Asset Quality (Details 7) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations	$ 1,372	$ 2,425	$ 1,604	$ 2,534
Provisions			(47)
Charge-offs	177	492	409	1,049
Recoveries	43	57	82	92
Balance at end of year - continuing operations	1,230	2,219	1,230	2,219
Discontinued Operations, Beginning Balance			114
Provision, Discontinued Operations			62
Charge-offs, Discontinued Operations			73
Recoveries, Discontinued Operations			6
Discontinued Operations, Ending Balance	109		109
Financing Receivable Allowance For Credit Losses Total Alll Including Discontinued Operations, Beginning Balance			1,718
Provisions, Total ALLL - Including Discontinued Operations			15
Charge-offs, Total ALLL - Including Discontinued Operations			482
Recoveries, Total ALLL - Including Discontinued Operations			88
Financing Receivable Allowance For Credit Losses Total Alll Including Discontinued Operations, Ending Balance	1,339		1,339
Commercial, financial and agricultural [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			485
Provisions			(22)
Charge-offs			93
Recoveries			25
Balance at end of year - continuing operations	395		395
Commercial real estate: Commercial Mortgage [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			416
Provisions			(18)
Charge-offs			62
Recoveries			7
Balance at end of year - continuing operations	343		343
Commercial real estate: Construction [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			145
Provisions			15
Charge-offs			62
Recoveries			8
Balance at end of year - continuing operations	106		106
Commercial Lease Financing [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			175
Provisions			(53)
Charge-offs			26
Recoveries			11
Balance at end of year - continuing operations	107		107
Commercial [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			1,221
Provisions			(78)
Charge-offs			243
Recoveries			51
Balance at end of year - continuing operations	951		951
Real estate - residential mortgage [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			49
Provisions			7
Charge-offs			17
Recoveries			2
Balance at end of year - continuing operations	41		41
Home Equity Key Community Bank [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			120
Provisions			30
Charge-offs			53
Recoveries			2
Balance at end of year - continuing operations	99		99
Home Equity Other [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			57
Provisions			4
Charge-offs			26
Recoveries			2
Balance at end of year - continuing operations	37		37
Home Equity [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			177
Provisions			34
Charge-offs			79
Recoveries			4
Balance at end of year - continuing operations	136		136
Consumer other - Key Community Bank [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			57
Provisions			9
Charge-offs			23
Recoveries			4
Balance at end of year - continuing operations	47		47
Consumer Marine [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			89
Provisions			(14)
Charge-offs			42
Recoveries			19
Balance at end of year - continuing operations	52		52
Consumer others [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			11
Provisions			(5)
Charge-offs			5
Recoveries			2
Balance at end of year - continuing operations	3		3
Consumer Other - Key Corporate Bank [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			100
Provisions			(19)
Charge-offs			47
Recoveries			21
Balance at end of year - continuing operations	55		55
Consumer Loans [Member]
Changes in Allowance for loan and lease losses by loan category
Balance at beginning of year - continuing operations			383
Provisions			31
Charge-offs			166
Recoveries			31
Balance at end of year - continuing operations	$ 279		$ 279