Derivative And Credit-Related Financial Instruments (Schedule Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	$ 20,538	[1]	$ 21,781	[1]
Fair Value of Gross Derivative Assets	500		750
Fair Value of Gross Derivative Liabilities	249		408
Derivative Asset, Netting Adjustment - Offsetting Liabilities	(187)		(279)
Derivative Liability, Netting Adjustment - Offsetting Assets	(187)		(279)
Derivative Asset, Netting Adjustment - Cash Collateral Received	(2)		(11)
Derivative Liability, Netting Adjustment - Cash Collateral Posted	(10)		0
Net Derivative Asset Included In Consolidated Balance Sheet	311	[2]	460	[2]
Net Derivative Liabilities Included In Consolidated Balance Sheet	52	[2]	129	[2]
Derivative Asset, Securities Pledged As Collateral	(138)		(180)
Derivative Liability, Securities Pledged As Collateral	(10)		(56)
Net Derivative Asset After Deducting Amounts Not Offset In Consolidated Balance Sheet	173		280
Net Derivative Liability After Deducting Amounts Not Offset In Consolidated Balance Sheet	42		73
Derivative Credit Risk Valuation Adjustment, Derivative Assets	2		4
Risk Management Purposes [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,703	[1]	1,925	[1]
Fair Value of Gross Derivative Assets	199		291
Fair Value of Gross Derivative Liabilities	0		0
Risk Management Purposes [Member] | Designated as Hedging Instrument [Member] | Fair Value Hedging [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,450	[1]	1,450	[1]
Fair Value of Gross Derivative Assets	198		290
Fair Value of Gross Derivative Liabilities	0		0
Risk Management Purposes [Member] | Derivatives Used As Economic Hedges [Member] | Foreign Exchange Spot Forward And Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	253	[1]	475	[1]
Fair Value of Gross Derivative Assets	1		1
Fair Value of Gross Derivative Liabilities	0		0
Customer-Initiated And Other Activities [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	18,835	[1]	19,856	[1]
Fair Value of Gross Derivative Assets	301		459
Fair Value of Gross Derivative Liabilities	249		408
Customer-Initiated And Other Activities [Member] | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	11,697	[1]	12,042	[1]
Fair Value of Gross Derivative Assets	182		266
Fair Value of Gross Derivative Liabilities	133		218
Customer-Initiated And Other Activities [Member] | Interest Rate Caps And Floors Written [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	277	[1]	545	[1]
Fair Value of Gross Derivative Assets	0		0
Fair Value of Gross Derivative Liabilities	1		3
Customer-Initiated And Other Activities [Member] | Interest Rate Caps and Floors Purchased [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	277	[1]	545	[1]
Fair Value of Gross Derivative Assets	1		3
Fair Value of Gross Derivative Liabilities	0		0
Customer-Initiated And Other Activities [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	11,143	[1]	10,952	[1]
Fair Value of Gross Derivative Assets	181		263
Fair Value of Gross Derivative Liabilities	132		215
Customer-Initiated And Other Activities [Member] | Energy Contracts
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	5,374	[1]	5,561	[1]
Fair Value of Gross Derivative Assets	105		173
Fair Value of Gross Derivative Liabilities	102		172
Customer-Initiated And Other Activities [Member] | Energy Caps and Floors Written [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,325	[1]	1,873	[1]
Fair Value of Gross Derivative Assets	1		0
Fair Value of Gross Derivative Liabilities	48		112
Customer-Initiated And Other Activities [Member] | Energy Caps and Floors Purchased [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,325	[1]	1,873	[1]
Fair Value of Gross Derivative Assets	48		112
Fair Value of Gross Derivative Liabilities	1		0
Customer-Initiated And Other Activities [Member] | Energy Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	2,724	[1]	1,815	[1]
Fair Value of Gross Derivative Assets	56		61
Fair Value of Gross Derivative Liabilities	53		60
Customer-Initiated And Other Activities [Member] | Foreign Exchange Spot, Forwards, Options and Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional/Contract Amount	1,764	[1]	2,253	[1]
Fair Value of Gross Derivative Assets	14		20
Fair Value of Gross Derivative Liabilities	$ 14		$ 18

[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 $2 million and $4 million at December 31, 2013 and 2012, respectively.