Derivative And Credit-Related Financial Instruments (Schedule Of Derivative Instruments) (Details) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	$ 21,385	$ 21,562
Fair Value of Gross Derivative Assets		669	894
Fair Value of Gross Derivative Liabilities		469	661
Derivative Asset, Netting Adjustment - Offsetting Liabilities		(116)	(133)
Derivative Liability, Netting Adjustment - Offsetting Assets		(116)	(133)
Derivative Asset, Netting Adjustment - Cash Collateral Received		(201)	(262)
Derivative Liability, Netting Adjustment, Cash Collateral Posted		(3)	0
Net Derivative Assets Included in the Consolidated Balance Sheets	[2]	352	499
Net Derivative Liabilities Included in the Consolidated Balance Sheets	[2]	350	528
Derivative Asset, Securities Pledged As Collateral		(122)	(239)
Derivative Liability, Securities Pledged As Collateral		0	(2)
Net Derivative Assets After Deducting Amounts Not Offset in the Consolidated Balance Sheets		230	260
Net Derivative Liabilities After Deducting Amounts Not Offset in the Consolidated Balance Sheets		350	526
Derivative Credit Risk Valuation Adjustment, Derivative Assets		4	2
Risk Management Purposes
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,657	2,308
Fair Value of Gross Derivative Assets		148	179
Fair Value of Gross Derivative Liabilities		4	0
Risk Management Purposes | Designated as Hedging Instrument | Fair Value Hedging | Interest Rate Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,000	1,800
Fair Value of Gross Derivative Assets		148	175
Fair Value of Gross Derivative Liabilities		2	0
Risk Management Purposes | Derivatives Used As Economic Hedges | Foreign Exchange Spot Forward And Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	657	508
Fair Value of Gross Derivative Assets		0	4
Fair Value of Gross Derivative Liabilities		2	0
Customer-Initiated And Other Activities
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	18,728	19,254
Fair Value of Gross Derivative Assets		521	715
Fair Value of Gross Derivative Liabilities		465	661
Customer-Initiated And Other Activities | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	12,431	12,328
Fair Value of Gross Derivative Assets		136	153
Fair Value of Gross Derivative Liabilities		88	102
Customer-Initiated And Other Activities | Interest Rate Caps And Floors Written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	312	274
Fair Value of Gross Derivative Assets		0	0
Fair Value of Gross Derivative Liabilities		1	0
Customer-Initiated And Other Activities | Interest Rate Caps and Floors Purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	312	274
Fair Value of Gross Derivative Assets		1	0
Fair Value of Gross Derivative Liabilities		0	0
Customer-Initiated And Other Activities | Interest Rate Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	11,807	11,780
Fair Value of Gross Derivative Assets		135	153
Fair Value of Gross Derivative Liabilities		87	102
Customer-Initiated And Other Activities | Energy Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	4,185	4,932
Fair Value of Gross Derivative Assets		349	527
Fair Value of Gross Derivative Liabilities		348	525
Customer-Initiated And Other Activities | Energy Caps and Floors Written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	939	1,218
Fair Value of Gross Derivative Assets		1	0
Fair Value of Gross Derivative Liabilities		92	173
Customer-Initiated And Other Activities | Energy Caps and Floors Purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	939	1,218
Fair Value of Gross Derivative Assets		92	173
Fair Value of Gross Derivative Liabilities		1	0
Customer-Initiated And Other Activities | Energy Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,307	2,496
Fair Value of Gross Derivative Assets		256	354
Fair Value of Gross Derivative Liabilities		255	352
Customer-Initiated And Other Activities | Foreign Exchange Spot, Forwards, Options and Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	[1]	2,112	1,994
Fair Value of Gross Derivative Assets		36	35
Fair Value of Gross Derivative Liabilities		$ 29	$ 34

[1] Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the consolidated balance sheets.

[2] Net derivative assets are included in “accrued income and other assets” and net derivative liabilities are included in “accrued expenses and other liabilities” on the consolidated balance sheets. Included in the fair value of net derivative assets and net derivative liabilities are credit valuation adjustments reflecting counterparty credit risk and credit risk of the Corporation. The fair value of net derivative assets included credit valuation adjustments for counterparty credit risk of $4 million and $2 million at June 30, 2015 and December 31, 2014, respectively.