Securities (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012 Securities	Dec. 31, 2011 Securities
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	52	45
Securities available-for-sale gross unrealized losses one year or loss	$ (44)	$ (105)
Securities available-for-sale aggregate fair value of investment one year or loss	20,077	10,107
Number of Securities available for sale greater than one year	53	54
Securities available-for-sale gross unrealized losses greater than one year	(184)	(245)
Securities available-for-sale aggregate fair value of investment greater than one year	3,056	3,017
Number of securities held-to-maturity in one year or less	51	678
Securities held-to-maturity gross unrealized losses one year or loss
Securities held-to-maturity aggregate fair value of investment one year or loss	4	2
Securities held-to-maturity greater than one year	1,072	482
Securities held-to-maturity gross unrealized losses greater than one year	(1)	(1)
Securities held-to-maturity aggregate fair value of investment greater than one year	10	17
US Treasury Securities [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	15	5
Securities available-for-sale gross unrealized losses one year or loss	(11)	(1)
Securities available-for-sale aggregate fair value of investment one year or loss	16,433	4,978
Number of Securities available for sale greater than one year	8	12
Securities available-for-sale gross unrealized losses greater than one year	(39)	(120)
Securities available-for-sale aggregate fair value of investment greater than one year	648	2,592
U.S. Government sponsored enterprises [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	7	6
Securities available-for-sale gross unrealized losses one year or loss	(1)
Securities available-for-sale aggregate fair value of investment one year or loss	252	8
Number of Securities available for sale greater than one year	16	15
Securities available-for-sale aggregate fair value of investment greater than one year	8	9
Number of securities held-to-maturity in one year or less	13	47
Securities held-to-maturity gross unrealized losses one year or loss
Securities held-to-maturity greater than one year	54	11
Mortgage-backed securities, US Government agency issued or guaranteed [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	11	14
Securities available-for-sale gross unrealized losses one year or loss	(1)	(6)
Securities available-for-sale aggregate fair value of investment one year or loss	1,231	833
Number of Securities available for sale greater than one year	1	2
Securities available-for-sale aggregate fair value of investment greater than one year	2	4
Number of securities held-to-maturity in one year or less	35	629
Securities held-to-maturity gross unrealized losses one year or loss
Securities held-to-maturity aggregate fair value of investment one year or loss		2
Securities held-to-maturity greater than one year	1,014	463
Securities held-to-maturity aggregate fair value of investment greater than one year	3	1
Obligations of U.S. states and political subdivisions [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	7	3
Securities available-for-sale gross unrealized losses one year or loss		(1)
Securities available-for-sale aggregate fair value of investment one year or loss	118	20
Number of Securities available for sale greater than one year	1	3
Securities available-for-sale aggregate fair value of investment greater than one year	7	25
Number of securities held-to-maturity in one year or less	2	2
Securities held-to-maturity gross unrealized losses one year or loss
Securities held-to-maturity greater than one year	2	4
Securities held-to-maturity aggregate fair value of investment greater than one year	1	2
Asset-backed Securities [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	6	2
Securities available-for-sale gross unrealized losses one year or loss	(1)
Securities available-for-sale aggregate fair value of investment one year or loss	74	45
Number of Securities available for sale greater than one year	20	22
Securities available-for-sale gross unrealized losses greater than one year	(105)	(125)
Securities available-for-sale aggregate fair value of investment greater than one year	359	387
Number of securities held-to-maturity in one year or less	1
Securities held-to-maturity gross unrealized losses one year or loss
Securities held-to-maturity aggregate fair value of investment one year or loss	4
Securities held-to-maturity greater than one year	2	4
Securities held-to-maturity gross unrealized losses greater than one year	(1)	(1)
Securities held-to-maturity aggregate fair value of investment greater than one year	6	14
Foreign debt securities [Member]
Gross unrealized losses and related fair values
Number of securities available for sale in one year or less	6	15
Securities available-for-sale gross unrealized losses one year or loss	(30)	(97)
Securities available-for-sale aggregate fair value of investment one year or loss	1,969	4,223
Number of Securities available for sale greater than one year	6
Securities available-for-sale gross unrealized losses greater than one year	(40)
Securities available-for-sale aggregate fair value of investment greater than one year	$ 2,032
Equity securities [Member]
Gross unrealized losses and related fair values
Number of Securities available for sale greater than one year	1

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