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		$ (10,473)	$ 8,046	$ 23,750	$ (172)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		1,266					1,266
Other comprehensive income (loss), net of tax		(12)						(12)
Dividends on common stock		(1,168)					(1,168)
Issuance of common stock, net		111				111
Purchases of treasury stock		(180)			(180)
Ending balance at Jun. 30, 2019		21,347	179		(10,653)	8,157	23,848	(184)
Beginning balance at Mar. 31, 2019		21,236	179		(10,653)	8,083	23,795	(168)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		635					635
Other comprehensive income (loss), net of tax		(16)						(16)
Dividends on common stock		(582)					(582)
Issuance of common stock, net		74				74
Ending balance at Jun. 30, 2019		21,347	179		(10,653)	8,157	23,848	(184)
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		(10,144)					(10,144)
Other comprehensive income (loss), net of tax		(91)						(91)
Dividends on common stock		(727)					(727)
Dividends on preferred stock		(219)	3			219	(441)
Issuance of common stock, net		192	1			191
Stock warrants	[1]	107				870	(763)
Purchases of treasury stock		(4)			(4)
Ending balance at Jun. 30, 2020		23,346	213	9,762	(10,657)	16,235	8,105	(312)
Beginning balance at Mar. 31, 2020		31,295	210	9,762	(10,653)	15,081	17,229	(334)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest		(8,131)					(8,131)
Other comprehensive income (loss), net of tax		22						22
Dividends on common stock		(8)					(8)
Dividends on preferred stock			3			219	(222)
Issuance of common stock, net		65				65	0
Stock warrants	[2]	107				870	(763)
Purchases of treasury stock		(4)			(4)
Ending balance at Jun. 30, 2020		$ 23,346	$ 213	$ 9,762	$ (10,657)	$ 16,235	$ 8,105	$ (312)

[1] Represents the declaration of the Common Stock Warrants and the reclassification of the Berkshire Warrants. Please see Note 6 - Derivatives and Note 13 - EPS and Stockholders' Equity, respectively, to these Consolidated Condensed Financial Statements for additional information.

[2] Represents the declaration of the Common Stock Warrants and the reclassification of the Berkshire Warrants. Please see Note 6 - Derivatives and Note 13 - EPS and Stockholders' Equity, respectively, to these Consolidated Condensed Financial Statements for additional information.