Summary of Significant Accounting Policies and Other Matters - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accounting Policies [Abstract]
Net income for common stock	$ 602	$ 419
Weighted average common shares outstanding – basic (shares)	354.1	342.2
Add: Incremental shares attributable to effect of potentially dilutive securities (shares)	1.0	0.8
Adjusted weighted average common shares outstanding – diluted (shares)	355.1	343.0
Net income per common share - basic (dollars per share)	$ 1.70	$ 1.23
Net income per common share - diluted (dollars per share)	$ 1.70	$ 1.22