Loan Sale and Servicing Activities and Variable Interest Entities (Certain Financial Information and Cash Flows Associated with Loan Sale and Servicing Activities) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Residential Mortgages [Member]
Servicing portfolio	$ 115,454,000,000		$ 115,454,000,000		$ 108,010,000,000
Carrying value of servicing assets	1,015,000,000		1,015,000,000		845,000,000
Servicing advances	463,000,000		463,000,000		501,000,000
Repurchase and recourse obligations	97,000,000		97,000,000		107,000,000
Carrying value of mortgage-backed securities held	5,639,000,000		5,639,000,000		3,365,000,000
Cash flows from sales of loans	2,015,000,000	$ 2,189,000,000	3,955,000,000	$ 4,284,000,000
Cash flows from repurchases of previously transferred loans	134,000,000	159,000,000	303,000,000	368,000,000
Cash flows from servicing fees	82,000,000	87,000,000	165,000,000	174,000,000
Cash flows from servicing advances recovered	47,000,000	39,000,000	38,000,000	69,000,000
Cash flows on mortgage-backed securities held	429,000,000	254,000,000	669,000,000	486,000,000
Commercial Mortgages [Member]
Servicing portfolio	197,932,000,000		197,932,000,000		186,032,000,000
Carrying value of servicing assets	543,000,000		543,000,000		506,000,000
Servicing advances	271,000,000		271,000,000		299,000,000
Repurchase and recourse obligations	35,000,000		35,000,000		35,000,000
Carrying value of mortgage-backed securities held	1,170,000,000		1,170,000,000		1,269,000,000
Cash flows from sales of loans	1,159,000,000	496,000,000	2,179,000,000	935,000,000
Cash flows from servicing fees	36,000,000	26,000,000	68,000,000	67,000,000
Cash flows from servicing advances recovered	21,000,000	23,000,000	28,000,000	55,000,000
Cash flows on mortgage-backed securities held	54,000,000	47,000,000	114,000,000	191,000,000
Home Equity Loans Lines [Member]
Servicing portfolio	3,438,000,000		3,438,000,000		3,833,000,000
Servicing advances	6,000,000		6,000,000		31,000,000
Repurchase and recourse obligations	28,000,000		28,000,000		$ 29,000,000
Cash flows from repurchases of previously transferred loans		3,000,000	2,000,000	9,000,000
Cash flows from servicing fees	4,000,000	5,000,000	8,000,000	10,000,000
Cash flows from servicing advances recovered	$ 1,000,000	$ 3,000,000	$ 25,000,000	$ 6,000,000