Fair Value Disclosures (Carrying Amounts and Fair Values of Financial Assets and Liabilities Not Recorded at Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
HTM securities	$ 20,432	$ 18,101
Deposits	131,586	127,475
Long-term debt	21,927	21,493
Carrying Amount [Member]
HTM securities	20,432	18,101
Loans and leases,net of ALLL (excluding covered)	116,371	112,264
Covered loans, net of ALLL	1,562	1,921
FDIC loss share receivable	689	843
Deposits	131,586	127,475
FDIC loss share payable	696	669
Long-term debt	21,927	21,493
Estimate of Fair Value, Fair Value Disclosure [Member]
HTM securities	20,264	17,530
Loans and leases,net of ALLL (excluding covered)	116,473	112,261
Covered loans, net of ALLL	1,789	2,200
FDIC loss share receivable	356	464
Deposits	131,877	127,810
FDIC loss share payable	692	652
Long-term debt	22,904	22,313
Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
HTM securities	20,264	17,491
Loans and leases,net of ALLL (excluding covered)	0	0
Covered loans, net of ALLL	0	0
FDIC loss share receivable	0	0
Deposits	131,877	127,810
FDIC loss share payable	0	0
Long-term debt	22,904	22,313
Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
HTM securities	0	39
Loans and leases,net of ALLL (excluding covered)	116,473	112,261
Covered loans, net of ALLL	1,789	2,200
FDIC loss share receivable	356	464
Deposits	0	0
FDIC loss share payable	692	652
Long-term debt	$ 0	$ 0