Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Derivative Financial Instruments, Assets [Member]
Derivative Position of the company
Derivative Asset, Fair Value	$ 1,941	$ 1,913
Netting (a)	(321)	(294)
Derivative Assets	1,620	1,619
Derivative Financial Instruments, Liabilities [Member]
Derivative Position of the company
Fair Value, Liabilities	2,387	2,554
Netting (a)	(875)	(1,889)
Derivative Liabilities	$ 1,512	$ 665

Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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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.

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- Definition

Fair value of derivative liability, 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.

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- Definition

Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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