Fair Value (Fair Value Option - Fair Value and Principal Balances) (Details) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Customer Resale Agreements [Member]
Fair value of items for which fair value option was elected	$ 813		$ 866
Aggregate unpaid principal balance of items for which fair value option was elected	761		806
Difference between fair value and aggregate unpaid principal balance	52		60
Commercial Mortgage Loans Held for Sale [Member]
Fair value of items for which fair value option was elected	856	[1]	877	[1]
Aggregate unpaid principal balance of items for which fair value option was elected	1,006	[1]	1,039	[1]
Difference between fair value and aggregate unpaid principal balance	(150)	[1]	(162)	[1]
Commercial Mortgage Loans Held for Sale [Member] | Performing Loans [Member]
Fair value of items for which fair value option was elected	839	[1]	847	[1]
Aggregate unpaid principal balance of items for which fair value option was elected	981	[1]	990	[1]
Difference between fair value and aggregate unpaid principal balance	(142)	[1]	(143)	[1]
Commercial Mortgage Loans Held for Sale [Member] | Nonaccrual Loans [Member]
Fair value of items for which fair value option was elected	17	[1]	30	[1]
Aggregate unpaid principal balance of items for which fair value option was elected	25	[1]	49	[1]
Difference between fair value and aggregate unpaid principal balance	(8)	[1]	(19)	[1]
Residential Mortgage Loans Held For Sale [Member]
Fair value of items for which fair value option was elected	1,351		1,878
Aggregate unpaid principal balance of items for which fair value option was elected	1,311		1,882
Difference between fair value and aggregate unpaid principal balance	40		(4)
Performing Loans [Member] | Residential Mortgage Loans Held For Sale [Member]
Fair value of items for which fair value option was elected	1,333		1,844
Aggregate unpaid principal balance of items for which fair value option was elected	1,286		1,839
Difference between fair value and aggregate unpaid principal balance	47		5
Loans 90 Days Or More Past Due [Member] | Residential Mortgage Loans Held For Sale [Member]
Fair value of items for which fair value option was elected	16		33
Aggregate unpaid principal balance of items for which fair value option was elected	21		41
Difference between fair value and aggregate unpaid principal balance	(5)		(8)
Nonaccrual Loans [Member] | Residential Mortgage Loans Held For Sale [Member]
Fair value of items for which fair value option was elected	2		1
Aggregate unpaid principal balance of items for which fair value option was elected	4		2
Difference between fair value and aggregate unpaid principal balance	(2)		(1)
Residential Mortgage Loans Portfolio [Member]
Fair value of items for which fair value option was elected	239		116
Aggregate unpaid principal balance of items for which fair value option was elected	368		142
Difference between fair value and aggregate unpaid principal balance	(129)		(26)
Residential Mortgage Loans Portfolio [Member] | Performing Loans [Member]
Fair value of items for which fair value option was elected	63		36
Aggregate unpaid principal balance of items for which fair value option was elected	80		44
Difference between fair value and aggregate unpaid principal balance	(17)		(8)
Residential Mortgage Loans Portfolio [Member] | Loans 90 Days Or More Past Due [Member]
Fair value of items for which fair value option was elected	85		64
Aggregate unpaid principal balance of items for which fair value option was elected	92		67
Difference between fair value and aggregate unpaid principal balance	(7)		(3)
Residential Mortgage Loans Portfolio [Member] | Nonaccrual Loans [Member]
Fair value of items for which fair value option was elected	91		16
Aggregate unpaid principal balance of items for which fair value option was elected	196		31
Difference between fair value and aggregate unpaid principal balance	(105)		(15)
Residential Mortgage Backed Agency Securities [Member]
Fair value of items for which fair value option was elected	1,023	[2]
Aggregate unpaid principal balance of items for which fair value option was elected	852	[2]
Difference between fair value and aggregate unpaid principal balance	$ 171	[2]

[1] There were no loans 90 days or more past due within this category at June 30, 2011 or December 31, 2010.

[2] These residential mortgage-backed agency hybrid securities are carried as trading securities.