Organization and Summary of Significant Accounting Policies (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Line Items]
Net income (loss)									$ (3,112)	$ 891	$ 537	[1]
Participating securities – mandatory convertible preferred stock									0	0	2
Net Income (Loss) Attributable to Common Stock	$ (92)	$ (593)	$ (880)	$ (1,547)	$ 110	$ 49	$ 138	$ 594	$ (3,112)	$ 891	$ 535
Number of common shares:
Weighted average outstanding (in shares)									573,889,502	539,345,343	574,631,756
Weighted average and potential dilutive outstanding (in shares)									573,889,502	540,382,914	576,642,808
Basic (in dollars per share)	$ (0.14)	$ (1.04)	$ (1.63)	$ (2.86)	$ 0.20	$ 0.09	$ 0.26	$ 1.10	$ (5.42)	$ 1.65	$ 0.93
Diluted (in dollars per share)	$ (0.14)	$ (1.04)	$ (1.63)	$ (2.86)	$ 0.20	$ 0.09	$ 0.26	$ 1.10	$ (5.42)	$ 1.65	$ 0.93
Stock Options
Number of common shares:
Effect of share-based compensation (in shares)									0	0	0
Restricted Stock
Number of common shares:
Effect of share-based compensation (in shares)									0	361,380	698,103
Restricted units
Number of common shares:
Effect of share-based compensation (in shares)									0	0	0
Performance units
Number of common shares:
Effect of share-based compensation (in shares)									0	676,191	1,312,949

[1] In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.