Loans And Allowance For Credit Losses (Schedule Of Outstanding Balances Of All Required Payments And The Related Carrying Amounts For PCI Loans) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		$ 316	$ 309
Financing Receivable, Recorded Investment, Current		43,840	42,340
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		122	150
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		194	159
Loans and Leases Receivable, Gross		44,156	42,649
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		30	36
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	265	381
Commercial		36	49
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Commercial Real Estate		15	51
Consumer		7	9
Outstanding balance		58	109
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Carrying Amount, Net		40	77
ALLL		0	1
Carrying amount, net		40	76
loans held for sale [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		13	0
Financing Receivable, Recorded Investment, Current		58	172
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0	0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		13	0
Loans and Leases Receivable, Gross		71	172
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0	40
Commercial And Industrial [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		171	146
Financing Receivable, Recorded Investment, Current		13,870	13,306
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		53	72
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		118	74
Loans and Leases Receivable, Gross		14,041	13,452
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		17	10
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	150	287
Finance Leases Portfolio Segment [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		0	0
Financing Receivable, Recorded Investment, Current		343	423
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0	0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0	0
Loans and Leases Receivable, Gross		343	423
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	8	14
Owner Occupied [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		61	68
Financing Receivable, Recorded Investment, Current		7,021	6,894
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		27	40
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		34	28
Loans and Leases Receivable, Gross		7,082	6,962
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		5	8
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	49	43
Municipal [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		0	0
Financing Receivable, Recorded Investment, Current		1,073	778
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		0	0
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0	0
Loans and Leases Receivable, Gross		1,073	778
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	1	1
Commercial Loan [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		232	214
Financing Receivable, Recorded Investment, Current		22,307	21,401
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		80	112
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		152	102
Loans and Leases Receivable, Gross		22,539	21,615
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		22	18
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	208	345
Commercial Real Estate [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		12	9
Financing Receivable, Recorded Investment, Current		2,158	2,010
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		6	7
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		6	2
Loans and Leases Receivable, Gross		2,170	2,019
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		1	1
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	1	1
Term [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		19	31
Financing Receivable, Recorded Investment, Current		8,925	9,291
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		8	9
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		11	22
Loans and Leases Receivable, Gross		8,944	9,322
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		2	12
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	30	18
Commercial Real Estate [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		31	40
Financing Receivable, Recorded Investment, Current		11,083	11,301
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		14	16
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		17	24
Loans and Leases Receivable, Gross		11,114	11,341
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		3	13
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	31	19
Home Equity Line of Credit [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		10	10
Financing Receivable, Recorded Investment, Current		2,735	2,635
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		6	4
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		4	6
Loans and Leases Receivable, Gross		2,745	2,645
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	1
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	4	5
One Through Four Family Residential [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		25	34
Financing Receivable, Recorded Investment, Current		6,497	5,857
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		10	12
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		15	22
Loans and Leases Receivable, Gross		6,522	5,891
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	20	11
Construction And Other Consumer Real Estate [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		11	7
Financing Receivable, Recorded Investment, Current		547	479
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		6	3
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		5	4
Loans and Leases Receivable, Gross		558	486
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		4	3
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	0	0
Revolving Credit Facility [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		4	3
Financing Receivable, Recorded Investment, Current		486	478
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		3	2
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		1	1
Loans and Leases Receivable, Gross		490	481
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		1	1
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	1	1
Consumer Portfolio Segment [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		3	1
Financing Receivable, Recorded Investment, Current		185	189
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		3	1
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		0	0
Loans and Leases Receivable, Gross		188	190
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	1	0
Consumer Loan [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Recorded Investment, Past Due		53	55
Financing Receivable, Recorded Investment, Current		10,450	9,638
Financing Receivable Recorded Investment Thirty To Eighty Nine Days Past Due		28	22
Financing Receivable Recorded Investments, Equal To and Greater Than 90 Days Past Due		25	33
Loans and Leases Receivable, Gross		10,503	9,693
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		5	5
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	$ 26	$ 17

[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.