Derivative Instruments Derivatives 2 - FV Gains and Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	$ (1,246)	$ 1,188		$ (2,531)	$ 1,750
Accrual of periodic settlements	4,904	5,667	[1]	9,642	11,971	[1]
Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(936)	691		(1,876)	1,122
Mortgage commitment derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(310)	497		(655)	628
Pay-fixed Swap [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(2,349)	8,313		(4,467)	10,903
Accrual of periodic settlements	(913)	(1,211)		(1,816)	(2,409)
Receive-fixed Swap [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	1,639	(7,123)		3,104	(9,033)
Accrual of periodic settlements	642	1,012		1,333	1,994
Basis Swap [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	8	(45)		43	(72)
Foreign Currency Swap [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	17	(63)		38	(133)
Pay-fixed Swaption [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	62	(468)		(37)	(451)
Receive-fixed Swaption [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	(59)	247		(101)	268
Other [Member] | Risk Management Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative fair value gains (losses), net	3	11		0	21
Accrual of periodic settlements	$ 14	$ 18		$ 27	$ 34

[1] Certain prior period amounts have been reclassified to conform with the current period presentation.