Acquisitions and Sale of Businesses - Impact of exited lines on earnings (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net investment income	$ 572	$ 588	$ 1,584	$ 1,710
Net earnings, including noncontrolling interests	164	143	27	678
Realized losses on subsidiaries	(30)	0	(30)	0
Income tax expense (benefit)	(30)	34	(63)	171
Neon Capital Limited
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Underwriting gain (loss), Property and Casualty Insurance	(38)	(19)	(82)	(33)
Net investment income	1	2	(5)	5
Other income and expenses, net	(3)	(3)	(5)	(8)
Net earnings, including noncontrolling interests	(40)	$ (20)	$ (92)	$ (36)
Realized losses on subsidiaries	(30)
Total pretax loss from Neon exited lines	(70)
Income tax expense (benefit)	(73)
Net earnings from Neon exited lines	$ 3