Fair Values (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Investment securities:
Equity securities	$ 371	$ 360
Debt securities and other	6,308	6,787
Derivatives	1,070	1,516
Total assets	7,749	8,663
Level 1 [Member]
Investment securities:
Equity securities	371	360
Debt securities and other	338	340
Derivatives	0	0
Total assets	709	700
Level 2 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	5,970	6,447
Derivatives	1,070	1,516
Total assets	7,040	7,963
Level 3 [Member]
Investment securities:
Total assets	$ 0	$ 0

For an unclassified balance sheet, this item represents equity securities categorized neither as held-to-maturity nor trading.

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

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+ Details