Earnings Per Share and Stockholders' Equity - Schedule of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic earnings (loss) per common share
Net income (loss) from continuing operations	$ 100	$ (6,716)	$ 399	$ (8,729)
Income (loss) from discontinued operations	3	(1,415)	(442)	(1,415)
NET INCOME (LOSS)	103	(8,131)	(43)	(10,144)
Less: Preferred stock dividends	(200)	(222)	(400)	(441)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (97)	$ (8,353)	$ (443)	$ (10,585)
Weighted-average number of basic shares (in shares)	934.2	915.5	933.8	906.2
Basic loss per common share (in usd per share)	$ (0.10)	$ (9.12)	$ (0.47)	$ (11.68)
Net loss attributable to common stockholders	$ (97)	$ (8,353)	$ (443)	$ (10,585)
Dilutive securities (in shares)	0.0	0.0	0.0	0.0
Total dilutive weighted-average common shares (in shares)	934.2	915.5	933.8	906.2
Diluted loss per common share (in usd per share)	$ (0.10)	$ (9.12)	$ (0.47)	$ (11.68)