial mortgage 15 15 3 Total commercial real estate loans 15 15 3 Total commercial loans 100 105 19 Real estate — residential mortgage 30 30 2 Home equity loans 64 64 17 Consumer direct loans 3 3 — Credit cards 3 3 — Consumer indirect loans 33 33 1 Total consumer loans 133 133 20 Total loans with an allowance recorded 233 238 39 Total $ 468 $ 540 $ 39 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet. (b) The Unpaid Principal Balance represents the customer’s legal obligation to us. December 31, 2016 Recorded Investment (a) Unpaid Principal Balance (b) Specific Allowance in millions With no related allowance recorded: Commercial and industrial $ 222 $ 301 — Commercial real estate: Commercial mortgage 2 3 — Total commercial real estate loans 2 3 — Total commercial loans 224 304 — Real estate — residential mortgage 20 20 — Home equity loans 61 61 — Consumer indirect loans 1 1 — Total consumer loans 82 82 — Total loans with no related allowance recorded 306 386 — With an allowance recorded: Commercial and industrial 62 73 $ 17 Commercial real estate: Commercial mortgage 4 4 — Total commercial real estate loans 4 4 — Total commercial loans 66 77 17 Real estate — residential mortgage 31 31 2 Home equity loans 64 64 18 Consumer direct loans 2 3 — Credit cards 3 3 — Consumer indirect loans 29 29 1 Total consumer loans 129 130 21 Total loans with an allowance recorded 195 207 38 Total $ 501 $ 593 $ 38 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet. (b) The Unpaid Principal Balance represents the customer’s legal obligation to us. The following table sets forth a further breakdown of the average recorded investment for individually impaired loans reported by Key: Average Recorded Investment (a) Three Months Ended March 31, in millions 2017 2016 Commercial and industrial $ 260 $ 215 Commercial real estate: Commercial mortgage 10 9 Construction — 6 Total commercial real estate loans 10 15 Total commercial loans 270 230 Real estate — residential mortgage 51 55 Home equity loans 125 129 Consumer direct loans 3 1 Credit cards 2 3 Consumer indirect loans 33 39 Total consumer loans 214 227 Total $ 484 $ 457 (a) The Recorded Investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. This amount is a component of total loans on our Consolidated Balance Sheet.
Breakdown of Nonperforming TDRs by Loans Category	A further breakdown of TDRs included in nonperforming loans by loan category as of March 31, 2017 , follows: March 31, 2017 Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment dollars in millions LOAN TYPE Nonperforming: Commercial and industrial 20 $ 100 $ 66 Commercial real estate: Commercial mortgage 7 5 4 Total commercial real estate loans 7 5 4 Total commercial loans 27 105 70 Real estate — residential mortgage 267 16 16 Home equity loans 1,186 72 64 Consumer direct loans 40 1 1 Credit cards 288 2 1 Consumer indirect loans 522 10 9 Total consumer loans 2,303 101 91 Total nonperforming TDRs 2,330 206 161 Prior-year accruing: (a) Commercial and industrial 4 29 16 Total commercial loans 4 29 16 Real estate — residential mortgage 526 35 35 Home equity loans 1,240 75 61 Consumer direct loans 32 2 1 Credit cards 440 3 1 Consumer indirect loans 365 55 27 Total consumer loans 2,603 170 125 Total prior-year accruing TDRs 2,607 199 141 Total TDRs 4,937 $ 405 $ 302 (a) All TDRs that were restructured prior to January 1, 2017 , and are fully accruing. A further breakdown of TDRs included in nonperforming loans by loan category as of December 31, 2016 , follows: December 31, 2016 Number of Loans Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment dollars in millions LOAN TYPE Nonperforming: Commercial and industrial 18 $ 91 $ 50 Commercial real estate: Commercial mortgage 7 2 1 Total commercial real estate loans 7 2 1 Total commercial loans 25 93 51 Real estate — residential mortgage 264 16 16 Home equity loans 1,199 77 69 Consumer direct loans 32 1 — Credit cards 336 2 2 Consumer indirect loans 124 4 3 Total consumer loans 1,955 100 90 Total nonperforming TDRs 1,980 193 141 Prior-year accruing: (a) Commercial and Industrial 5 30 16 Total commercial loans 5 30 16 Real estate — residential mortgage 477 35 35 Home equity loans 1,231 70 57 Consumer direct loans 35 2 2 Credit cards 410 3 1 Consumer indirect loans 377 56 28 Total consumer loans 2,530 166 123 Total prior-year accruing TDRs 2,535 196 139 Total TDRs 4,515 $ 389 $ 280 (a) All TDRs that were restructured prior to January 1, 2016 , and are fully accruing.
Post-Modification Outstanding Recorded Investment by Concession Type for Our Commercial Accruing and Nonaccruing TDRs	The following table shows the post-modification outstanding recorded investment by concession type for our commercial and consumer accruing and nonaccruing TDRs that occurred during the three months ended March 31, 2017, and March 31, 2016. Three Months Ended March 31, in millions 2017 2016 Commercial loans: Interest rate reduction $ 7 — Other 21 $ 3 Total $ 28 $ 3 Consumer loans: Interest rate reduction $ 3 $ 2 Forgiveness of principal — 12 Other 12 2 Total $ 15 $ 16 Total commercial and consumer TDRs $ 43 $ 19 Total loans 86,125 60,438
Past Due Loans Including Current Loans	The following aging analysis of past due and current loans as of March 31, 2017 , and December 31, 2016 , provides further information regarding Key’s credit exposure. Aging Analysis of Loan Portfolio (a) March 31, 2017 Current 30-59 Days Past Due (b) 60-89 Days Past Due (b) 90 and Greater Days Past Due (b) Non-performing Loans Total Past Due and Non-performing Loans Purchased Credit Impaired Total Loans (c), (d) in millions LOAN TYPE Commercial and industrial $ 39,621 $ 60 $ 47 $ 24 $ 258 $ 389 $ 102 $ 40,112 Commercial real estate: Commercial mortgage 14,891 25 10 11 32 78 291 15,260 Construction 2,242 — — — 2 2 26 2,270 Total commercial real estate loans 17,133 25 10 11 34 80 317 17,530 Commercial lease financing 4,634 12 8 6 5 31 — 4,665 Total commercial loans $ 61,388 $ 97 $ 65 $ 41 $ 297 $ 500 $ 419 $ 62,307 Real estate — residential mortgage $ 5,065 $ 16 $ 7 $ 4 $ 54 $ 81 $ 361 $ 5,507 Home equity loans 12,225 42 27 14 207 290 26 12,541 Consumer direct loans 1,709 8 4 5 3 20 6 1,735 Credit cards 1,011 7 5 11 3 26 — 1,037 Consumer indirect loans 2,951 27 7 4 9 47 — 2,998 Total consumer loans $ 22,961 $ 100 $ 50 $ 38 $ 276 $ 464 $ 393 $ 23,818 Total loans $ 84,349 $ 197 $ 115 $ 79 $ 573 $ 964 $ 812 $ 86,125 (a) Amounts in table represent recorded investment and exclude loans held for sale. Recorded investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. (b) Past due loan amounts exclude PCI, even if contractually past due (or if we do not expect to collect principal or interest in full based on the original contractual terms), as we are currently accreting income over the remaining term of the loans. (c) Net of unearned income, net deferred loan fees and costs, and unamortized discounts and premiums. (d) Future accretable yield related to PCI loans is not included in the analysis of the loan portfolio. December 31, 2016 Current 30-59 Days Past Due (b) 60-89 Days Past Due (b) 90 and Greater Days Past Due (b) Non-performing Loans Total Past Due and Non-performing Loans Purchased Credit Impaired Total Loans (c), (d) in millions LOAN TYPE Commercial and industrial $ 39,242 $ 58 $ 28 $ 31 $ 297 $ 414 112 $ 39,768 Commercial real estate: Commercial mortgage 14,655 93 9 6 26 134 322 15,111 Construction 2,314 — — 2 3 5 26 2,345 Total commercial real estate loans 16,969 93 9 8 29 139 348 17,456 Commercial lease financing 4,641 28 3 5 8 44 — 4,685 Total commercial loans $ 60,852 $ 179 $ 40 $ 44 $ 334 $ 597 460 $ 61,909 Real estate — residential mortgage $ 5,098 $ 17 $ 5 $ 3 $ 56 $ 81 $ 368 $ 5,547 Home equity loans 12,327 49 29 16 223 317 30 12,674 Consumer direct loans 1,705 44 15 11 6 76 7 1,788 Credit cards 1,082 9 6 12 2 29 — 1,111 Consumer indirect loans 2,993 7 4 1 4 16 — 3,009 Total consumer loans $ 23,205 $ 126 $ 59 $ 43 $ 291 $ 519 $ 405 $ 24,129 Total loans $ 84,057 $ 305 $ 99 $ 87 $ 625 $ 1,116 $ 865 $ 86,038 (a) Amounts in table represent recorded investment and exclude loans held for sale. Recorded investment represents the face amount of the loan increased or decreased by applicable accrued interest, net deferred loan fees and costs, and unamortized premium or discount, and reflects direct charge-offs. (b) Past due loan amounts exclude purchased impaired loans, even if contractually past due (or if we do not expect to collect principal or interest in full based on the original contractual terms), as we are currently accreting income over the remaining term of the loans. (c) Net of unearned income, net deferred loan fees and costs, and unamortized discounts and premiums. (d) Future accretable yield related to purchased credit impaired loans is not included in the analysis of the loan portfolio.
Financing Receivable Credit Quality Indicators	Commercial Credit Exposure — Excluding PCI Credit Risk Profile by Creditworthiness Category (a), (b) in millions Commercial and industrial RE — Commercial RE — Construction Commercial lease Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, RATING 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 Pass $ 38,268 $ 37,845 $ 14,536 $ 14,308 $ 2,199 $ 2,287 $ 4,602 $ 4,632 $ 59,605 $ 59,072 Criticized (Accruing) 1,484 1,514 401 455 43 30 58 45 1,986 2,044 Criticized (Nonaccruing) 258 297 32 26 2 2 5 8 297 333 Total $ 40,010 $ 39,656 $ 14,969 $ 14,789 $ 2,244 $ 2,319 $ 4,665 $ 4,685 $ 61,888 $ 61,449 (a) Credit quality indicators are updated on an ongoing basis and reflect credit quality information as of the dates indicated. (b) The term criticized refers to those loans that are internally classified by Key as special mention or worse, which are asset quality categories defined by regulatory authorities. These assets have an elevated level of risk and may have a high probability of default or total loss. Pass rated refers to all loans not classified as criticized. Consumer Credit Exposure — Excluding PCI Non-PCI Loans by Refreshed FICO Score (a) in millions Residential — Prime Consumer direct loans Credit cards Consumer indirect loans Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 750 and above $ 9,935 $ 9,818 $ 472 $ 498 $ 408 $ 453 $ 1,263 $ 1,266 $ 12,078 $ 12,035 660 to 749 5,821 5,266 644 661 498 525 1,190 1,195 8,153 7,647 Less than 660 1,665 1,617 199 194 131 132 545 543 2,540 2,486 No Score 240 1,122 414 428 — 1 — 5 654 1,556 Total $ 17,661 $ 17,823 $ 1,729 $ 1,781 $ 1,037 $ 1,111 $ 2,998 $ 3,009 $ 23,425 $ 23,724 (a) Borrower FICO scores provide information about the credit quality of our consumer loan portfolio as they provide an indication as to the likelihood that a debtor will repay its debts. The scores are obtained from a nationally recognized consumer rating agency and are presented in the above table at the dates indicated. Commercial Credit Exposure — PCI Credit Risk Profile by Creditworthiness Category (a), (b) in millions Commercial and Industrial RE — Commercial RE — Construction Commercial Lease Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, RATING 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 Pass $ 26 $ 12 $ 118 $ 139 $ 20 $ 21 — — $ 164 $ 172 Criticized 76 100 173 183 6 5 — — 255 288 Total $ 102 $ 112 $ 291 $ 322 $ 26 $ 26 — — $ 419 $ 460 (a) Credit quality indicators are updated on an ongoing basis and reflect credit quality information as of the dates indicated. (b) The term “criticized” refers to those loans that are internally classified by Key as special mention or worse, which are asset quality categories defined by regulatory authorities. These assets have an elevated level of risk and may have a high probability of default or total loss. Pass rated refers to all loans not classified as criticized. Consumer Credit Exposure — PCI PCI Loans by Refreshed FICO Score (a) in millions Residential — Prime Consumer direct loans Credit cards Consumer indirect loans Total March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, March 31, December 31, 2017 2016 2017 2016 2017 2016 2017 2016 2017 2016 750 and above $ 136 $ 133 — — — — — — $ 136 $ 133 660 to 749 143 127 $ 2 $ 2 — — — — 145 129 Less than 660 103 133 3 4 — — — — 106 137 No Score 5 5 1 1 — — — — 6 6 Total $ 387 $ 398 $ 6 $ 7 — — — — $ 393 $ 405 (a) Borrower FICO scores provide information about the credit quality of our consumer loan portfolio as they provide an indication as to the likelihood that a debtor will repay its debts. The scores are obtained from a nationally recognized consumer rating agency and are presented in the above table at the dates indicated.
Summary of Allowance for Loan and Lease Losses	A summary of the changes in the ALLL for the periods indicated is presented in the table below: Three months ended March 31, in millions 2017 2016 Balance at beginning of period — continuing operations $ 858 $ 796 Charge-offs (77 ) (60 ) Recoveries 19 14 Net loans and leases charged off (58 ) (46 ) Provision for loan and lease losses from continuing operations 70 76 Balance at end of period — continuing operations $ 870 $ 826
Changes in Allowance for Loan and Lease Losses by Loan Category	The changes in the ALLL by loan category for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: Three months ended March 31, 2017 : in millions December 31, 2016 Provision Charge-offs Recoveries March 31, 2017 Commercial and Industrial $ 508 $ 31 $ (32 ) $ 5 $ 512 Commercial real estate: Real estate — commercial mortgage 144 2 — — 146 Real estate — construction 22 6 — 1 29 Total commercial real estate loans 166 8 — 1 175 Commercial lease financing 42 3 (7 ) 2 40 Total commercial loans 716 42 (39 ) 8 727 Real estate — residential mortgage 17 (3 ) 2 2 18 Home equity loans 54 4 (8 ) 3 53 Consumer direct loans 24 9 (10 ) 1 24 Credit cards 38 10 (11 ) 1 38 Consumer indirect loans 9 8 (11 ) 4 10 Total consumer loans 142 28 (38 ) 11 143 Total ALLL — continuing operations 858 70 (a) (77 ) 19 870 Discontinued operations 24 3 (6 ) 2 23 Total ALLL — including discontinued operations $ 882 $ 73 $ (83 ) $ 21 $ 893 (a) Excludes a credit for losses on lending-related commitments of $7 million . Three months ended March 31, 2016 : in millions December 31, 2015 Provision Charge-offs Recoveries March 31, 2016 Commercial and Industrial $ 450 $ 50 $ (26 ) $ 3 $ 477 Commercial real estate: Real estate — commercial mortgage 134 — (1 ) 2 135 Real estate — construction 25 (3 ) — 1 $ 23 Total commercial real estate loans 159 (3 ) (1 ) 3 158 Commercial lease financing 47 (1 ) (3 ) — 43 Total commercial loans 656 46 (30 ) 6 678 Real estate — residential mortgage 18 2 (2 ) 2 20 Home equity loans 57 14 (10 ) 3 64 Consumer direct loans 20 5 (6 ) 1 20 Credit cards 32 6 (8 ) 1 31 Consumer indirect loans 13 3 (4 ) 1 13 Total consumer loans 140 30 (30 ) 8 148 Total ALLL — continuing operations 796 76 (a) (60 ) 14 826 Discontinued operations 28 2 (9 ) 3 24 Total ALLL — including discontinued operations $ 824 $ 78 $ (69 ) $ 17 $ 850 (a) Excludes a provision for losses on lending-related commitments of $13 million .
Allowance for Loan and Lease Losses and Corresponding Loan Balances	A breakdown of the individual and collective ALLL and the corresponding loan balances as of March 31, 2017 , follows: Allowance Outstanding March 31, 2017 Individually Evaluated for Impairment Collectively Evaluated for Impairment Purchased Credit Impaired Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Purchased Credit Impaired in millions Commercial and industrial $ 16 $ 495 1 $ 40,112 $ 237 $ 39,773 $ 102 Commercial real estate: Commercial mortgage 3 140 3 15,260 16 14,953 291 Construction — 29 — 2,270 — 2,244 26 Total commercial real estate loans 3 169 3 17,530 16 17,197 317 Commercial lease financing — 40 — 4,665 — 4,665 — Total commercial loans 19 704 4 62,307 253 61,635 419 Real estate — residential mortgage 2 15 1 5,507 51 5,095 361 Home equity loans 17 35 1 12,541 124 12,391 26 Consumer direct loans — 24 — 1,735 3 1,726 6 Credit cards — 38 — 1,037 3 1,034 — Consumer indirect loans 1 9 — 2,998 35 2,963 — Total consumer loans 20 121 2 23,818 216 23,209 393 Total ALLL — continuing operations 39 825 6 86,125 469 84,844 812 Discontinued operations 2 21 — 1,500 (a) 23 1,477 (a) — Total ALLL — including discontinued operations $ 41 $ 846 6 $ 87,625 $ 492 $ 86,321 $ 812 (a) Amount includes $3 million of loans carried at fair value that are excluded from ALLL consideration. A breakdown of the individual and collective ALLL and the corresponding loan balances as of December 31, 2016 , follows: Allowance Outstanding December 31, 2016 Individually Evaluated for Impairment Collectively Evaluated for Impairment Purchased Credit Impaired Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Purchased Credit Impaired in millions Commercial and Industrial $ 17 $ 486 5 $ 39,768 $ 284 $ 39,372 $ 112 Commercial real estate: Commercial mortgage — 144 — 15,111 5 14,784 322 Construction — 22 — 2,345 — 2,319 26 Total commercial real estate loans — 166 — 17,456 5 17,103 348 Commercial lease financing — 42 — 4,685 — 4,685 — Total commercial loans 17 694 5 61,909 289 61,160 460 Real estate — residential mortgage 2 15 — 5,547 51 5,128 368 Home equity loans 17 37 — 12,674 125 12,519 30 Consumer direct loans — 24 — 1,788 3 1,778 7 Credit cards — 38 — 1,111 3 1,108 — Consumer indirect loans 1 8 — 3,009 30 2,979 — Total consumer loans 20 122 — 24,129 212 23,512 405 Total ALLL — continuing operations 37 816 5 86,038 501 84,672 865 Discontinued operations 2 22 — 1,565 (a) 22 1,543 (a) — Total ALLL — including discontinued operations $ 39 $ 838 $ 5 $ 87,603 $ 523 $ 86,215 $ 865 (a) Amount includes $3 million of loans carried at fair value that are excluded from ALLL consideration.
Changes in Liability for Credit Losses on Lending Related Commitments	Changes in the liability for credit losses on unfunded lending-related commitments are summarized as follows: Three months ended March 31, in millions 2017 2016 Balance at beginning of period $ 55 $ 56 Provision (credit) for losses on lending-related commitments (7 ) 13 Balance at end of period $ 48 $ 69

