Asset Quality (Details 1) (USD $) In Millions	Jun. 30, 2011
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 1,341
Unpaid Principal Balance	706
Related Allowance	127
Average Recorded Investment	1,456
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	498
Unpaid Principal Balance	206
Related Allowance	0
Average Recorded Investment	602
Commercial Real Estate Loans [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	331
Unpaid Principal Balance	201
Related Allowance	71
Average Recorded Investment	302
Commercial Lease Financing [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	38
Unpaid Principal Balance	25
Related Allowance	12
Average Recorded Investment	40
Commercial Lease Financing [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Commercial Loans [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	516
Unpaid Principal Balance	305
Related Allowance	115
Average Recorded Investment	554
Commercial Loans [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	731
Unpaid Principal Balance	322
Related Allowance	0
Average Recorded Investment	807
Home Equity Loans [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	22
Unpaid Principal Balance	22
Related Allowance	7
Average Recorded Investment	21
Home Equity Loans [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	2
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	2
Loans with no related allowance recorded [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	733
Unpaid Principal Balance	322
Related Allowance	0
Average Recorded Investment	809
Loans with an allowance recorded [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	608
Unpaid Principal Balance	384
Related Allowance	127
Average Recorded Investment	647
Commercial, financial and agricultural [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	147
Unpaid Principal Balance	79
Related Allowance	32
Average Recorded Investment	212
Commercial, financial and agricultural [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	233
Unpaid Principal Balance	116
Related Allowance	0
Average Recorded Investment	205
Commercial real estate: Commercial Mortgage [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	215
Unpaid Principal Balance	145
Related Allowance	49
Average Recorded Investment	202
Commercial real estate: Commercial Mortgage [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	241
Unpaid Principal Balance	123
Related Allowance	0
Average Recorded Investment	269
Commercial real estate: Construction [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	116
Unpaid Principal Balance	56
Related Allowance	22
Average Recorded Investment	100
Commercial real estate: Construction [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	257
Unpaid Principal Balance	83
Related Allowance	0
Average Recorded Investment	333
Real estate - residential mortgage [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	45
Unpaid Principal Balance	33
Related Allowance	4
Average Recorded Investment	47
Real estate - residential mortgage [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Home Equity Key Community Bank [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	22
Unpaid Principal Balance	22
Related Allowance	7
Average Recorded Investment	21
Home Equity Key Community Bank [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	2
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	2
Home Equity Other [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Home Equity Other [Member] | Impaired Financing Receivable With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Consumer other - Key Community Bank [Member] | Impaired Financing Receivable With Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	25
Unpaid Principal Balance	24
Related Allowance	1
Average Recorded Investment	$ 25