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	Dec. 31, 2011		Dec. 31, 2010
Securities held to maturity	$ 14,094		$ 0
Deposits	124,939		107,213
Long-term debt	21,803		21,730
Fair value [Member]
Securities held to maturity	14,098	[1]	0	[1]
Loans and leases, net of allowance for loan and lease losses, not recorded at fair value	104,855	[2],[3]	100,360	[2],[3]
Deposits	124,853		104,091
Long-term debt	23,001		22,733
Carrying Amount [Member]
Securities held to maturity	14,094	[1]	0	[1]
Loans and leases, net of allowance for loan and lease losses, not recorded at fair value	105,213	[2],[3]	101,380	[2],[3]
Deposits	124,939		107,213
Long-term debt	$ 21,803		$ 21,730

[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] December 31, 2010 balance includes loans held for sale carried at the lower of cost or market.

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