CONSOLIDATED CONDENSED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Common Stock	Preferred Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2018	$ 21,330	$ 179	$ 0	$ (10,473)	$ 8,046	$ 23,750	$ (172)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	631					631
Other comprehensive income (loss), net of tax	4						4
Dividends on common stock	(586)					(586)
Issuance of common stock, net	37				37
Purchases of treasury stock	(180)			(180)
Ending balance at Mar. 31, 2019	21,236	179	0	(10,653)	8,083	23,795	(168)
Beginning balance at Dec. 31, 2019	34,232	209	9,762	(10,653)	14,955	20,180	(221)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(2,013)					(2,013)
Other comprehensive income (loss), net of tax	(113)						(113)
Dividends on common stock	(719)					(719)
Dividends on preferred stock	(219)					(219)
Issuance of common stock, net	127	1			126
Ending balance at Mar. 31, 2020	$ 31,295	$ 210	$ 9,762	$ (10,653)	$ 15,081	$ 17,229	$ (334)