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value of Assets and Liabilities Measured on Recurring Basis	The following tables present these assets and liabilities at March 31, 2017 , and December 31, 2016 . March 31, 2017 Level 1 Level 2 Level 3 Total in millions ASSETS MEASURED ON A RECURRING BASIS Trading account assets: U.S. Treasury, agencies and corporations — $ 586 — $ 586 States and political subdivisions — 47 — 47 Collateralized mortgage obligations — — — — Other mortgage-backed securities — 248 — 248 Other securities $ 1 35 — 36 Total trading account securities 1 916 — 917 Commercial loans — 4 — 4 Total trading account assets 1 920 — 921 Securities available for sale: U.S. Treasury, agencies and corporations — 185 — 185 States and political subdivisions — 11 — 11 Agency residential collateralized mortgage obligations (a) — 14,563 — 14,563 Agency residential mortgage-backed securities (a) — 1,742 — 1,742 Agency commercial mortgage-backed securities — 1,910 — 1,910 Other securities 3 — $ 17 20 Total securities available for sale 3 18,411 17 18,431 Other investments: Principal investments: Direct — — 21 21 Indirect (measured at NAV) (b) — — — 155 Total principal investments — — 21 176 Equity and mezzanine investments: Indirect (measured at NAV) (b) — — — 2 Total equity and mezzanine investments — — — 2 Total other investments — — 21 178 Loans, net of unearned income — — — — Loans held for sale — 62 — 62 Derivative assets: Interest rate — 777 5 782 Foreign exchange 91 7 — 98 Commodity — 150 — 150 Credit — 2 1 3 Other — 5 4 9 Derivative assets 91 941 10 1,042 Netting adjustments (c) — — — (464 ) Total derivative assets 91 941 10 578 Accrued income and other assets — — — — Total assets on a recurring basis at fair value $ 95 $ 20,334 $ 48 $ 20,170 LIABILITIES MEASURED ON A RECURRING BASIS Bank notes and other short-term borrowings: Short positions $ 214 $ 729 — $ 943 Derivative liabilities: Interest rate — 531 — 531 Foreign exchange 78 8 — 86 Commodity — 140 — 140 Credit — 6 — 6 Other — 16 — 16 Derivative liabilities 78 701 — 779 Netting adjustments (c) — — — (524 ) Total derivative liabilities 78 701 — 255 Accrued expense and other liabilities — — — — Total liabilities on a recurring basis at fair value $ 292 $ 1,430 — $ 1,198 (a) “Collateralized mortgage obligations” and “Other mortgage-back securities” were renamed to “Agency residential collateralized mortgage obligations” and “Agency residential mortgage-backed securities”, respectively, in September 2016. There was no reclassification of previously reported balances. (b) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (c) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The net basis takes into account the impact of bilateral collateral and master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Total derivative assets and liabilities include these netting adjustments. December 31, 2016 Level 1 Level 2 Level 3 Total in millions ASSETS MEASURED ON A RECURRING BASIS Trading account assets: U.S. Treasury, agencies and corporations — $ 655 — $ 655 States and political subdivisions — 8 — 8 Collateralized mortgage obligations — — — — Other mortgage-backed securities — 113 — 113 Other securities — 73 — 73 Total trading account securities — 849 — 849 Commercial loans — 18 — 18 Total trading account assets — 867 — 867 Securities available for sale: U.S. Treasury, agencies and corporations — 184 — 184 States and political subdivisions — 11 — 11 Agency residential collateralized mortgage obligations (a) — 16,408 — 16,408 Agency residential mortgage-backed securities (a) — 1,846 — 1,846 Agency commercial mortgage-backed securities — 1,743 — 1,743 Other securities $ 3 — $ 17 20 Total securities available for sale 3 20,192 17 20,212 Other investments: Principal investments: Direct — — 27 27 Indirect (measured at NAV) (b) — — — 158 Total principal investments — — 27 185 Equity and mezzanine investments: Indirect (measured at NAV) (b) — — — 6 Total equity and mezzanine investments — — — 6 Total other investments — — 27 191 Loans, net of unearned income — — — — Loans held for sale — 62 — 62 Derivative assets: Interest rate — 923 7 930 Foreign exchange 114 9 — 123 Commodity — 176 — 176 Credit — — 1 1 Other — 2 2 4 Derivative assets 114 1,110 10 1,234 Netting adjustments (c) — — — (431 ) Total derivative assets 114 1,110 10 803 Accrued income and other assets — 8 — 8 Total assets on a recurring basis at fair value $ 117 $ 22,239 $ 54 $ 22,143 LIABILITIES MEASURED ON A RECURRING BASIS Bank notes and other short-term borrowings: Short positions $ 192 $ 616 — $ 808 Derivative liabilities: Interest rate — 737 — 737 Foreign exchange 102 11 — 113 Commodity — 165 — 165 Credit — 4 — 4 Other — 1 — 1 Derivative liabilities 102 918 — 1,020 Netting adjustments (c) — — — (384 ) Total derivative liabilities 102 918 — 636 Accrued expense and other liabilities — 14 — 14 Total liabilities on a recurring basis at fair value $ 294 $ 1,548 — $ 1,458 (a) “Collateralized mortgage obligations” and “Other mortgage-back securities” were renamed to “Agency residential collateralized mortgage obligations” and “Agency residential mortgage-backed securities”, respectively, in September 2016. There was no reclassification of previously reported balances. (b) Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the consolidated balance sheet. (c) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The net basis takes into account the impact of bilateral collateral and master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Total derivative assets and liabilities include these netting adjustments.
Change in Fair Values of Level 3 Financial Instruments	The following table shows the components of the change in the fair values of our Level 3 financial instruments for the three months ended March 31, 2017 , and March 31, 2016 . We mitigate the credit risk, interest rate risk, and risk of loss related to many of these Level 3 instruments by using securities and derivative positions classified as Level 1 or Level 2. Level 1 and Level 2 instruments are not included in the following table. Therefore, the gains or losses shown do not include the impact of our risk management activities. in millions Beginning of Period Balance Gains (Losses) Included in Earnings Purchases Sales Settlements Transfers Other Transfers into Level 3 (a) Transfers out of Level 3 (a) End of Period Balance (f) Unrealized Gains (Losses) Included in Earnings Three months ended March 31, 2017 Securities available for sale Other securities $ 17 — — — — — — — $ 17 — Other investments Principal investments Direct 27 $ (2 ) (b) — $ (4 ) — — — — 21 $ (6 ) (b) Other indirect — — — — — — — — — — Derivative instruments (c) Interest rate 7 — — — — — $ 1 (e) $ (3 ) (e) 5 — Credit 1 (3 ) (d) — — $ 3 — — — 1 — Other (g) 2 — — — — $ 2 — — 4 — in millions Beginning of Period Balance Gains (Losses) Included in Earnings Purchases Sales Settlements Transfers into Level 3 (a) Transfers out of Level 3 (a) End of Period Balance (f) Unrealized Gains (Losses) Included in Earnings Three months ended March 31, 2016 Securities available for sale Other securities $ 17 — — — — — — $ 17 — Other investments Principal investments Direct 50 $ (3 ) (b) — — — — — 47 $ (3 ) (b) Other indirect 20 (1 ) (b) — $ (1 ) — — — 18 (1 ) (b) Derivative instruments (c) Interest rate 16 4 (d) — — — $ 3 (e) $ (7 ) (e) 16 — Credit 1 (2 ) (d) — — $ 3 — — 2 — (a) Our policy is to recognize transfers into and transfers out of Level 3 as of the end of the reporting period. (b) Realized and unrealized gains and losses on principal investments are reported in “net gains (losses) from principal investing” on the income statement. Realized and unrealized losses on other and private equity and mezzanine investments are reported in “other income” on the income statement. (c) Amounts represent Level 3 derivative assets less Level 3 derivative liabilities. (d) Realized and unrealized gains and losses on derivative instruments are reported in “corporate services income” and “other income” on the income statement. (e) Certain derivatives previously classified as Level 2 were transferred to Level 3 because Level 3 unobservable inputs became significant. Certain derivatives previously classified as Level 3 were transferred to Level 2 because Level 3 unobservable inputs became less significant. (f) There were no issuances for the three-month periods ended March 31, 2017 , and March 31, 2016 . (g) Amounts represent Level 3 interest rate lock commitments.
Assets and Liabilities Measured at Fair Value on Nonrecurring Basis	The following table presents our assets measured at fair value on a nonrecurring basis at March 31, 2017 , and December 31, 2016 : March 31, 2017 December 31, 2016 in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ASSETS MEASURED ON A NONRECURRING BASIS Impaired loans — — $ 11 $ 11 — — $ 11 $ 11 Loans held for sale (a) — — 1 1 — — — — Accrued income and other assets — — 6 6 — — 11 11 Total assets on a nonrecurring basis at fair value — — $ 18 $ 18 — — $ 22 $ 22 (a) During the first three months of 2017 , we transferred $17 million of commercial loans and leases at their current fair value from held-to-maturity portfolio to held-for-sale status, compared to $35 million during 2016 .
Quantitative Information about Level 3 Fair Value Measurements	The range and weighted average of the significant unobservable inputs used to fair value our material Level 3 recurring and nonrecurring assets at March 31, 2017 , and December 31, 2016 , along with the valuation techniques used, are shown in the following table: March 31, 2017 Fair Value of Level 3 Assets Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Recurring Other investments — principal investments — direct: $ 21 Individual analysis of the condition of each investment Debt instruments EBITDA multiple 6.00 - 6.30 (6.20) Equity instruments of private companies EBITDA multiple (where applicable) N/A (6.3) Nonrecurring Impaired loans 11 Fair value of underlying collateral Discount 00.00 - 70.00% (16.00%) December 31, 2016 Fair Value of Level 3 Assets Valuation Technique Significant Unobservable Input Range (Weighted-Average) dollars in millions Recurring Other investments — principal investments — direct: $ 27 Individual analysis of the condition of each investment Debt instruments EBITDA multiple 6.30 - 7.00 (6.50) Equity instruments of private companies EBITDA multiple (where applicable) N/A (6.3) Nonrecurring Impaired loans 11 Fair value of underlying collateral Discount 00.00 - 70.00% (46.00%)
Fair Value Disclosures of Financial Instruments	The levels in the fair value hierarchy ascribed to our financial instruments and the related carrying amounts at March 31, 2017 , and December 31, 2016 , are shown in the following tables: March 31, 2017 Fair Value in millions Carrying Amount Level 1 Level 2 Level 3 Measured at NAV Netting Adjustment Total ASSETS Cash and short-term investments (a) $ 3,074 $ 3,074 — — — — $ 3,074 Trading account assets (b) 921 1 $ 920 — — — 921 Securities available for sale (b) 18,431 3 18,411 $ 17 — — 18,431 Held-to-maturity securities (c) 10,186 — 9,954 — — — 9,954 Other investments (b) 689 — — 527 $ 157 — 684 Loans, net of allowance (d) 85,255 — 83,520 — — — 83,520 Loans held for sale (b) 1,384 — 62 1,322 — — 1,384 Derivative assets (b) 578 91 941 10 — $ (464 ) (f) 578 LIABILITIES Deposits with no stated maturity (a) $ 93,429 — $ 93,429 — — — $ 93,429 Time deposits (e) 10,553 — 10,649 — — — 10,649 Short-term borrowings (a) 1,385 $ 214 1,171 — — — 1,385 Long-term debt (e) 12,324 12,372 289 — — — 12,661 Derivative liabilities (b) 255 78 701 — — $ (524 ) (f) 255 December 31, 2016 Fair Value in millions Carrying Amount Level 1 Level 2 Level 3 Measured at NAV Netting Adjustment Total ASSETS Cash and short-term investments (a) $ 3,452 $ 3,452 — — — — $ 3,452 Trading account assets (b) 867 — $ 867 — — — 867 Securities available for sale (b) 20,212 3 20,192 $ 17 — — 20,212 Held-to-maturity securities (c) 10,232 — 10,007 — — — 10,007 Other investments (b) 738 — — 569 $ 164 — 733 Loans, net of allowance (d) 85,180 — — 83,285 — — 83,285 Loans held for sale (b) 1,104 — 62 1,042 — — 1,104 Derivative assets (b) 803 114 1,110 10 — $ (431 ) (f) 803 LIABILITIES Deposits with no stated maturity (a) $ 93,906 — $ 93,906 — — — $ 93,906 Time deposits (e) 10,181 — 10,267 — — — 10,267 Short-term borrowings (a) 2,310 $ 192 2,118 — — — 2,310 Long-term debt (e) 12,384 12,386 304 — — — 12,690 Derivative liabilities (b) 636 102 918 — — $ (384 ) (f) 636 Valuation Methods and Assumptions (a) Fair value equals or approximates carrying amount. The fair value of deposits with no stated maturity does not take into consideration the value ascribed to core deposit intangibles. (b) Information pertaining to our methodology for measuring the fair values of these assets and liabilities is included in the sections entitled “Qualitative Disclosures of Valuation Techniques” and “Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis” in this Note. Investments accounted for under the equity method are not included in this table. (c) Fair values of held-to-maturity securities are determined by using models that are based on security-specific details, as well as relevant industry and economic factors. The most significant of these inputs are quoted market prices, interest rate spreads on relevant benchmark securities, and certain prepayment assumptions. We review the valuations derived from the models to ensure that they are reasonable and consistent with the values placed on similar securities traded in the secondary markets. (d) The fair value of loans is based on the present value of the expected cash flows. The projected cash flows are based on the contractual terms of the loans, adjusted for prepayments and use of a discount rate based on the relative risk of the cash flows, taking into account the loan type, maturity of the loan, liquidity risk, servicing costs, and a required return on debt and capital. In addition, an incremental liquidity discount is applied to certain loans, using historical sales of loans during periods of similar economic conditions as a benchmark. The fair value of loans includes lease financing receivables at their aggregate carrying amount, which is equivalent to their fair value. (e) Fair values of time deposits and long-term debt are based on discounted cash flows utilizing relevant market inputs. (f) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The net basis takes into account the impact of bilateral collateral and master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Total derivative assets and liabilities include these netting adjustments.
Principal Investments [Member]
Fair Value of Direct and Indirect Investments, Related Unfunded Commitments and Financial Support Provided	The following table presents the fair value of our indirect investments and related unfunded commitments at March 31, 2017 . We did not provide any financial support to investees related to our direct and indirect investments for the three months ended March 31, 2017 , and March 31, 2016 . March 31, 2017 Fair Value Unfunded Commitments in millions INVESTMENT TYPE Indirect investments Passive funds (a) (measured at NAV) $ 2 $ 1 Total $ 2 $ 1 (a) We invest in passive funds, which are multi-investor private equity funds. These investments can never be redeemed. Instead, distributions are received through the liquidation of the underlying investments in the funds. Some funds have no restrictions on sale, while others require investors to remain in the fund until maturity. The funds will be liquidated over a period of one to three years. The purpose of KREEC’s funding is to allow funds to make additional investments and keep a certain market value threshold in the funds. KREEC is obligated to provide financial support, as all investors are required, to the funds based on its ownership percentage, as noted in the Limited Partnership Agreements.
Private Equity and Mezzanine Investments [Member]
Fair Value of Direct and Indirect Investments, Related Unfunded Commitments and Financial Support Provided	The following table presents the fair value of our direct and indirect principal investments and related unfunded commitments at March 31, 2017 , as well as financial support provided for the three months ended March 31, 2017 , and March 31, 2016 . Financial support provided Three months ended March 31, March 31, 2017 2017 2016 in millions Fair Value Unfunded Commitments Funded Commitments Funded Other Funded Commitments Funded Other INVESTMENT TYPE Direct investments (a) $ 21 — — — — $ 13 Indirect investments (b) (measured at NAV) 155 $ 37 $ 1 — $ 1 — Total $ 176 $ 37 $ 1 — $ 1 $ 13 (a) Our direct investments consist of equity and debt investments directly in independent business enterprises. Operations of the business enterprises are handled by management of the portfolio company. The purpose of funding these enterprises is to provide financial support for business development and acquisition strategies. We infuse equity capital based on an initial contractual cash contribution and later from additional requests on behalf of the companies’ management. (b) Our indirect investments consist of buyout funds, venture capital funds, and fund of funds. These investments are generally not redeemable. Instead, distributions are received through the liquidation of the underlying investments of the fund. An investment in any one of these funds typically can be sold only with the approval of the fund’s general partners. We estimate that the underlying investments of the funds will be liquidated over a period of one to eight years. The purpose of funding our capital commitments to these investments is to allow the funds to make additional follow-on investments and pay fund expenses until the fund dissolves. We, and all other investors in the fund, are obligated to fund the full amount of our respective capital commitments to the fund based on our and their respective ownership percentages, as noted in the applicable Limited Partnership Agreement.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Details of Securities	The amortized cost, unrealized gains and losses, and approximate fair value of our securities available for sale and held-to-maturity securities are presented in the following tables. Gross unrealized gains and losses represent the difference between the amortized cost and the fair value of securities on the balance sheet as of the dates indicated. Accordingly, the amount of these gains and losses may change in the future as market conditions change. March 31, 2017 in millions Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE U.S. Treasury, agencies, and corporations $ 188 — $ 3 $ 185 States and political subdivisions 11 — — 11 Agency residential collateralized mortgage obligations 14,790 $ 29 256 14,563 Agency residential mortgage-backed securities 1,751 5 14 1,742 Agency commercial mortgage-backed securities 1,956 — 46 1,910 Other securities 21 — 1 20 Total securities available for sale $ 18,717 $ 34 $ 320 $ 18,431 HELD TO MATURITY SECURITIES Agency residential collateralized mortgage obligations $ 7,973 $ 2 $ 188 $ 7,787 Agency residential mortgage-backed securities 605 — 5 600 Agency commercial mortgage-backed securities 1,593 3 44 1,552 Other securities 15 — — 15 Total held-to-maturity securities $ 10,186 $ 5 $ 237 $ 9,954 December 31, 2016 in millions Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value SECURITIES AVAILABLE FOR SALE U.S. Treasury, agencies, and corporations $ 188 — $ 4 $ 184 States and political subdivisions 11 — — 11 Agency residential collateralized mortgage obligations 16,652 $ 31 275 16,408 Agency residential mortgage-backed securities 1,857 6 17 1,846 Agency commercial mortgage-backed securities 1,778 — 35 1,743 Other securities 21 — 1 20 Total securities available for sale $ 20,507 $ 37 $ 332 $ 20,212 HELD TO MATURITY SECURITIES Agency residential collateralized mortgage obligations $ 8,404 $ 1 $ 173 $ 8,232 Agency residential mortgage-backed securities 629 — 5 624 Agency commercial mortgage-backed securities 1,184 1 49 1,136 Other securities 15 — — 15 Total held-to-maturity securities $ 10,232 $ 2 $ 227 $ 10,007
Available for Sale Securities (Unrealized Loss Position)	The following table summarizes our securities that were in an unrealized loss position as of March 31, 2017 , and December 31, 2016 . Duration of Unrealized Loss Position Less than 12 Months 12 Months or Longer Total in millions Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses March 31, 2017 Securities available for sale: U.S Treasury, agencies, and corporations $ 185 $ 3 — — $ 185 $ 3 Agency residential collateralized mortgage obligations 10,573 205 $ 1,507 $ 51 12,080 256 Agency residential mortgage-backed securities 1,527 14 — — 1,527 14 Agency commercial mortgage-backed securities 1,910 46 — — 1,910 46 Other securities (a) — — 3 1 3 1 Held-to-maturity: Agency residential collateralized mortgage obligations $ 6,634 $ 169 $ 521 $ 19 $ 7,155 $ 188 Agency residential mortgage-backed securities (a) 525 5 — — 525 5 Agency commercial mortgage-backed securities 1,001 44 — — 1,001 44 Other securities (b) 4 — — — 4 — Total temporarily impaired securities $ 22,359 $ 486 $ 2,031 $ 71 $ 24,390 $ 557 December 31, 2016 Securities available for sale: U.S. Treasury, agencies, and corporations $ 182 $ 4 — — $ 182 $ 4 Agency residential collateralized mortgage obligations 12,345 231 $ 1,410 $ 44 13,755 275 Agency residential mortgage-backed securities 1,452 17 — — 1,452 17 Agency commercial mortgage-backed securities 1,482 35 — — 1,482 35 Other securities (a) 2 — 3 1 5 1 Held-to-maturity: Agency residential collateralized mortgage obligations 7,028 156 518 17 7,546 173 Agency residential mortgage-backed securities 547 5 — — 547 5 Agency commercial mortgage-backed securities 996 49 — — 996 49 Other securities (b) 4 — — — 4 — Total temporarily impaired securities $ 24,038 $ 497 $ 1,931 $ 62 $ 25,969 $ 559 (a) Gross unrealized losses totaled less than $1 million for other securities available for sale at March 31, 2017 , and December 31, 2016 . (b) Gross unrealized losses totaled less than $1 million for other securities held to maturity at March 31, 2017 , and December 31, 2016
Cumulative Credit Portion of Impairments on Debt Securities	As shown in the following table, we did not have any impairment losses recognized in earnings for the three months ended March 31, 2017 . Three months ended March 31, 2017 in millions Balance at December 31, 2016 $ 4 Impairment recognized in earnings — Balance at March 31, 2017 $ 4
Securities by Maturity	The following table shows our securities by remaining maturity. CMOs and other mortgage-backed securities (both of which are included in the securities available-for-sale portfolio) as well as the CMOs in the held-to-maturity portfolio are presented based on their expected average lives. The remaining securities, in both the available-for-sale and held-to-maturity portfolios, are presented based on their remaining contractual maturity. Actual maturities may differ from expected or contractual maturities since borrowers have the right to prepay obligations with or without prepayment penalties. Securities Available for Sale Held to Maturity Securities March 31, 2017 Amortized Cost Fair Value Amortized Cost Fair Value in millions Due in one year or less $ 177 $ 179 $ 55 $ 56 Due after one through five years 16,595 16,354 6,935 6,798 Due after five through ten years 1,737 1,693 2,936 2,862 Due after ten years 208 205 260 238 Total $ 18,717 $ 18,431 $ 10,186 $ 9,954

Derivatives and Hedging Activ37

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments	The following table summarizes the fair values of our derivative instruments on a gross and net basis as of March 31, 2017 , and December 31, 2016 . The change in the notional amounts of these derivatives by type from December 31, 2016 , to March 31, 2017 , indicates the volume of our derivative transaction activity during the first three months of 2017 . The notional amounts are not affected by bilateral collateral and master netting agreements. The derivative asset and liability balances are presented on a gross basis, prior to the application of bilateral collateral and master netting agreements. Total derivative assets and liabilities are adjusted to take into account the impact of legally enforceable master netting agreements that allow us to settle all derivative contracts with a single counterparty on a net basis and to offset the net derivative position with the related cash collateral. Where master netting agreements are not in effect or are not enforceable under bankruptcy laws, we do not adjust those derivative assets and liabilities with counterparties. Securities collateral related to legally enforceable master netting agreements is not offset on the balance sheet. Our derivative instruments are included in “derivative assets” or “derivative liabilities” on the balance sheet, as indicated in the following table: March 31, 2017 December 31, 2016 Fair Value Fair Value in millions Notional Amount Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedging instruments: Interest rate $ 24,917 $ 98 $ 20 $ 24,237 $ 189 $ 94 Foreign exchange 284 3 2 282 6 4 Total 25,201 101 22 24,519 195 98 Derivatives not designated as hedging instruments: Interest rate 58,963 684 511 55,315 741 643 Foreign exchange 6,897 95 84 6,230 117 109 Commodity 1,569 150 140 1,474 176 165 Credit 418 3 6 360 1 4 Other (a) 2,625 9 16 390 4 1 Total 70,472 941 757 63,769 1,039 922 Netting adjustments (b) — (464 ) (524 ) — (431 ) (384 ) Net derivatives in the balance sheet 95,673 578 255 88,288 803 636 Other collateral (c) — (11 ) (71 ) — (21 ) (97 ) Net derivative amounts $ 95,673 $ 567 $ 184 $ 88,288 $ 782 $ 539 (a) Other derivatives include interest rate lock commitments and forward sale commitments related to our residential mortgage banking activities, forward purchase and sales contracts consisting of contractual commitments associated with “to be announced” securities and when issued securities, and when-issued security transactions in connection with an “at-the-market” equity offering program. (b) Netting adjustments represent the amounts recorded to convert our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. (c) Other collateral represents the amount that cannot be used to offset our derivative assets and liabilities from a gross basis to a net basis in accordance with the applicable accounting guidance. The other collateral consists of securities and is exchanged under bilateral collateral and master netting agreements that allow us to offset the net derivative position with the related collateral. The application of the other collateral cannot reduce the net derivative position below zero. Therefore, excess other collateral, if any, is not reflected above.
Pre-Tax Net Gains (Losses) on Fair Value Hedges	The following table summarizes the pre-tax net gains (losses) on our fair value hedges for the three -month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. Three months ended March 31, 2017 in millions Income Statement Location of Net Gains (Losses) on Derivative Net Gains (Losses) on Derivative Hedged Item Income Statement Location of Net Gains (Losses) on Hedged Item Net Gains (Losses) on Hedged Item Interest rate Other income $ (35 ) Long-term debt Other income $ 35 (a) Interest rate Interest expense — Long-term debt 18 Total $ (17 ) $ 35 Three months ended March 31, 2016 in millions Income Statement Location of Net Gains (Losses) on Derivative Net Gains (Losses) on Derivative Hedged Item Income Statement Location of Net Gains (Losses) on Hedged Item Net Gains (Losses) on Hedged Item Interest rate Other income $ 115 Long-term debt Other income $ (115 ) (a) Interest rate Interest expense — Long-term debt 27 Total $ 142 $ (115 ) (a) Net gains (losses) on hedged items represent the change in fair value caused by fluctuations in interest rates.
Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location	The following table summarizes the pre-tax net gains (losses) on our cash flow and net investment hedges for the three -month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. The table includes the effective portion of net gains (losses) recognized in OCI during the period, the effective portion of net gains (losses) reclassified from OCI into income during the current period, and the portion of net gains (losses) recognized directly in income, representing the amount of hedge ineffectiveness. Three months ended March 31, 2017 in millions Net Gains (Losses) Recognized in OCI (Effective Portion) Income Statement Location of Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Income Statement Location of Net Gains (Losses) Recognized in Income (Ineffective Portion) Net Gains (Losses) Recognized in Income (Ineffective Portion) Cash Flow Hedges Interest rate $ (22 ) Interest income — Loans $ 15 Other income — Interest rate — Interest expense — Long-term debt (1 ) Other income — Interest rate — Investment banking and debt placement fees — Other income — Net Investment Hedges Foreign exchange contracts (3 ) Other Income — Other income — Total $ (25 ) $ 14 — Three months ended March 31, 2016 in millions Net Gains (Losses) Recognized in OCI (Effective Portion) Income Statement Location of Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion) Income Statement Location of Net Gains (Losses) Recognized in Income (Ineffective Portion) Net Gains (Losses) Recognized in Income (Ineffective Portion) Cash Flow Hedges Interest rate $ 133 Interest income — Loans $ 23 Other income — Interest rate (4 ) Interest expense — Long-term debt (1 ) Other income — Interest rate (1 ) Investment banking and debt placement fees — Other income — Net Investment Hedges Foreign exchange contracts (14 ) Other Income — Other income — Total $ 114 $ 22 —
After-Tax Change in AOCI Resulting from Cash Flow Hedges	The after-tax change in AOCI resulting from cash flow and net investment hedges is as follows: in millions December 31, 2016 2017 Hedging Activity Reclassification of Gains to Net Income March 31, 2017 AOCI resulting from cash flow and net investment hedges $ (14 ) $ (15 ) $ (9 ) $ (38 )
Pre-Tax Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments	The following table summarizes the pre-tax net gains (losses) on our derivatives that are not designated as hedging instruments for the three-month periods ended March 31, 2017 , and March 31, 2016 , and where they are recorded on the income statement. Three months ended March 31, 2017 Three months ended March 31, 2016 in millions Corporate Services Income Consumer Mortgage Income (a) Other Income Total Corporate Services Income Other Income Total NET GAINS (LOSSES) Interest rate $ 6 — $ (1 ) $ 5 $ 6 $ (1 ) $ 5 Foreign exchange 11 — — 11 10 — 10 Commodity 2 — — 2 1 — 1 Credit 1 — (5 ) (4 ) 1 (2 ) (1 ) Other — $ (1 ) (1 ) (2 ) — — — Total net gains (losses) $ 20 $ (1 ) $ (7 ) $ 12 $ 18 $ (3 ) $ 15 (a) As a result of the First Niagara acquisition, we began recognizing net gains (losses) on other derivatives related to our residential mortgage banking activities in “consumer mortgage income” in December 2016.
Fair Value of Derivative Assets by Type	The following table summarizes the fair value of our derivative assets by type at the dates indicated. These assets represent our gross exposure to potential loss after taking into account the effects of bilateral collateral and master netting agreements and other means used to mitigate risk. in millions March 31, 2017 December 31, 2016 Interest rate $ 452 $ 782 Foreign exchange 41 62 Commodity 50 110 Credit 1 — Other 9 4 Derivative assets before collateral 553 958 Less: Related collateral (25 ) 155 Total derivative assets $ 578 $ 803
Fair Value of Credit Derivatives Purchased and Sold	The following table summarizes the fair value of our credit derivatives purchased and sold by type as of March 31, 2017 , and December 31, 2016 . The fair value of credit derivatives presented below does not take into account the effects of bilateral collateral or master netting agreements. March 31, 2017 December 31, 2016 in millions Purchased Sold Net Purchased Sold Net Single-name credit default swaps $ (2 ) — $ (2 ) $ (2 ) — $ (2 ) Traded credit default swap indices (1 ) — (1 ) (1 ) — (1 ) Other (a) — — — — $ — — Total credit derivatives $ (3 ) — $ (3 ) $ (3 ) $ — (3 ) (a) As of both March 31, 2017 , and December 31, 2016 , the fair value of other credit derivatives sold totaled less than $1 million .
Credit Derivatives Sold and Held	The following table provides information on the types of credit derivatives sold by us and held on the balance sheet at March 31, 2017 , and December 31, 2016 . The notional amount represents the maximum amount that the seller could be required to pay. The payment/performance risk assessment is based on the default probabilities for the underlying reference entities’ debt obligations using a Moody’s credit ratings matrix known as Moody’s “Idealized” Cumulative Default Rates. The payment/performance risk shown in the table represents a weighted-average of the default probabilities for all reference entities in the respective portfolios. These default probabilities are directly correlated to the probability that we will have to make a payment under the credit derivative contracts. March 31, 2017 December 31, 2016 dollars in millions Notional Amount Average Term (Years) Payment / Performance Risk Notional Amount Average Term (Years) Payment / Performance Risk Other $ 8 11.40 12.85 % $ 4 6.49 17.93 % Total credit derivatives sold $ 8 — — $ 4 — —
Credit Risk Contingent Feature	The following table summarizes the additional cash and securities collateral that KeyBank would have been required to deliver under the ISDA Master Agreements had the credit risk contingent features been triggered for the derivative contracts in a net liability position as of March 31, 2017 , and December 31, 2016 . The additional collateral amounts were calculated based on scenarios under which KeyBank’s ratings are downgraded one, two, or three ratings as of March 31, 2017 , and December 31, 2016 , and take into account all collateral already posted. A similar calculation was performed for KeyCorp, and no additional collateral would have been required as of December 31, 2016 . For more information about the credit ratings for KeyBank and KeyCorp, see the discussion under the heading “Factors affecting liquidity” in the section entitled “Liquidity risk management” in Item 2 of this report. March 31, 2017 December 31, 2016 in millions Moody’s S&P Moody’s S&P KeyBank’s long-term senior unsecured credit ratings A3 A- A3 A- One rating downgrade $ 2 $ 2 $ 2 $ 2 Two rating downgrades 2 2 2 2 Three rating downgrades 2 2 4 4

