Net Earnings Per Common Share (Basic And Diluted Net Earnings Per Common Share Based On The Weighted Average Outstanding Shares) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive Effect of Common Stock Warrants									11,959	7,778	0
Dilutive Effect of Stock Options									953	1,099	414
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 226	$ 223	$ 197	$ 238	$ 124	$ 161	$ 168	$ 139	$ 884	$ 592	$ 469
Undistributed Earnings Applicable to Nonvested Shares									5	4	4
Undistributed Earnings (Loss) Available to Common Shareholders, Diluted									643	457	350
Less common and preferred dividends, Basic									(236)	(131)	(115)
Undistributed earnings (loss) applicable to nonvested shares, Basic									648	461	354
Distributed earnings applicable to common shares, Basic									(200)	(88)	(57)
Net Income (Loss) Available to Common Stockholders, Diluted									$ 843	$ 545	$ 407
Weighted average common shares outstanding									193,589	200,776	203,855
Net earnings (loss) per common share, Basic	$ 1.14	$ 1.11	$ 0.95	$ 1.16	$ 0.57	$ 0.75	$ 0.76	$ 0.63	$ 4.36	$ 2.71	$ 2.00
Weighted average diluted common shares outstanding, Diluted									206,501	209,653	204,269
Net earnings (loss) per common share, Diluted	$ 1.08	$ 1.04	$ 0.88	$ 1.08	$ 0.54	$ 0.72	$ 0.73	$ 0.61	$ 4.08	$ 2.60	$ 1.99