Earnings Per Common Share ("EPS") (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net Income		$ 331	$ 528	$ 954	$ 1,245
Weighted-average common shares outstanding (for basic calculation)		285.0	296.0	287.0	298.0
Effect of dilutive share-based employee compensation		4.0	6.0	4.0	6.0
Weighted-average common and dilutive potential common shares outstanding (for diluted calculation)		289.0	302.0	291.0	304.0
Basic EPS		$ 1.16	$ 1.78	$ 3.33	$ 4.17
Diluted EPS		$ 1.14	$ 1.75	$ 3.28	$ 4.10
Unexercised employee stock options and stock appreciation rights (in millions) excluded from the diluted EPS computation	[1]	2.0	0.1	1.9	1.5

[1] These unexercised employee stock options and stock appreciation rights were not included in the computation of diluted EPS because to do so would have been antidilutive for the periods presented.