Mortgage Servicing Assets (Tabl

Mortgage Servicing Assets (Tables)	3 Months Ended
	Mar. 31, 2017
Commercial Mortgage Backed Securities [Member]
Servicing Assets at Fair Value [Line Items]
Changes in Carrying Amount of Mortgage Servicing Assets	Changes in the carrying amount of commercial mortgage servicing assets are summarized as follows: Three months ended March 31, in millions 2017 2016 Balance at beginning of period $ 356 $ 321 Servicing retained from loan sales 28 7 Purchases 7 12 Amortization (22 ) (22 ) Balance at end of period $ 369 $ 318 Fair value at end of period $ 480 $ 408
Schedule of Range and Weighted-Average of Significant Unobservable Inputs	The range and weighted average of the significant unobservable inputs used to determine the fair value of our commercial mortgage servicing assets at March 31, 2017 , and December 31, 2016 , along with the valuation techniques, are shown in the following table: March 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Commercial mortgage servicing assets Discounted cash flow Expected defaults 1.00 - 3.00% (1.30%) Residual cash flows discount rate 7.00 - 15.00% (8.60%) Escrow earn rate 1.20 - 3.20% (2.60%) Servicing cost $150 - $38,500 ($1,342) Loan assumption rate 0.00 - 3.00% (1.25%) Percentage late 0.00 - 2.00% (.31%) December 31, 2016 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Commercial mortgage servicing assets Discounted cash flow Expected defaults 1.00 - 3.00% (1.40%) Residual cash flows discount rate 7.00 - 12.00% (8.00%) Escrow earn rate 1.10 - 3.00% (2.40%) Servicing cost $150 - $2,700 ($1,124) Loan assumption rate 0.00 - 3.00% (1.13%) Percentage late 0.00 - 2.00% (.34%)
Residential Mortgage Backed Securities [Member]
Servicing Assets at Fair Value [Line Items]
Changes in Carrying Amount of Mortgage Servicing Assets	Changes in the carrying amount of residential mortgage servicing assets are summarized as follows: Three months ended March 31, 2017 in millions Balance at beginning of period $ 28 Servicing retained from loan sales 2 Amortization (1 ) Balance at end of period $ 29 Fair value at end of period $ 35
Schedule of Range and Weighted-Average of Significant Unobservable Inputs	The range and weighted-average of the significant unobservable inputs used to fair value our mortgage servicing assets at March 31, 2017 , along with the valuation techniques, are shown in the following table: March 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) dollars in millions Residential mortgage servicing assets Discounted cash flow Prepayment speed 7.68 - 19.68% (9.24%) Discount rate 8.50 - 11.00% (8.55%) Servicing cost $76 - $3,335 ($83.03)

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities Information	The table below reflects the size of the private equity funds in which KCC was invested as well as our maximum exposure to loss in connection with these investments at March 31, 2017 . Unconsolidated VIEs in millions Total Assets Total Liabilities Maximum Exposure to Loss March 31, 2017 KCC indirect investments $ 19,029 $ 135 $ 192 December 31, 2016 KCC indirect investments $ 32,755 $ 201 $ 195 The assets and liabilities presented in the table below convey the size of KCDC’s direct and indirect investments at March 31, 2017 , and December 31, 2016 . As these investments represent unconsolidated VIEs, the assets and liabilities of the investments themselves are not recorded on our balance sheet. Unconsolidated VIEs in millions Total Assets Total Liabilities Maximum Exposure to Loss March 31, 2017 LIHTC investments $ 4,785 $ 1,972 $ 1,451 December 31, 2016 LIHTC investments $ 4,814 $ 2,003 $ 1,465

Acquisition, Divestiture, and40

Acquisition, Divestiture, and Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Components of Income (Loss) from Discontinued Operations, Net of Taxes for Education Lending Business	The components of “income (loss) from discontinued operations, net of taxes” for the education lending business are as follows: Three months ended March 31, in millions 2017 2016 Net interest income $ 5 $ 7 Provision for credit losses 3 2 Net interest income after provision for credit losses 2 5 Noninterest income 2 1 Noninterest expense 4 5 Income (loss) before income taxes — 1 Income taxes — — Income (loss) from discontinued operations, net of taxes (a) — $ 1 (a) Includes after-tax charges of $6 million for each of the three-month periods ended March 31, 2017 , and March 31, 2016 , determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations.
Components of Assets of Education Lending Business	The discontinued assets of our education lending business included on the balance sheet are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Held-to-maturity securities $ 1 $ 1 Portfolio loans at fair value 3 3 Loans, net of unearned income (a) 1,497 1,562 Less: Allowance for loan and lease losses 23 24 Net loans 1,477 1,541 Accrued income and other assets 27 28 Total assets $ 1,505 $ 1,570 (a) At March 31, 2017 , and December 31, 2016 , unearned income was less than $1 million .
Quantitative Information about Level 3 Fair Value Measurements	The following table shows the significant unobservable inputs used to measure the fair value of the portfolio loans accounted for at fair value as of March 31, 2017 , and December 31, 2016 : March 31, 2017 Fair Value of Level 3 Assets and Liabilities Valuation Technique Significant Unobservable Input Range (Weighted-Average) dollars in millions Portfolio loans accounted for at fair value $ 3 Market approach Indicative bids 84.50-104.00% December 31, 2016 Fair Value of Level 3 Assets and Liabilities Valuation Technique Significant Unobservable Input Range (Weighted-Average) dollars in millions Portfolio loans accounted for at fair value $ 3 Market approach Indicative bids 84.50-104.00%
Principal and Fair Value Amounts for Portfolio Loans at Carrying Value, and Portfolio Loans at Fair Value	The following table shows the principal and fair value amounts for our portfolio loans at carrying value at March 31, 2017 , and December 31, 2016 . Our policies for determining past due loans, placing loans on nonaccrual, applying payments on nonaccrual loans, and resuming accrual of interest are disclosed in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Nonperforming Loans” beginning on page 108 of our 2016 Form 10-K. March 31, 2017 December 31, 2016 in millions Principal Fair Value Principal Fair Value Portfolio loans at carrying value Accruing loans past due 90 days or more $ 20 N/A $ 22 N/A Loans placed on nonaccrual status 4 N/A 5 N/A
Portfolio Loans at Fair Value and Related Contractual Amounts	The following table shows the portfolio loans at fair value and their related contractual amounts as of March 31, 2017 , and December 31, 2016 . March 31, 2017 December 31, 2016 in millions Contractual Amount Fair Value Contractual Amount Fair Value ASSETS Portfolio loans $ 3 $ 3 $ 3 $ 3
Consolidated Assets at Fair Value on Recurring Basis	The following tables present the assets of the portfolio loans measured at fair value on a recurring basis at March 31, 2017 , and December 31, 2016 . March 31, 2017 in millions Level 1 Level 2 Level 3 Total ASSETS MEASURED ON A RECURRING BASIS Portfolio loans — — $ 3 $ 3 Total assets on a recurring basis at fair value — — $ 3 $ 3 December 31, 2016 in millions Level 1 Level 2 Level 3 Total ASSETS MEASURED ON A RECURRING BASIS Portfolio loans — — $ 3 $ 3 Total assets on a recurring basis at fair value — — $ 3 $ 3
Change in Fair Values of Level 3 Portfolio Loans Held for Sale, Portfolio Loans, and Consolidated Education Loan Securitization Trusts	The following table shows the change in the fair values of the Level 3 portfolio loans held for sale, portfolio loans, and consolidated education loan securitization trusts for the three-month periods ended March 31, 2017 , and March 31, 2016 . in millions Portfolio Student Loans Balance at December 31, 2016 $ 3 Settlements — Balance at March 31, 2017 (a) $ 3 Balance at December 31, 2015 $ 4 Settlements (1 ) Balance at March 31, 2016 (a) $ 3 (a) There were no purchases, sales, issuances, gains (losses) recognized in earnings, transfers into Level 3, or transfers out of Level 3 for the three -month period ended March 31, 2017 . There were no purchases, sales, issuances, gains (losses) recognized in earnings, transfers into Level 3, or transfers out of Level 3 for the three -month period ended March 31, 2016 .
Components of Assets from Discontinued Operations	The discontinued assets of Austin included on the balance sheet are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Cash and due from banks $ 15 $ 15 Total assets $ 15 $ 15
Combined Results of Discontinued Operations	The combined results of the discontinued operations are as follows: Three months ended March 31, in millions 2017 2016 Net interest income $ 5 $ 7 Provision for credit losses 3 2 Net interest income after provision for credit losses 2 5 Noninterest income 2 1 Noninterest expense 4 5 Income (loss) before income taxes — 1 Income taxes — — Income (loss) from discontinued operations, net of taxes (a) — $ 1 (a) Includes after-tax charges of $6 million and for each of the three-month periods ended March 31, 2017 , and March 31, 2016 , determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations.
Combined Assets of Discontinued Operations	The combined assets of the discontinued operations are as follows. There were no discontinued liabilities for the periods presented below. in millions March 31, 2017 December 31, 2016 Cash and due from banks $ 15 $ 15 Held-to-maturity securities 1 1 Portfolio loans at fair value 3 3 Loans, net of unearned income (a) 1,497 1,562 Less: Allowance for loan and lease losses 23 24 Net loans 1,477 1,541 Accrued income and other assets 27 28 Total assets $ 1,520 $ 1,585 (a) At March 31, 2017 , and December 31, 2016 , unearned income was less than $1 million .

Securities Financing Activiti41

Securities Financing Activities (Tables)	3 Months Ended
	Mar. 31, 2017
Banking and Thrift [Abstract]
Summarized Securities Financing Agreements	The following table summarizes our securities financing agreements at March 31, 2017 , and December 31, 2016 : March 31, 2017 in millions Gross Amount Presented in Balance Sheet Netting Adjustments (a) Collateral (b) Net Amounts Offsetting of financial assets: Reverse repurchase agreements $ 4 $ (3 ) $ (1 ) — Total $ 4 $ (3 ) $ (1 ) — Offsetting of financial liabilities: Repurchase agreements (c) $ 437 $ (3 ) $ (434 ) — Total $ 437 $ (3 ) $ (434 ) — December 31, 2016 in millions Gross Amount Presented in Balance Sheet Netting Adjustments (a) Collateral (b) Net Amounts Offsetting of financial assets: Reverse repurchase agreements $ 3 $ (3 ) — — Total $ 3 $ (3 ) — — Offsetting of financial liabilities: Repurchase agreements (c) $ 497 $ (3 ) $ (494 ) — Total $ 497 $ (3 ) $ (494 ) — (a) Netting adjustments take into account the impact of master netting agreements that allow us to settle with a single counterparty on a net basis. (b) These adjustments take into account the impact of bilateral collateral agreements that allow us to offset the net positions with the related collateral. The application of collateral cannot reduce the net position below zero. Therefore, excess collateral, if any, is not reflected above. (c) Repurchase agreements are collateralized by federal agency CMOs and U.S. Treasury securities and contracted on an overnight basis. These securities are reported in “securities available for sale” on our balance sheet.

Employee Benefits (Tables)

Employee Benefits (Tables)	3 Months Ended
	Mar. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Net Pension Cost (Benefit) for All Funded and Unfunded Plans	The components of net pension cost (benefit) for all funded and unfunded plans are as follows: Three months ended March 31, in millions 2017 2016 Interest cost on PBO $ 12 $ 10 Expected return on plan assets (17 ) (13 ) Amortization of losses 4 4 Net pension cost $ (1 ) $ 1
Net Postretirement Benefit Cost for All Funded and Unfunded Plans	The components of net postretirement benefit cost for all funded and unfunded plans are as follows: Three months ended March 31, in millions 2017 2016 Interest cost on APBO — $ 1 Expected return on plan assets — (1 ) Net postretirement benefit cost — —

Trust Preferred Securities Is43

Trust Preferred Securities Issued by Unconsolidated Subsidiaries (Tables)	3 Months Ended
	Mar. 31, 2017
Banking and Thrift [Abstract]
Summary of Trust Preferred Securities, Common Stock and Related Debentures	The trust preferred securities, common stock, and related debentures are summarized as follows: dollars in millions Trust Preferred Securities, Net of Discount (a) Common Stock Principal Amount of Debentures, Net of Discount (b) Interest Rate of Trust Preferred Securities and Debentures (c) Maturity of Trust Preferred Securities and Debentures March 31, 2017 KeyCorp Capital I $ 155 $ 6 $ 161 1.738 % 2028 KeyCorp Capital II 105 4 109 6.875 2029 KeyCorp Capital III 138 4 142 7.750 2029 HNC Statutory Trust III 18 1 19 2.453 2035 Willow Grove Statutory Trust I 18 1 19 2.441 2036 HNC Statutory Trust IV 16 1 17 2.319 2037 Westbank Capital Trust II 7 — 7 3.342 2034 Westbank Capital Trust III 7 — 7 3.342 2034 Total $ 464 $ 17 $ 481 4.811 % — December 31, 2016 $ 475 $ 17 $ 492 4.845 % — (a) The trust preferred securities must be redeemed when the related debentures mature, or earlier if provided in the governing indenture. Each issue of trust preferred securities carries an interest rate identical to that of the related debenture. Certain trust preferred securities include basis adjustments related to fair value hedges totaling $58 million at March 31, 2017 , and $59 million at December 31, 2016 . See Note 8 (“ Derivatives and Hedging Activities ”) for an explanation of fair value hedges. (b) We have the right to redeem these debentures. If the debentures purchased by KeyCorp Capital I, HNC Statutory Trust III, Willow Grove Statutory Trust I, HNC Statutory Trust IV, Westbank Capital Trust II, or Westbank Capital Trust III are redeemed before they mature, the redemption price will be the principal amount, plus any accrued but unpaid interest. If the debentures purchased by KeyCorp Capital II or KeyCorp Capital III are redeemed before they mature, the redemption price will be the greater of: (i) the principal amount, plus any accrued but unpaid interest, or (ii) the sum of the present values of principal and interest payments discounted at the Treasury Rate (as defined in the applicable indenture), plus 20 basis points for KeyCorp Capital II or 25 basis points for KeyCorp Capital III, or 50 basis points in the case of redemption upon either a tax or a capital treatment event for either KeyCorp Capital II or KeyCorp Capital III, plus any accrued but unpaid interest. The principal amount of certain debentures includes basis adjustments related to fair value hedges totaling $58 million at March 31, 2017 , and $59 million at December 31, 2016 . See Note 8 for an explanation of fair value hedges. The principal amount of debentures, net of discounts, is included in “long-term debt” on the balance sheet. (c) The interest rates for the trust preferred securities issued by KeyCorp Capital II and KeyCorp Capital III are fixed. The trust preferred securities issued by KeyCorp Capital I have a floating interest rate, equal to three-month LIBOR plus 74 basis points, that reprices quarterly. The trust preferred securities issued by HNC Statutory Trust III have a floating interest rate, equal to three-month LIBOR plus 140 basis points, that reprices quarterly. The trust preferred securities issued by Willow Grove Statutory Trust I have a floating interest rate, equal to three-month LIBOR plus 131 basis points, that reprices quarterly. The trust preferred securities issued by HNC Statutory Trust IV have a floating interest rate, equal to three-month LIBOR plus 128 basis points, that reprices quarterly. The trust preferred securities issued by Westbank Capital Trust II and Westbank Capital Trust III each have a floating interest rate, equal to three-month LIBOR plus 219 basis points, that reprices quarterly. The total interest rates are weighted-average rates.

Contingent Liabilities and Gu44

Contingent Liabilities and Guarantees (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Guarantees	The following table shows the types of guarantees that we had outstanding at March 31, 2017 . Information pertaining to the basis for determining the liabilities recorded in connection with these guarantees is included in Note 1 (“ Summary of Significant Accounting Policies ”) under the heading “Guarantees” beginning on page 115 of our 2016 Form 10-K. March 31, 2017 Maximum Potential Undiscounted Future Payments Liability Recorded in millions Financial guarantees: Standby letters of credit $ 11,779 $ 70 Recourse agreement with FNMA 2,664 5 Residential mortgage reserve 1,270 5 Return guarantee agreement with LIHTC investors 3 3 Written put options (a) 2,052 43 Total $ 17,768 $ 126 (a) The maximum potential undiscounted future payments represent notional amounts of derivatives qualifying as guarantees.

Accumulated Other Comprehensi45

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Changes in AOCI	Our changes in AOCI for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: in millions Unrealized gains (losses) on securities available for sale Unrealized gains (losses) on derivative financial instruments Foreign currency translation adjustment Net pension and postretirement benefit costs Total Balance at December 31, 2016 $ (185 ) $ (14 ) $ (3 ) $ (339 ) $ (541 ) Other comprehensive income before reclassification, net of income taxes 6 (15 ) 1 1 (7 ) Amounts reclassified from accumulated other comprehensive income, net of income taxes (a) — (9 ) — 3 (6 ) Net current-period other comprehensive income, net of income taxes 6 (24 ) 1 4 (13 ) Balance at March 31, 2017 $ (179 ) $ (38 ) $ (2 ) $ (335 ) $ (554 ) Balance at December 31, 2015 $ (58 ) $ 20 $ (2 ) $ (365 ) $ (405 ) Other comprehensive income before reclassification, net of income taxes 128 72 5 (2 ) 203 Amounts reclassified from accumulated other comprehensive income, net of income taxes (a) — (14 ) — 3 (11 ) Net current-period other comprehensive income, net of income taxes 128 58 5 1 192 Balance at March 31, 2016 $ 70 $ 78 $ 3 $ (364 ) $ (213 ) (a) See table below for details about these reclassifications .
Reclassifications Out of AOCI	Our reclassifications out of AOCI for the three months ended March 31, 2017 , and March 31, 2016 , are as follows: Three months ended March 31, 2017 Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income is Presented in millions Unrealized gains (losses) on derivative financial instruments Interest rate $ 15 Interest income — Loans Interest rate (1 ) Interest expense — Long-term debt 14 Income (loss) from continuing operations before income taxes 5 Income taxes $ 9 Income (loss) from continuing operations Net pension and postretirement benefit costs Amortization of losses $ (4 ) Personnel expense Amortization of unrecognized prior service credit — Personnel expense (4 ) Income (loss) from continuing operations before income taxes (1 ) Income taxes $ (3 ) Income (loss) from continuing operations Three months ended March 31, 2016 Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income is Presented in millions Unrealized gains (losses) on derivative financial instruments Interest rate $ 23 Interest income — Loans Interest rate (1 ) Interest expense — Long-term debt 22 Income (loss) from continuing operations before income taxes 8 Income taxes $ 14 Income (loss) from continuing operations Net pension and postretirement benefit costs Amortization of losses $ (4 ) Personnel expense (4 ) Income (loss) from continuing operations before income taxes (1 ) Income taxes $ (3 ) Income (loss) from continuing operations

