Derivative And Credit-Related Financial Instruments (Schedule Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	$ 21,667	[1]	$ 20,538	[1]
Fair Value of Gross Derivative Assets	517		500
Fair Value of Gross Derivative Liabilities	286		249
Derivative Asset, Netting Adjustment - Offsetting Liabilities	(158)		(187)
Derivative Liability, Netting Adjustment - Offsetting Assets	(158)		(187)
Derivative Asset, Netting Adjustment - Cash Collateral Received	(1)		(2)
Derivative Liability, Netting Adjustment, Cash Collateral Posted	(35)		(10)
Net Derivative Assets Included in the Consolidated Balance Sheets	358	[2]	311	[2]
Net Derivative Liabilities Included in the Consolidated Balance Sheets	93	[2]	52	[2]
Derivative Asset, Securities Pledged As Collateral	(86)		(138)
Derivative Liability, Securities Pledged As Collateral	(52)		(10)
Net Derivative Assets After Deducting Amounts Not Offset in the Consolidated Balance Sheets	272		173
Net Derivative Liabilities After Deducting Amounts Not Offset in the Consolidated Balance Sheets	41		42
Derivative Credit Risk Valuation Adjustment, Derivative Assets	2		2
Risk Management Purposes
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	2,085	[1]	1,703	[1]
Fair Value of Gross Derivative Assets	182		199
Fair Value of Gross Derivative Liabilities	1		0
Risk Management Purposes | Designated as Hedging Instrument | Fair Value Hedging | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,550	[1]	1,450	[1]
Fair Value of Gross Derivative Assets	181		198
Fair Value of Gross Derivative Liabilities	0		0
Risk Management Purposes | Derivatives Used As Economic Hedges | Foreign Exchange Spot Forward And Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	535	[1]	253	[1]
Fair Value of Gross Derivative Assets	1		1
Fair Value of Gross Derivative Liabilities	1		0
Customer-Initiated And Other Activities
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	19,582	[1]	18,835	[1]
Fair Value of Gross Derivative Assets	335		301
Fair Value of Gross Derivative Liabilities	285		249
Customer-Initiated And Other Activities | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	11,962	[1]	11,697	[1]
Fair Value of Gross Derivative Assets	163		182
Fair Value of Gross Derivative Liabilities	115		133
Customer-Initiated And Other Activities | Interest Rate Caps And Floors Written
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	275	[1]	277	[1]
Fair Value of Gross Derivative Assets	0		0
Fair Value of Gross Derivative Liabilities	1		1
Customer-Initiated And Other Activities | Interest Rate Caps and Floors Purchased
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	275	[1]	277	[1]
Fair Value of Gross Derivative Assets	1		1
Fair Value of Gross Derivative Liabilities	0		0
Customer-Initiated And Other Activities | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	11,412	[1]	11,143	[1]
Fair Value of Gross Derivative Assets	162		181
Fair Value of Gross Derivative Liabilities	114		132
Customer-Initiated And Other Activities | Energy Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	5,578	[1]	5,374	[1]
Fair Value of Gross Derivative Assets	153		105
Fair Value of Gross Derivative Liabilities	151		102
Customer-Initiated And Other Activities | Energy Caps and Floors Written [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,427	[1]	1,325	[1]
Fair Value of Gross Derivative Assets	4		1
Fair Value of Gross Derivative Liabilities	53		48
Customer-Initiated And Other Activities | Energy Caps and Floors Purchased [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,427	[1]	1,325	[1]
Fair Value of Gross Derivative Assets	53		48
Fair Value of Gross Derivative Liabilities	4		1
Customer-Initiated And Other Activities | Energy Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	2,724	[1]	2,724	[1]
Fair Value of Gross Derivative Assets	96		56
Fair Value of Gross Derivative Liabilities	94		53
Customer-Initiated And Other Activities | Foreign Exchange Spot, Forwards, Options and Swaps
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	2,042	[1]	1,764	[1]
Fair Value of Gross Derivative Assets	19		14
Fair Value of Gross Derivative Liabilities	$ 19		$ 14

[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 totaled $2 million at both June 30, 2014 and December 31, 2013.