Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ 45	$ 231	$ 1,939	$ 450	$ 1,173	$ (2,675)	$ 2,215	$ (1,052)
Number of common shares:
Weighted average outstanding (in shares)	1,101,231,113			1,110,259,907			1,100,895,642	1,113,705,502
Weighted average and potential dilutive outstanding (in shares)	1,104,027,634			1,112,522,861			1,102,867,675	1,113,705,502
Earnings (loss) per common share
Basic (in dollars per share)	$ 0.04			$ 0.41			$ 2.01	$ (0.94)
Diluted (in dollars per share)	$ 0.04			$ 0.40			$ 2.01	$ (0.94)
Stock options
Number of common shares:
Issued upon assumed exercise of outstanding stock options (in shares)	0			0			0	0
Restricted Common Stock
Number of common shares:
Effect of issuance of non-vested restricted common stock and units (in shares)	932,868			796,253			839,031	0
Restricted units
Number of common shares:
Effect of issuance of non-vested restricted common stock and units (in shares)	1,689,617			1,466,701			1,133,002	0
Performance units
Number of common shares:
Effect of issuance of non-vested performance units (in shares)	174,036			0			0	0