Share-Based Compensation (Summary Of Values Related To Vested And Unvested Restricted Stock Awards) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic Value of Awards Vested During the Period (Millions of dollars)	$ 0	$ 17	$ 20
Granted (in USD per share)	$ 0	$ 0	$ 0
Unrecognized compensation cost	$ 0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic Value of Awards Vested During the Period (Millions of dollars)	$ 144	$ 99	$ 90
Granted (in USD per share)	$ 133.94	$ 75.81	$ 55.27
Unrecognized compensation cost	$ 75
Weighted average recognition period, in years	2 years