Legal Proceedings, Contingencies and Commitments (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Litigation settlement payment amount	$ 118
Accrued reserve for contingent liabilities	86	$ 86
Letter of Credit, reserve amount	2	1
Mortgage loans (interest-rate lock commitments)
Loss Contingencies [Line Items]
Commitments to extend credit	5,276	2,172
HELOC commitments
Loss Contingencies [Line Items]
Commitments to extend credit	119	88
Other consumer commitments
Loss Contingencies [Line Items]
Commitments to extend credit	25	7
Warehouse loan commitments
Loss Contingencies [Line Items]
Commitments to extend credit	754	827
Standby and commercial letters of credit
Loss Contingencies [Line Items]
Commitments to extend credit	11	10
Commercial and industrial
Loss Contingencies [Line Items]
Commitments to extend credit	157	276
Other commercial commitments
Loss Contingencies [Line Items]
Commitments to extend credit	396	169
DOJ Agreement
Loss Contingencies [Line Items]
Litigation Settlement Liability	$ 84	$ 82
Discount rate (as a percent)	8.00%	8.70%