Line of Business Results (Table

Line of Business Results (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Financial Information of Business Groups	The table on the following pages shows selected financial data for our major business segments for the three -month periods ended March 31, 2017 , and March 31, 2016 . Three months ended March 31, Key Community Bank Key Corporate Bank dollars in millions 2017 2016 2017 2016 SUMMARY OF OPERATIONS Net interest income (TE) $ 631 $ 399 $ 304 $ 218 Noninterest income 277 196 275 207 Total revenue (TE) (a) 908 595 579 425 Provision for credit losses 47 42 17 43 Depreciation and amortization expense 28 13 20 13 Other noninterest expense 599 423 283 224 Income (loss) from continuing operations before income taxes (TE) 234 117 259 145 Allocated income taxes and TE adjustments 87 43 78 27 Income (loss) from continuing operations 147 74 181 118 Income (loss) from discontinued operations, net of taxes — — — — Net income (loss) 147 74 181 118 Less: Net income (loss) attributable to noncontrolling interests — — — — Net income (loss) attributable to Key $ 147 $ 74 $ 181 $ 118 AVERAGE BALANCES (b) Loans and leases $ 47,036 $ 30,789 $ 37,737 $ 27,722 Total assets (a) 50,962 32,856 44,167 33,413 Deposits 79,393 52,803 21,003 18,074 OTHER FINANCIAL DATA Net loan charge-offs (b) $ 43 $ 23 $ 14 $ 18 Return on average allocated equity (b) 12.60 % 11.10 % 24.86 % 22.92 % Return on average allocated equity 12.60 11.10 24.86 22.92 Average full-time equivalent employees (c) 10,804 7,376 2,384 2,126 (a) Substantially all revenue generated by our major business segments is derived from clients that reside in the United States. Substantially all long-lived assets, including premises and equipment, capitalized software, and goodwill held by our major business segments, are located in the United States. (b) From continuing operations. (c) The number of average full-time equivalent employees was not adjusted for discontinued operations. Other Segments Total Segments Reconciling Items Key 2017 2016 2017 2016 2017 2016 2017 2016 $ (5 ) $ (9 ) $ 930 $ 608 $ (1 ) $ 4 $ 929 $ 612 33 30 585 433 (8 ) (2 ) 577 431 28 21 1,515 1,041 (9 ) 2 1,506 1,043 (1 ) 5 63 90 — (1 ) 63 89 1 1 49 27 44 37 93 64 10 9 892 656 28 (17 ) 920 639 18 6 511 268 (81 ) (17 ) 430 251 (5 ) (8 ) 160 62 (55 ) 2 105 64 23 14 351 206 (26 ) (19 ) 325 187 — — — — — 1 — 1 23 14 351 206 (26 ) (18 ) 325 188 2 (1 ) 2 (1 ) (1 ) 1 1 — $ 21 $ 15 $ 349 $ 207 $ (25 ) $ (19 ) $ 324 $ 188 $ 1,328 $ 1,603 $ 86,101 $ 60,114 $ 32 $ 42 $ 86,133 $ 60,156 36,549 27,729 131,678 93,998 1,063 479 132,741 94,477 2,030 756 102,426 71,633 (348 ) (35 ) 102,078 71,598 $ 1 $ 5 $ 58 $ 46 — — $ 58 $ 46 53.56 % 33.33 % 18.04 % 16.88 % (1.38 )% (1.34 )% 8.65 % 6.87 % 53.56 33.33 18.04 16.88 (1.38 ) (1.27 ) 8.65 6.90 3 8 13,191 9,510 5,195 3,893 18,386 13,403

Basis of Presentation and Acc47

Basis of Presentation and Accounting Policies - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Excess tax benefits recognized pertaining to share-based payment arrangements	$ 18

Business Combination - Narrativ

Business Combination - Narrative (Details)	Aug. 01, 2016USD ($)Branch$ / sharesshares	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 09, 2016Branch	Jul. 29, 2016$ / shares
Business Acquisition [Line Items]
Number of branches acquired | Branch	390
Number of branches sold | Branch				18
Goodwill acquired			$ 1,386,000,000
Merger and acquisition integration costs		$ 81,000,000
First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Total consideration paid	$ 3,992,000,000
Maximum period for change in fair value estimate		1 year
Intangible assets acquired	385,000,000
Goodwill acquired	1,367,000,000
Merger and acquisition integration costs		$ 1,000,000
Key Community Bank [Member]
Business Acquisition [Line Items]
Goodwill acquired			1,109,000,000
Key Community Bank [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Goodwill acquired	1,100,000,000
Key Corporate Bank [Member]
Business Acquisition [Line Items]
Goodwill acquired			$ 277,000,000
Key Corporate Bank [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Goodwill acquired	$ 273,000,000
Core Deposits [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Intangible assets acquired		$ 356,000,000
Weighted average useful life		10 years
Commercial Credit Card [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Weighted average useful life		6 years
Consumer Credit Card [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Weighted average useful life		9 years
Common Stock [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Shares available for issuance upon conversion of acquiree stock | shares	0.680
Cash paid upon conversion of acquiree stock	$ 2.30
Shares received by acquiree, per share | $ / shares	$ 10.26
Closing price of acquiree stock, per share | $ / shares					$ 11.70
Number of shares received by acquiree | shares	240,000,000
Fair value of acquiree options to purchase common stock	$ 26,000,000
PCI [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Contractually required payments receivable	22,600,000,000
Fair value of acquired receivables	22,200,000,000
Estimated cash flows not expected to be collected	$ 399,000,000

Business Combination - Schedule

Business Combination - Schedule of Purchase Price Calculation and Identifiable Assets Purchased and Liabilities Assumed (Details) - USD ($) $ in Millions	Aug. 01, 2016	Mar. 31, 2017	Dec. 31, 2016
LIABILITIES
Goodwill			$ 1,386
First Niagara Bank, N.A. [Member]
Consideration paid:
KeyCorp common stock issued	$ 2,831
Cash payments to First Niagara stockholders	811
Exchange of First Niagara preferred stock for KeyCorp preferred stock	350
Total consideration paid	3,992
ASSETS
Cash and due from banks and short-term investments	620
Investment securities	9,012
Other investments	297
Loans	23,645
Premises and equipment	245
Other intangible assets	385
Accrued income and other assets	1,449
Total assets	35,653
LIABILITIES
Deposits	28,994
Bank notes and other short-term borrowings	2,698
Accrued expense and other liabilities	490
Long-term debt	846
Total liabilities	33,028
Net identifiable assets acquired	2,625
Goodwill	1,367
Tax adjustment on previous fair value measurements	194
Increase (decrease) in tax adjustment on previous fair value measurements		$ 19
Scenario, Previously Reported [Member] | First Niagara Bank, N.A. [Member]
LIABILITIES
Tax adjustment on previous fair value measurements	$ 175

Business Combination - Informat

Business Combination - Information About Acquired Loan Portfolio as of Acquisition Date (Details) - USD ($) $ in Millions	Aug. 01, 2016	Dec. 31, 2012
Business Acquisition [Line Items]
Accretable yield		$ 5
PCI [Member] | First Niagara Bank, N.A. [Member]
Business Acquisition [Line Items]
Contractual required payments receivable	$ 1,378
Nonaccretable difference	189
Expected cash flows	1,189
Accretable yield	205
Fair value	$ 984

Business Combination - Schedu51

Business Combination - Schedule of Changes in Goodwill by Reporting Unit (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 2,446	$ 1,060
Acquisition of First Niagara		1,386
Tax adjustment on previous fair value measurements	(19)
Goodwill, ending balance	2,427	2,446
Key Community Bank [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	2,088	979
Acquisition of First Niagara		1,109
Tax adjustment on previous fair value measurements	(15)
Goodwill, ending balance	2,073	2,088
Key Corporate Bank [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	358	81
Acquisition of First Niagara		277
Tax adjustment on previous fair value measurements	(4)
Goodwill, ending balance	$ 354	$ 358

Business Combination - Schedu52

Business Combination - Schedule of Operations Included in Consolidated Statement of Income and Unaudited Pro Forma Information (Details) - First Niagara Bank, N.A. [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Business Acquisition, Pro Forma Information [Abstract]
Net interest income (TE), Pro forma	$ 886
Noninterest income, Pro forma	506
Net income (loss) attributable to common shareholders, Pro forma	$ 245

Earnings Per Common Share - Bas

Earnings Per Common Share - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
EARNINGS
Income (loss) from continuing operations		$ 325	$ 187
Less: Net income (loss) attributable to noncontrolling interests		1	0
Income (loss) from continuing operations attributable to Key		324	187
Less: Dividends on Preferred Stock		28	5
Income (loss) from continuing operations attributable to Key common shareholders		296	182
Income (loss) from discontinued operations, net of taxes		0	1
Net income (loss) attributable to Key common shareholders		$ 296	$ 183
WEIGHTED-AVERAGE COMMON SHARES
Weighted-average common shares outstanding (in shares)		1,068,609	827,381
Effect of convertible preferred stock (in shares)		0	0
Effect of common share options and other stock awards (in shares)		17,931	7,679
Weighted-average common shares and potential common shares outstanding (in shares)	[1]	1,086,540	835,060
EARNINGS PER COMMON SHARE
Income (loss) from continuing operations attributable to Key common shareholders (in usd per share)		$ 0.28	$ 0.22
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[2]	0.28	0.22
Income (loss) from continuing operations attributable to Key common shareholders - assuming dilution (in usd per share)		0.27	0.22
Income (loss) from discontinued operations, net of taxes (in usd per share)		0	0
Net income (loss) attributable to Key common shareholders (in usd per share)	[2]	$ 0.27	$ 0.22
[1]	Assumes conversion of common share options and other stock awards and/or convertible preferred stock, as applicable.
[2]	EPS may not foot due to rounding.

Loans and Loans Held for Sale -

Loans and Loans Held for Sale - Loans by Category (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Residential — prime loans:
Total loans	$ 86,125	$ 86,038	$ 60,438
Commercial lease financing includes receivables held as collateral for secured borrowing	55	68
Purchased loans	19,000	21,000
Loans	85,255	85,180
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial	40,112	39,768
Commercial real estate:
Commercial mortgage	15,260	15,111
Construction	2,270	2,345
Total commercial real estate loans	17,530	17,456
Commercial lease financing	4,665	4,685
Total commercial/consumer loans	62,307	61,909
Consumer Portfolio Segment [Member]
Commercial real estate:
Total commercial/consumer loans	23,818	24,129
Residential — prime loans:
Real estate — residential mortgage	5,507	5,547
Home equity loans	12,541	12,674
Total residential — prime loans	18,048	18,221
Consumer direct loans	1,735	1,788
Credit cards	1,037	1,111
Consumer indirect loans	2,998	3,009
Total loans		24,129
Commercial Credit Card [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial	114	116
PCI Loans [Member]
Residential — prime loans:
Purchased loans	812	865
Discontinued Operations [Member]
Residential — prime loans:
Total loans	1,497	1,562
Education Lending [Member] | Discontinued Operations [Member]
Residential — prime loans:
Total loans	1,497	1,562
Loans	$ 1,500	$ 1,600

Loans and Loans Held for Sale55

Loans and Loans Held for Sale - Loans Held for Sale (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and industrial	$ 171	$ 19
Real estate — construction	0	1
Commercial lease financing	1	0
Total loans held for sale	1,384	1,104	$ 1,137
Commercial Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate	1,150	1,022
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real estate	62	62
Total loans held for sale	62	62
First Niagara Bank, N.A. [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractually required payments receivable	$ 62	$ 62

Loans and Loans Held for Sale56

Loans and Loans Held for Sale - Summary of Changes in Loans Held for Sale (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at beginning of the period	$ 1,104	$ 1,137
New originations	2,563	2,846
Transfers from (to) held to maturity, net	17	11
Loan sales	(2,299)	(2,889)
Loan draws (payments), net	(1)	(1)
Balance at end of period	1,384	1,104
Loans held for sale	1,104	1,137
Residential Mortgage [Member]
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at beginning of the period	62
Balance at end of period	62	62
Loans held for sale	$ 62	$ 62

Asset Quality - Nonperforming A

Asset Quality - Nonperforming Assets and Past Due Loans (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total nonperforming loans	$ 573		$ 625
OREO	49		51
Other nonperforming assets	1		0
Total nonperforming assets	623		676
Nonperforming assets from discontinued operations-education lending	4		5
TDRs included in nonperforming loans	161		141
TDRs with an allocated specific allowance	84		59
Specifically allocated allowance for restructured loans	30		27
Accruing loans past due 90 days or more	79		87
Accruing loans past due 30 through 89 days	312		404
Purchased credit impaired loans	812		865
Financial receivable, modifications, subsequent default, recorded investment	1	$ 3
Restructured loans	23		22
Foreclosed Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Carrying value of foreclosed residential real estate	$ 31		$ 29

Asset Quality - PCI and Non-Imp

Asset Quality - PCI and Non-Impaired Loans Receivable (Details) - USD ($) $ in Millions	Aug. 01, 2016	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accretable yield		$ 5
First Niagara Bank, N.A. [Member] | PCI [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual required payments receivable	$ 1,378
Nonaccretable difference	189
Expected cash flows	1,189
Accretable yield	205
Fair value	$ 984

Asset Quality - Additional Info

Asset Quality - Additional Information (Detail)	3 Months Ended			12 Months Ended
	Mar. 31, 2017USD ($)SecurityLoan	Sep. 30, 2016USD ($)	Mar. 31, 2016USD ($)SecurityLoan	Dec. 31, 2016USD ($)	Dec. 31, 2012USD ($)	Sep. 09, 2016Branch	Aug. 01, 2016USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of branches sold | Branch						18
Estimated gross contractual amount receivable of PCI loans					$ 41,000,000
Estimated cash flows nonaccretable amount					11,000,000
Accretable yield					$ 5,000,000
Percentage of carrying amount of our commercial nonperforming loans outstanding	75.00%
Percentage of nonperforming loans outstanding face value	79.00%
Percentage of loans held for sale and other nonperforming assets	79.00%
Number of largest nonperforming loans | SecurityLoan	20
Aggregate carrying amount of largest nonperforming loans	$ 228,000,000
Percentage of total loans on nonperforming status	40.00%
Net reduction to interest income	$ 6,000,000		$ 5,000,000
Total restructured loans	302,000,000			$ 280,000,000
Addition in restructured loans	47,000,000			107,000,000
Restructured loans partially in payments and charge-offs	25,000,000			107,000,000
Financial receivable, modifications, subsequent default, recorded investment	1,000,000		3,000,000
Commitments outstanding to lend additional funds to borrowers	15,000,000			14,000,000
Loans, net of unearned income	86,125,000,000		60,438,000,000	86,038,000,000
Minimum outstanding impaired commercial loans	$ 2,500,000
Number of days to designate commercial loans will be charged off in full or charged down to the fair value of the underlying collateral payment due period	180 days
Number of days to designate the charge-off policy for consumer loans taking effect, payment due period	120 days
Number of days to designate home equity and residential mortgage loans to get charged down to net realizable value payment due period	180 days
Number of days to designate the charge-off policy for credit card loans taking effect, payment due period	180 days
Provision (credit) for loan and lease losses	$ 73,000,000		$ 78,000,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | SecurityLoan	0		0
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | SecurityLoan	3		51
Real Estate - Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivable, modifications, subsequent default, recorded investment	$ 140,000,000			141,000,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income recognized on outstanding balances	3,000,000		$ 4,000,000
Commercial Portfolio Segment [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	62,307,000,000			61,909,000,000
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income				24,129,000,000
Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	23,818,000,000
Consumer Portfolio Segment [Member] | Real Estate - Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	5,507,000,000			5,547,000,000
Continuing Operations [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for loan losses	$ 12,000,000
Percentage of Increase (decrease) in allowance for loan losses	1.40%
Provision (credit) for loan and lease losses	$ 70,000,000		76,000,000
Continuing Operations [Member] | Purchase Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision (credit) for loan and lease losses	4,000,000			$ 11,000,000
Continuing Operations [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for loan losses	$ 11,000,000
Percentage of Increase (decrease) in allowance for loan losses	1.50%
Provision (credit) for loan and lease losses	$ 42,000,000		46,000,000
Continuing Operations [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for loan losses	$ 1,000,000
Percentage of Increase (decrease) in allowance for loan losses	0.70%
Provision (credit) for loan and lease losses	$ 1,000,000
Continuing Operations [Member] | Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision (credit) for loan and lease losses	28,000,000		30,000,000
Continuing Operations [Member] | Consumer Portfolio Segment [Member] | Real Estate - Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision (credit) for loan and lease losses	$ (3,000,000)		$ 2,000,000
Purchase Credit Impaired Loans [Member] | First Niagara Bank, N.A. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractually required payments receivable							$ 22,600,000,000
Fair value of acquired receivables							22,200,000,000
Estimated cash flows not expected to be collected							399,000,000
Accretable yield							$ 205,000,000

Asset Quality - Changes in Outs

Asset Quality - Changes in Outstanding Unpaid Principal Balance, Carrying Amount, and Accretable Yield for PCI Loans (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Carrying Amount
Outstanding Unpaid Principal Balance	$ 812	$ 865
PCI Loans [Member]
Accretable Yield
Balance at beginning of period	197	5
Additions	0	205
Accretion	(19)	(29)
Net reclassifications from nonaccretable to accretable	25	35
Payments received, net	(11)	(19)
Disposals	0	0
Balance at end of period	192	197
Carrying Amount
Balance at beginning of period	865	11
Balance at end of period	812	865
Outstanding Unpaid Principal Balance	$ 930	$ 1,002	$ 17

Asset Quality - Breakdown of In

Asset Quality - Breakdown of Individually Impaired Loans (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	$ 235		$ 306
With related allowance recorded, Recorded Investment	233		195
Recorded Investment	468		501
With no related allowance recorded, Unpaid Principal Balance	302		386
With related allowance recorded, Unpaid Principal Balance	238		207
Unpaid Principal Balance	540		593
Specific Allowance	39		38
Average Recorded Investment	484	$ 457
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	153		224
With related allowance recorded, Recorded Investment	100		66
With no related allowance recorded, Unpaid Principal Balance	220		304
With related allowance recorded, Unpaid Principal Balance	105		77
Specific Allowance	19		17
Average Recorded Investment	270	230
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	82		82
With related allowance recorded, Recorded Investment	133		129
With no related allowance recorded, Unpaid Principal Balance	82		82
With related allowance recorded, Unpaid Principal Balance	133		130
Specific Allowance	20		21
Average Recorded Investment	214	227
Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	152		222
With related allowance recorded, Recorded Investment	85		62
With no related allowance recorded, Unpaid Principal Balance	217		301
With related allowance recorded, Unpaid Principal Balance	90		73
Specific Allowance	16		17
Average Recorded Investment	260	215
Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	1		2
With related allowance recorded, Recorded Investment	15		4
With no related allowance recorded, Unpaid Principal Balance	3		3
With related allowance recorded, Unpaid Principal Balance	15		4
Specific Allowance	3		0
Average Recorded Investment	10	9
Commercial Real Estate: Construction [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	6
Commercial Real Estate Loans [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	1		2
With related allowance recorded, Recorded Investment	15		4
With no related allowance recorded, Unpaid Principal Balance	3		3
With related allowance recorded, Unpaid Principal Balance	15		4
Specific Allowance	3		0
Average Recorded Investment	10	15
Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	20		20
With related allowance recorded, Recorded Investment	30		31
With no related allowance recorded, Unpaid Principal Balance	20		20
With related allowance recorded, Unpaid Principal Balance	30		31
Specific Allowance	2		2
Average Recorded Investment	51	55
Home Equity Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	60		61
With related allowance recorded, Recorded Investment	64		64
With no related allowance recorded, Unpaid Principal Balance	60		61
With related allowance recorded, Unpaid Principal Balance	64		64
Specific Allowance	17		18
Average Recorded Investment	125	129
Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With no related allowance recorded, Recorded Investment	2		1
With related allowance recorded, Recorded Investment	33		29
With no related allowance recorded, Unpaid Principal Balance	2		1
With related allowance recorded, Unpaid Principal Balance	33		29
Specific Allowance	1		1
Average Recorded Investment	33	39
Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With related allowance recorded, Recorded Investment	3		2
With related allowance recorded, Unpaid Principal Balance	3		3
Specific Allowance	0		0
Average Recorded Investment	3	1
Credit Cards [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
With related allowance recorded, Recorded Investment	3		3
With related allowance recorded, Unpaid Principal Balance	3		3
Specific Allowance	0		$ 0
Average Recorded Investment	$ 2	$ 3

Asset Quality - Breakdown of No

Asset Quality - Breakdown of Nonperforming TDRs by Loans Category (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)SecurityLoan	Dec. 31, 2016USD ($)SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	4,937
Pre-modification Outstanding Recorded Investment	$ 405
Post-modification Outstanding Recorded Investment	$ 302
Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		1,980
Pre-modification Outstanding Recorded Investment		$ 193
Post-modification Outstanding Recorded Investment		$ 141
Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		25
Pre-modification Outstanding Recorded Investment		$ 93
Post-modification Outstanding Recorded Investment		$ 51
Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		1,955
Pre-modification Outstanding Recorded Investment		$ 100
Post-modification Outstanding Recorded Investment		$ 90
Nonperforming [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	2,330
Pre-modification Outstanding Recorded Investment	$ 206
Post-modification Outstanding Recorded Investment	$ 161
Prior-Year Accruing [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	2,607
Pre-modification Outstanding Recorded Investment	$ 199
Post-modification Outstanding Recorded Investment	$ 141
Prior-Year Accruing [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		35
Pre-modification Outstanding Recorded Investment		$ 2
Post-modification Outstanding Recorded Investment		$ 2
Commercial and Industrial [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		18
Pre-modification Outstanding Recorded Investment		$ 91
Post-modification Outstanding Recorded Investment		$ 50
Commercial and Industrial [Member] | Nonperforming [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	20
Pre-modification Outstanding Recorded Investment	$ 100
Post-modification Outstanding Recorded Investment	$ 66
Commercial and Industrial [Member] | Prior-Year Accruing [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	4	5
Pre-modification Outstanding Recorded Investment	$ 29	$ 30
Post-modification Outstanding Recorded Investment	$ 16	$ 16
Commercial Loans [Member] | Nonperforming [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	27
Pre-modification Outstanding Recorded Investment	$ 105
Post-modification Outstanding Recorded Investment	$ 70
Commercial Loans [Member] | Prior-Year Accruing [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	4	5
Pre-modification Outstanding Recorded Investment	$ 29	$ 30
Post-modification Outstanding Recorded Investment	$ 16	$ 16
Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		7
Pre-modification Outstanding Recorded Investment		$ 2
Post-modification Outstanding Recorded Investment		$ 1
Commercial Real Estate: Commercial Mortgage [Member] | Nonperforming [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	7
Pre-modification Outstanding Recorded Investment	$ 5
Post-modification Outstanding Recorded Investment	$ 4
Commercial Real Estate: Commercial Mortgage [Member] | Prior-Year Accruing [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		477
Pre-modification Outstanding Recorded Investment		$ 35
Post-modification Outstanding Recorded Investment		$ 35
Commercial Real Estate Loans [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		7
Pre-modification Outstanding Recorded Investment		$ 2
Post-modification Outstanding Recorded Investment		$ 1
Commercial Real Estate Loans [Member] | Nonperforming [Member] | Commercial Loans [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	7
Pre-modification Outstanding Recorded Investment	$ 5
Post-modification Outstanding Recorded Investment	$ 4
Commercial Real Estate Loans [Member] | Prior-Year Accruing [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		1,231
Pre-modification Outstanding Recorded Investment		$ 70
Post-modification Outstanding Recorded Investment		$ 57
Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		264
Pre-modification Outstanding Recorded Investment		$ 16
Post-modification Outstanding Recorded Investment		$ 16
Real Estate - Residential Mortgage [Member] | Nonperforming [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	267
Pre-modification Outstanding Recorded Investment	$ 16
Post-modification Outstanding Recorded Investment	$ 16
Real Estate - Residential Mortgage [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	526	410
Pre-modification Outstanding Recorded Investment	$ 35	$ 3
Post-modification Outstanding Recorded Investment	$ 35	$ 1
Home Equity Loans [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	1,186	1,199
Pre-modification Outstanding Recorded Investment	$ 72	$ 77
Post-modification Outstanding Recorded Investment	$ 64	$ 69
Home Equity Loans [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	1,240	377
Pre-modification Outstanding Recorded Investment	$ 75	$ 56
Post-modification Outstanding Recorded Investment	$ 61	$ 28
Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		32
Pre-modification Outstanding Recorded Investment		$ 1
Post-modification Outstanding Recorded Investment		$ 0
Consumer Direct Loans [Member] | Nonperforming [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	40
Pre-modification Outstanding Recorded Investment	$ 1
Post-modification Outstanding Recorded Investment	$ 1
Consumer Direct Loans [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	32	2,530
Pre-modification Outstanding Recorded Investment	$ 2	$ 166
Post-modification Outstanding Recorded Investment	$ 1	$ 123
Consumer Credit Card [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan		336
Pre-modification Outstanding Recorded Investment		$ 2
Post-modification Outstanding Recorded Investment		$ 2
Consumer Credit Card [Member] | Nonperforming [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	288
Pre-modification Outstanding Recorded Investment	$ 2
Post-modification Outstanding Recorded Investment	$ 1
Consumer Credit Card [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	440	2,535
Pre-modification Outstanding Recorded Investment	$ 3	$ 196
Post-modification Outstanding Recorded Investment	$ 1	$ 139
Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	522	124
Pre-modification Outstanding Recorded Investment	$ 10	$ 4
Post-modification Outstanding Recorded Investment	$ 9	$ 3
Consumer Indirect Loans [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	365	4,515
Pre-modification Outstanding Recorded Investment	$ 55	$ 389
Post-modification Outstanding Recorded Investment	$ 27	$ 280
Consumer Portfolio Segment [Member] | Nonperforming [Member] | Consumer Portfolio Segment [Member] | Nonperforming [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	2,303
Pre-modification Outstanding Recorded Investment	$ 101
Post-modification Outstanding Recorded Investment	$ 91
Consumer Portfolio Segment [Member] | Prior-Year Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | SecurityLoan	2,603
Pre-modification Outstanding Recorded Investment	$ 170
Post-modification Outstanding Recorded Investment	$ 125

