Investment Securities (Critical Estimates Used in Roll Rate Analysis) (Details)	6 Months Ended	12 Months Ended				12 Months Ended			12 Months Ended					12 Months Ended				12 Months Ended				12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010 Sub-Prime [Member] Maximum [Member]		Jun. 30, 2011 Sub-Prime [Member] Maximum [Member]		Dec. 31, 2010 Alt-A [Member] Maximum [Member]	Jun. 30, 2011 Alt-A [Member] Maximum [Member]		Dec. 31, 2010 Non-Agency Prime [Member] Maximum [Member]		Jun. 30, 2011 Non-Agency Prime [Member] Maximum [Member]		Jun. 30, 2011 Maximum [Member]	Dec. 31, 2010 Sub-Prime [Member] Minimum [Member]		Jun. 30, 2011 Sub-Prime [Member] Minimum [Member]		Dec. 31, 2010 Alt-A [Member] Minimum [Member]		Jun. 30, 2011 Alt-A [Member] Minimum [Member]		Dec. 31, 2010 Non-Agency Prime [Member] Minimum [Member]		Jun. 30, 2011 Non-Agency Prime [Member] Minimum [Member]		Dec. 31, 2010 Residential, Subprime, Financing Receivable [Member] Minimum [Member]	Dec. 31, 2010 Sub-Prime [Member]		Dec. 31, 2010 Alt-A [Member]		Dec. 31, 2010 Non-Agency Prime [Member]
Prepayment rate		3.00%		3.00%			5.00%		10.00%				8.00%			1.00%				3.00%		7.00%		6.00%		2.00%			7.00%
Cumulative loss estimates				51.00%			36.00%				19.00%					45.00%				14.00%				9.00%			33.00%		21.00%		13.00%
Loss severity				70.00%	[1]		59.00%	[1]			54.00%	[1]				68.00%	[1]			57.00%	[1]			51.00%	[1]		67.00%	[1]	49.00%	[1]	49.00%	[1]
Peak-to-trough housing price decline	37.00%	40.00%	[2]			40.00%			40.00%	[2]				35.00%	[2]			35.00%	[2]			35.00%	[2]

[1] Loss severity rates consider the initial loan-to-value ratio, lien position, geography, expected collateral value and other factors.

[2] Management's expectation of the Case-Shiller National Home Price Index.