Share-based compensation (Pre-tax and After-tax Share-based Compensation Expense) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Payment Arrangement, Expense, Tax Benefit		$ 29	$ 19	$ 10
Restricted stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense, pre-tax		230	210	210
Share-based compensation expense, after-tax		179	164	164
Stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense, pre-tax		60	55	45
Share-based compensation expense, after-tax	[1]	$ 38	$ 36	$ 38

[1] The windfall tax benefit recorded to Income tax expense in the Consolidated statement of operations was $29 million, $19 million, and $10 million for the years ended December 31, 2022, 2021, and 2020, respectively.