Fair Value Measurements (Assets And Liabilities Recorded At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	$ 9,534	[1]	$ 9,307	[1]
Derivative assets	517		500
Derivative liabilities	93	[2]	52	[2]
U.S. Treasury and Other U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	65		45
Residential Mortgage-Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	9,141	[3]	8,926	[3]
State And Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	23		22
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	55		56
Equity and Other Non-Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	250		258
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	103		108
Investment securities available-for-sale	9,534		9,307
Derivative assets	521		503
Total assets at fair value	10,158		9,918
Derivative liabilities	288		251
Deferred compensation plan liabilities	96		96
Total liabilities at fair value	384		347
Recurring [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	98		103
Investment securities available-for-sale	197		167
Derivative assets	0		0
Total assets at fair value	295		270
Derivative liabilities	0		0
Deferred compensation plan liabilities	96		96
Total liabilities at fair value	96		96
Recurring [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	5		5
Investment securities available-for-sale	9,195		8,981
Derivative assets	517		500
Total assets at fair value	9,717		9,486
Derivative liabilities	286		249
Deferred compensation plan liabilities	0		0
Total liabilities at fair value	286		249
Recurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Investment securities available-for-sale	142		159
Derivative assets	4		3
Total assets at fair value	146		162
Derivative liabilities	2		2
Deferred compensation plan liabilities	0		0
Total liabilities at fair value	2		2
Recurring [Member] | Interest Rate Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	344		380
Derivative liabilities	115		133
Recurring [Member] | Interest Rate Contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Interest Rate Contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	344		380
Derivative liabilities	115		133
Recurring [Member] | Interest Rate Contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Energy Derivative Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	153		105
Derivative liabilities	151		102
Recurring [Member] | Energy Derivative Contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Energy Derivative Contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	153		105
Derivative liabilities	151		102
Recurring [Member] | Energy Derivative Contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Foreign Exchange Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20		15
Derivative liabilities	20		14
Recurring [Member] | Foreign Exchange Contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Foreign Exchange Contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20		15
Derivative liabilities	20		14
Recurring [Member] | Foreign Exchange Contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Derivative liabilities	0		0
Recurring [Member] | Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4		3
Recurring [Member] | Warrants | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Recurring [Member] | Warrants | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0		0
Recurring [Member] | Warrants | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4		3
Recurring [Member] | Other Derivative Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	2		2
Recurring [Member] | Other Derivative Liabilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0		0
Recurring [Member] | Other Derivative Liabilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0		0
Recurring [Member] | Other Derivative Liabilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	2		2
Recurring [Member] | Deferred Compensation Plan Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	96		96
Recurring [Member] | Deferred Compensation Plan Assets | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	96		96
Recurring [Member] | Deferred Compensation Plan Assets | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Recurring [Member] | Deferred Compensation Plan Assets | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Recurring [Member] | U.S. Treasury and Other U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	65		45
Recurring [Member] | U.S. Treasury and Other U.S. Government Agency Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	65		45
Recurring [Member] | U.S. Treasury and Other U.S. Government Agency Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0		0
Recurring [Member] | U.S. Treasury and Other U.S. Government Agency Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale	0		0
Recurring [Member] | Residential Mortgage-Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	3	[3]	2	[3]
Investment securities available-for-sale	9,141	[3]	8,926	[3]
Recurring [Member] | Residential Mortgage-Backed Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	[3]	0	[3]
Investment securities available-for-sale	0	[3]	0	[3]
Recurring [Member] | Residential Mortgage-Backed Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	3	[3]	2	[3]
Investment securities available-for-sale	9,141	[3]	8,926	[3]
Recurring [Member] | Residential Mortgage-Backed Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0	[3]	0	[3]
Investment securities available-for-sale	0	[3]	0	[3]
Recurring [Member] | State And Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1		3
Investment securities available-for-sale	23		22
Recurring [Member] | State And Municipal Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Investment securities available-for-sale	0		0
Recurring [Member] | State And Municipal Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1		3
Investment securities available-for-sale	0		0
Recurring [Member] | State And Municipal Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Recurring [Member] | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1
Investment securities available-for-sale	55		56
Recurring [Member] | Corporate Debt Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0
Investment securities available-for-sale	0		0
Recurring [Member] | Corporate Debt Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1
Investment securities available-for-sale	54		55
Recurring [Member] | Corporate Debt Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0
Investment securities available-for-sale	1	[4]	1	[4]
Recurring [Member] | Equity and Other Non-Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2		7
Investment securities available-for-sale	250		258
Recurring [Member] | Equity and Other Non-Debt Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2		7
Investment securities available-for-sale	132		122
Recurring [Member] | Equity and Other Non-Debt Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	0		0
Investment securities available-for-sale	0		0
Recurring [Member] | Equity and Other Non-Debt Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 0		$ 0

[1] Included auction-rate securities at amortized cost and fair value of $145 million and $142 million, respectively, as of June 30, 2014 and $169 million and $159 million, respectively, as of December 31, 2013.

[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.

[3] Residential mortgage-backed securities issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.

[4] Auction-rate securities.