Loan Sale and Servicing Activities and Variable Interest Entities (Certain Financial Information and Cash Flows Associated with Loan Sale and Servicing Activities) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Quantifying Misstatement In Current Year Financial Statements Amount		$ 6,200,000,000
Residential Mortgages [Member]
Servicing portfolio	108,010,000,000	113,994,000,000
Carrying value of servicing assets	845,000,000	1,087,000,000
Servicing advances	501,000,000	571,000,000
Repurchase and recourse obligations	107,000,000	131,000,000
Carrying value of mortgage-backed securities held	3,365,000,000	4,144,000,000
Cash flows from sales of loans	8,344,000,000	14,650,000,000
Cash flows from repurchases of previously transferred loans	744,000,000	1,191,000,000
Cash flows from servicing fees	346,000,000	362,000,000
Cash flows from servicing advances recovered	70,000,000	11,000,000
Cash flows on mortgage-backed securities held	934,000,000	1,456,000,000
Commercial Mortgages [Member]
Servicing portfolio	186,032,000,000	176,510,000,000
Carrying value of servicing assets	506,000,000	549,000,000
Servicing advances	299,000,000	412,000,000
Repurchase and recourse obligations	35,000,000	33,000,000
Carrying value of mortgage-backed securities held	1,269,000,000	1,475,000,000
Cash flows from sales of loans	3,469,000,000	2,754,000,000
Cash flows from servicing fees	132,000,000	176,000,000
Cash flows from servicing advances recovered	113,000,000	93,000,000
Cash flows on mortgage-backed securities held	308,000,000	411,000,000
Home Equity Loans Lines [Member]
Servicing portfolio	3,833,000,000	4,321,000,000
Servicing advances	31,000,000	11,000,000
Repurchase and recourse obligations	29,000,000	22,000,000
Cash flows from repurchases of previously transferred loans	14,000,000	9,000,000
Cash flows from servicing fees	19,000,000	21,000,000
Cash flows from servicing advances (funded)	(20,000,000)	(6,000,000)
Quantifying Misstatement In Current Year Financial Statements Amount		$ 581,000,000