Goodwill and Other Intangible Assets (Commercial and Residential Mortgage Loan Servicing Assets - Key Valuation Assumptions) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of Adverse Change In Assumption [Line Items]
Fair Value	$ 1,558	$ 1,351
Servicing Contracts [Member] | Commercial Mortgage [Member]
Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of Adverse Change In Assumption [Line Items]
Fair Value	$ 543	$ 506	$ 515	$ 552
Weighted-average life	4 years 11 months	4 years 8 months
Weighted-average constant prepayment rate	5.94%	8.03%
Decline in fair value from 10% adverse change in prepayment rate	$ 10	$ 10
Decline in fair value from 20% adverse change in prepayment rate	$ 20	$ 19
Effective discount rate	7.62%	6.59%
Decline in fair value from 10% adverse change in interest rate	$ 15	$ 13
Decline in fair value from 20% adverse change in interest rate	29	26
Servicing Contracts [Member] | Residential Mortgage [Member]
Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of Adverse Change In Assumption [Line Items]
Fair Value	$ 1,015	$ 845	$ 967	$ 1,087
Weighted-average life	6 years 9 months	6 years 1 month
Weighted-average constant prepayment rate	9.69%	11.16%
Decline in fair value from 10% adverse change in prepayment rate	$ 41	$ 36
Decline in fair value from 20% adverse change in prepayment rate	$ 78	$ 69
Effective discount rate	9.66%	10.36%
Decline in fair value from 10% adverse change in adjusted spread	$ 37	$ 31
Decline in fair value from 20% adverse change in adjusted spread	$ 72	$ 61