Loans And Leases (Impaired Loans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2012		Mar. 31, 2011	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	$ 238			$ 238
Unpaid Principal Balance	367			367
Related Allowance	0	[1]		0	[1]
Average Recorded Investment	238		416
Interest Revenue Recognized	4		5
Additional allowance for loan losses	22			22
With No Related Allowance Recorded [Member] | CRE-Property Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	199			199
Unpaid Principal Balance	227			227
Average Recorded Investment	199		205
Interest Revenue Recognized	4		4
With No Related Allowance Recorded [Member] | CRE-Property Development - Acquired Credit-Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	0			0
Unpaid Principal Balance	34			34
Average Recorded Investment	0		0
Interest Revenue Recognized	0		0
With No Related Allowance Recorded [Member] | CRE-Other-Acquired Credit-Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	8			8
Unpaid Principal Balance	69			69
Average Recorded Investment	8		16
Interest Revenue Recognized	0		0
With No Related Allowance Recorded [Member] | CRE-Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	0			0
Unpaid Principal Balance	0			0
Average Recorded Investment	0		14
Interest Revenue Recognized	0		1
With An Allowance Recorded [Member] | CRE-Property Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	0			0
Unpaid Principal Balance	0			0
Average Recorded Investment	0		79
Interest Revenue Recognized	0		0
With An Allowance Recorded [Member] | CRE-Property Development - Acquired Credit-Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	0			0
Unpaid Principal Balance	0			0
Average Recorded Investment	0		19
Interest Revenue Recognized	0		0
With An Allowance Recorded [Member] | CRE-Other-Acquired Credit-Impaired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	31			31
Unpaid Principal Balance	37			37
Related Allowance	0	[1]		0	[1]
Average Recorded Investment	31		76
Interest Revenue Recognized	0		0
With An Allowance Recorded [Member] | CRE-Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	0			0
Unpaid Principal Balance	0			0
Related Allowance	0	[1]		0	[1]
Average Recorded Investment	0		7
Interest Revenue Recognized	$ 0		$ 0

[1] As of both March 31, 2012 and December 31, 2011, we maintained an allowance for loan losses of $22 million associated with loans and leases that were not impaired.