Loans - Consumer, Excluding Credit Card Loan Portfolio, Loan Modifications, New TDRs (Details) - Consumer, excluding credit card - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Impaired [Line Items]
New TDRs	$ 201	$ 198	$ 503	$ 521
Prime, including option ARMs | Mortgages
Financing Receivable, Impaired [Line Items]
New TDRs	49	89	170	208
Subprime | Mortgages
Financing Receivable, Impaired [Line Items]
New TDRs	13	29	47	82
Senior lien | Home equity
Financing Receivable, Impaired [Line Items]
New TDRs	29	27	87	74
Junior lien | Home equity
Financing Receivable, Impaired [Line Items]
New TDRs	$ 110	$ 53	$ 199	$ 157