Goodwill and Other Intangibles - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the goodwill balance during the period			$ 0
Goodwill	$ 207,000,000		207,000,000		$ 207,000,000
Amortizable intangible assets related to property and casualty insurance acquisitions	34,000,000		34,000,000		43,000,000
Accumulated amortization	59,000,000		59,000,000		$ 50,000,000
Amortization of intangible assets	$ 3,000,000	$ 3,000,000	$ 9,000,000	$ 9,000,000