Derivative Financial Instruments (Details 2) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	$ 189	$ (1,003)	$ 805	$ (2,180)
Realized Gains (Losses) on derivative and hedging activities, net	(170)	(227)	(355)	(432)
Unrealized Gain (Loss) on Hedged Item	(529)	1,325	(1,202)	2,625
Unrealized Gain Loss On Derivatives, Total	189	(1,003)	805	(2,180)
Realized gains (losses) on derivative and hedging activities, net, total	25	(32)	30	(31)
Unrealized Gain Loss On Hedged Item, Total	(529)	1,325	(1,202)	2,625
Derivative Gain Loss On Derivative Net, Total	(315)	290	(367)	414
Total Gain (Loss)	(510)	95	(752)	13
Less: realized gains recorded in interest expense	195	195	385	401
Other Contract [Member] | Trading Hedging [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	20	12	23	6
Realized Gains (Losses) on derivative and hedging activities, net	13	(1)	12	(2)
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	33	11	35	4
Fair Value [Member] | Cross currency interest rate swaps [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	173	(1,733)	874	(3,081)
Realized Gains (Losses) on derivative and hedging activities, net	83	81	159	182
Unrealized Gain (Loss) on Hedged Item	(299)	1,800	(1,177)	3,163
Total Gain (Loss)	(43)	148	(144)	264
Cross currency interest rate swaps [Member] | Trading Hedging [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	16	33	(1)	26
Realized Gains (Losses) on derivative and hedging activities, net	2	2	4	3
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	18	35	3	29
Cash Flow [Member] | Interest rate swaps [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives		1	(2)
Realized Gains (Losses) on derivative and hedging activities, net	(9)	(15)	(23)	(30)
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	(9)	(14)	(25)	(30)
Fair Value [Member] | Interest rate swaps [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	203	437	5	492
Realized Gains (Losses) on derivative and hedging activities, net	121	129	249	249
Unrealized Gain (Loss) on Hedged Item	(230)	(475)	(25)	(538)
Total Gain (Loss)	94	91	229	203
Interest rate swaps [Member] | Trading Hedging [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	54	289	32	400
Realized Gains (Losses) on derivative and hedging activities, net	17	(6)	57
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	71	283	89	400
Floor Income contracts [Member] | Trading Hedging [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	(277)	(42)	(126)	(23)
Realized Gains (Losses) on derivative and hedging activities, net	(202)	(222)	(428)	(433)
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	(479)	(264)	(554)	(456)
Cash Flow [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives		1	(2)
Realized Gains (Losses) on derivative and hedging activities, net	(9)	(15)	(23)	(30)
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	(9)	(14)	(25)	(30)
Fair Value [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	376	(1,296)	879	(2,589)
Realized Gains (Losses) on derivative and hedging activities, net	204	210	408	431
Unrealized Gain (Loss) on Hedged Item	(529)	1,325	(1,202)	2,625
Total Gain (Loss)	51	239	85	467
Trading Hedging [Member]
Impact of Derivatives on Consolidated Statements of Income
Unrealized Gain (Loss) on Derivatives	(187)	292	(72)	409
Realized Gains (Losses) on derivative and hedging activities, net	(170)	(227)	(355)	(432)
Unrealized Gain (Loss) on Hedged Item			0
Total Gain (Loss)	$ (357)	$ 65	$ (427)	$ (23)