Loan Sale and Servicing Activities and Variable Interest Entities (Certain Financial Information and Cash Flows Associated with Loan Sale and Servicing Activities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Residential Mortgages [Member]
Servicing portfolio	$ 110,933		$ 110,933		$ 113,994
Carrying value of servicing assets	967		967		1,087
Servicing advances	502		502		571
Repurchase and recourse obligations	101		101		131
Carrying value of mortgage-backed securities held	3,717		3,717		4,144
Cash flows from sales of loans	2,189	4,190	4,284	7,994
Cash flows from repurchases of previously transferred loans	159	278	368	650
Cash flows from servicing fees	87	89	174	179
Cash flows from servicing advances recovered	39	30	69	24
Cash flows on mortgage-backed securities held	254	389	486	756
Commercial Mortgages [Member]
Servicing portfolio	176,967		176,967		176,510
Carrying value of servicing assets	515		515		549
Servicing advances	356		356		412
Repurchase and recourse obligations	35		35		33
Carrying value of mortgage-backed securities held	1,206		1,206		1,475
Cash flows from sales of loans	496	489	935	1,415
Cash flows from servicing fees	26	43	67	89
Cash flows from servicing advances recovered	23	8	55	3
Cash flows on mortgage-backed securities held	47	70	191	193
Home Equity Loans Lines [Member]
Servicing portfolio	4,130		4,130		4,321
Servicing advances	5		5		11
Repurchase and recourse obligations	25		25		22
Cash flows from repurchases of previously transferred loans	3	2	9	4
Cash flows from servicing fees	5	5	10	11
Cash flows from servicing advances recovered	3		6
Cash flows from servicing advances (funded)		(1)		(1)
Prior period correction of an error					$ 581