Variable Interest Entities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Variable Interest Entities [Member]	Dec. 31, 2010 Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Carrying amounts of assets	$ 26,873	$ 32,279	$ 25,701	$ 10,900	$ 14,100
Carrying amount of liabilities	25,150	29,433		9,900	13,100
Other net realized gains (losses) on initial consolidation				16	76
Net realized gains related to deconsolidation	$ 271

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The amount of the gain (loss) recognized by the parent and included in its attributable portion of net income for the period due to deconsolidation of a subsidiary or derecognition of a group of assets. The gain (loss) recognized and included in the net income attributable to the parent for the period is generally computed as the difference between: (a) the aggregate of: (1) the fair value of any consideration received; (2) the fair value of any retained noncontrolling investment in the former subsidiary at the date the subsidiary was deconsolidated; and (3) the carrying amount of any noncontrolling interest in the former subsidiary (including any accumulated other comprehensive income attributable to the noncontrolling interest) at the date the subsidiary was deconsolidated and (b) the carrying amount of the former subsidiary's assets and liabilities.

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