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		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accounting Policies [Abstract]
Net income for common stock	$ 526	$ 613	$ 2,185	$ 1,470
Weighted average common shares outstanding – basic (shares)	345.0	354.6	348.4	354.4
Add: Incremental shares attributable to effect of potentially dilutive securities (shares)	1.5	1.3	1.5	1.3
Adjusted weighted average common shares outstanding – diluted (shares)	346.5	355.9	349.9	355.7
Net income per common share - basic (dollars per share)	$ 1.53	$ 1.73	$ 6.27	$ 4.15
Net income per common share - diluted (dollars per share)	$ 1.52	$ 1.72	$ 6.24	$ 4.13