Fair value measurements (Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) - Level 3 - Guaranteed Minimum Income Benefit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance - Beginning of year, liabilities	$ 745	[1]	$ 1,089	[2]	$ 897	[2]
Transfers Into Level 3, liabilities	0		0		0
Transfers out of Level 3, liabilities	0		0		0
Change in Net Unrealized Gains (Losses) included in OCI, Liabilities	0		0		0
Purchased, liabilities	0		0		0
Sales, liabilities	0		0		0
Settlements, liabilities	0		0		0
Other, liabilities	(72)	[3]	(28)	[1]	(10)	[2]
Balance - End of year, liabilities	736	[3]	745	[1]	1,089	[2]
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ 0		$ 0		$ 0
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenues	[3]	Revenues	[1]	Revenues	[2]

[1] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

[2] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

[3] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.