Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash and securities collateral placed with counterparties	$ 1,323	$ 1,448
Cash collateral received from counterparties	969	1,410
noncash collateral received	13	43
Derivative Asset, Fair Value, Gross Asset	4,874	5,701
Nontrading Derivative Assets	4,874	5,687
Trading Derivative Assets	0	14
Derivative Liability, Fair Value, Gross Liability	5,072	5,379
Nontrading Derivative Liabilities	5,072	5,367
Trading Derivative Liabilities		$ 12

Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624163-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph a

-Clause 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 205G

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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