Loans - Wholesale Loan Portfolio - Real Estate Class of Loans (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 889,907	$ 832,792	$ 747,508
Wholesale
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 383,790	$ 357,050	$ 324,502
% of criticized to total real estate retained loans	2.43%	2.06%
% of criticized nonaccrual to total real estate retained loans	0.51%	0.28%
Wholesale | Criticized nonaccrual
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 1,954	$ 988
Real estate | Wholesale
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 106,315	$ 92,820
% of criticized to total real estate retained loans	0.94%	1.60%
% of criticized nonaccrual to total real estate retained loans	0.19%	0.25%
Real estate | Wholesale | Commercial construction and development
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 9,200	$ 7,300
Real estate | Wholesale | Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 71,978	$ 64,271
% of criticized to total real estate retained loans	0.75%	0.87%
% of criticized nonaccrual to total real estate retained loans	0.08%	0.13%
Real estate | Wholesale | Other Commercial
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 34,337	$ 28,549
% of criticized to total real estate retained loans	1.34%	3.22%
% of criticized nonaccrual to total real estate retained loans	0.42%	0.51%
Real estate | Wholesale | Criticized
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 998	$ 1,482
Real estate | Wholesale | Criticized | Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Retained	539	562
Real estate | Wholesale | Criticized | Other Commercial
Loans and Leases Receivable Disclosure [Line Items]
Retained	459	920
Real estate | Wholesale | Criticized nonaccrual
Loans and Leases Receivable Disclosure [Line Items]
Retained	200	231
Real estate | Wholesale | Criticized nonaccrual | Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Retained	57	85
Real estate | Wholesale | Criticized nonaccrual | Other Commercial
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 143	$ 146