Subsidiary Debt - HomeServices (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Par value	$ 49,746
Subsidiary debt
Debt Instrument [Line Items]
Par value	36,545
Subsidiary debt	36,659	$ 36,319
HomeServices | Subsidiary debt
Debt Instrument [Line Items]
Par value	148
Subsidiary debt	$ 148	$ 186
HomeServices | Subsidiary debt | Variable-rate term loan (2021 - 0.950%, 2020 - 1.147%), due 2026
Debt Instrument [Line Items]
Stated rate	0.95%	1.147%
Par value	$ 148
Subsidiary debt	$ 148	$ 186