Asset Quality (Details 5) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	$ 49,605	$ 47,840
Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	20,386	16,883
RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	7,409	8,069
RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1,172	1,631
Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	5,636	6,105
Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	34,603	32,688
AAA-AA [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	165	100
AAA-AA [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans		2
AAA-AA [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1	3
AAA-AA [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	605	655
AAA-AA [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	771	760
A [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	680	671
A [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	64	63
A [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1	1
A [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	992	1,245
A [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1,737	1,980
BBB-BB [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	17,652	13,546
BBB-BB [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	5,925	5,553
BBB-BB [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	791	747
BBB-BB [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	3,709	3,590
BBB-BB [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	28,077	23,436
B [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	868	955
B [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	553	941
B [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	58	262
B [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	197	343
B [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1,676	2,501
CCC-C [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1,021	1,611
CCC-C [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	867	1,510
CCC-C [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	321	618
CCC-C [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	133	272
CCC-C [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	2,342	4,011
Commercial [Member] | Commercial, financial and agricultural [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	20,386	16,883
Commercial [Member] | RE-Commercial [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	7,409	8,069
Commercial [Member] | RE-Construction [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	1,172	1,631
Commercial [Member] | Commercial Lease [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	5,636	6,105
Commercial [Member] | Commercial Loan [Member]
Commercial Credit Exposure Credit Risk Profile by Creditworthiness Category
Total Loans	$ 34,603	$ 32,688