Long-Term Debt (Details Textual) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended				1 Months Ended	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2009	Jun. 02, 2009	May 11, 2009	Jun. 30, 2008 Medium-term Notes [Member]	Dec. 31, 2011 Medium-term Notes [Member]	Dec. 31, 2010 Medium-term Notes [Member]	Dec. 31, 2011 Medium-term Notes [Member] Parent Company [Member]	Dec. 31, 2011 Medium-term Notes [Member] Key Bank [Member]
Debt Instrument [Line Items]
Euro medium term note, maximum issuable amount								$ 10,000,000,000		$ 1,000,000,000	$ 9,000,000,000
Euro note available for future issuance								9,400,000,000
Issuance of euro medium term notes original maturities							Nine months or more
Issuance of medium term notes									750,000,000
Additional debt securities authorized and available for issuance under the medium-term note program								1,600,000,000
Long term borrowings (Textual) [Abstract]
Bank note, maximum issuable amount			20,000,000,000
Original maturity of bank note, minimum			30 days
Original maturity of bank note, maximum			30 years
Bank note available for future issuance			16,500,000,000
Estimated gross proceeds from public at the market offering						750,000,000
Additional issuance of securities	1,000,000,000
Increased estimated gross proceeds from public at the market offering					1,000,000,000
Number of additional shares issued under public at the market offering				205,438,975
Average issue price under public at the market offering					$ 4.87
Proceeds from Issuance of Common Stock		625,000,000		987,000,000
Authorized and available for issuance of preferred stock or capital securities			$ 1,300,000,000