Loans And Allowance For Credit Losses (Summary Of Nonaccrual Loans) (Details) - USD ($) $ in Millions		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	[1]	$ 331	$ 381
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		34	40
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		7	7
Finance Leases Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		13	14
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		89	74
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		1	1
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		461	443
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		38	29
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		45	36
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		9	11
One Through Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		35	36
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		1	2
Revolving Credit Facility [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		0	1
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		45	50
Financing Receivables, Total [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		551	529
Commercial and Industrial Sector [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total		$ 358	$ 354

[1] 1 Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.