Net Earnings (Loss) Per Share from Continuing Operations (Net Earnings (Loss) Per Share Computations from Continuing Operations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net earnings (loss) from continuing operations:
Net earnings (loss) from continuing operations	$ 213	$ (1,691)
Attributable to participating securities	(2)	(1)
Basic and diluted earnings (loss) from continuing operations	$ 211	$ (1,692)
Common shares:
Common shares outstanding - total	654	383
Attributable to participating securities	(5)	(6)
Common shares outstanding - basic	649	377
Dilutive effect of potential common shares issuable	2
Common shares outstanding - diluted	651	377
Net earnings (loss) per share from continuing operations:
Basic	$ 0.33	$ (4.48)
Diluted	$ 0.32	$ (4.48)