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, 2012		Dec. 31, 2011
Securities held to maturity	$ 12,576		$ 14,094
FDIC loss share receivable	831		1,100
Deposits	126,059		124,939
Long-term debt	22,561		21,803
Carrying Amount [Member]
Securities held to maturity	12,576	[1]	14,094	[1]
Loans and leases, excluding covered loans	105,133	[2]	100,495	[2]
Covered loans	3,816	[2]	4,718	[2]
FDIC loss share receivable	831		1,100
Deposits	126,059		124,939
Long-term debt	22,561		21,803
Estimate of Fair Value, Fair Value Disclosure [Member]
Securities held to maturity	12,744		14,098
Loans and leases, excluding covered loans	105,429		100,036
Covered loans	4,653		5,706
FDIC loss share receivable	454		910
Deposits	126,369		125,317
Long-term debt	24,030		23,001
Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities held to maturity	12,705
Loans and leases, excluding covered loans	0
Covered loans	0
FDIC loss share receivable	0
Deposits	126,369
Long-term debt	24,030
Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Securities held to maturity	39
Loans and leases, excluding covered loans	105,429
Covered loans	4,653
FDIC loss share receivable	454
Deposits	0
Long-term debt	$ 0

[1] The carrying value excludes amounts deferred in other comprehensive income resulting from the transfer of securities available for sale to securities held to maturity.

[2] The carrying value is net of the allowance for loan and lease losses.