Asset Quality - Post-Modificati

Asset Quality - Post-Modification Outstanding Recorded Investment by Concession Type for Our Commercial Accruing and Nonaccruing TDRs (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Total commercial and consumer TDRs	$ 43	$ 19
Total loans	86,125	60,438	$ 86,038
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Total loans			24,129
Commercial Loans [Member] | Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Interest rate reduction	7	0
Other	21	3
Total	28	3
Total loans	62,307		$ 61,909
Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Interest rate reduction	3	2
Forgiveness of principal	0	12
Other	12	2
Total	15	$ 16
Total loans	$ 23,818

Asset Quality - Past Due Loans

Asset Quality - Past Due Loans Including Current Loans (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 84,349	$ 84,057
Days Past Due	964	1,116
Non-performing Loans	573	625
Purchased Credit Impaired	812	865
Total loans	86,125	86,038	$ 60,438
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		24,129
Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	39,621	39,242
Days Past Due	389	414
Non-performing Loans	258	297
Purchased Credit Impaired	102	112
Total loans	40,112	39,768
Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	14,891	14,655
Days Past Due	78	134
Non-performing Loans	32	26
Purchased Credit Impaired	291	322
Total loans	15,260	15,111
Commercial Real Estate: Construction [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,242	2,314
Days Past Due	2	5
Non-performing Loans	2	3
Purchased Credit Impaired	26	26
Total loans	2,270	2,345
Commercial Real Estate Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	17,133	16,969
Days Past Due	80	139
Non-performing Loans	34	29
Purchased Credit Impaired	317	348
Total loans	17,530	17,456
Commercial Lease Financing [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4,634	4,641
Days Past Due	31	44
Non-performing Loans	5	8
Purchased Credit Impaired	0	0
Total loans	4,665	4,685
Commercial Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	61,388	60,852
Days Past Due	500	597
Non-performing Loans	297	334
Purchased Credit Impaired	419	460
Total loans	62,307	61,909
Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	5,065	5,098
Days Past Due	81	81
Non-performing Loans	54	56
Purchased Credit Impaired	361	368
Total loans	5,507	5,547
Home Equity Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12,225	12,327
Days Past Due	290	317
Non-performing Loans	207	223
Purchased Credit Impaired	26	30
Total loans	12,541	12,674
Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,709	1,705
Days Past Due	20	76
Non-performing Loans	3	6
Purchased Credit Impaired	6	7
Total loans	1,735	1,788
Consumer Credit Card Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,011	1,082
Days Past Due	26	29
Non-performing Loans	3	2
Purchased Credit Impaired	0	0
Total loans	1,037	1,111
Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,951	2,993
Days Past Due	47	16
Non-performing Loans	9	4
Purchased Credit Impaired	0	0
Total loans	2,998	3,009
Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	22,961	23,205
Days Past Due	464	519
Non-performing Loans	276	291
Purchased Credit Impaired	393	405
Total loans	23,818
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	197	305
30-59 Days Past Due [Member] | Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	60	58
30-59 Days Past Due [Member] | Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	25	93
30-59 Days Past Due [Member] | Commercial Real Estate: Construction [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	0	0
30-59 Days Past Due [Member] | Commercial Real Estate Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	25	93
30-59 Days Past Due [Member] | Commercial Lease Financing [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	12	28
30-59 Days Past Due [Member] | Commercial Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	97	179
30-59 Days Past Due [Member] | Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	16	17
30-59 Days Past Due [Member] | Home Equity Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	42	49
30-59 Days Past Due [Member] | Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	8	44
30-59 Days Past Due [Member] | Consumer Credit Card Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	7	9
30-59 Days Past Due [Member] | Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	27	7
30-59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	100	126
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	115	99
60-89 Days Past Due [Member] | Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	47	28
60-89 Days Past Due [Member] | Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	10	9
60-89 Days Past Due [Member] | Commercial Real Estate: Construction [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	0	0
60-89 Days Past Due [Member] | Commercial Real Estate Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	10	9
60-89 Days Past Due [Member] | Commercial Lease Financing [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	8	3
60-89 Days Past Due [Member] | Commercial Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	65	40
60-89 Days Past Due [Member] | Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	7	5
60-89 Days Past Due [Member] | Home Equity Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	27	29
60-89 Days Past Due [Member] | Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	4	15
60-89 Days Past Due [Member] | Consumer Credit Card Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	5	6
60-89 Days Past Due [Member] | Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	7	4
60-89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	50	59
90 and Greater Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	79	87
90 and Greater Days Past Due [Member] | Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	24	31
90 and Greater Days Past Due [Member] | Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	11	6
90 and Greater Days Past Due [Member] | Commercial Real Estate: Construction [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	0	2
90 and Greater Days Past Due [Member] | Commercial Real Estate Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	11	8
90 and Greater Days Past Due [Member] | Commercial Lease Financing [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	6	5
90 and Greater Days Past Due [Member] | Commercial Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	41	44
90 and Greater Days Past Due [Member] | Real Estate - Residential Mortgage [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	4	3
90 and Greater Days Past Due [Member] | Home Equity Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	14	16
90 and Greater Days Past Due [Member] | Consumer Direct Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	5	11
90 and Greater Days Past Due [Member] | Consumer Credit Card Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	11	12
90 and Greater Days Past Due [Member] | Consumer Indirect Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	4	1
90 and Greater Days Past Due [Member] | Consumer Portfolio Segment [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days Past Due	$ 38	$ 43

Asset Quality - Financing Recei

Asset Quality - Financing Receivable Credit Quality Indicators (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 86,125	$ 86,038	$ 60,438
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,010	39,656
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	38,268	37,845
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial and Industrial [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,484	1,514
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial and Industrial [Member] | Criticized (Nonaccruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	258	297
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,969	14,789
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,536	14,308
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Commercial [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	401	455
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Commercial [Member] | Criticized (Nonaccruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	32	26
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,244	2,319
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,199	2,287
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Construction [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	43	30
Commercial Portfolio Segment Excluding PCI Loans [Member] | RE Construction [Member] | Criticized (Nonaccruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2	2
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,665	4,685
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Leases [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,602	4,632
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Leases [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	58	45
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Leases [Member] | Criticized (Nonaccruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5	8
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Portfolio Segment Excluding PCI Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	61,888	61,449
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Portfolio Segment Excluding PCI Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	59,605	59,072
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Portfolio Segment Excluding PCI Loans [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,986	2,044
Commercial Portfolio Segment Excluding PCI Loans [Member] | Commercial Portfolio Segment Excluding PCI Loans [Member] | Criticized (Nonaccruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	297	333
Commercial Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	419	460
Commercial Portfolio Segment, PCI [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	164	172
Commercial Portfolio Segment, PCI [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	255	288
Commercial Portfolio Segment, PCI [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	102	112
Commercial Portfolio Segment, PCI [Member] | Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	26	12
Commercial Portfolio Segment, PCI [Member] | Commercial and Industrial [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	76	100
Commercial Portfolio Segment, PCI [Member] | RE Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	291	322
Commercial Portfolio Segment, PCI [Member] | RE Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	118	139
Commercial Portfolio Segment, PCI [Member] | RE Commercial [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	173	183
Commercial Portfolio Segment, PCI [Member] | RE Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	26	26
Commercial Portfolio Segment, PCI [Member] | RE Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	20	21
Commercial Portfolio Segment, PCI [Member] | RE Construction [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6	5
Commercial Portfolio Segment, PCI [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment, PCI [Member] | Commercial Leases [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment, PCI [Member] | Commercial Leases [Member] | Criticized (Accruing) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0

Asset Quality - Consumer Loans

Asset Quality - Consumer Loans by Refreshed FICO Score (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 86,125	$ 86,038	$ 60,438
Consumer Portfolio Segment Excluding PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	23,425	23,724
Consumer Portfolio Segment Excluding PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17,661	17,823
Consumer Portfolio Segment Excluding PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,729	1,781
Consumer Portfolio Segment Excluding PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,037	1,111
Consumer Portfolio Segment Excluding PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,998	3,009
Consumer Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	393	405
Consumer Portfolio Segment, PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	387	398
Consumer Portfolio Segment, PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6	7
Consumer Portfolio Segment, PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Consumer Portfolio Segment, PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment Excluding PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,078	12,035
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,935	9,818
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	472	498
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	408	453
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,263	1,266
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	136	133
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment, PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	136	133
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment, PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, 750 and Above [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment Excluding PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,153	7,647
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,821	5,266
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	644	661
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	498	525
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,190	1,195
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	145	129
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment, PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	143	127
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2	2
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment, PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, 660 to 749 [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment Excluding PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,540	2,486
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,665	1,617
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	199	194
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	131	132
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	545	543
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	106	137
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment, PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	103	133
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3	4
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment, PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, Less than 660 [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, No Score [Member] | Consumer Portfolio Segment Excluding PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	654	1,556
FICO Score, No Score [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	240	1,122
FICO Score, No Score [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	414	428
FICO Score, No Score [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	1
FICO Score, No Score [Member] | Consumer Portfolio Segment Excluding PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	5
FICO Score, No Score [Member] | Consumer Portfolio Segment, PCI [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6	6
FICO Score, No Score [Member] | Consumer Portfolio Segment, PCI [Member] | Residential Prime Financing Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5	5
FICO Score, No Score [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Direct Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1	1
FICO Score, No Score [Member] | Consumer Portfolio Segment, PCI [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
FICO Score, No Score [Member] | Consumer Portfolio Segment, PCI [Member] | Consumer Indirect Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0

Asset Quality - Summary of Allo

Asset Quality - Summary of Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 882	$ 824
Charge-offs	(83)	(69)
Recoveries	21	17
Provision for loan and lease losses from continuing operations	63	89
Ending balance	893	850
Continuing Operations [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	858	796
Charge-offs	(77)	(60)
Recoveries	19	14
Net loans and leases charged off	(58)	(46)
Provision for loan and lease losses from continuing operations	70	76
Ending balance	$ 870	$ 826

Asset Quality - Changes in Allo

Asset Quality - Changes in Allowance for Loan and Lease Losses by Loan Category (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 882	$ 824	$ 824
Provision	73	78
Charge-offs	(83)	(69)
Recoveries	21	17
Ending balance	893	850	882
Provision (credit) for losses on lending-related commitments	(7)	13
Continuing Operations [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	858	796	796
Provision	70	76
Charge-offs	(77)	(60)
Recoveries	19	14
Ending balance	870	826	858
Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	716	656	656
Provision	42	46
Charge-offs	(39)	(30)
Recoveries	8	6
Ending balance	727	678	716
Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision	1
Continuing Operations [Member] | Commercial and Industrial [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	508	450	450
Provision	31	50
Charge-offs	(32)	(26)
Recoveries	5	3
Ending balance	512	477	508
Continuing Operations [Member] | Commercial Real Estate: Commercial Mortgage [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	144	134	134
Provision	2	0
Charge-offs	0	(1)
Recoveries	0	2
Ending balance	146	135	144
Continuing Operations [Member] | RE Construction [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	22	25	25
Provision	6	(3)
Charge-offs	0	0
Recoveries	1	1
Ending balance	29	23	22
Continuing Operations [Member] | Commercial Real Estate [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	166	159	159
Provision	8	(3)
Charge-offs	0	(1)
Recoveries	1	3
Ending balance	175	158	166
Continuing Operations [Member] | Commercial Lease Financing [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	42	47	47
Provision	3	(1)
Charge-offs	(7)	(3)
Recoveries	2	0
Ending balance	40	43	42
Continuing Operations [Member] | Real Estate - Residential Mortgage [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	17	18	18
Provision	(3)	2
Charge-offs	2	(2)
Recoveries	2	2
Ending balance	18	20	17
Continuing Operations [Member] | Home Equity Loans [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	54	57	57
Provision	4	14
Charge-offs	(8)	(10)
Recoveries	3	3
Ending balance	53	64	54
Continuing Operations [Member] | Consumer Direct Loans [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	24	20	20
Provision	9	5
Charge-offs	(10)	(6)
Recoveries	1	1
Ending balance	24	20	24
Continuing Operations [Member] | Credit Cards [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	38	32	32
Provision	10	6
Charge-offs	(11)	(8)
Recoveries	1	1
Ending balance	38	31	38
Continuing Operations [Member] | Consumer Indirect Loans [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	9	13	13
Provision	8	3
Charge-offs	(11)	(4)
Recoveries	4	1
Ending balance	10	13	9
Continuing Operations [Member] | Consumer Loans [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	142	140	140
Provision	28	30
Charge-offs	(38)	(30)
Recoveries	11	8
Ending balance	143	148	142
Discontinued Operations [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	24	28	28
Provision	3	2
Charge-offs	(6)	(9)
Recoveries	2	3
Ending balance	$ 23	$ 24	$ 24

Asset Quality - Allowance for L

Asset Quality - Allowance for Loan and Lease Losses and Corresponding Loan Balances (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Purchase Credit Impairment, Outstanding	$ 812	$ 865
Individually Evaluated for Impairment, Allowance, Total ALLL - Including Discontinued Operations	41	39
Collectively Evaluated for Impairment, Allowance, Total ALLL - Including Discontinued Operations	846	838
Purchased Credit Impaired, Allowance, Total ALLL - Including Discontinued Operations	6	5
Loans, Outstanding, Total ALLL - Including Discontinued Operations	87,625	87,603
Individually Evaluated for Impairment, Outstanding, Total ALLL - Including Discontinued Operations	492	523
Collectively Evaluated for Impairment, Outstanding, Total ALLL - Including Discontinued Operations	86,321	86,215
Purchased Credit Impaired, Outstanding, Total ALLL - Including Discontinued Operations	812	865
Loans at fair value	3
Continuing Operations [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	39	37
Collectively Evaluated for Impairment, Allowance	825	816
Purchase Credit Impairment, Allowance	6	5
Total loans	86,125	86,038
Individually Evaluated for Impairment, Outstanding	469	501
Collectively Evaluated for Impairment, Outstanding	84,844	84,672
Purchase Credit Impairment, Outstanding	812	865
Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Purchase Credit Impairment, Allowance	4	5
Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans		24,129
Discontinued Operations [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance		2
Collectively Evaluated for Impairment, Allowance	21	22
Purchase Credit Impairment, Allowance	0	0
Total loans	1,500	1,565
Individually Evaluated for Impairment, Outstanding	23	22
Collectively Evaluated for Impairment, Outstanding	1,477	1,543
Purchase Credit Impairment, Outstanding	0	0
Loans at fair value	3	3
Commercial and Industrial [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	16	17
Collectively Evaluated for Impairment, Allowance	495	486
Purchase Credit Impairment, Allowance	1	5
Total loans	40,112	39,768
Individually Evaluated for Impairment, Outstanding	237	284
Collectively Evaluated for Impairment, Outstanding	39,773	39,372
Purchase Credit Impairment, Outstanding	102	112
Commercial Real Estate: Commercial Mortgage [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	3	0
Collectively Evaluated for Impairment, Allowance	140	144
Purchase Credit Impairment, Allowance	3	0
Total loans	15,260	15,111
Individually Evaluated for Impairment, Outstanding	16	5
Collectively Evaluated for Impairment, Outstanding	14,953	14,784
Purchase Credit Impairment, Outstanding	291	322
Commercial Real Estate: Construction [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	0	0
Collectively Evaluated for Impairment, Allowance	29	22
Purchase Credit Impairment, Allowance	0	0
Total loans	2,270	2,345
Individually Evaluated for Impairment, Outstanding	0	0
Collectively Evaluated for Impairment, Outstanding	2,244	2,319
Purchase Credit Impairment, Outstanding	26	26
Commercial Real Estate Loans [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	3	0
Collectively Evaluated for Impairment, Allowance	169	166
Purchase Credit Impairment, Allowance	3	0
Total loans	17,530	17,456
Individually Evaluated for Impairment, Outstanding	16	5
Collectively Evaluated for Impairment, Outstanding	17,197	17,103
Purchase Credit Impairment, Outstanding	317	348
Commercial Lease Financing [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	0	0
Collectively Evaluated for Impairment, Allowance	40	42
Purchase Credit Impairment, Allowance	0	0
Total loans	4,665	4,685
Individually Evaluated for Impairment, Outstanding	0	0
Collectively Evaluated for Impairment, Outstanding	4,665	4,685
Purchase Credit Impairment, Outstanding	0	0
Commercial Loans [Member] | Continuing Operations [Member] | Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	19	17
Collectively Evaluated for Impairment, Allowance	704	694
Total loans	62,307	61,909
Individually Evaluated for Impairment, Outstanding	253	289
Collectively Evaluated for Impairment, Outstanding	61,635	61,160
Purchase Credit Impairment, Outstanding	419	460
Real Estate - Residential Mortgage [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	2	2
Collectively Evaluated for Impairment, Allowance	15	15
Purchase Credit Impairment, Allowance	1	0
Total loans	5,507	5,547
Individually Evaluated for Impairment, Outstanding	51	51
Collectively Evaluated for Impairment, Outstanding	5,095	5,128
Purchase Credit Impairment, Outstanding	361	368
Home Equity Loans [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	17	17
Collectively Evaluated for Impairment, Allowance	35	37
Purchase Credit Impairment, Allowance	1	0
Total loans	12,541	12,674
Individually Evaluated for Impairment, Outstanding	124	125
Collectively Evaluated for Impairment, Outstanding	12,391	12,519
Purchase Credit Impairment, Outstanding	26	30
Consumer Direct Loans [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	0	0
Collectively Evaluated for Impairment, Allowance	24	24
Purchase Credit Impairment, Allowance	0	0
Total loans	1,735	1,788
Individually Evaluated for Impairment, Outstanding	3	3
Collectively Evaluated for Impairment, Outstanding	1,726	1,778
Purchase Credit Impairment, Outstanding	6	7
Consumer Credit Card Financing Receivable [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	0	0
Collectively Evaluated for Impairment, Allowance	38	38
Purchase Credit Impairment, Allowance	0	0
Total loans	1,037	1,111
Individually Evaluated for Impairment, Outstanding	3	3
Collectively Evaluated for Impairment, Outstanding	1,034	1,108
Purchase Credit Impairment, Outstanding	0	0
Consumer Indirect Loans [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	1	1
Collectively Evaluated for Impairment, Allowance	9	8
Purchase Credit Impairment, Allowance	0	0
Total loans	2,998	3,009
Individually Evaluated for Impairment, Outstanding	35	30
Collectively Evaluated for Impairment, Outstanding	2,963	2,979
Purchase Credit Impairment, Outstanding	0	0
Consumer Loans [Member] | Continuing Operations [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually Evaluated for Impairment, Allowance	20	20
Collectively Evaluated for Impairment, Allowance	121	122
Purchase Credit Impairment, Allowance	2	0
Total loans	23,818
Individually Evaluated for Impairment, Outstanding	216	212
Collectively Evaluated for Impairment, Outstanding	23,209	23,512
Purchase Credit Impairment, Outstanding	393	405
Education Lending [Member] | Discontinued Operations [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans at fair value	$ 3	$ 3

Asset Quality - Changes in Liab

Asset Quality - Changes in Liability for Credit Losses on Lending Related Commitments (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 55	$ 56
Provision (credit) for losses on lending-related commitments	(7)	13
Balance at end of period	$ 48	$ 69

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)security	Dec. 31, 2016USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale adjusted to fair value	$ 1	$ 0
Fair value of OREO property re-evaluated period	90 days
Third party broker price opinion periodic review period	180 days
Loans, net of allowance	$ 85,255,000,000	85,180,000,000
Loans at fair value	3,000,000
Discontinued Operations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans at fair value	3,000,000	3,000,000
Discontinued Operations [Member] | Education Lending [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net of allowance	1,500,000,000	1,600,000,000
Loans at fair value	3,000,000	3,000,000
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value on non recurring basis	0	0
Loans held for sale adjusted to fair value	1,384,000,000	1,104,000,000
Loans at fair value	83,520,000,000	83,285,000,000
Fair Value [Member] | Discontinued Operations [Member] | Education Lending [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net of allowance	1,300,000,000	1,300,000,000
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net of allowance	85,255,000,000	85,180,000,000
Carrying Amount [Member] | Discontinued Operations [Member] | Education Lending [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net of allowance	$ 1,500,000,000	1,500,000,000
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of convertible preferred securities | security	2
Level 3 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale adjusted to fair value	$ 1,322,000,000	1,042,000,000
Loans at fair value	0	83,285,000,000
Consumer Portfolio Segment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Real estate — residential mortgage	$ 5,507,000,000	$ 5,547,000,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Direct and Indirect Investments, Related Unfunded Commitments and Financial Support Provided (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Indirect Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair Value	$ 2
Unfunded Commitments	1
Indirect Investments [Member] | Passive Funds [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair Value	2
Unfunded Commitments	$ 1
Minimum [Member] | Passive Funds [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Liquidation period of funds	1 year
Minimum [Member] | Indirect Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Liquidation period of funds	1 year
Maximum [Member] | Passive Funds [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Liquidation period of funds	3 years
Maximum [Member] | Indirect Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Liquidation period of funds	8 years
Principal Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair Value	$ 176
Unfunded Commitments	37
Funded Commitments	1	$ 1
Funded Other	0	13
Principal Investments [Member] | Direct Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair Value	21
Unfunded Commitments	0
Funded Commitments	0	0
Funded Other	0	13
Principal Investments [Member] | Indirect Investments [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Fair Value	155
Unfunded Commitments	37
Funded Commitments	1	1
Funded Other	$ 0	$ 0

