Securities (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Available for Sale Securities (Unrealized Loss Position)
Fair value, less than 12 months	$ 4	$ 4,028
Fair value, 12 months or longer	0
Fair Value	4	4,028
Gross unrealized losses, less than 12 months	0	87
Gross unrealized losses, 12 months or longer	0
Gross unrealized losses, Total	0	87
Collateralized Mortgage Backed Securities [Member]
Available for Sale Securities (Unrealized Loss Position)
Fair value, less than 12 months	1	4,028
Fair value, 12 months or longer	0
Fair Value	1	4,028
Gross unrealized losses, less than 12 months	0	87
Gross unrealized losses, 12 months or longer	0
Gross unrealized losses, Total	0	87
Other Debt Securities [Member]
Available for Sale Securities (Unrealized Loss Position)
Held-to-maturity Securities, Collateralized mortgage obligations Fair Value less than 12 months	3
Held-to-maturity Securities, Collateralized mortgage obligations Fair Value 12 months or longer	0
Held-to-maturity Securities, Collateralized mortgage obligations Fair Value	3
Held-to-maturity Securities, Gross unrealized losses, less than 12 months	0
Held-to-maturity Securities, Gross unrealized losses, 12 months or longer	0
Held-to-maturity Securities, Gross unrealized losses	$ 0

This item represents the excess of [amortized] cost over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 21

-Subparagraph a(2)

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 17

-Subparagraph a(1)

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