Loans and Leases (Impaired Loans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Institutional [Member]
Financing Receivable, Impaired [Line Items]
Additional allowance for loan losses	$ 22		$ 22		$ 22
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	204	338	216	377
Interest Revenue Recognized	4	4	12	14
Impaired Financing Receivable, Recorded Investment	204		204		238
Unpaid Principal Balance	326		326		367
CRE - Property Development [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	199		199		199
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	226		226		227
CRE - Property Development - Acquired Credit Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0		0		0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	34		34		34
CRE - Other - Acquired Credit Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5		5		8
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0		0		31
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	66		66		69
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0		0		37
With No Related Allowance Recorded [Member] | CRE - Property Development [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	199	274	199	280
Interest Revenue Recognized	4	4	12	12
With No Related Allowance Recorded [Member] | CRE - Property Development - Acquired Credit Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0	0	6
Interest Revenue Recognized	0	0	0	0
With No Related Allowance Recorded [Member] | CRE - Other - Acquired Credit Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	5	23	17	46
Interest Revenue Recognized	0	0	0	0
With No Related Allowance Recorded [Member] | CRE - Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	3	0	7
Interest Revenue Recognized	0	0	0	1
With Allowance Recorded [Member] | CRE - Other - Acquired Credit Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	31	0	31
Interest Revenue Recognized	0	0	0	1
With Allowance Recorded [Member] | CRE - Other [Member] | Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	7	0	7
Interest Revenue Recognized	$ 0	$ 0	$ 0	$ 0