Loans and Allowance for Loan Losses (Loans and Lending-related Commitments subnote) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable and Allowance for Credit Losses
Provision for loan losses			$ 35	$ (13)
Provision for lending-related commitments			$ 12	$ 14
Other Revenues
Financing Receivable and Allowance for Credit Losses
Provision for loan losses	$ 5	$ 2
Other Non-interest Expenses
Financing Receivable and Allowance for Credit Losses
Provision for lending-related commitments	$ 4	$ 16