Loans - Wholesale Loan Portfolio - Real Estate Class of Loans (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	$ 735,369	$ 724,177	$ 719,884
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	321,534	308,263	308,208
Wholesale | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	73,626	69,151
Percentage of criticized loans to total retained loans	2.89%	3.72%
Percentage of longs on nonaccrual status to total retained loans	0.39%	0.50%
Wholesale | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	46,711	44,389
Percentage of criticized loans to total retained loans	2.00%	2.57%
Percentage of longs on nonaccrual status to total retained loans	0.34%	0.43%
Wholesale | Commercial lessors
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	16,833	15,949
Percentage of criticized loans to total retained loans	6.68%	8.30%
Percentage of longs on nonaccrual status to total retained loans	0.75%	0.90%
Wholesale | Commercial construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	3,944	3,674
Percentage of criticized loans to total retained loans	1.22%	2.20%
Percentage of longs on nonaccrual status to total retained loans	0.00%	0.08%
Wholesale | Other Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	6,138	5,139
Percentage of criticized loans to total retained loans	0.36%	0.56%
Percentage of longs on nonaccrual status to total retained loans	0.03%	0.18%
Wholesale | Criticized | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	2,129	2,575
Wholesale | Criticized | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	935	1,142
Wholesale | Criticized | Commercial lessors
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	1,124	1,323
Wholesale | Criticized | Commercial construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	48	81
Wholesale | Criticized | Other Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	22	29
Wholesale | Criticized nonaccrual | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	288	346
Wholesale | Criticized nonaccrual | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	159	191
Wholesale | Criticized nonaccrual | Commercial lessors
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	127	143
Wholesale | Criticized nonaccrual | Commercial construction and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	0	3
Wholesale | Criticized nonaccrual | Other Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans retained	$ 2	$ 9