Investments - Rollforward of credit loss allowance for bank loans (Details) - Bank loans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	$ (67)	$ 0
Net decreases related to credit losses	(15)	(28)
Reduction of allowance related to sales	21	9
Write-offs	0	5
Ending balance	(61)	(67)
Discontinued Operations, Held-for-sale
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	(16)
Ending balance		(16)
Cumulative effect of change in accounting principle
Debt and Equity Securities, FV-NI [Line Items]
Beginning balance	$ 0	(53)
Ending balance		$ 0