Investment Securities (Details 7) (USD $) In Millions	Sep. 30, 2011
Available-for-sale
Fair Value Less Than 12 Months	$ 12,509
Unrealized Losses Less Than 12 Months	(67)
Fair Value 12 Months or Greater	3,615
Unrealized Losses 12 Months or Greater	(579)
Fair Value Total	16,124
Unrealized Losses Total	(646)
Held-to-maturity
Fair Value Less Than 12 Months	1,769
Unrealized Losses Less Than 12 Months	(4)
Fair Value 12 Months or Greater	155
Unrealized Losses 12 Months or Greater	(42)
Fair Value Total	1,924
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(46)
Residential [Member] \| Agency [Member]
Held-to-maturity
Fair Value Less Than 12 Months	1,769
Unrealized Losses Less Than 12 Months	(4)
Fair Value Total	1,769
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(4)
Agency [Member] \| Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	10,936
Unrealized Losses Less Than 12 Months	(21)
Fair Value 12 Months or Greater	141
Fair Value Total	11,077
Unrealized Losses Total	(21)
Commercial Mortgage Backed Securities [Member] \| Non-agency [Member]
Held-to-maturity
Fair Value 12 Months or Greater	3
Unrealized Losses 12 Months or Greater	(2)
Fair Value Total	3
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(2)
Non-agency [Member] \| Commercial Mortgage Backed Securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	22
Fair Value Total	22
Non-agency Prime [Member] \| Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	103
Unrealized Losses Less Than 12 Months	(4)
Fair Value 12 Months or Greater	689
Unrealized Losses 12 Months or Greater	(93)
Fair Value Total	792
Unrealized Losses Total	(97)
Residential [Member] \| Non-agency Non-prime [Member]
Held-to-maturity
Fair Value 12 Months or Greater	1
Unrealized Losses 12 Months or Greater	(1)
Fair Value Total	1
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(1)
Non-agency Non-prime [Member] \| Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	59
Unrealized Losses Less Than 12 Months	(6)
Fair Value 12 Months or Greater	699
Unrealized Losses 12 Months or Greater	(230)
Fair Value Total	758
Unrealized Losses Total	(236)
Other Investments [Member]
Available-for-sale
Fair Value Less Than 12 Months	1
Fair Value 12 Months or Greater	3
Unrealized Losses 12 Months or Greater	(1)
Fair Value Total	4
Unrealized Losses Total	(1)
U.S. Treasury and agency [Member]
Available-for-sale
Fair Value Less Than 12 Months	208
Fair Value Total	208
Obligations of state and political subdivisions [Member]
Held-to-maturity
Fair Value 12 Months or Greater	9
Unrealized Losses 12 Months or Greater	(1)
Fair Value Total	9
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(1)
Obligations of state and political subdivisions [Member]
Available-for-sale
Fair Value Less Than 12 Months	457
Unrealized Losses Less Than 12 Months	(3)
Fair Value 12 Months or Greater	1,087
Unrealized Losses 12 Months or Greater	(37)
Fair Value Total	1,544
Unrealized Losses Total	(40)
Collateralized Debt Obligations [Member]
Held-to-maturity
Fair Value 12 Months or Greater	31
Unrealized Losses 12 Months or Greater	(3)
Fair Value Total	31
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(3)
Collateralized Debt Obligations [Member]
Available-for-sale
Fair Value Less Than 12 Months	16
Unrealized Losses Less Than 12 Months	(3)
Fair Value 12 Months or Greater	7
Unrealized Losses 12 Months or Greater	(2)
Fair Value Total	23
Unrealized Losses Total	(5)
Other [Member]
Held-to-maturity
Fair Value 12 Months or Greater	15
Unrealized Losses 12 Months or Greater	(7)
Fair Value Total	15
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(7)
Other [Member]
Available-for-sale
Fair Value Less Than 12 Months	460
Unrealized Losses Less Than 12 Months	(12)
Fair Value 12 Months or Greater	117
Unrealized Losses 12 Months or Greater	(14)
Fair Value Total	577
Unrealized Losses Total	(26)
Corporate Debt Securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	186
Unrealized Losses Less Than 12 Months	(4)
Fair Value 12 Months or Greater	641
Unrealized Losses 12 Months or Greater	(136)
Fair Value Total	827
Unrealized Losses Total	(140)
Perpetual preferred securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	61
Unrealized Losses Less Than 12 Months	(14)
Fair Value 12 Months or Greater	231
Unrealized Losses 12 Months or Greater	(66)
Fair Value Total	292
Unrealized Losses Total	(80)
Other Debt Securities [Member]
Held-to-maturity
Fair Value 12 Months or Greater	96
Unrealized Losses 12 Months or Greater	(28)
Fair Value Total	96
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	$ (28)

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