Fair Value Measurements - Fai73

Fair Value Measurements - Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	$ 921,000,000	$ 867,000,000
Securities available for sale	18,431,000,000	20,212,000,000
Loans, net of unearned income	86,125,000,000	86,038,000,000	$ 60,438,000,000
Loans held for sale	1	0
Derivative Assets, Netting adjustments	(464,000,000)	(431,000,000)
Total derivative assets	578,000,000	803,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative Liabilities, Netting adjustments	(524,000,000)	(384,000,000)
Total derivative liabilities	255,000,000	636,000,000
Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	14,563,000,000	16,408,000,000
U.S. Treasury, Agencies and Corporations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	185,000,000	184,000,000
States and Political Subdivisions [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	11,000,000	11,000,000
Other Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	20,000,000	20,000,000
Agency Residential Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,742,000,000	1,846,000,000
Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,910,000,000	1,743,000,000
Recurring [Member]
ASSETS MEASURED ON A RECURRING BASIS
Commercial loans	4,000,000	18,000,000
Total trading account assets	921,000,000	867,000,000
Securities available for sale	18,431,000,000	20,212,000,000
Total other investments	178,000,000	191,000,000
Loans, net of unearned income	0	0
Loans held for sale	62,000,000	62,000,000
Derivative assets, gross	1,042,000,000	1,234,000,000
Derivative Assets, Netting adjustments	(464,000,000)	(431,000,000)
Total derivative assets	578,000,000	803,000,000
Accrued income and other assets	0	8,000,000
Total assets at fair value	20,170,000,000	22,143,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	779,000,000	1,020,000,000
Derivative Liabilities, Netting adjustments	(524,000,000)	(384,000,000)
Total derivative liabilities	255,000,000	636,000,000
Accrued expense and other liabilities	0	14,000,000
Total liabilities on a recurring basis at fair value	1,198,000,000	1,458,000,000
Recurring [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	14,563,000,000	16,408,000,000
Recurring [Member] | Trading Account Assets [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	917,000,000	849,000,000
Recurring [Member] | U.S. Treasury, Agencies and Corporations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	586,000,000	655,000,000
Securities available for sale	185,000,000	184,000,000
Recurring [Member] | States and Political Subdivisions [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	47,000,000	8,000,000
Securities available for sale	11,000,000	11,000,000
Recurring [Member] | Other Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	36,000,000	73,000,000
Securities available for sale	20,000,000	20,000,000
Recurring [Member] | Agency Residential Mortgage Backed Securities [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		1,846,000,000
Recurring [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,910,000,000
Recurring [Member] | Principal Investments Direct [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	21,000,000	27,000,000
Recurring [Member] | Principal Investments Indirect [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	155,000,000	158,000,000
Recurring [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	176,000,000	185,000,000
Recurring [Member] | Equity And Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2,000,000	6,000,000
Recurring [Member] | Private Equity and Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	2,000,000	6,000,000
Recurring [Member] | Other Mortgage-Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	248,000,000	113,000,000
Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,742,000,000
Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		1,743,000,000
Recurring [Member] | Short Positions [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	943,000,000	808,000,000
Recurring [Member] | Interest Rate [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	782,000,000	930,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	531,000,000	737,000,000
Recurring [Member] | Foreign Exchange [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	98,000,000	123,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	86,000,000	113,000,000
Recurring [Member] | Commodity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	150,000,000	176,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	140,000,000	165,000,000
Recurring [Member] | Credit [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	3,000,000	1,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	6,000,000	4,000,000
Recurring [Member] | Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	9,000,000	4,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	16,000,000	1,000,000
Level 1 [Member] | Recurring [Member]
ASSETS MEASURED ON A RECURRING BASIS
Commercial loans	0	0
Total trading account assets	1,000,000	0
Securities available for sale	3,000,000	3,000,000
Total other investments	0	0
Loans, net of unearned income	0	0
Loans held for sale	0	0
Derivative assets, gross	91,000,000	114,000,000
Derivative Assets, Netting adjustments	0	0
Total derivative assets	91,000,000	114,000,000
Accrued income and other assets	0	0
Total assets at fair value	95,000,000	117,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	78,000,000	102,000,000
Derivative Liabilities, Netting adjustments	0	0
Total derivative liabilities	78,000,000	102,000,000
Accrued expense and other liabilities	0	0
Total liabilities on a recurring basis at fair value	292,000,000	294,000,000
Level 1 [Member] | Recurring [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 1 [Member] | Recurring [Member] | Trading Account Assets [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,000,000	0
Level 1 [Member] | Recurring [Member] | U.S. Treasury, Agencies and Corporations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 1 [Member] | Recurring [Member] | States and Political Subdivisions [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 1 [Member] | Recurring [Member] | Other Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	1,000,000	0
Securities available for sale	3,000,000	3,000,000
Level 1 [Member] | Recurring [Member] | Agency Residential Mortgage Backed Securities [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		0
Level 1 [Member] | Recurring [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0
Level 1 [Member] | Recurring [Member] | Principal Investments Direct [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 [Member] | Recurring [Member] | Principal Investments Indirect [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 [Member] | Recurring [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 [Member] | Recurring [Member] | Equity And Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 [Member] | Recurring [Member] | Private Equity and Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 1 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 1 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0
Level 1 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		0
Level 1 [Member] | Recurring [Member] | Short Positions [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	214,000,000	192,000,000
Level 1 [Member] | Recurring [Member] | Interest Rate [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 1 [Member] | Recurring [Member] | Foreign Exchange [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	91,000,000	114,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	78,000,000	102,000,000
Level 1 [Member] | Recurring [Member] | Commodity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 1 [Member] | Recurring [Member] | Credit [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 1 [Member] | Recurring [Member] | Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Loans held for sale	62,000,000
Level 2 [Member] | Recurring [Member]
ASSETS MEASURED ON A RECURRING BASIS
Commercial loans	4,000,000	18,000,000
Total trading account assets	920,000,000	867,000,000
Securities available for sale	18,411,000,000	20,192,000,000
Total other investments	0	0
Loans, net of unearned income	0	0
Loans held for sale		62,000,000
Derivative assets, gross	941,000,000	1,110,000,000
Derivative Assets, Netting adjustments	0	0
Total derivative assets	941,000,000	1,110,000,000
Accrued income and other assets	0	8,000,000
Total assets at fair value	20,334,000,000	22,239,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	701,000,000	918,000,000
Derivative Liabilities, Netting adjustments	0	0
Total derivative liabilities	701,000,000	918,000,000
Accrued expense and other liabilities	0	14,000,000
Total liabilities on a recurring basis at fair value	1,430,000,000	1,548,000,000
Level 2 [Member] | Recurring [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	14,563,000,000	16,408,000,000
Level 2 [Member] | Recurring [Member] | Trading Account Assets [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	916,000,000	849,000,000
Level 2 [Member] | Recurring [Member] | U.S. Treasury, Agencies and Corporations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	586,000,000	655,000,000
Securities available for sale	185,000,000	184,000,000
Level 2 [Member] | Recurring [Member] | States and Political Subdivisions [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	47,000,000	8,000,000
Securities available for sale	11,000,000	11,000,000
Level 2 [Member] | Recurring [Member] | Other Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	35,000,000	73,000,000
Securities available for sale	0	0
Level 2 [Member] | Recurring [Member] | Agency Residential Mortgage Backed Securities [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		1,846,000,000
Level 2 [Member] | Recurring [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,910,000,000
Level 2 [Member] | Recurring [Member] | Principal Investments Direct [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 [Member] | Recurring [Member] | Principal Investments Indirect [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 [Member] | Recurring [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 [Member] | Recurring [Member] | Equity And Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 [Member] | Recurring [Member] | Private Equity and Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 2 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	248,000,000	113,000,000
Level 2 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	1,742,000,000
Level 2 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		1,743,000,000
Level 2 [Member] | Recurring [Member] | Short Positions [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	729,000,000	616,000,000
Level 2 [Member] | Recurring [Member] | Interest Rate [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	777,000,000	923,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	531,000,000	737,000,000
Level 2 [Member] | Recurring [Member] | Foreign Exchange [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	7,000,000	9,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	8,000,000	11,000,000
Level 2 [Member] | Recurring [Member] | Commodity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	150,000,000	176,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	140,000,000	165,000,000
Level 2 [Member] | Recurring [Member] | Credit [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	2,000,000	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	6,000,000	4,000,000
Level 2 [Member] | Recurring [Member] | Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	5,000,000	2,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	16,000,000	1,000,000
Level 3 [Member] | Recurring [Member]
ASSETS MEASURED ON A RECURRING BASIS
Commercial loans	0	0
Total trading account assets	0	0
Securities available for sale	17,000,000	17,000,000
Total other investments	21,000,000	27,000,000
Loans, net of unearned income	0	0
Loans held for sale	0	0
Derivative assets, gross	10,000,000	10,000,000
Derivative Assets, Netting adjustments	0	0
Total derivative assets	10,000,000	10,000,000
Accrued income and other assets	0	0
Total assets at fair value	48,000,000	54,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Derivative Liabilities, Netting adjustments	0	0
Total derivative liabilities	0	0
Accrued expense and other liabilities	0	0
Total liabilities on a recurring basis at fair value	0	0
Level 3 [Member] | Recurring [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 3 [Member] | Recurring [Member] | Trading Account Assets [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 3 [Member] | Recurring [Member] | U.S. Treasury, Agencies and Corporations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 3 [Member] | Recurring [Member] | States and Political Subdivisions [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	0	0
Level 3 [Member] | Recurring [Member] | Other Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Securities available for sale	17,000,000	17,000,000
Level 3 [Member] | Recurring [Member] | Agency Residential Mortgage Backed Securities [Member] | Collateralized Mortgage Obligations [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		0
Level 3 [Member] | Recurring [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0
Level 3 [Member] | Recurring [Member] | Principal Investments Direct [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	21,000,000	27,000,000
Level 3 [Member] | Recurring [Member] | Principal Investments Indirect [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 [Member] | Recurring [Member] | Principal Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	21,000,000	27,000,000
Level 3 [Member] | Recurring [Member] | Equity And Mezzanine Indirect Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 [Member] | Recurring [Member] | Private Equity and Mezzanine Investments [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total other investments	0	0
Level 3 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total trading account securities	0	0
Level 3 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale	0
Level 3 [Member] | Recurring [Member] | Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
ASSETS MEASURED ON A RECURRING BASIS
Securities available for sale		0
Level 3 [Member] | Recurring [Member] | Short Positions [Member]
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 3 [Member] | Recurring [Member] | Interest Rate [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	5,000,000	7,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 3 [Member] | Recurring [Member] | Foreign Exchange [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 3 [Member] | Recurring [Member] | Commodity [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	0	0
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 3 [Member] | Recurring [Member] | Credit [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	1,000,000	1,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	0	0
Level 3 [Member] | Recurring [Member] | Other [Member]
ASSETS MEASURED ON A RECURRING BASIS
Derivative assets, gross	4,000,000	2,000,000
LIABILITIES MEASURED ON A RECURRING BASIS
Derivative liabilities, gross	$ 0	$ 0

Fair Value Measurements - Chang

Fair Value Measurements - Change in Fair Values of Level 3 Financial Instruments (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Issuance of financial instrument	$ 0	$ 0
Securities Available for Sale [Member] | Other Securities [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	17,000,000	17,000,000	$ 17,000,000
Gains (Losses) Included in Earnings	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Transfers Other	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	17,000,000	17,000,000	17,000,000
Unrealized Gains (Losses) Included in Earnings	0		0
Other Investments [Member] | Principal Investments Direct [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	27,000,000	50,000,000	50,000,000
Gains (Losses) Included in Earnings	(2,000,000)	(3,000,000)
Purchases	0	0
Sales	(4,000,000)	0
Settlements	0	0
Transfers Other	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	21,000,000	47,000,000	27,000,000
Unrealized Gains (Losses) Included in Earnings	(6,000,000)		(3,000,000)
Other Investments [Member] | Other Indirect [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	0	20,000,000	20,000,000
Gains (Losses) Included in Earnings	0	(1,000,000)
Purchases	0	0
Sales	0	(1,000,000)
Settlements	0	0
Transfers Other	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	0	18,000,000	0
Unrealized Gains (Losses) Included in Earnings	0		(1,000,000)
Interest Rate [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	7,000,000	16,000,000	16,000,000
Gains (Losses) Included in Earnings	0	4,000,000
Purchases	0	0
Sales	0	0
Settlements	0	0
Transfers Other	0
Transfers into Level 3	1,000,000	3,000,000
Transfers out of Level 3	(3,000,000)	(7,000,000)
Ending Balance	5,000,000	16,000,000	7,000,000
Unrealized Gains (Losses) Included in Earnings	0		0
Credit [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	1,000,000	1,000,000	1,000,000
Gains (Losses) Included in Earnings	(3,000,000)	(2,000,000)
Purchases	0	0
Sales	0	0
Settlements	3,000,000	3,000,000
Transfers Other	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending Balance	1,000,000	$ 2,000,000	1,000,000
Unrealized Gains (Losses) Included in Earnings	0		0
Other [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	2,000,000
Gains (Losses) Included in Earnings	0
Purchases	0
Sales	0
Settlements	0
Transfers Other	2,000,000
Transfers into Level 3	0
Transfers out of Level 3	0
Ending Balance	4,000,000		$ 2,000,000
Unrealized Gains (Losses) Included in Earnings	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
ASSETS MEASURED ON A NONRECURRING BASIS
Loans held for sale	$ 1		$ 0
Nonrecurring [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans	11,000,000		11,000,000
Loans held for sale	1,000,000		0
Accrued income and other assets	6,000,000		11,000,000
Total assets at fair value	18,000,000		22,000,000
Transfer of commercial and consumer loans from held-to-maturity to held-for-sale, current fair value	17,000,000	$ 35,000,000
Level 1 [Member] | Nonrecurring [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans	0		0
Loans held for sale	0		0
Accrued income and other assets	0		0
Total assets at fair value	0		0
Level 2 [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Loans held for sale	62,000,000
Level 2 [Member] | Nonrecurring [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans	0		0
Loans held for sale	0		0
Accrued income and other assets	0		0
Total assets at fair value	0		0
Level 3 [Member] | Nonrecurring [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans	11,000,000		11,000,000
Loans held for sale	1,000,000		0
Accrued income and other assets	6,000,000		11,000,000
Total assets at fair value	$ 18,000,000		$ 22,000,000

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	$ 689	$ 738
Nonrecurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Impaired loans	11	11
Level 3 [Member] | Nonrecurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Impaired loans	11	11
Level 3 [Member] | Other Investments [Member] | Recurring [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	$ 21	$ 27
Level 3 [Member] | Discount [Member] | Nonrecurring [Member] | Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	0.00%	0.00%
Level 3 [Member] | Discount [Member] | Nonrecurring [Member] | Maximum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	70.00%	70.00%
Level 3 [Member] | Discount [Member] | Nonrecurring [Member] | Weighted Average [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	16.00%	46.00%
Level 3 [Member] | EBITDA Multiple [Member] | Recurring [Member] | Minimum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	6.00%	6.30%
Level 3 [Member] | EBITDA Multiple [Member] | Recurring [Member] | Maximum [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	6.30%	7.00%
Level 3 [Member] | EBITDA Multiple [Member] | Recurring [Member] | Weighted Average [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	6.20%	6.50%
Level 3 [Member] | EBITDA Multiple (Where Applicable) [Member] | Recurring [Member] | Weighted Average [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	6.30%	6.30%

Fair Value Measurements - Fai77

Fair Value Measurements - Fair Value Disclosures of Financial Instruments (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Trading account assets	$ 921,000,000	$ 867,000,000
Securities available for sale	18,431,000,000	20,212,000,000
Held-to-maturity securities	10,186,000,000	10,232,000,000
Held-to-maturity securities	9,954,000,000	10,007,000,000
Other investments	689,000,000	738,000,000
Loans, net of allowance	85,255,000,000	85,180,000,000
Loans, net of allowance	3,000,000
Loans held for sale	1,384,000,000	1,104,000,000	$ 1,137,000,000
Loans held for sale	1	0
Derivative assets	578,000,000	803,000,000
LIABILITIES
Long-term debt	12,324,000,000	12,384,000,000
Derivative liabilities	255,000,000	636,000,000
Level 2 [Member]
ASSETS
Loans held for sale	62,000,000
Carrying Amount [Member]
ASSETS
Cash and short-term investments	3,074,000,000	3,452,000,000
Trading account assets	921,000,000	867,000,000
Securities available for sale	18,431,000,000	20,212,000,000
Held-to-maturity securities	10,186,000,000	10,232,000,000
Other investments	689,000,000	738,000,000
Loans, net of allowance	85,255,000,000	85,180,000,000
Loans held for sale	1,384,000,000	1,104,000,000
Derivative assets	578,000,000	803,000,000
LIABILITIES
Deposits with no stated maturity	93,429,000,000	93,906,000,000
Time deposits	10,553,000,000	10,181,000,000
Short-term borrowings	1,385,000,000	2,310,000,000
Long-term debt	12,324,000,000	12,384,000,000
Derivative liabilities	255,000,000	636,000,000
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities measured at fair value on non recurring basis	0	0
ASSETS
Cash and short-term investments	3,074,000,000	3,452,000,000
Trading account assets	921,000,000	867,000,000
Securities available for sale	18,431,000,000	20,212,000,000
Held-to-maturity securities	9,954,000,000	10,007,000,000
Other investments	684,000,000	733,000,000
Loans, net of allowance	83,520,000,000	83,285,000,000
Loans held for sale	1,384,000,000	1,104,000,000
Derivative assets	578,000,000	803,000,000
Derivative assets, Netting Adjustment	(464,000,000)	(431,000,000)
LIABILITIES
Deposits with no stated maturity	93,429,000,000	93,906,000,000
Time deposits	10,649,000,000	10,267,000,000
Short-term borrowings	1,385,000,000	2,310,000,000
Long-term debt	12,661,000,000	12,690,000,000
Derivative liabilities	255,000,000	636,000,000
Derivative liabilities, Netting Adjustment	(524,000,000)	(384,000,000)
Fair Value [Member] | Level 1 [Member]
ASSETS
Cash and short-term investments	3,074,000,000	3,452,000,000
Trading account assets	1,000,000	0
Securities available for sale	3,000,000	3,000,000
Held-to-maturity securities	0	0
Other investments	0	0
Loans, net of allowance	0	0
Loans held for sale	0	0
Derivative assets	91,000,000	114,000,000
LIABILITIES
Deposits with no stated maturity	0	0
Time deposits	0	0
Short-term borrowings	214,000,000	192,000,000
Long-term debt	12,372,000,000	12,386,000,000
Derivative liabilities	78,000,000	102,000,000
Fair Value [Member] | Level 2 [Member]
ASSETS
Cash and short-term investments	0	0
Trading account assets	920,000,000	867,000,000
Securities available for sale	18,411,000,000	20,192,000,000
Held-to-maturity securities		10,007,000,000
Other investments	0	0
Loans, net of allowance	83,520,000,000	0
Loans held for sale	62,000,000	62,000,000
Derivative assets	941,000,000	1,110,000,000
LIABILITIES
Deposits with no stated maturity	93,429,000,000	93,906,000,000
Time deposits	10,649,000,000	10,267,000,000
Short-term borrowings	1,171,000,000	2,118,000,000
Long-term debt	289,000,000	304,000,000
Derivative liabilities	701,000,000	918,000,000
Fair Value [Member] | Level 3 [Member]
ASSETS
Cash and short-term investments	0	0
Trading account assets	0	0
Securities available for sale	17,000,000	17,000,000
Held-to-maturity securities	0	0
Other investments	527,000,000	569,000,000
Loans, net of allowance	0	83,285,000,000
Loans held for sale	1,322,000,000	1,042,000,000
Derivative assets	10,000,000	10,000,000
LIABILITIES
Deposits with no stated maturity	0	0
Time deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Derivative liabilities	0	0
Other Investments [Member] | Fair Value [Member]
ASSETS
Other investments, Measured at NAV	$ 157,000,000	$ 164,000,000

Securities - Details of Securit

Securities - Details of Securities (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	$ 18,717	$ 20,507
Available for sale, Gross Unrealized Gains	34	37
Available for sale, Gross Unrealized Losses	320	332
Available for sale, Fair Value	18,431	20,212
Held to maturities, Amortized Cost	10,186	10,232
Held to maturities, Gross Unrealized Gains	5	2
Held to maturities, Gross Unrealized Losses	237	227
Held to maturities, Fair Value	9,954	10,007
U.S. Treasury, Agencies and Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	188	188
Available for sale, Gross Unrealized Gains	0	0
Available for sale, Gross Unrealized Losses	3	4
Available for sale, Fair Value	185	184
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	11	11
Available for sale, Gross Unrealized Gains	0	0
Available for sale, Gross Unrealized Losses	0	0
Available for sale, Fair Value	11	11
Agency Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	1,751	1,857
Available for sale, Gross Unrealized Gains	5	6
Available for sale, Gross Unrealized Losses	14	17
Available for sale, Fair Value	1,742	1,846
Held to maturities, Amortized Cost	605	629
Held to maturities, Gross Unrealized Gains	0	0
Held to maturities, Gross Unrealized Losses	5	5
Held to maturities, Fair Value	600	624
Agency Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held to maturities, Gross Unrealized Losses	44	49
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	21	21
Available for sale, Gross Unrealized Gains	0	0
Available for sale, Gross Unrealized Losses	1	1
Available for sale, Fair Value	20	20
Held to maturities, Amortized Cost	15	15
Held to maturities, Gross Unrealized Gains	0	0
Held to maturities, Gross Unrealized Losses	0	0
Held to maturities, Fair Value	15	15
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	14,790	16,652
Available for sale, Gross Unrealized Gains	29	31
Available for sale, Gross Unrealized Losses	256	275
Available for sale, Fair Value	14,563	16,408
Held to maturities, Amortized Cost	7,973	8,404
Held to maturities, Gross Unrealized Gains	2	1
Held to maturities, Gross Unrealized Losses	188	173
Held to maturities, Fair Value	7,787	8,232
Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held to maturities, Gross Unrealized Losses	5	5
Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Amortized Cost	1,956	1,778
Available for sale, Gross Unrealized Gains	0	0
Available for sale, Gross Unrealized Losses	46	35
Available for sale, Fair Value	1,910	1,743
Held to maturities, Amortized Cost	1,593	1,184
Held to maturities, Gross Unrealized Gains	3	1
Held to maturities, Gross Unrealized Losses	44	49
Held to maturities, Fair Value	$ 1,552	$ 1,136

Securities - Available for Sale

Securities - Available for Sale Securities (Unrealized Loss Position) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Gross unrealized losses	$ 237	$ 227
Fair value less than 12 months, total temporarily impaired securities	22,359	24,038
Gross unrealized losses less than 12 months, total temporarily impaired securities	486	497
Fair value 12 months or longer, total temporarily impaired securities	2,031	1,931
Gross unrealized losses 12 months or longer, total temporarily impaired securities	71	62
Fair value, total temporarily impaired securities	24,390	25,969
Gross unrealized losses, total temporarily impaired securities	557	559
U.S. Treasury, Agencies and Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	185	182
Gross unrealized losses, less than 12 months	3	4
Fair value, 12 months or longer	0	0
Gross unrealized losses, 12 months or longer	0	0
Fair Value	185	182
Gross unrealized losses, Total	3	4
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	10,573	12,345
Gross unrealized losses, less than 12 months	205	231
Fair value, 12 months or longer	1,507	1,410
Gross unrealized losses, 12 months or longer	51	44
Fair Value	12,080	13,755
Gross unrealized losses, Total	256	275
Held-to-maturity Securities, Fair Value less than 12 months	6,634	7,028
Held-to-maturity Securities, Gross unrealized losses, less than 12 months	169	156
Held-to-maturity Securities, Fair Value 12 months or longer	521	518
Held-to-maturity Securities, Gross unrealized losses, 12 months or longer	19	17
Held-to-maturity Securities, Fair Value	7,155	7,546
Held-to-maturity Securities, Gross unrealized losses	188	173
Agency Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Gross unrealized losses	5	5
Agency Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	1,910	1,482
Gross unrealized losses, less than 12 months	46	35
Fair value, 12 months or longer	0	0
Gross unrealized losses, 12 months or longer	0	0
Fair Value	1,910	1,482
Gross unrealized losses, Total	46	35
Held-to-maturity Securities, Fair Value less than 12 months	1,001	996
Held-to-maturity Securities, Gross unrealized losses, less than 12 months	44	49
Held-to-maturity Securities, Fair Value 12 months or longer	0	0
Held-to-maturity Securities, Gross unrealized losses, 12 months or longer	0	0
Held-to-maturity Securities, Fair Value	1,001	996
Held-to-maturity Securities, Gross unrealized losses	44	49
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	0	2
Gross unrealized losses, less than 12 months	0	0
Fair value, 12 months or longer	3	3
Gross unrealized losses, 12 months or longer	1	1
Fair Value	3	5
Gross unrealized losses, Total	1	1
Held-to-maturity Securities, Fair Value less than 12 months	4	4
Held-to-maturity Securities, Gross unrealized losses, less than 12 months	0	0
Held-to-maturity Securities, Fair Value 12 months or longer	0	0
Held-to-maturity Securities, Gross unrealized losses, 12 months or longer	0	0
Held-to-maturity Securities, Fair Value	4	4
Held-to-maturity Securities, Gross unrealized losses	0	0
Gross unrealized losses, available for sale securities (less than)	1	1
Gross unrealized losses, held-to-maturity securities (less than)	1	1
Other Mortgage-Backed Securities [Member] | Agency Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value, less than 12 months	1,527	1,452
Gross unrealized losses, less than 12 months	14	17
Fair value, 12 months or longer	0	0
Gross unrealized losses, 12 months or longer	0	0
Fair Value	1,527	1,452
Gross unrealized losses, Total	14	17
Held-to-maturity Securities, Fair Value less than 12 months	525	547
Held-to-maturity Securities, Gross unrealized losses, less than 12 months	5	5
Held-to-maturity Securities, Fair Value 12 months or longer	0	0
Held-to-maturity Securities, Gross unrealized losses, 12 months or longer	0	0
Held-to-maturity Securities, Fair Value	525	547
Held-to-maturity Securities, Gross unrealized losses	5	5
Other Mortgage-Backed Securities [Member] | Agency Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Gross unrealized losses	$ 44	$ 49

