Segments of Operations - Assets by segment (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total assets	$ 28,831	$ 28,931
Property and casualty insurance
Segment Reporting Information [Line Items]
Total assets	22,225	21,312
Other
Segment Reporting Information [Line Items]
Total assets	$ 6,606	$ 7,619