Investment Securities (Rollforward of Cumulative OTTI Credit Losses Recognized in Earnings) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended							3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2011 Residential Mortgage-backed Non-agency [Member]	Jun. 30, 2010 Residential Mortgage-backed Non-agency [Member]	Jun. 30, 2011 Residential Mortgage-backed Non-agency [Member]	Jun. 30, 2010 Residential Mortgage-backed Non-agency [Member]	Jun. 30, 2011 Asset backed [Member]	Jun. 30, 2010 Asset backed [Member]	Jun. 30, 2011 Asset backed [Member]	Jun. 30, 2010 Asset backed [Member]	Jun. 30, 2011 Other Debt Securities [Member]	Mar. 31, 2011 Other Debt Securities [Member]	Jun. 30, 2010 Other Debt Securities [Member]	Mar. 31, 2010 Other Debt Securities [Member]	Dec. 31, 2009 Other Debt Securities [Member]	Jun. 30, 2011 Debt Securities [Member]	Jun. 30, 2010 Debt Securities [Member]	Jun. 30, 2011 Debt Securities [Member]	Jun. 30, 2010 Debt Securities [Member]	Jun. 30, 2010 Commercial Mortgage-backed Non-agency [Member]	Jun. 30, 2011 Commercial Mortgage-backed Non-agency [Member]	Jun. 30, 2010 Commercial Mortgage-backed Non-agency [Member]	Mar. 31, 2011 Commercial Mortgage-backed Non-agency [Member]
Beginning balance	$ (737)	$ (540)	$ (709)	$ (479)	$ (228)	$ (188)	$ (223)	$ (145)	$ (12)	$ (13)	$ (12)	$ (12)	$ (12)	$ (984)	$ (746)	$ (955)	$ (642)	$ (6)	$ (11)	$ (6)	$ (6)
Loss where impairment was not previously recognized		(14)	(3)	(26)	(3)	(6)	(3)	(11)	(1)					(3)	(23)	(7)	(40)	(3)		(3)
Additional loss where credit impairment was previously recognized	(35)	(67)	(60)	(128)	(1)	(4)	(6)	(42)						(36)	(71)	(66)	(170)
Reduction due to credit impaired securities sold	11		11	12										11		16	12		5
Ending balance	$ (761)	$ (621)	$ (761)	$ (621)	$ (232)	$ (198)	$ (232)	$ (198)	$ (13)	$ (13)	$ (12)	$ (12)	$ (12)	$ (1,012)	$ (840)	$ (1,012)	$ (840)	$ (9)	$ (6)	$ (9)	$ (6)