Investment Securities (Details 7) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012
Available-for-sale
Fair Value Less Than 12 Months	$ 3,110
Unrealized Losses Less Than 12 Months	(10)
Fair Value 12 Months or Greater	2,813
Fair Value Total	5,923
Unrealized Losses 12 Months or Greater	(431)
Unrealized Losses Total	(441)
Held-to-maturity
Unrealized Losses Less Than 12 Months	(8)
Fair Value Less Than 12 Months	3,745
Fair Value 12 Months or Greater	138
Unrealized Losses 12 Months or Greater	(29)
Fair Value Total	3,883
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(37)
Collateralized Debt/Loan Obligations [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	0
Fair Value 12 Months or Greater	4
Unrealized Losses 12 Months or Greater	0
Fair Value Total	4
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	0
Other [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	1
Fair Value 12 Months or Greater	12
Unrealized Losses 12 Months or Greater	(6)
Fair Value Total	13
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(6)
Obligations of state and political subdivisions [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	0
Fair Value 12 Months or Greater	5
Unrealized Losses 12 Months or Greater	0
Fair Value Total	5
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	0
Other Debt Securities [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	0
Fair Value 12 Months or Greater	98
Unrealized Losses 12 Months or Greater	(22)
Fair Value Total	98
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(22)
Other Investments [Member]
Available-for-sale
Fair Value Less Than 12 Months	1
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	3
Fair Value Total	4
Unrealized Losses 12 Months or Greater	0
Unrealized Losses Total	0
U.S. Treasury and agencies [Member]
Available-for-sale
Fair Value Less Than 12 Months	2
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	0
Fair Value Total	2
Unrealized Losses 12 Months or Greater	0
Unrealized Losses Total	0
Obligations of state and political subdivisions [Member]
Available-for-sale
Fair Value Less Than 12 Months	29
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	126
Fair Value Total	155
Unrealized Losses 12 Months or Greater	(3)
Unrealized Losses Total	(3)
Obligations of foreign governments [Member]
Available-for-sale
Fair Value Less Than 12 Months	6
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	0
Fair Value Total	6
Unrealized Losses 12 Months or Greater	0
Unrealized Losses Total	0
Collateralized Debt/Loan Obligations [Member]
Available-for-sale
Fair Value Less Than 12 Months	21
Unrealized Losses Less Than 12 Months	(2)
Fair Value 12 Months or Greater	12
Fair Value Total	33
Unrealized Losses 12 Months or Greater	(3)
Unrealized Losses Total	(5)
Other [Member]
Available-for-sale
Fair Value Less Than 12 Months	20
Unrealized Losses Less Than 12 Months	(2)
Fair Value 12 Months or Greater	53
Fair Value Total	73
Unrealized Losses 12 Months or Greater	(11)
Unrealized Losses Total	(13)
Corporate Debt Securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	77
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	639
Fair Value Total	716
Unrealized Losses 12 Months or Greater	(120)
Unrealized Losses Total	(120)
Perpetual preferred securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	22
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	133
Fair Value Total	155
Unrealized Losses 12 Months or Greater	(25)
Unrealized Losses Total	(25)
Agency [Member] | Residential [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	(8)
Fair Value Less Than 12 Months	3,744
Fair Value 12 Months or Greater	16
Unrealized Losses 12 Months or Greater	0
Fair Value Total	3,760
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(8)
Agency [Member] | Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	2,893
Unrealized Losses Less Than 12 Months	(1)
Fair Value 12 Months or Greater	528
Fair Value Total	3,421
Unrealized Losses 12 Months or Greater	(1)
Unrealized Losses Total	(2)
Non-agency [Member] | Commercial Non-Agency Mortgage Backed Securities [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	0
Fair Value 12 Months or Greater	2
Unrealized Losses 12 Months or Greater	(1)
Fair Value Total	2
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	(1)
Non-agency [Member] | Commercial Non-Agency Mortgage Backed Securities [Member]
Available-for-sale
Fair Value Less Than 12 Months	19
Unrealized Losses Less Than 12 Months	(3)
Fair Value 12 Months or Greater	1
Fair Value Total	20
Unrealized Losses 12 Months or Greater	0
Unrealized Losses Total	(3)
Residential Non-agency Prime [Member] | Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	12
Unrealized Losses Less Than 12 Months	0
Fair Value 12 Months or Greater	650
Fair Value Total	662
Unrealized Losses 12 Months or Greater	(77)
Unrealized Losses Total	(77)
Residential Non-agency Non-Prime [Member] | Residential [Member]
Held-to-maturity
Unrealized Losses Less Than 12 Months	0
Fair Value Less Than 12 Months	0
Fair Value 12 Months or Greater	1
Unrealized Losses 12 Months or Greater	0
Fair Value Total	1
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	0
Residential Non-agency Non-Prime [Member] | Residential [Member]
Available-for-sale
Fair Value Less Than 12 Months	8
Unrealized Losses Less Than 12 Months	(2)
Fair Value 12 Months or Greater	668
Fair Value Total	676
Unrealized Losses 12 Months or Greater	(191)
Unrealized Losses Total	$ (193)