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
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 213	$ 238
Dividends	64	47
Undistributed Earnings, Basic	149	191
Undistributed Earnings Applicable to Nonvested Shares	1	1
Undistributed Earnings (Loss) Available to Common Shareholders, Diluted	148	190
Distributed Earnings	$ 56	$ 39
Weighted Average Number of Shares Outstanding, Basic	184,767	196,722
Dilutive Effect of Common Stock Warrants	9,739	12,382
Dilutive Effect of Stock Options	735	1,139
Earnings Per Share, Basic	$ 1.10	$ 1.16
Net Income (Loss) Available to Common Stockholders, Diluted	$ 204	$ 229
Weighted Average Number of Shares Outstanding, Diluted	195,241	210,243
Earnings Per Share, Diluted	$ 1.04	$ 1.09