Loans - Consumer, Excluding Credit Card Loans, Loan Modifications, New TDRs (Details) - Consumer, excluding credit card - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
New TDRs	$ 668	$ 732	$ 1,687
Prime, including option ARMs | Mortgages
Financing Receivable, Impaired [Line Items]
New TDRs	209	287	770
Subprime | Mortgages
Financing Receivable, Impaired [Line Items]
New TDRs	58	124	319
Senior lien | Home equity
Financing Receivable, Impaired [Line Items]
New TDRs	108	110	210
Junior lien | Home equity
Financing Receivable, Impaired [Line Items]
New TDRs	$ 293	$ 211	$ 388