Acquisition of Businesses - Narrative (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
	Jul. 03, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Business Acquisition [Line Items]
Payments to acquire subsidiaries			$ 234	$ 10
Crop Risk Services
Business Acquisition [Line Items]
Payments to acquire subsidiaries	$ 234
Net tangible assets acquired, at fair value	24
Acquisition expenses incurred	3
Goodwill recorded	85
Amount of goodwill expected to be tax deductible	79
Crop Risk Services | Customer relationships
Business Acquisition [Line Items]
Intangible assets acquired	124
Finite-lived intangible assets useful life			14 years
Crop Risk Services | Crop year 2022
Business Acquisition [Line Items]
Gross written premiums	$ 1,200
Insurance Agency
Business Acquisition [Line Items]
Payments to acquire subsidiaries		$ 10
Consideration transferred		$ 12