Parent Company Financial Statements - Statement of Condition (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets:
Interest-bearing deposits with banks	$ 75,338	$ 93,523
Trading account assets	849	924
Investment securities available for sale	70,070	94,913
Other assets	33,940	32,600
Total assets	245,192	274,119
Liabilities:
Long-term debt	11,534	10,042
Total liabilities	224,057	252,791
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Total shareholders’ equity	21,103	21,328	$ 20,248	$ 20,825
Total liabilities and equity	245,192	274,119
Parent Company
Assets:
Interest-bearing deposits with banks	5,735	6,030
Trading account assets	308	279
Investment securities available for sale	35	35
Consolidated banking subsidiary	20,584	19,978
Consolidated non-banking subsidiaries	2,816	2,739
Unconsolidated entities	315	288
Consolidated banking subsidiary	1,558	1,526
Consolidated non-banking subsidiaries and unconsolidated entities	275	331
Other assets	515	447
Total assets	32,141	31,653
Liabilities:
Commercial paper	0	2,485
Accrued expenses and other liabilities	643	514
Long-term debt	10,363	7,326
Total liabilities	11,006	10,325
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Total shareholders’ equity	21,135	21,328
Total liabilities and equity	$ 32,141	$ 31,653