Goodwill and Other Intangible Assets (Commercial Mortgage Servicing Rights) (Details) (Mortgage Servicing Rights [Member], USD $) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Commercial Mortgage [Member]		Sep. 30, 2011 Commercial Mortgage [Member]		Sep. 30, 2012 Commercial Mortgage [Member] Originated MSRs [Member]	Sep. 30, 2011 Commercial Mortgage [Member] Originated MSRs [Member]	Sep. 30, 2012 Commercial Mortgage [Member] Purchased MSRs [Member]	Sep. 30, 2011 Commercial Mortgage [Member] Purchased MSRs [Member]
Servicing Assets At Amortized Value [Line Items]
Beginning balance - January 1			$ 468		$ 665
Additions			43	[1]	100	[1]	27	37	16	63
Amortization expense			(113)	[2]	(126)	[2]
Change in valuation allowance			4		(157)
Ending balance			402		482
Beginning balance - valuation allowance	(193)	(197)	(197)		(40)
Provision			44		161
Recoveries			24		4
Other			24	[2]
Ending balance - valuation allowance	$ (193)	$ (197)	$ (193)		$ (197)

[1] Additions for the first nine months of 2012 and first nine months of 2011 included $27 million and $37 million, respectively, from loans sold with servicing retained. Additions for the first nine months of 2012 and first nine months of 2011 included $16 million and $63 million, respectively, from purchases of servicing rights from third parties.

[2] Includes a direct write down of servicing rights for $24 million recognized in the first quarter of 2012 primarily due to market-driven changes in interest rates.