Loans - Consumer, Excluding Credit Card Loans, Other Consumer Impaired Loans and Loan Modifications (Details) - Consumer, excluding credit card - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Residential real estate - PCI
Financing Receivable, Impaired [Line Items]
Remaining weighted-average life of portfolio	8 years
Total other consumer
Financing Receivable, Impaired [Line Items]
With an allowance	$ 614	$ 527
Without an allowance	30	31
Total impaired loans	644	558
Allowance for loan losses related to impaired loans	119	118
Unpaid principal balance of impaired loans	753	668
Impaired loans on nonaccrual status	508	449
Average impaired loans	635	566	$ 599
Loans modified in TDRs	362	384
TDRs on nonaccrual status	$ 226	$ 275