Income Taxes (Schedule of Temporary Tax Differences That Gave Rise to Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets
ALLL	$ 553	$ 556
Postretirement plans	431	372
Net unrealized loss on AFS securities	124	36
Equity-based compensation	129	137
Reserves and expense accruals	255	247
Investments in qualified affordable housing projects	110	0
Other	292	198
Total deferred tax assets	1,894	1,546
Deferred tax liabilities
Prepaid pension plan expense	509	477
MSRs	331	312
Lease financing	663	375
Loan fees & expenses	70	265
Identifiable intangible assets	207	139
Derivatives & hedging	77	122
Investments in qualified affordable housing projects	0	25
Other	92	93
Total deferred tax liabilities	1,949	1,808
Net deferred tax asset (liability)	$ (55)	$ (262)