Computation of Basic/Diluted Earnings Per Common Share - (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Consolidated net income	$ 280	$ 395	$ 876	$ 619	$ 675	$ 1,496
Denominator:
Denominator for basic earnings per common share - weighted-average common shares outstanding (in shares)	782		777		781	776
Effect of dilutive stock options and awards under the treasury stock method (in shares)	6		6		6	8
Denominator for diluted earnings per common share—weighted-average common shares outstanding plus dilutive common shares under the treasury stock method (in shares)	788		783		787	784
Basic earnings per common share (in dollars per share)	$ 0.36		$ 1.13		$ 0.86	$ 1.93
Diluted earnings per common share (in dollars per share)	$ 0.36		$ 1.12		$ 0.86	$ 1.91