Asset Quality (Details 8) (USD $) In Millions	Jun. 30, 2011
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	$ 46
Collectively Evaluated for Impairment	1,184
Loans	47,840
Financing receivable individually evaluated for impairment specifically allocated allowance	488
Collectively Evaluated for Impairment	47,352
Individually Evaluated for Impairment, Discontinued Operations	0
Collectively Evaluated for Impairment, Discontinued Operations	109
Loans, Discontinued Operations	6,261
Financing Receivable Individually Evaluated For Impairment, Discontinued Operations	0
Financing Receivable Collectively Evaluated For Impairment, Discontinued Operations	6,261
Individually Evaluated For Impairment, Total ALLL - Including Discontinued Operations	46
Collectively Evaluated For Impairment, Total ALLL - Including Discontinued Operations	1,293
Loans Total ALL - Including Discontinued Operations	54,101
Individually Evaluated For Impairment Total ALLL - Including Discontinued Operations	488
Collectively Evaluated For Impairment Total ALLL - Including Discontinued Operations	53,613
Commercial, financial and agricultural [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	14
Collectively Evaluated for Impairment	381
Loans	16,883
Financing receivable individually evaluated for impairment specifically allocated allowance	157
Collectively Evaluated for Impairment	16,726
Commercial real estate: Commercial Mortgage [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	21
Collectively Evaluated for Impairment	322
Loans	8,069
Financing receivable individually evaluated for impairment specifically allocated allowance	213
Collectively Evaluated for Impairment	7,856
Commercial real estate: Construction [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	11
Collectively Evaluated for Impairment	95
Loans	1,631
Financing receivable individually evaluated for impairment specifically allocated allowance	116
Collectively Evaluated for Impairment	1,515
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	32
Collectively Evaluated for Impairment	417
Loans	9,700
Financing receivable individually evaluated for impairment specifically allocated allowance	329
Collectively Evaluated for Impairment	9,371
Commercial Lease Financing [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	107
Loans	6,105
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	6,105
Commercial [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	46
Collectively Evaluated for Impairment	905
Loans	32,688
Financing receivable individually evaluated for impairment specifically allocated allowance	486
Collectively Evaluated for Impairment	32,202
Real estate - residential mortgage [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	41
Loans	1,838
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	1,838
Home Equity Key Community Bank [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	99
Loans	9,431
Financing receivable individually evaluated for impairment specifically allocated allowance	2
Collectively Evaluated for Impairment	9,429
Home Equity Other [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	37
Loans	595
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	595
Home Equity [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	136
Loans	10,026
Financing receivable individually evaluated for impairment specifically allocated allowance	2
Collectively Evaluated for Impairment	10,024
Consumer other - Key Community Bank [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	47
Loans	1,157
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	1,157
Consumer Marine [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	52
Loans	1,989
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	1,989
Consumer others [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	3
Loans	142
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	142
Consumer Other - Key Corporate Bank [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	55
Loans	2,131
Financing receivable individually evaluated for impairment specifically allocated allowance	0
Collectively Evaluated for Impairment	2,131
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Individually Evaluated for Impairment	0
Collectively Evaluated for Impairment	279
Loans	15,152
Financing receivable individually evaluated for impairment specifically allocated allowance	2
Collectively Evaluated for Impairment	$ 15,150