Consolidated Statements of Income (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
INTEREST INCOME
Loans	$ 2,155		$ 2,206		$ 2,653
Loans held for sale	20		14		17
Securities available for sale	399		583		644
Held-to-maturity securities	69		12		2
Trading account assets	18		26		37
Short-term investments	6		6		6
Other investments	38		42		49
Total interest income	2,705		2,889		3,408
INTEREST EXPENSE
Deposits	257		390		671
Federal funds purchased and securities sold under repurchase agreements	4		5		6
Bank notes and other short-term borrowings	7		11		14
Long-term debt	173		216		206
Total interest expense	441		622		897
NET INTEREST INCOME	2,264		2,267		2,511
Provision for loan and lease losses	229		(60)		638
Net interest income (expense) after provision for loan and lease losses	2,035		2,327		1,873
NONINTEREST INCOME
Trust and investment services income	421		434		444
Service charges on deposit accounts	287		281		301
Operating lease income	75		122		173
Letter of credit and loan fees	221		213		194
Corporate-owned life insurance income	122		121		137
Net securities gains (losses)			1	[1]	14	[1]
Electronic banking fees	72		114		117
Gains on leased equipment	111		25		20
Insurance income	50		53		64
Net gains (losses) from loan sales	150		75		76
Net gains (losses) from principal investing	72		78		66
Investment banking and capital markets income (loss)	165		134		145
Other income	221		157		203
Total noninterest income	1,967		1,808		1,954
NONINTEREST EXPENSE
Personnel	1,618		1,520		1,471
Net occupancy	260		258		270
Operating lease expense	57		94		142
Computer processing	166		166		185
Business services and professional fees	193		186		176
FDIC assessment	31		52		124
OREO expense, net	15		13		68
Equipment	107		103		100
Marketing	68		60		72
Provision (credit) for losses on lending-related commitments	(16)		(28)		(48)
Intangible asset amortization on credit cards	14
Other intangible asset amortization	9		4		14
Other expense	385		362		460
Total noninterest expense	2,907		2,790		3,034
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	1,095		1,345		793
Income taxes	239		369		186
INCOME (LOSS) FROM CONTINUING OPERATIONS	856		976		607
Income (loss) from discontinued operations, net of taxes of $6, ($26) and ($14) (see Note 13)	9		(44)		(23)
NET INCOME (LOSS)	865		932		584
Less: Net income (loss) attributable to noncontrolling interests	7		12		30
NET INCOME (LOSS) ATTRIBUTABLE TO KEY	858		920		554
Income (loss) from continuing operations attributable to Key common shareholders	827		857		413
Net income (loss) attributable to Key common shareholders	$ 836		$ 813		$ 390
Per common share:
Income (loss) from continuing operations attributable to Key common shareholders	$ 0.88		$ 0.92		$ 0.47
Income (loss) from discontinued operations, net of taxes	$ 0.01		$ (0.05)		$ (0.03)
Net income (loss) attributable to Key common shareholders	$ 0.89	[2]	$ 0.87	[2]	$ 0.45	[2]
Per common share - assuming dilution:
Income (loss) from continuing operations attributable to Key common shareholders	$ 0.88		$ 0.92		$ 0.47
Income (loss) from discontinued operations, net of taxes	$ 0.01		$ (0.05)		$ (0.03)
Net income (loss) attributable to Key common shareholders	$ 0.89	[2]	$ 0.87	[2]	$ 0.44	[2]
Cash dividends declared per common share	$ 0.18		$ 0.10		$ 0.04
Weighted-average common shares outstanding (000)	938,941	[3]	931,934	[3]	874,748	[3]
Weighted-average common shares and potential common shares outstanding (000)	943,259		935,801		878,153

[1] For 2012, 2011, and 2010, we did not have any impairment losses related to securities.

[2] EPS may not foot due to rounding.

[3] Assumes conversion of stock options and/or Preferred Series A, as applicable.