Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012
ASSETS
Cash and due from banks	$ 748		$ 584		$ 973
Short-term investments	3,535		3,940		2,208
Trading account assets	806		605		663
Securities available for sale	12,606		12,094		11,962
Held-to-maturity securities (fair value: $4,730, $3,992 and $4,212)	4,835		3,931		4,153
Other investments	1,007		1,064		1,106
Loans, net of unearned income of $827, $957 and $980	53,597		52,822		51,419
Less: Allowance for loan and lease losses	868		888		888
Net loans	52,729		51,934		50,531
Loans held for sale	699		599		628
Premises and equipment	890		965		942
Operating lease assets	293		288		290
Goodwill	979		979		979
Other intangible assets	137		171		182
Corporate-owned life insurance	3,384		3,333		3,309
Derivative assets	475		693		771
Accrued income and other assets (including $24 of consolidated LIHTC guaranteed funds VIEs, see Note 9)	2,747	[1]	2,774	[1]	2,853	[1]
Discontinued assets (including $2,158 of consolidated education loan securitization trust VIEs (see Note 9) and $148 of loans in portfolio at fair value)	4,838	[1]	5,282	[1]	5,400	[1]
Total assets	90,708		89,236		86,950
Deposits in domestic offices:
NOW and money market deposit accounts	33,132		32,380		30,573
Savings deposits	2,489		2,433		2,393
Certificates of deposit ($100,000 or more)	2,698		2,879		3,226
Other time deposits	3,833		4,575		4,941
Total interest-bearing	42,152		42,267		41,133
Noninterest-bearing	25,778		23,319		22,486
Deposits in foreign office - interest-bearing	605		407		569
Total deposits	68,535		65,993		64,188
Federal funds purchased and securities sold under repurchase agreements	1,455		1,609		1,746
Bank notes and other short-term borrowings	466		287		388
Derivative liabilities	450		584		657
Accrued expense and other liabilities	1,375		1,387		1,205
Long-term debt	6,154		6,847		6,119
Discontinued liabilities (including $2,037 of consolidated education loan securitization trust VIEs at fair value, see Note 9)	2,037	[1]	2,220	[1]	2,368	[1]
Total liabilities	80,472		78,927		76,671
Preferred stock, $1 par value, authorized 25,000,000 shares:
Common shares, $1 par value; authorized 1,400,000,000 shares; issued 1,016,969,905, 1,016,969,905 and 1,016,969,905 shares	1,017		1,017		1,017
Capital surplus	4,029		4,126		4,118
Retained earnings	7,431		6,913		6,762
Treasury stock, at cost (119,148,654, 91,201,285 and 80,775,030)	(2,193)		(1,952)		(1,868)
Accumulated other comprehensive income (loss)	(369)		(124)		(69)
Key shareholders' equity	10,206		10,271		10,251
Noncontrolling interests	30		38		28
Total equity	10,236		10,309		10,279
Total liabilities and equity	90,708		89,236		86,950
Series A Preferred Stock [Member]
Preferred stock, $1 par value, authorized 25,000,000 shares:
Preferred stock	$ 291		$ 291		$ 291

[1] The assets of the VIEs can only be used by the particular VIE and there is no recourse to Key with respect to the liabilities of the consolidated LIHTC or education loan securitization trust VIEs.