Securities Available for Sale, Other-Than-Temporary Impaired Debt Securities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Securities available for sale	$ 541	$ 692	$ 1,094
Total recorded directly to OCI for non-credit-related impairment	(74)	(172)	1,340
Total OTTI losses recorded on debt securities	349	500	2,352
Debt Securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Securities available for sale	423	672	1,012
Credit-related OTTI [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Securities available for sale	422	400	982
Other than temporary impairment on securities we intend to sell [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Securities available for sale	1	272	30
US States and Political Subdivisions [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total recorded directly to OCI for non-credit-related impairment	(1)	(4)	3
Residential [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Securities available for sale	252	175	591
Total recorded directly to OCI for non-credit-related impairment	(171)	(326)	1,124
Commercial [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total recorded directly to OCI for non-credit-related impairment	105	138	179
Collateralized debt obligations [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total recorded directly to OCI for non-credit-related impairment	4	54	20
Other Debt Securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total recorded directly to OCI for non-credit-related impairment	(13)	(33)	16
Corporate debt securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total recorded directly to OCI for non-credit-related impairment	$ 2	$ (1)	$ (2)

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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The amount of other than temporary impairment (OTTI) loss on a debt security, categorized as Available-for-sale, related to factors other than credit losses when the entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis. This amount, which includes the portion attributable to the noncontrolling interest, if any, is a portion of the deduction from the total impairment losses of investments (before taxes) presented on the income statement; this amount is also referred to as the amount incurred by the reporting entity or the consolidated entity.

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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