Fair Value Option (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Components of gain on instruments at fair value and related derivatives
Interest rate component	$ (49)	$ (245)	$ (394)	$ (329)
Credit risk component	77	44	(79)	61
Total mark-to-market on financial instruments designated at fair value	28	(201)	(473)	(268)
Net realized gains on the financial instrument		(2)	(1)	2
Mark-to-market on the related derivatives	98	228	372	295
Net realized gain (losses) on the related long-term debt derivatives	15	15	31	32
Gain (loss) on instruments designated at fair value and related derivatives	141	40	(71)	61
Loans [Member]
Components of gain on instruments at fair value and related derivatives
Interest rate component		(1)	1	(2)
Credit risk component	2	(15)	34	16
Total mark-to-market on financial instruments designated at fair value	2	(16)	35	14
Net realized gains on the financial instrument		(2)	(1)	2
Mark-to-market on the related derivatives		(1)		(1)
Gain (loss) on instruments designated at fair value and related derivatives	2	(19)	34	15
Long-Term Debt [Member]
Components of gain on instruments at fair value and related derivatives
Interest rate component	(123)	(52)	(40)	(16)
Credit risk component	131	36	(90)	7
Total mark-to-market on financial instruments designated at fair value	8	(16)	(130)	(9)
Mark-to-market on the related derivatives	142	55	27	16
Net realized gain (losses) on the related long-term debt derivatives	15	15	31	32
Gain (loss) on instruments designated at fair value and related derivatives	165	54	(72)	39
Hybrid Instruments [Member]
Components of gain on instruments at fair value and related derivatives
Interest rate component	74	(192)	(355)	(311)
Credit risk component	(56)	23	(23)	38
Total mark-to-market on financial instruments designated at fair value	18	(169)	(378)	(273)
Mark-to-market on the related derivatives	(44)	174	345	280
Gain (loss) on instruments designated at fair value and related derivatives	$ (26)	$ 5	$ (33)	$ 7