Derivative Financial Instruments (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	$ (633)	$ (376)	$ (390)	$ (333)
Interest Income (Expense) [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	(52)	(7)	(111)	(9)
Gain (Loss) on Hedged Items	147	167	311	281
Interest Income (Expense) [Member] | Interest rate contracts / AFS securities [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	(39)	(13)	(84)	(22)
Gain (Loss) on Hedged Items	162	187	341	319
Interest Income (Expense) [Member] | Interest rate contracts / commercial loans [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative		(6)		(11)
Interest Income (Expense) [Member] | Interest rate contracts / subordinated debt [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	(13)	12	(27)	24
Gain (Loss) on Hedged Items	(15)	(20)	(30)	(38)
Other income [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	(581)	(369)	(279)	(324)
Gain (Loss) on Hedged Items	551	358	259	323
Other income [Member] | Interest rate contracts / AFS securities [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	(582)	(370)	(285)	(318)
Gain (Loss) on Hedged Items	552	367	265	320
Other income [Member] | Interest rate contracts / commercial loans [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative				1
Gain (Loss) on Hedged Items		(1)		(2)
Other income [Member] | Interest rate contracts / subordinated debt [Member]
Gains and losses on the hedged items in fair value hedges
Gain (Loss) on Derivative	1	1	6	(7)
Gain (Loss) on Hedged Items	$ (1)	$ (8)	$ (6)	$ 5