Revenue from Contract with Customer - Real Estate Services (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 25,920	$ 25,602	$ 26,337
Real estate
Disaggregation of Revenue [Line Items]
Total operating revenue	4,354	4,322	5,268
HomeServices | Real estate
Disaggregation of Revenue [Line Items]
Customer revenue	4,059	4,055	4,933
Other revenue	295	267	335
Total operating revenue	4,354	4,322	5,268
HomeServices | Brokerage
Disaggregation of Revenue [Line Items]
Customer revenue	4,006	4,000	4,867
HomeServices | Franchise
Disaggregation of Revenue [Line Items]
Customer revenue	$ 53	$ 55	$ 66