Quarterly Financial Information (Financial Information By Quarter) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Gross interest income	$ 656	$ 631	$ 606	$ 588	$ 562	$ 557	$ 558	$ 515	$ 2,481	$ 2,192	$ 1,954
Interest Income (Expense), Net	576	565	548	541	526	522	528	489	2,230	2,065	1,867
Provision for loan losses	7	(11)	5	(40)	(11)	5	7	23	(39)	24	93
Noninterest Income	140	136	138	138	140	140	132	132	552	544	516
Noninterest expense	419	420	428	411	417	413	405	414	1,678	1,649	1,585
Income before income taxes	290	292	253	308	260	244	248	184	1,143	936	705
Net income	226	223	197	238	124	161	168	139	884	592	469
Other Preferred Stock Dividends and Adjustments	(9)	(8)	(10)	(7)	(10)	(8)	(12)	(10)	(34)	(40)	(48)
Preferred stock redemption	0	0	0	0	0	0	(2)	0	0	(2)	(10)
Net earnings applicable to common shareholders	$ 217	$ 215	$ 187	$ 231	$ 114	$ 153	$ 154	$ 129	$ 850	$ 550	$ 411
Basic, per share	$ 1.14	$ 1.11	$ 0.95	$ 1.16	$ 0.57	$ 0.75	$ 0.76	$ 0.63	$ 4.36	$ 2.71	$ 2.00
Diluted	$ 1.08	$ 1.04	$ 0.88	$ 1.08	$ 0.54	$ 0.72	$ 0.73	$ 0.61	$ 4.08	$ 2.60	$ 1.99