Securities - Additional Informa

Securities - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)MortgageLoanposition	Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Pledged available for sale and held-to-maturity securities	$ 8,900
Agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized loss attributable to mortgage-backed securities (less than)	1
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	$ 256	$ 275
Number of fixed rate collateralized mortgage obligations | MortgageLoan	367
Weighted-average maturity collateralized mortgage, in years	4 years 2 months 9 days
Residential Mortgage Backed Securities [Member] | Agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	$ 14	$ 17
Number of other mortgage-backed securities positions | position	234
Weighted-average maturity mortgage-backed securities, in years	3 years 10 months 6 days

Securities - Cumulative Credit

Securities - Cumulative Credit Portion of Impairments on Debt Securities (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Cumulative Impairments on Debt Securities, Beginning Balance	$ 4
Impairment recognized in earnings	0
Cumulative Impairments on Debt Securities, Ending Balance	$ 4

Securities - Securities by Matu

Securities - Securities by Maturity (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Amortized Cost of Securities Available for sale, Due in one year or less	$ 177
Amortized Cost of Securities Available for sale, Due after one through five years	16,595
Amortized Cost of Securities Available for sale, Due after five through ten years	1,737
Amortized Cost of Securities Available for sale, Due after ten years	208
Total Amortized Cost of Securities Available for sale	18,717
Fair Value of Securities Available for sale, Due in one year or less	179
Fair Value of Securities Available for sale, Due after one through five years	16,354
Fair Value of Securities Available for sale, Due after five through ten years	1,693
Fair Value of Securities Available for sale, Due after ten years	205
Total Fair Value of Securities Available for sale	18,431	$ 20,212
Amortized Cost of Held-to-Maturity Securities, Due in one year or less	55
Amortized Cost of Held-to-Maturity Securities, Due after one through five years	6,935
Amortized Cost of Held-to-Maturity Securities, Due after five through ten years	2,936
Amortized Cost of Held-to-Maturity Securities, Due after ten years	260
Held to maturities, Amortized Cost	10,186	10,232
Fair Value of Held-to-Maturity Securities, Due in one year or less	56
Fair Value of Held-to-Maturity Securities, Due after one through five years	6,798
Fair Value of Held-to-Maturity Securities, Due after five through ten years	2,862
Fair Value of Held-to-Maturity Securities, Due after ten years	238
Total Fair Value of Held-to-Maturity Securities	$ 9,954	$ 10,007

Derivatives and Hedging Activ83

Derivatives and Hedging Activities - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)rating	Dec. 31, 2016USD ($)rating
Credit Derivatives [Line Items]
Derivative assets after effects of bilateral collateral and master netting agreements	$ 27
Derivative liabilities after effects of bilateral collateral and master netting agreements	(8)
Derivative assets not designated as hedging instruments after effects of bilateral collateral and master netting agreements, and a reserve for potential future losses	551
Derivative liabilities not designated as hedging instruments after effects of bilateral collateral and master netting agreements, and a reserve for potential future losses	263
Reclassify of after-tax net losses on derivative instruments from AOCI	$ 8
Length of time hedge in cash flow hedge	12 months
Reclassification of net losses related to terminated cash flow hedges from AOCI to income	$ (3)
Maximum length of time over which forecasted transactions are hedged, years	11 years
Other Comprehensive income unrealized gain on derivatives arising during period net of tax	$ 38
Cash collateral netted against derivative assets	(25)	$ 155
Collateral netted against derivative liabilities	35	108
Cash collateral not netted transferred with clearing organization		448
Cash collateral not netted transferred from clearing organization		59
Cash paid in variation margin to settle CME-cleared derivatives	194
Cash received in variation margin to settle CME-cleared derivatives	68
Increase (decrease) in derivative assets	(121)
Increase (decrease) in derivative liabilities	394
Gross exposure on derivatives, after taking into account the effects of bilateral collateral and master netting agreements	464
Net exposure on derivatives, after taking into account, the effects of bilateral collateral and master netting agreements	239
Over-collateralization on derivatives to broker-dealers and banks, after the application of master netting agreements and collateral	215
Additional collateral held in the form of securities	24
Default reserve associated with uncollateralized contracts	5
Gross exposure on derivatives after taking into account effects of master netting agreements	382
Net exposure on derivatives with clients after application of master netting agreements collateral and related reserve	339
Banking Subsidiary [Member]
Credit Derivatives [Line Items]
Net liability position totaled	98
Derivative assets included in net liability position	164
Derivative liabilities included in net liability position	262
Cash and securities collateral posted	$ 100
Additional collateral amount		$ 1
Banking Subsidiary [Member] | Unsecured Debt [Member]
Credit Derivatives [Line Items]
Number of ratings above noninvestment | rating	4	4
Banking Subsidiary [Member] | Maximum [Member] | Unsecured Debt [Member]
Credit Derivatives [Line Items]
Payments to terminate contracts (less than for the $1 million)	$ 3	$ 4
Key Corp [Member]
Credit Derivatives [Line Items]
Additional collateral amount		$ 1

Derivatives and Hedging Activ84

Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount	$ 95,673	$ 88,288
Derivative Assets, Netting adjustments	(464)	(431)
Derivative Assets, net	567	782
Derivative Liabilities, Netting adjustments	(524)	(384)
Derivative Liabilities, net	184	539
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	25,201	24,519
Derivative Assets	101	195
Derivative Liabilities	22	98
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	70,472	63,769
Derivative Assets	941	1,039
Derivative Liabilities	757	922
Interest Rate [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	24,917	24,237
Derivative Assets	98	189
Derivative Liabilities	20	94
Interest Rate [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	58,963	55,315
Derivative Assets	684	741
Derivative Liabilities	511	643
Foreign Exchange [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	284	282
Derivative Assets	3	6
Derivative Liabilities	2	4
Foreign Exchange [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,897	6,230
Derivative Assets	95	117
Derivative Liabilities	84	109
Commodity [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,569	1,474
Derivative Assets	150	176
Derivative Liabilities	140	165
Credit [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	418	360
Derivative Assets	3	1
Derivative Liabilities	6	4
Other [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,625	390
Derivative Assets	9	4
Derivative Liabilities	16	1
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	95,673	88,288
Derivative Assets, net	578	803
Derivative Liabilities, net	255	636
Counterparty And Cash Collateral Netting [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Derivative Assets, net	(11)	(21)
Derivative Liabilities, net	$ (71)	$ (97)

Derivatives and Hedging Activ85

Derivatives and Hedging Activities - Pre-Tax Net Gains (Losses) on Fair Value Hedges (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	$ (17)	$ 142
Net Gains (Losses) on Hedged Item	35	(115)
Other Income [Member] | Interest Rate [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	(35)	115
Net Gains (Losses) on Hedged Item	35	(115)
Interest Expense [Member] | Interest Rate [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	$ 18	$ 27

Derivatives and Hedging Activ86

Derivatives and Hedging Activities - Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI (Effective Portion)	$ (25)	$ 114
Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion)	14	22
Net Gains (Losses) Recognized in Income (Ineffective Portion)	0	0
Interest Income [Member] | Interest Rate [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI (Effective Portion)	(22)	133
Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion)	15	23
Interest Expense [Member] | Interest Rate [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI (Effective Portion)	0	(4)
Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion)	(1)	(1)
Investment Banking and Debt Placement Fees [Member] | Interest Rate [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI (Effective Portion)	0	(1)
Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion)	0	0
Other Income [Member] | Interest Rate [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in Income (Ineffective Portion)	0	0
Other Income [Member] | Foreign Exchange [Member] | Net Investment Hedges [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI (Effective Portion)	(3)	(14)
Net Gains (Losses) Reclassified From OCI Into Income (Effective Portion)	0	0
Net Gains (Losses) Recognized in Income (Ineffective Portion)	$ 0	$ 0

Derivatives and Hedging Activ87

Derivatives and Hedging Activities - After-Tax Change in AOCI Resulting from Cash Flow Hedges (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
December 31, 2016	$ (14)
2,017	(15)
Reclassification of Gains to Net Income	(9)
March 31, 2017	$ (38)

Derivatives and Hedging Activ88

Derivatives and Hedging Activities - Pre-Tax Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	$ 12	$ 15
Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	5	5
Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	11	10
Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	2	1
Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(4)	(1)
Other Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(2)	0
Corporate Services Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	20	18
Corporate Services Income [Member] | Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	6	6
Corporate Services Income [Member] | Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	11	10
Corporate Services Income [Member] | Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	2	1
Corporate Services Income [Member] | Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	1	1
Corporate Services Income [Member] | Other Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0
Consumer Mortgage Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(1)
Consumer Mortgage Income [Member] | Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0
Consumer Mortgage Income [Member] | Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0
Consumer Mortgage Income [Member] | Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0
Consumer Mortgage Income [Member] | Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0
Consumer Mortgage Income [Member] | Other Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(1)
Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(7)	(3)
Other Income [Member] | Interest Rate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(1)	(1)
Other Income [Member] | Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0
Other Income [Member] | Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	0	0
Other Income [Member] | Credit [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	(5)	(2)
Other Income [Member] | Other Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total net gains (losses)	$ (1)	$ 0

Derivatives and Hedging Activ89

Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 553	$ 958
Less: Related collateral	(25)	155
Total derivative assets	578	803
Interest Rate [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	452	782
Foreign Exchange [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	41	62
Commodity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	50	110
Credit [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	1	0
Other [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 9	$ 4

Derivatives and Hedging Activ90

Derivatives and Hedging Activities - Fair Value of Credit Derivatives Purchased and Sold (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Credit Derivatives [Line Items]
Purchased	$ (3)	$ (3)
Sold	0	0
Net	(3)	(3)
Single Name Credit Default Swaps [Member]
Credit Derivatives [Line Items]
Purchased	(2)	(2)
Sold	0	0
Net	(2)	(2)
Traded Credit Default Swap Indices [Member]
Credit Derivatives [Line Items]
Purchased	(1)	(1)
Sold	0	0
Net	(1)	(1)
Other [Member]
Credit Derivatives [Line Items]
Purchased	0	0
Sold	0	0
Net	0	0
Maximum [Member] | Other [Member]
Credit Derivatives [Line Items]
Sold	$ (1)	$ (1)

Derivatives and Hedging Activ91

Derivatives and Hedging Activities - Credit Derivatives Sold and Held (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Credit Derivatives [Line Items]
Notional Amount	$ 8	$ 4
Average Term (Years)	0 years	0 years
Payment / Performance Risk	0.00%	0.00%
Other [Member]
Credit Derivatives [Line Items]
Notional Amount	$ 8	$ 4
Average Term (Years)	11 years 4 months 24 days	6 years 5 months 26 days
Payment / Performance Risk	12.85%	17.93%

Derivatives and Hedging Activ92

Derivatives and Hedging Activities - Credit Risk Contingent Feature (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	$ 24
Standard & Poor's, A- Rating [Member] | One Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	2	$ 2
Standard & Poor's, A- Rating [Member] | Two Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	2	2
Standard & Poor's, A- Rating [Member] | Three Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	2	4
Moody's, A3 Rating [Member] | One Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	2	2
Moody's, A3 Rating [Member] | Two Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	2	2
Moody's, A3 Rating [Member] | Three Rating Downgrade [Member]
Credit Derivatives [Line Items]
Additional collateral aggregate fair value	$ 2	$ 4

Mortgage Servicing Assets - Cha

Mortgage Servicing Assets - Changes in Carrying Amount of Mortgage Servicing Assets (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Commercial Mortgage Backed Securities [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of period	$ 356	$ 321
Servicing retained from loan sales	28	7
Purchases	7	12
Amortization	(22)	(22)
Balance at end of period	369	318
Fair value at end of period	480	$ 408
Residential Mortgage Backed Securities [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of period	28
Servicing retained from loan sales	2
Amortization	(1)
Balance at end of period	29
Fair value at end of period	$ 35

Mortgage Servicing Assets - Sch

Mortgage Servicing Assets - Schedule of Range and Weighted-Average of Significant Unobservable Inputs (Detail) - Discounted Cash Flow [Member] - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Commercial Mortgage Backed Securities [Member] | Minimum [Member]
Servicing Assets at Fair Value [Line Items]
Expected defaults	1.00%	1.00%
Residual cash flows discount rate	7.00%	7.00%
Escrow earn rate	1.20%	1.10%
Servicing cost	$ 150,000,000	$ 150,000,000
Loan assumption rate	0.00%	0.00%
Percentage late	0.00%	0.00%
Commercial Mortgage Backed Securities [Member] | Maximum [Member]
Servicing Assets at Fair Value [Line Items]
Expected defaults	3.00%	3.00%
Residual cash flows discount rate	15.00%	12.00%
Escrow earn rate	3.20%	3.00%
Servicing cost	$ 38,500,000,000	$ 2,700,000,000
Loan assumption rate	3.00%	3.00%
Percentage late	2.00%	2.00%
Commercial Mortgage Backed Securities [Member] | Weighted Average [Member]
Servicing Assets at Fair Value [Line Items]
Expected defaults	1.30%	1.40%
Residual cash flows discount rate	8.60%	8.00%
Escrow earn rate	2.60%	2.40%
Servicing cost	$ 1,342,000,000	$ 1,124,000,000
Loan assumption rate	1.25%	1.13%
Percentage late	0.31%	0.34%
Residential Mortgage Backed Securities [Member] | Minimum [Member]
Servicing Assets at Fair Value [Line Items]
Prepayment speed	7.68%
Expected defaults	8.50%
Servicing cost	$ 76,000,000
Residential Mortgage Backed Securities [Member] | Maximum [Member]
Servicing Assets at Fair Value [Line Items]
Prepayment speed	19.68%
Expected defaults	11.00%
Servicing cost	$ 3,335,000,000
Residential Mortgage Backed Securities [Member] | Weighted Average [Member]
Servicing Assets at Fair Value [Line Items]
Prepayment speed	9.24%
Expected defaults	8.55%
Servicing cost	$ 83,030,000

Mortgage Servicing Assets - Add

Mortgage Servicing Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Aug. 01, 2016
Commercial Mortgage Backed Securities [Member]
Servicing Assets at Fair Value [Line Items]
Contractual fee income from servicing commercial mortgage loans	$ 38	$ 35
Amortization of servicing commercial mortgage loans	22	$ 23
Residential Mortgage Backed Securities [Member]
Servicing Assets at Fair Value [Line Items]
Contractual fee income from servicing commercial mortgage loans	3
Amortization of servicing commercial mortgage loans	$ 1
Residential Mortgage Backed Securities [Member] | First Niagara Bank, N.A. [Member]
Servicing Assets at Fair Value [Line Items]
Fair value of mortgage servicing assets			$ 28

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Variable Interest Entity [Line Items]
Investments in operating partnerships	$ 172,000,000		$ 178,000,000
Liabilities related to investments in qualified affordable housing projects	4,000,000		4,000,000
Recurring [Member]
Variable Interest Entity [Line Items]
Fair value of indirect principal investments	178,000,000		191,000,000
Recurring [Member] | Principal Investments Indirect [Member]
Variable Interest Entity [Line Items]
Fair value of indirect principal investments	155,000,000		158,000,000
Other Investments [Member] | Recurring [Member] | Principal Investments Indirect [Member]
Variable Interest Entity [Line Items]
Fair value of indirect principal investments	155,000,000		158,000,000
LIHTC Investments [Member]
Variable Interest Entity [Line Items]
Investments in operating partnerships	4,785,000,000		4,814,000,000
Liabilities related to investments in qualified affordable housing projects	1,972,000,000		2,003,000,000
Tax credit of investment	39,000,000	$ 33,000,000
LIHTC Investments [Member] | Qualified affordable housing projects investment [Member]
Variable Interest Entity [Line Items]
Liabilities related to investments in qualified affordable housing projects	439,000,000		462,000,000
LIHTC Investments [Member] | Accrued Income And Other Assets [Member]
Variable Interest Entity [Line Items]
Investments in operating partnerships	1,200,000,000		1,200,000,000
LIHTC Investments [Member] | Investments [Member]
Variable Interest Entity [Line Items]
Amortization of investment	40,000,000	$ 33,000,000
Guaranteed Funds [Member] | Investments [Member]
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	3,000,000		1,000,000
VIE, liabilities	$ 0		$ 0

Variable Interest Entities - Va

Variable Interest Entities - Variable Interest Entities Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Total Assets	$ 172	$ 178
Total Liabilities	4	4
LIHTC Investments [Member]
Variable Interest Entity [Line Items]
Total Assets	4,785	4,814
Total Liabilities	1,972	2,003
Maximum Exposure to Loss	1,451	1,465
KCC Indirect Investments [Member]
Variable Interest Entity [Line Items]
Total Assets	19,029	32,755
Total Liabilities	135	201
Maximum Exposure to Loss	$ 192	$ 195

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Total income tax expense (benefit), rate	22.40%	23.00%
Combined federal and state statutory tax rate	37.20%
Income tax benefit (as a percent)	4.70%	1.00%
Merger and acquisition integration costs	$ 81
Total income expense (benefit), rate excluding merger and integration expenses	24.80%
Federal deferred tax asset	$ 468		$ 607
Valuation allowance	26		$ 26
Key Corp [Member]
Income Tax Contingency [Line Items]
Unrecognized tax benefits	50
First Niagara Bank, N.A. [Member]
Income Tax Contingency [Line Items]
Merger and acquisition integration costs	1
Allocated bad debt deductions	$ 92

Acquisition, Divestiture, and99

Acquisition, Divestiture, and Discontinued Operations - Additional Information (Detail)	Aug. 01, 2016USD ($)	Oct. 30, 2015$ / sharesshares	Sep. 30, 2014USD ($)	Mar. 31, 2017USD ($)SecurityLoanTrustTDR	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)TDR	Sep. 09, 2016USD ($)Branch	Jun. 30, 2015USD ($)Trust	Jan. 01, 2010Trust
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of branches sold | Branch							18
Trust assets removed				$ 1,520,000,000		$ 1,585,000,000
Number of TDRs | SecurityLoan				4,937
Allowance for loan held as investment				$ 870,000,000		858,000,000
Portfolio loans held for sale at fair value				1		$ 0
Number of outstanding securitizations trusts | Trust								3
Loans at fair value				3,000,000
Income (loss) from discontinued operations, net of taxes				$ 0	$ 1,000,000
First Niagara Financial Group, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total consideration	$ 4,000,000,000
Acquiree shares equivalent of acquirer common stock | shares		0.680
Cash payable per acquiree common stock | $ / shares		$ 2.30
Number of branches sold | Branch							18
Loans included in divestiture							$ 439,000,000
Deposits included in divestiture							$ 1,600,000,000
Pacific Crest Securities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of outstanding securitization trusts | Trust				3
Proceeds from sale of residual interests			$ 57,000,000
Number of continuing securitization trusts | Trust				8
Estimated fair value of the assets and deposits acquired			1,000,000
Education Loans [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of TDRs | TDR				2,316		2,163
Investment recorded				$ 23,000,000		$ 22,000,000
Allowance for loan held as investment						2,000,000
Trust [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio loans held for sale at fair value								$ 179,000,000
Trust [Member] | Pacific Crest Securities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Trust assets removed			1,700,000,000
Trust liabilities removed			$ 1,600,000,000
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans included in divestiture				1,477,000,000		1,541,000,000
Number of outstanding securitization trusts | Trust									10
Trust assets removed				1,520,000,000		1,585,000,000
Allowance for loan held as investment				2,000,000
Loans at fair value				3,000,000		3,000,000
Income (loss) from discontinued operations, net of taxes				0	1,000,000
Discontinued Operations [Member] | Austin Capital Management [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Trust assets removed				15,000,000		$ 15,000,000
Income (loss) from discontinued operations, net of taxes				$ 0	$ 0

Acquisition, Divestiture, an100

Acquisition, Divestiture, and Discontinued Operations - Components of Income (Loss) from Discontinued Operations, Net of Taxes for Education Lending Business (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income taxes	$ 0	$ 0
Income (loss) from discontinued operations, net of taxes	0	1
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	5	7
Provision for credit losses	3	2
Net interest income after provision for credit losses	2	5
Noninterest income	2	1
Noninterest expense	4	5
Income (loss) before income taxes	0	1
Income taxes	0	0
Income (loss) from discontinued operations, net of taxes	0	1
Charges determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations, after tax	6	6
Education Lending [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	5	7
Provision for credit losses	3	2
Net interest income after provision for credit losses	2	5
Noninterest income	2	1
Noninterest expense	4	5
Income (loss) before income taxes	0	1
Income taxes	0	0
Income (loss) from discontinued operations, net of taxes	0	1
Charges determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations, after tax	$ 6	$ 6

Acquisition, Divestiture, an101

Acquisition, Divestiture, and Discontinued Operations - Components of Assets of Education Lending Business (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio loans at fair value	$ 3
Loans, net of unearned income	86,125	$ 86,038	$ 60,438
Total assets	1,520	1,585
Unearned income on loans (less than)	783	826
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio loans at fair value	3	3
Loans, net of unearned income	1,497	1,562
Less: Allowance for loan and lease losses	23	24
Net loans	1,477	1,541
Accrued income and other assets	27	28
Total assets	1,520	1,585
Unearned income on loans (less than)	1	1
Education Lending [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Held-to-maturity securities	1	1
Portfolio loans at fair value	3	3
Loans, net of unearned income	1,497	1,562
Less: Allowance for loan and lease losses	23	24
Net loans	1,477	1,541
Accrued income and other assets	27	28
Total assets	1,505	1,570
Unearned income on loans (less than)	$ 1	$ 1

Acquisition, Divestiture, an102

Acquisition, Divestiture, and Discontinued Operations - Quantitative Information about Level 3 Fair Value Measurements (Details) - Level 3 [Member] - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Minimum [Member] | Portfolio Loan Indicative Bids [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	84.50%	84.50%
Maximum [Member] | Portfolio Loan Indicative Bids [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Percentage of significant unobservable inputs	104.00%	104.00%
Portfolio Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Portfolio loans accounted for at fair value	$ 3	$ 3

Acquisition, Divestiture, an103

Acquisition, Divestiture, and Discontinued Operations - Principal and Fair Value Amounts for Portfolio Loans at Carrying Value, and Portfolio Loans at Fair Value (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accruing loans past due 90 days or more	$ 79	$ 87
Portfolio [Member] | Carrying Amount [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accruing loans past due 90 days or more	20	22
Loans placed on nonaccrual status	$ 4	$ 5

