Investment Securities (Details) (USD $) In Millions	6 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Schedule of Available for Sale Securities by Type
Cost	$ 9,207	$ 13,937
Gross Unrealized Gains	469	444
Gross Unrealized Losses	(247)	(371)
Investment securities	9,429	14,010
U.S. States and Political Subdivisions Debt Securities [Member]
Schedule of Available for Sale Securities by Type
Cost	5,363	6,140
Gross Unrealized Gains	40	24
Gross Unrealized Losses	(246)	(367)
Investment securities	5,157	5,797
U.S. Government agency obligations [Member]
Schedule of Available for Sale Securities by Type
Cost	352	3,402
Gross Unrealized Gains	5	12
Gross Unrealized Losses	0	(1)
Investment securities	357	3,413
U.S. Government treasury obligations [Member]
Schedule of Available for Sale Securities by Type
Cost	1,935	2,450
Gross Unrealized Gains	8	6
Gross Unrealized Losses	0	0
Investment securities	1,943	2,456
Corporate debt securities [Member]
Schedule of Available for Sale Securities by Type
Cost	1,011	1,431
Gross Unrealized Gains	15	15
Gross Unrealized Losses	0	(1)
Investment securities	1,026	1,445
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available for Sale Securities by Type
Cost	277	272
Gross Unrealized Gains	9	6
Gross Unrealized Losses	(1)	(2)
Investment securities	285	276
Equity securities [Member]
Schedule of Available for Sale Securities by Type
Cost	98	98
Gross Unrealized Gains	386	377
Gross Unrealized Losses	0	0
Investment securities	484	475
Foreign government bonds and obligations [Member]
Schedule of Available for Sale Securities by Type
Cost	111	95
Gross Unrealized Gains	6	4
Gross Unrealized Losses	0	0
Investment securities	117	99
Availabe For Sale Securities Other [Member]
Schedule of Available for Sale Securities by Type
Cost	60	49
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities	$ 60	$ 49

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading. Such securities are reported at fair value, with unrealized gains and losses excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain or loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

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This item represents the gross unrealized losses for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized losses are the excess of the carrying value of the Available-for-sale Securities over their fair value as of the reporting date. Such gross unrealized losses are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding loss of an Available-for-sale Security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge, as should other than temporary declines in fair value below costs basis.

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