Fair Value Disclosures (Narrative) (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010	Jun. 30, 2011		Jun. 30, 2010		Dec. 31, 2010
Valuation adjustment related to the mortgage servicing assets	$ (60,000,000)		$ (232,000,000)	$ (20,000,000)		$ (227,000,000)
Realization of the expected net servicing cash flows	(29,000,000)		(31,000,000)	(57,000,000)	[1]	(62,000,000)	[1]
Derivative instruments related to MSR losses	(59,000,000)		(241,000,000)
Assets measured at fair value	23,888,000,000	[2]		23,888,000,000	[2]			29,007,000,000	[2]
Assets measured at fair value on a nonrecurring basis, impaired loans	776,000,000			776,000,000				705,000,000
Assets measured at fair value on a nonrecurring basis, foreclosed real estate	1,200,000,000			1,200,000,000				1,300,000,000
Losses related to write-downs of impaired loans	119,000,000		256,000,000	222,000,000		415,000,000
Losses related to write-downs of foreclosed real estate	85,000,000		193,000,000	171,000,000		318,000,000
Loans held for sale, carried at the lower of cost or market	116,000,000			116,000,000
Income statement effect of changes in fair value produced gains				20,000,000		240,000,000
Fair Value, Measurements, Nonrecurring [Member]
Assets measured at fair value	$ 2,000,000,000			$ 2,000,000,000				$ 2,000,000,000

[1] Represents the realization of expected net servicing cash flows, expected borrower payments and the passage of time.

[2] Excludes loans held for sale carried at the lower of cost or market.