Acquisition, Divestiture, an104

Acquisition, Divestiture, and Discontinued Operations - Portfolio Loans at Fair Value and Related Contractual Amounts (Detail) - Discontinued Operations [Member] - Trust [Member] - Education Lending [Member] - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio contractual amount of loans	$ 3	$ 3
Portfolio fair value of loans	$ 3	$ 3

Acquisition, Divestiture, an105

Acquisition, Divestiture, and Discontinued Operations - Consolidated Assets at Fair Value on Recurring Basis (Detail) - Recurring [Member] - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
ASSETS MEASURED ON A RECURRING BASIS
Total assets at fair value	$ 20,170	$ 22,143
Trust [Member] | Education Lending [Member]
ASSETS MEASURED ON A RECURRING BASIS
Portfolio loans	3	3
Total assets at fair value	3	3
Level 1 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total assets at fair value	95	117
Level 1 [Member] | Trust [Member] | Education Lending [Member]
ASSETS MEASURED ON A RECURRING BASIS
Portfolio loans	0	0
Total assets at fair value	0	0
Level 2 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total assets at fair value	20,334	22,239
Level 2 [Member] | Trust [Member] | Education Lending [Member]
ASSETS MEASURED ON A RECURRING BASIS
Portfolio loans	0	0
Total assets at fair value	0	0
Level 3 [Member]
ASSETS MEASURED ON A RECURRING BASIS
Total assets at fair value	48	54
Level 3 [Member] | Trust [Member] | Education Lending [Member]
ASSETS MEASURED ON A RECURRING BASIS
Portfolio loans	3	3
Total assets at fair value	$ 3	$ 3

Acquisition, Divestiture, an106

Acquisition, Divestiture, and Discontinued Operations - Change in Fair Values of Level 3 Portfolio Loans Held for Sale, Portfolio Loans, and Consolidated Education Loan Securitization Trusts (Details) - Discontinued Operations [Member] - Education Lending [Member] - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases, sales, issuances, gains (losses) recognized in earnings	$ 0	$ 0
Portfolio Student Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3,000,000	4,000,000
Settlements	0	(1,000,000)
Ending Balance	$ 3,000,000	$ 3,000,000

Acquisition, Divestiture, an107

Acquisition, Divestiture, and Discontinued Operations - Components of Assets and Liabilities from Discontinued Operations (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets	$ 1,520	$ 1,585
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets	1,520	1,585
Discontinued Operations [Member] | Austin Capital Management [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and due from banks	15	15
Total assets	$ 15	$ 15

Acquisition, Divestiture, an108

Acquisition, Divestiture, and Discontinued Operations - Combined Results of Discontinued Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income taxes	$ 0	$ 0
Income (loss) from discontinued operations, net of taxes	0	1
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	5	7
Provision for credit losses	3	2
Net interest income after provision for credit losses	2	5
Noninterest income	2	1
Noninterest expense	4	5
Income (loss) before income taxes	0	1
Income taxes	0	0
Income (loss) from discontinued operations, net of taxes	0	1
Charges determined by applying a matched funds transfer pricing methodology to the liabilities assumed necessary to support the discontinued operations, after tax	$ 6	$ 6

Acquisition, Divestiture, an109

Acquisition, Divestiture, and Discontinued Operations - Combined Assets and Liabilities of Discontinued Operations (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and due from banks	$ 549	$ 677	$ 474	$ 607
Held-to-maturity securities	10,186	10,232
Portfolio loans at fair value	3
Loans, net of unearned income	86,125	86,038	$ 60,438
Total assets	1,520	1,585
Unearned income on loans (less than)	783	826
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and due from banks	15	15
Held-to-maturity securities	1	1
Portfolio loans at fair value	3	3
Loans, net of unearned income	1,497	1,562
Less: Allowance for loan and lease losses	23	24
Net loans	1,477	1,541
Accrued income and other assets	27	28
Total assets	1,520	1,585
Unearned income on loans (less than)	$ 1	$ 1

Securities Financing Activit110

Securities Financing Activities Summarized Securities Financing Agreements (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	$ 0	$ 0
Total	0	0
Repurchase agreements	0	0
Total	0	0
Counterparty And Cash Collateral Netting [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	(1)	0
Total	(1)	0
Repurchase agreements	(434)	(494)
Total	(434)	(494)
Federal Agency CMOs [Member]
Securities Financing Transaction [Line Items]
Assets pledged as collateral	569
Liabilities pledged as collateral	434
Gross Amounts Presented In Balance Sheets [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	4	3
Total	4	3
Repurchase agreements	437	497
Total	437	497
Netting Adjustments [Member]
Securities Financing Transaction [Line Items]
Reverse repurchase agreements	(3)	(3)
Total	(3)	(3)
Repurchase agreements	(3)	(3)
Total	$ (3)	$ (3)

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - benefit_plan	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2009
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Age of employees under condition one	55 years
Period of service under condition one	5 years
Age of employees under condition two	50 years
Period of service under condition two	15 years
Minimum period of service at the time of termination hired before 2001	15 years
First Niagara Bank, N.A. [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit plans		2

Employee Benefits - Net Pension

Employee Benefits - Net Pension Cost (Benefit) for All Funded and Unfunded Plans (Detail) - Pension Plans [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Interest cost on PBO	$ 12	$ 10
Expected return on plan assets	(17)	(13)
Amortization of losses	4	4
Net pension/postretirement benefit cost	$ (1)	$ 1

Employee Benefits - Net Postret

Employee Benefits - Net Postretirement Benefit Cost for All Funded and Unfunded Plans (Detail) - Other Postretirement Benefit Plans [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Interest cost on APBO	$ 0	$ 1
Expected return on plan assets	0	(1)
Net pension/postretirement benefit cost	$ 0	$ 0

Trust Preferred Securities I114

Trust Preferred Securities Issued by Unconsolidated Subsidiaries - Summary of Trust Preferred Securities, Common Stock and Related Debentures (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Stock	$ 1,257	$ 1,257
Debentures adjustments related to financial instrument hedging	58	59
Harleysville Statutory Trust I and Alliance Capital Trust II [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust preferred securities redeemed	9
KeyCorp Capital I [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	155
Common Stock	6
Principal Amount of of Debentures, Net of Discount	$ 161
Interest Rate of Trust Preferred Securities and Debentures	1.738%
KeyCorp Capital II [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 105
Common Stock	4
Principal Amount of of Debentures, Net of Discount	$ 109
Interest Rate of Trust Preferred Securities and Debentures	6.875%
KeyCorp Capital III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 138
Common Stock	4
Principal Amount of of Debentures, Net of Discount	$ 142
Interest Rate of Trust Preferred Securities and Debentures	7.75%
HNC Statutory Trust III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 18
Common Stock	1
Principal Amount of of Debentures, Net of Discount	$ 19
Interest Rate of Trust Preferred Securities and Debentures	2.453%
Willow Grove Statutory Trust I [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 18
Common Stock	1
Principal Amount of of Debentures, Net of Discount	$ 19
Interest Rate of Trust Preferred Securities and Debentures	2.441%
HNC Statutory Trust IV [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 16
Common Stock	1
Principal Amount of of Debentures, Net of Discount	$ 17
Interest Rate of Trust Preferred Securities and Debentures	2.319%
Westbank Capital Trust II [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 7
Common Stock	0
Principal Amount of of Debentures, Net of Discount	$ 7
Interest Rate of Trust Preferred Securities and Debentures	3.342%
Westbank Capital Trust III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 7
Common Stock	0
Principal Amount of of Debentures, Net of Discount	$ 7
Interest Rate of Trust Preferred Securities and Debentures	3.342%
Business Trusts [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust Preferred Securities, Net of Discount	$ 464	475
Common Stock	17	17
Principal Amount of of Debentures, Net of Discount	$ 481	$ 492
Interest Rate of Trust Preferred Securities and Debentures	4.811%	4.845%
Treasury Rate [Member] | KeyCorp Capital II [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	0.20%
Treasury Rate [Member] | KeyCorp Capital III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	0.25%
London Interbank Offered Rate (LIBOR) [Member] | KeyCorp Capital I [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	0.74%
London Interbank Offered Rate (LIBOR) [Member] | HNC Statutory Trust III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	1.40%
London Interbank Offered Rate (LIBOR) [Member] | Willow Grove Statutory Trust I [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	1.31%
London Interbank Offered Rate (LIBOR) [Member] | HNC Statutory Trust IV [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	1.28%
London Interbank Offered Rate (LIBOR) [Member] | Westbank Capital Trust II and III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	2.19%
Redemption upon either tax or a capital treatment event [Member] | Treasury Rate [Member] | Keycorp Capital II and III [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Basis spread on variable rate	0.50%

Contingent Liabilities and G115

Contingent Liabilities and Guarantees - Guarantees (Detail) $ in Millions	Mar. 31, 2017USD ($)
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	$ 17,768
Liability Recorded	126
Written Put Options [Member]
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	2,052
Liability Recorded	43
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	11,779
Liability Recorded	70
Recourse Agreement with FNMA [Member]
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	2,664
Liability Recorded	5
Residential Mortgage Reserve [Member]
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	1,270
Liability Recorded	5
Return Guarantee Agreement with LIHTC Investors [Member]
Guarantor Obligations [Line Items]
Maximum Potential Undiscounted Future Payments	3
Liability Recorded	$ 3

Contingent Liabilities and G116

Contingent Liabilities and Guarantees - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Commitments Contingencies And Guarantees [Line Items]
Default guarantees, value	$ 126
Written Put Options [Member]
Commitments Contingencies And Guarantees [Line Items]
Default guarantees, value	$ 43
Weighted average life of written put options	3 years
Standby Letters of Credit [Member]
Commitments Contingencies And Guarantees [Line Items]
Remaining weighted-average life of standby letters of credit in years	2 years
Default guarantees, value	$ 70
Recourse Agreement with FNMA [Member]
Commitments Contingencies And Guarantees [Line Items]
Weighted-average remaining term for outstanding commercial mortgage loans in years	7 years 6 months
Unpaid principal balance outstanding of loans sold	$ 9,100
Maximum potential amount of undiscounted future payments possibly required as percentage of principal balance of loans outstanding	29.00%
Default guarantees, value	$ 5
Residential Mortgage Reserve [Member]
Commitments Contingencies And Guarantees [Line Items]
Unpaid principal balance outstanding of loans sold	$ 4,200
Maximum potential amount of undiscounted future payments possibly required as percentage of principal balance of loans outstanding	30.00%
Weighted-average loan to value ratio (as a percent)	71.00%
Liability for estimated repurchase obligations on loans sold	$ 5
Default guarantees, value	$ 5
Return Guarantee Agreement with LIHTC Investors [Member]
Commitments Contingencies And Guarantees [Line Items]
Compliance period of property	15 years
Default guarantees, value	$ 3
Default Guarantees [Member]
Commitments Contingencies And Guarantees [Line Items]
Default guarantees, value	$ 1
Minimum [Member] | Standby Letters of Credit [Member]
Commitments Contingencies And Guarantees [Line Items]
Remaining actual life of standby letters of credit	1 year
Minimum [Member] | Low [Member]
Commitments Contingencies And Guarantees [Line Items]
Guarantee Obligations	0.00%
Minimum [Member] | Moderate [Member]
Commitments Contingencies And Guarantees [Line Items]
Guarantee Obligations	30.00%
Minimum [Member] | High [Member]
Commitments Contingencies And Guarantees [Line Items]
Guarantee Obligations	70.00%
Maximum [Member] | Standby Letters of Credit [Member]
Commitments Contingencies And Guarantees [Line Items]
Remaining actual life of standby letters of credit	18 years
Maximum [Member] | Low [Member]
Commitments Contingencies And Guarantees [Line Items]
Guarantee Obligations	30.00%
Maximum [Member] | Moderate [Member]
Commitments Contingencies And Guarantees [Line Items]
Guarantee Obligations	70.00%

Accumulated Other Comprehens117

Accumulated Other Comprehensive Income - Changes in AOCI (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 15,240
Total other comprehensive income (loss), net of tax	(13)	$ 192
Ending Balance	14,978
Unrealized Gains (Losses) on Securities Available for Sale [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(185)	(58)
Other comprehensive income before reclassification, net of income taxes	6	128
Amounts reclassified from accumulated other comprehensive income, net of income taxes	0	0
Total other comprehensive income (loss), net of tax	6	128
Ending Balance	(179)	70
Unrealized Gains (Losses) on Derivative Financial Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(14)	20
Other comprehensive income before reclassification, net of income taxes	(15)	72
Amounts reclassified from accumulated other comprehensive income, net of income taxes	(9)	(14)
Total other comprehensive income (loss), net of tax	(24)	58
Ending Balance	(38)	78
Foreign Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3)	(2)
Other comprehensive income before reclassification, net of income taxes	1	5
Amounts reclassified from accumulated other comprehensive income, net of income taxes	0	0
Total other comprehensive income (loss), net of tax	1	5
Ending Balance	(2)	3
Net Pension and Postretirement Benefit Costs [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(339)	(365)
Other comprehensive income before reclassification, net of income taxes	1	(2)
Amounts reclassified from accumulated other comprehensive income, net of income taxes	3	3
Total other comprehensive income (loss), net of tax	4	1
Ending Balance	(335)	(364)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(541)	(405)
Other comprehensive income before reclassification, net of income taxes	(7)	203
Amounts reclassified from accumulated other comprehensive income, net of income taxes	(6)	(11)
Total other comprehensive income (loss), net of tax	(13)	192
Ending Balance	$ (554)	$ (213)

Accumulated Other Comprehens118

Accumulated Other Comprehensive Income - Reclassifications Out of AOCI (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income — Loans	$ 877	$ 562
Interest expense — Long-term debt	(68)	(46)
Income (loss) from continuing operations before income taxes	430	251
Income taxes	94	56
INCOME (LOSS) FROM CONTINUING OPERATIONS	325	187
Personnel expense	556	404
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains (Losses) on Derivative Financial Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before income taxes	14	22
Income taxes	5	8
INCOME (LOSS) FROM CONTINUING OPERATIONS	9	14
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension and Postretirement Benefit Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before income taxes	(4)	(4)
Income taxes	(1)	(1)
INCOME (LOSS) FROM CONTINUING OPERATIONS	(3)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension and Postretirement Benefit Costs [Member] | Amortization of Losses [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Personnel expense	(4)	(4)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension and Postretirement Benefit Costs [Member] | Amortization of Prior Service Credit [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Personnel expense	0
Interest Income [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains (Losses) on Derivative Financial Instruments [Member] | Interest Rate [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income — Loans	15	23
Interest Expense [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains (Losses) on Derivative Financial Instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense — Long-term debt	$ (1)	$ (1)

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail)	Feb. 15, 2017USD ($)$ / shares	Mar. 31, 2017USD ($)$ / sharesshares	Mar. 31, 2016USD ($)$ / shares	Dec. 31, 2016USD ($)$ / sharesshares	Mar. 20, 2017shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Repurchase of common shares | $		$ 107,000,000	$ 0
Cash dividends declared on common shares (in usd per share)		$ 0.085	$ 0.075
Common stock issued upon conversion (in shares) | shares					7.0922
Dividend payable per share		$ 0.395573
Preferred stock | $		$ 1,025,000,000		$ 1,665,000,000
Preferred stock, shares outstanding (in shares) | shares				2,900,234
Dividend payable | $		$ 118,000,000	$ 68,000,000
Series A Preferred Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Preferred stock, dividend rate				7.75%
Dividend payable per share		$ 1.9375
Preferred stock | $				$ 290,000,000
Preferred stock, par value (in usd per share)				$ 1
Preferred stock, liquidation preference				$ 100
Preferred stock, shares authorized (in shares) | shares				7,475,000
Series C Preferred Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividend payable per share	$ 0.539063
Preferred stock | $				$ 350,000,000
Preferred stock, par value (in usd per share)				$ 1
Preferred stock, liquidation preference				$ 25
Preferred stock, shares authorized (in shares) | shares				14,000,000
Preferred stock, shares outstanding (in shares) | shares		14,000,000		14,000,000
Preferred stock, redemption price per share (in usd per share)	$ 25
Dividend payable | $	$ 7,000,000
Depository Shares, Series D [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued | $		$ 525,000,000		$ 525,000,000
Series D Preferred Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividend payable per share		$ 12.50
Preferred stock, par value (in usd per share)		1
Preferred stock, liquidation preference		$ 25,000
Preferred stock, shares authorized (in shares) | shares		21,000		21,000
Preferred stock, shares outstanding (in shares) | shares		21,000		21,000
Dividend payable | $		$ 7,000,000
Depository receipt ratio		0.04		0.04
Depository Shares, Series E [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Shares issued | $		$ 500,000,000		$ 500,000,000
Series E Preferred Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Preferred stock, par value (in usd per share)		$ 1
Preferred stock, liquidation preference		$ 1,000
Preferred stock, shares authorized (in shares) | shares		500,000		500,000
Preferred stock, shares outstanding (in shares) | shares		500,000		500,000
Dividend payable | $		$ 8,000,000
Depository receipt ratio		0.025		0.025
2016 Capital Plan [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Authorized amount of share repurchases | $		$ 350,000,000
Common shares repurchased, value | $		160,000,000
Repurchase of common shares | $		107,000,000
Employee equity compensation program common share repurchases | $		$ 53,000,000
Cash dividends declared on common shares (in usd per share)		$ 0.085
Proposed increase in cash dividends declared on common shares, per share		$ 0.095

Line of Business Results - Addi

Line of Business Results - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017Branchindustry_sector
Segment Reporting [Abstract]
Number of state branch network | Branch	15
Number of business units | industry_sector	7
Federal income tax rate	35.00%
State income tax rate	2.20%

Line of Business Results - Fina

Line of Business Results - Financial Information of Business Groups (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)employee	Mar. 31, 2016USD ($)employee
Segment Reporting Information [Line Items]
Net interest income (TE)	$ 929	$ 612
Noninterest income	577	431
Total revenue (TE)	1,506	1,043
Provision for credit losses	63	89
Depreciation and amortization expense	93	64
Other noninterest expense	920	639
Income (loss) from continuing operations before income taxes	430	251
Allocated income taxes and TE adjustments	105	64
INCOME (LOSS) FROM CONTINUING OPERATIONS	325	187
Income (loss) from discontinued operations, net of taxes	0	1
NET INCOME (LOSS)	325	188
Less: Net income (loss) attributable to noncontrolling interests	1	0
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	324	188
AVERAGE BALANCES
Loans and leases	86,133	60,156
Total assets	132,741	94,477
Deposits	102,078	71,598
OTHER FINANCIAL DATA
Net loan charge-offs	$ 58	$ 46
Return on average allocated equity	8.65%	6.87%
Return on average allocated equity	8.65%	6.90%
Average full-time equivalent employees | employee	18,386	13,403
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net interest income (TE)	$ 930	$ 608
Noninterest income	585	433
Total revenue (TE)	1,515	1,041
Provision for credit losses	63	90
Depreciation and amortization expense	49	27
Other noninterest expense	892	656
Income (loss) from continuing operations before income taxes	511	268
Allocated income taxes and TE adjustments	160	62
INCOME (LOSS) FROM CONTINUING OPERATIONS	351	206
Income (loss) from discontinued operations, net of taxes	0	0
NET INCOME (LOSS)	351	206
Less: Net income (loss) attributable to noncontrolling interests	2	(1)
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	349	207
AVERAGE BALANCES
Loans and leases	86,101	60,114
Total assets	131,678	93,998
Deposits	102,426	71,633
OTHER FINANCIAL DATA
Net loan charge-offs	$ 58	$ 46
Return on average allocated equity	18.04%	16.88%
Return on average allocated equity	18.04%	16.88%
Average full-time equivalent employees | employee	13,191	9,510
Operating Segments [Member] | Key Community Bank [Member]
Segment Reporting Information [Line Items]
Net interest income (TE)	$ 631	$ 399
Noninterest income	277	196
Total revenue (TE)	908	595
Provision for credit losses	47	42
Depreciation and amortization expense	28	13
Other noninterest expense	599	423
Income (loss) from continuing operations before income taxes	234	117
Allocated income taxes and TE adjustments	87	43
INCOME (LOSS) FROM CONTINUING OPERATIONS	147	74
Income (loss) from discontinued operations, net of taxes	0	0
NET INCOME (LOSS)	147	74
Less: Net income (loss) attributable to noncontrolling interests	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	147	74
AVERAGE BALANCES
Loans and leases	47,036	30,789
Total assets	50,962	32,856
Deposits	79,393	52,803
OTHER FINANCIAL DATA
Net loan charge-offs	$ 43	$ 23
Return on average allocated equity	12.60%	11.10%
Return on average allocated equity	12.60%	11.10%
Average full-time equivalent employees | employee	10,804	7,376
Operating Segments [Member] | Key Corporate Bank [Member]
Segment Reporting Information [Line Items]
Net interest income (TE)	$ 304	$ 218
Noninterest income	275	207
Total revenue (TE)	579	425
Provision for credit losses	17	43
Depreciation and amortization expense	20	13
Other noninterest expense	283	224
Income (loss) from continuing operations before income taxes	259	145
Allocated income taxes and TE adjustments	78	27
INCOME (LOSS) FROM CONTINUING OPERATIONS	181	118
Income (loss) from discontinued operations, net of taxes	0	0
NET INCOME (LOSS)	181	118
Less: Net income (loss) attributable to noncontrolling interests	0	0
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	181	118
AVERAGE BALANCES
Loans and leases	37,737	27,722
Total assets	44,167	33,413
Deposits	21,003	18,074
OTHER FINANCIAL DATA
Net loan charge-offs	$ 14	$ 18
Return on average allocated equity	24.86%	22.92%
Return on average allocated equity	24.86%	22.92%
Average full-time equivalent employees | employee	2,384	2,126
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Net interest income (TE)	$ (5)	$ (9)
Noninterest income	33	30
Total revenue (TE)	28	21
Provision for credit losses	(1)	5
Depreciation and amortization expense	1	1
Other noninterest expense	10	9
Income (loss) from continuing operations before income taxes	18	6
Allocated income taxes and TE adjustments	(5)	(8)
INCOME (LOSS) FROM CONTINUING OPERATIONS	23	14
Income (loss) from discontinued operations, net of taxes	0	0
NET INCOME (LOSS)	23	14
Less: Net income (loss) attributable to noncontrolling interests	2	(1)
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	21	15
AVERAGE BALANCES
Loans and leases	1,328	1,603
Total assets	36,549	27,729
Deposits	2,030	756
OTHER FINANCIAL DATA
Net loan charge-offs	$ 1	$ 5
Return on average allocated equity	53.56%	33.33%
Return on average allocated equity	53.56%	33.33%
Average full-time equivalent employees | employee	3	8
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Net interest income (TE)	$ (1)	$ 4
Noninterest income	(8)	(2)
Total revenue (TE)	(9)	2
Provision for credit losses	0	(1)
Depreciation and amortization expense	44	37
Other noninterest expense	28	(17)
Income (loss) from continuing operations before income taxes	(81)	(17)
Allocated income taxes and TE adjustments	(55)	2
INCOME (LOSS) FROM CONTINUING OPERATIONS	(26)	(19)
Income (loss) from discontinued operations, net of taxes	0	1
NET INCOME (LOSS)	(26)	(18)
Less: Net income (loss) attributable to noncontrolling interests	(1)	1
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	(25)	(19)
AVERAGE BALANCES
Loans and leases	32	42
Total assets	1,063	479
Deposits	(348)	(35)
OTHER FINANCIAL DATA
Net loan charge-offs	$ 0	$ 0
Return on average allocated equity	(1.38%)	(1.34%)
Return on average allocated equity	(1.38%)	(1.27%)
Average full-time equivalent employees | employee	5,195	3,893