Restructuring Costs (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Restructuring Reserve [Roll Forward]
Balance at beginning of period	$ 77	$ 43
Additions related to merger integration and transition costs	10	44
Payments of merger-related restructuring costs	(28)	(13)
Balance at end of period	$ 59	$ 74