Share-Based Compensation - Share-based compensation expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 92	$ 88	$ 87
Share based compensation expense, net of tax	80	77	76
Options and SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	11	12	12
Share based compensation expense, net of tax	10	11	11
Restricted Common Shares And Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	54	50	47
Share based compensation expense, net of tax	45	42	39
Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	23	22	24
Share based compensation expense, net of tax	21	20	22
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	4	4	4
Share based compensation expense, net of tax	$ 4	$ 4	$ 4