Restrictions on Cash, Dividends and Lending Activities (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Restrictions on Cash Dividends and Lending Activities (Textual) [Abstract]
Average Reserve Balance Maintained	$ 240,000,000
Capital Infusions to Subsidiary	0
Short term investments held for discharge of obligations	2,100,000,000
Nonbank Subsidiaries [Member]
Cash Dividends Lending Restrictions [Line Items]
Dividends paid by non banking subsidiaries	33,000,000
Noncash dividends contributed by non banking subsidiaries	12,000,000
Key Bank [Member]
Cash Dividends Lending Restrictions [Line Items]
Dividends paid by non banking subsidiaries	300,000,000
Capacity to Pay Additional Dividends	$ 1,300,000,000