Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Other Intangible Assets [Member]	Dec. 31, 2012 Other Intangible Assets [Member]	Jun. 30, 2013 Servicing Contracts [Member]	Dec. 31, 2012 Servicing Contracts [Member]	Jun. 30, 2013 Servicing Contracts [Member] Other Loans [Member]	Jun. 30, 2012 Servicing Contracts [Member] Other Loans [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount			$ 1,676	$ 1,676	$ 2,456	$ 2,071
Valuation allowance					(103)	(176)
Accumulated amortization			(1,024)	(950)	(852)	(824)
Intangible Assets, Net Carrying Value	$ 2,153	$ 1,797	$ 652	$ 726	$ 1,501	$ 1,071	$ 1	$ 1