Asset Quality (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 388	$ 621
Unpaid Principal Balance	751	1,213
Specific Allowance	51	58
Average Recorded Investment	505	1,134
Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		389
Unpaid Principal Balance		847
Specific Allowance		0
Average Recorded Investment		453
Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		232
Unpaid Principal Balance		366
Specific Allowance		58
Average Recorded Investment		681
Commercial, financial and agricultural [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	88	61
Unpaid Principal Balance	195	133
Specific Allowance	0	0
Average Recorded Investment	75	66
Commercial, financial and agricultural [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	62	89
Unpaid Principal Balance	70	133
Specific Allowance	26	26
Average Recorded Investment	75	237
Commercial real estate: Commercial Mortgage [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	100	162
Unpaid Principal Balance	240	310
Specific Allowance	0	0
Average Recorded Investment	131	166
Commercial real estate: Commercial Mortgage [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	96	86
Unpaid Principal Balance	115	130
Specific Allowance	21	18
Average Recorded Investment	91	237
Commercial real estate: Construction [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	30	166
Unpaid Principal Balance	113	404
Specific Allowance	0	0
Average Recorded Investment	98	219
Commercial real estate: Construction [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	12	45
Unpaid Principal Balance	18	85
Specific Allowance	4	7
Average Recorded Investment	29	184
Commercial Real Estate Loans [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	130	328
Unpaid Principal Balance	353	714
Specific Allowance	0	0
Average Recorded Investment	229	385
Commercial Real Estate Loans [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	108	131
Unpaid Principal Balance	133	215
Specific Allowance	25	25
Average Recorded Investment	120	421
Commercial Lease Financing [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Specific Allowance	0	0
Average Recorded Investment	0	0
Commercial Lease Financing [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	12
Unpaid Principal Balance	0	18
Specific Allowance	0	7
Average Recorded Investment	6	17
Commercial Loans [Member] | Impaired Financing Receivable with No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	218	389
Unpaid Principal Balance	548	847
Specific Allowance	0	0
Average Recorded Investment	304	451
Commercial Loans [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	170	232
Unpaid Principal Balance	203	366
Specific Allowance	51	58
Average Recorded Investment	201	675
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
Specific Allowance		0
Average Recorded Investment		2
Real estate - residential mortgage [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Specific Allowance		0
Average Recorded Investment		3
Other Consumer [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Specific Allowance		0
Average Recorded Investment		3
Consumer Indirect loans [Member] | Impaired Financing Receivable with Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Specific Allowance		0
Average Recorded Investment		$ 3