Securities Available for Sale, Other-Than-Temporary Impaired Debt Securities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	$ 76	$ 82	$ 114	$ 133
Total changes to OCI for non-credit-related OTTI	(7)	(30)	(56)	(45)
Total OTTI losses (gains) recorded on debt securities	64	47	49	82
Debt Securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	71	77	105	127
Total changes to OCI for non-credit-related OTTI	(7)	(30)	(56)	(45)
Total OTTI losses (gains) recorded on debt securities	64	47	49	82
Debt Securities [Member] \| Credit-related OTTI [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	33	74	56	124
Debt Securities [Member] \| Intent-to-sell OTTI [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	38	3	49	3
US States and Political Subdivisions [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	0	9	0	9
Total changes to OCI for non-credit-related OTTI	0	(7)	0	(7)
Residential [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	22	34	37	48
Total changes to OCI for non-credit-related OTTI	(7)	(54)	(16)	(63)
Commercial [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	26	3	41	33
Total changes to OCI for non-credit-related OTTI	0	0	(41)	(6)
Collateralized loan and other debt obligations [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	0	1	0	1
Total changes to OCI for non-credit-related OTTI	0	1	(1)	1
Other Debt Securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	22	27	24	32
Total changes to OCI for non-credit-related OTTI	0	30	2	31
Corporate debt securities [Member]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract]
Total OTTI recorded as part of gross realized losses	0	3	2	4
Total changes to OCI for non-credit-related OTTI	$ 0	$ 0	$ 0	$ (1)

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.

+ References+ Details

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.

+ References+ Details