Earnings Per Share and Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic earnings (loss) per common share
Net income (loss) from continuing operations	$ 299	$ (2,013)
Loss from discontinued operations	(445)	0
NET LOSS	(146)	(2,013)
Less: Preferred stock dividends	(200)	(219)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (346)	$ (2,232)
Weighted-average number of basic shares (in shares)	933.1	896.7
Basic loss per common share (in usd per share)	$ (0.37)	$ (2.49)
Net loss, net of participating securities	$ (346)	$ (2,232)
Diluted shares (in shares)	947.9	896.7
Diluted loss per common share (in usd per share)	$ (0.36)	$ (2.49)