Employee Benefit Obligations - Weighted Average Assumptions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted-average assumptions used to determine net periodic benefit cost
Pension expense		$ 79
Settlement losses and other one-time charges (a)		10
Forecast
Weighted-average assumptions used to determine net periodic benefit cost
Pension expense	$ 22
Defined Benefit Pension Plans
Weighted-average assumptions used to determine benefit obligations
Effect of one quarter of a percentage point reduction in the expected return on pension assets assumption, on pension expense		9
Effect of quarter of a percentage point reduction in the discount rate applied to the pension liability, on pension expense		8
Weighted-average assumptions used to determine net periodic benefit cost
Settlement losses and other one-time charges (a)		14	$ 135	$ 120
Market related value of plan assets used to calculate expected return		$ 3,651	$ 5,633	$ 5,573
U.K. | Defined Benefit Pension Plans
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)		5.01%	1.81%	1.39%
Rate of compensation increase (as a percent)		3.50%	3.50%	3.50%
Pension increase (as a percent)		3.43%	3.64%	3.19%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)		1.81%	1.39%	2.07%
Rate of compensation increase (as a percent)		3.50%	3.50%	3.50%
Pension increase (as a percent)		3.64%	3.19%	3.22%
Expected long-term rate of return on assets (as a percent)		1.91%	1.74%	2.57%
Germany | Defined Benefit Pension Plans
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)		3.69%	1.12%	0.80%
Rate of compensation increase (as a percent)		2.68%	2.50%	2.50%
Pension increase (as a percent)		1.80%	1.70%	1.50%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)		1.12%	0.80%	1.11%
Rate of compensation increase (as a percent)		2.50%	2.50%	2.50%
Pension increase (as a percent)		1.70%	1.50%	1.50%
United States | Defined Benefit Pension Plans
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)		5.52%	2.87%	2.49%
Rate of compensation increase (as a percent)		4.47%	4.48%	4.05%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)		2.87%	2.49%	3.35%
Rate of compensation increase (as a percent)		4.48%	4.05%	4.03%
Expected long-term rate of return on assets (as a percent)		6.11%	6.32%	6.00%
Settlement losses and other one-time charges (a)		$ 14	$ 135	$ 120