Derivative Financial Instruments (Details 8) (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 derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	$ 110	$ 241	$ 403	$ 312
Other income [Member] | Interest rate contracts [Member]
Gains and losses on derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	195	146	105	135
Other income [Member] | Foreign exchange contracts [Member]
Gains and losses on derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	36	6	50	(1)
Other income [Member] | Equity contracts [Member]
Gains and losses on derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	(118)	89	246	192
Other income [Member] | Credit contracts [Member]
Gains and losses on derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	(1)	(1)	(3)	(3)
Residential mortgage banking revenue [Member] | Interest rate contracts [Member]
Gains and losses on derivative instruments held for other purposes
Derivative instruments, gain (loss) recognized in income net	$ (2)	$ 1	$ 5	$ (11)